Communication linkage scheduling method of logistics unmanned aerial vehicle and intelligent turnover cabinet

Abstract

The present application belongs to the field of logistics signal processing, and particularly relates to a communication linkage scheduling method for a logistics unmanned aerial vehicle and an intelligent turnover cabinet, comprising: calculating the real-time straight-line distance between the unmanned aerial vehicle and the intelligent turnover cabinet, establishing a bidirectional communication link and obtaining the real-time state of the cabinet body when the distance is less than or equal to a first preset threshold; performing phased scheduling according to the distance interval, sending a proximity warning signal at a long distance, sending a hatch opening instruction at a short distance, and issuing a hovering in position signal after confirming that the opening is in place; in the linkage process, real-time collection of interference parameters such as electromagnetic interference intensity is performed, the modulation coding mode and the transmission power are dynamically adjusted, and the packet loss rate and the retransmission number are monitored, and when the threshold is exceeded, the frequency band is reselected and the link is rebuilt; in the second phase of scheduling, the hatch state and the hovering positioning accuracy are continuously monitored, and when both meet the conditions, a cargo handover permission signal is generated, triggering the delivery or pick-up action; the present application improves the reliability and environmental adaptability of the collaborative operation of the unmanned aerial vehicle and the turnover cabinet.

Description

Technical Field

[0001] This invention belongs to the field of logistics signal processing, and in particular relates to a communication and linkage scheduling method between logistics drones and intelligent turnover cabinets. Background Technology

[0002] With the rapid development of scenarios such as drone logistics delivery, automated warehousing, and unmanned delivery stations, the requirements for collaborative operation between drones and ground-based intelligent turnover cabinets are continuously increasing in terms of collaborative accuracy, real-time action, and communication reliability. Currently, the communication linkage between drones and intelligent turnover cabinets mostly adopts a one-way trigger mode based on a fixed distance threshold, which can only achieve basic collaborative functions under ideal environments and fixed location conditions. However, this type of solution has defects such as coarse collaborative granularity, poor adaptability of communication links, and insufficient environmental anti-interference capabilities. It lacks a phased collaborative control and two-way status feedback mechanism for the drone approach process, and cannot dynamically adjust the communication configuration according to the electromagnetic interference, signal attenuation, and other conditions in complex outdoor operating environments. It is prone to problems such as packet loss in command transmission, misalignment of action timing, and delayed handover response, making it difficult to guarantee the accuracy of goods handover and operational safety in complex scenarios, and failing to meet the growing demand for high-reliability collaborative operations in automated drone last-mile logistics delivery. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention proposes a communication and coordination scheduling method for logistics drones and intelligent turnover cabinets. This method includes: calculating the real-time straight-line distance between the drone and the intelligent turnover cabinet; establishing a two-way communication link and acquiring the real-time status of the cabinet when the distance is less than or equal to a first preset threshold; performing phased scheduling based on distance ranges: sending an approach warning signal when the distance is far, and sending a door opening command when the distance is close, and issuing a hovering positioning signal after confirming the door is fully opened; during the coordination process, collecting interference parameters such as electromagnetic interference intensity in real time, dynamically adjusting the modulation coding method and transmission power, and monitoring packet loss rate and retransmission count; re-selecting a frequency band and rebuilding the link when the threshold is exceeded; continuously monitoring the door status and hovering positioning accuracy in the second stage of scheduling; generating a cargo handover permission signal when both conditions are met, triggering a delivery or retrieval action; this invention improves the reliability and environmental adaptability of the collaborative operation between drones and turnover cabinets.

[0004] To achieve the above objectives, the present invention provides the following technical solution: The communication and coordination scheduling method between logistics drones and smart turnover cabinets includes: The real-time flight location information of the drone and the preset location information of the smart turnover cabinet are obtained, and the real-time straight-line distance between the drone and the smart turnover cabinet is calculated. Determine whether the real-time straight-line distance is less than or equal to a first preset distance threshold. If so, establish a two-way communication link between the UAV and the smart turnover cabinet, and obtain the real-time status data of the smart turnover cabinet. The real-time status data includes the door opening and closing status, the position status of the cargo receiving mechanism, and cabinet communication quality indication parameters. Based on the distance range of the real-time straight-line distance, a phased linkage scheduling strategy is executed. When the real-time straight-line distance is within the first distance range, the first phase of scheduling is executed, and an approach warning signal is sent to the intelligent turnover cabinet. When the real-time straight-line distance is within the second distance range, the second phase of scheduling is executed, and a door opening command is sent to the intelligent turnover cabinet. After confirming that the door is open in place based on the real-time status data, a hovering positioning signal is sent to the UAV. The first distance range is greater than a second preset distance threshold and less than or equal to the first preset distance threshold, and the second distance range is less than or equal to the second preset distance threshold.

[0005] Specifically, the communication-coordinated scheduling method also includes: During the coordinated scheduling process, interference parameters of the current working environment are collected in real time; The modulation and coding scheme and transmission power of the bidirectional communication link are dynamically adjusted according to the interference parameters, and the packet loss rate and retransmission count of the current communication link are recorded. When the packet loss rate is greater than the first preset packet loss threshold or the number of retransmissions is greater than the first preset retransmission number threshold, the communication frequency band is reselected and the bidirectional communication link is rebuilt. During the second phase of scheduling and execution, the opening and closing status of the smart turnover cabinet and the hovering positioning accuracy of the UAV are continuously monitored. When the opening and closing status of the cabinet is in place and the hovering positioning accuracy is greater than the preset accuracy threshold, a cargo handover permission signal is generated.

[0006] Specifically, dynamically adjusting the modulation and coding scheme and transmission power of the bidirectional communication link includes: S51. Real-time acquisition of interference parameters of the current working environment, including electromagnetic interference intensity value E, signal received power value P_rx and signal-to-noise ratio SNR; S52. Determine whether the electromagnetic interference intensity value E is greater than the preset electromagnetic interference threshold E_th; If E > E_th, then the current interference level is directly determined to be a high-level interference level, and step S54 is executed. If E≤E_th, then proceed to step S53; S53. Determine whether the signal received power value P_rx is less than the preset lower limit threshold P_min, or whether the signal-to-noise ratio SNR is less than the preset lower limit threshold SNR_min. If P_rx < P_min or SNR < SNR_min, determine that the current interference level is the medium interference level; If P_rx ≥ P_min and SNR ≥ SNR_min, determine that the current interference level is the low interference level; The communication linkage scheduling method of the logistics UAV and the intelligent turnover cabinet according to claim 3, wherein dynamically adjusting the modulation coding method and the transmission power of the bidirectional communication link includes: S54. According to the current interference level, match the corresponding modulation coding scheme and transmission power gear from a preset interference level mapping table; S55. Configure the bidirectional communication link based on the selected modulation coding scheme and transmission power gear, and continuously monitor the current packet loss rate L_loss and the retransmission count N_retrans at a preset period; S56. Judge whether the current packet loss rate L_loss is greater than a first preset packet loss threshold L_th1, or whether the retransmission count N_retrans is greater than a first preset retransmission count threshold N_th1; If L_loss > L_th1 or N_retrans > N_th1, execute step S57; If L_loss ≤ L_th1 and N_retrans ≤ N_th1, maintain the current configuration; S57. Upgrade the current interference level by one level, and return to step S54 to reselect the modulation coding scheme and transmission power gear.

[0007] Specifically, reselecting the communication frequency band and reconstructing the bidirectional communication link includes: S611. When it is judged that the packet loss rate L_loss is greater than the first preset packet loss threshold L_th1 or the retransmission count N_retrans is greater than the first preset retransmission count threshold N_th1, obtain the current flight phase identifier Phase_current, and the flight phase identifier includes a first phase identifier Phase_1 and a second phase identifier Phase_2, wherein the first phase identifier Phase_1 corresponds to the state where the real-time straight-line distance D is greater than a second preset distance threshold D2 and less than or equal to a first preset distance threshold D1, and the second phase identifier Phase_2 corresponds to the state where the real-time straight-line distance D is less than or equal to the second preset distance threshold D2; S612. Judge whether the current flight phase identifier Phase_current is the second phase identifier Phase_2; If Phase_current is Phase_2, the frequency band reselection operation is delayed, and a delay timer T_delay is started. Step S613 is executed after the real-time straight-line distance D is greater than the second preset distance threshold D2 or after the timer T_delay times out. If Phase_current is Phase_1, then proceed to step S613 immediately; S613. Obtain the preset list of available frequency bands.

[0008] Specifically, reselecting the communication frequency band and rebuilding the bidirectional communication link also includes: S614. For each candidate frequency band in the available frequency band list F_list, perform a quality assessment operation sequentially, specifically as follows: S6141. Temporarily switch the current bidirectional communication link to the candidate frequency band, and continuously send N_probe link quality probe frames on the candidate frequency band, where N_probe is the preset number of probes; S6142. Receive the link quality feedback information returned under the candidate frequency band, and calculate the average measured signal received power, average measured signal-to-noise ratio, and average measured round-trip delay of the candidate frequency band. S6143. Calculate the comprehensive quality score of the candidate frequency band based on the average measured signal received power, the average measured signal-to-noise ratio, and the average measured round-trip delay, combined with the preset frequency band quality scoring formula. S6144. Record the candidate frequency bands and their comprehensive quality scores in the frequency band evaluation result table.

[0009] Specifically, reselecting the communication frequency band and rebuilding the bidirectional communication link also includes: S615. Traverse the frequency band evaluation result table and select the candidate frequency band with the highest comprehensive quality score as the target frequency band F_target; if there are multiple candidate frequency bands with the same comprehensive quality score and all of them are the highest, then the current working frequency band shall be selected first. S616. Before switching frequency bands, save the context state information of the current communication link. The context state information includes at least the current door opening / closing state value and the current hovering positioning accuracy value. S617. Switch the bidirectional communication link from the current operating frequency band to the target frequency band, and rebuild the bidirectional communication link based on the target frequency band; S618. On the reconstructed two-way communication link, the door opening / closing status value and hovering positioning accuracy value are synchronized to both the UAV and the smart turnover cabinet to restore the communication link status.

[0010] Specifically, establishing a two-way communication link between the drone and the smart turnover cabinet includes: S211. Obtain the real-time straight-line distance D and the real-time flight speed vector of the UAV at the current moment. Calculate the radial relative approach speed between the drone and the smart turnover cabinet. ,in The position vector of the drone pointing towards the smart turnover cabinet; The modulo symbol; S212. Determine whether the real-time straight-line distance D is less than or equal to the first preset distance threshold D. th ; If not, continue to wait and periodically check the distance; If so, then determine the radial relative approach velocity. Is it greater than the preset speed threshold? ; like Greater than If the condition is met, a fast link establishment mode is triggered. In this mode, the maximum number of handshake retransmissions during link establishment is set to a first retransmission threshold, the initial transmit power is set to a first initial transmit power value, and the handshake response waiting timer duration is set to a first waiting duration. The first retransmission threshold is less than the default retransmission number in the standard link establishment mode, the first initial transmit power value is greater than the default initial transmit power in the standard link establishment mode, and the first waiting duration is less than the default waiting duration in the standard link establishment mode. like Less than or equal to If this is not the case, the standard link establishment mode will be triggered, using the default maximum number of handshake retransmissions, default initial transmit power, and default waiting time.

[0011] Specifically, establishing a two-way communication link between the drone and the smart turnover cabinet includes: S213. During the link establishment process, the signal-to-noise ratio of the received first handshake response frame is collected in real time, and it is determined whether the signal-to-noise ratio is less than the preset handshake signal-to-noise ratio threshold. If it is less than, the current transmit power will be increased by a preset step value, and the handshake request frame will be resent. This process will be repeated until a valid handshake response frame is received or the maximum number of retransmissions in the current mode is reached. S214. After the link is successfully established, record the actual time taken for this link establishment, and determine whether the actual time taken is greater than the preset maximum allowed establishment time. If the value is greater than the specified value, a delay establishment flag is generated and set to a valid state. The delay establishment flag is then fed back to the phased linkage scheduling strategy to instruct the phased linkage scheduling strategy to send an approach warning signal one scheduling cycle in advance or to adjust the timing of sending the hatch opening command. If the actual time taken is less than or equal to the preset maximum allowable establishment time, the delayed establishment flag will be set to invalid, and the original scheduling sequence will remain unchanged.

[0012] Specifically, after triggering the fast link establishment mode, the methods for determining the first retransmission count threshold, the first initial transmit power value, and the first waiting time include: when Greater than However, when the first speed limit is less than or equal to the first speed limit, the first retransmission number threshold is set to half of the default retransmission number in the standard link establishment mode and rounded down. The first initial transmit power value is set to the default initial transmit power value in the standard link establishment mode plus the first power increment. The first waiting time is set to half of the default waiting time in the standard link establishment mode. when When the speed exceeds the first speed limit, the first retransmission threshold is set to one, the first initial transmit power value is set to the default initial transmit power value in standard link establishment mode plus the second power increment, where the second power increment is greater than the first power increment, and the first waiting time is set to one-third of the default waiting time in standard link establishment mode. Among them, the first speed upper limit is greater than the preset speed threshold, and the first power increment and the second power increment are both preset positive values.

[0013] Compared with the prior art, the beneficial effects of the present invention are: This invention employs a phased, coordinated scheduling strategy. When the drone is far from the intelligent turnover cabinet, an approach warning signal is sent in advance, putting the cabinet into a standby state and initiating pre-opening preparations for the door, effectively shortening the response delay for cargo handover. Once the distance enters the near-field range, a door opening command is sent, and confirmation of proper opening is based on cabinet door status feedback. This avoids invalid hovering or waiting due to the cabinet door not being ready, significantly improving the timeliness and reliability of collaborative operations. Simultaneously, this invention collects environmental interference parameters such as electromagnetic interference intensity, signal attenuation, and signal-to-noise ratio in real time during the coordinated process. It dynamically adjusts the modulation and coding scheme and transmission power of the communication link, and monitors packet loss rate and retransmission count. When link quality deteriorates, it automatically switches the communication frequency band and rebuilds the connection, thereby maintaining stable and reliable two-way communication in complex outdoor environments. Furthermore, in the second-stage scheduling, this invention continuously monitors the opening and closing status of the hatch and the hovering positioning accuracy of the UAV. Only when both meet the preset conditions is a cargo handover permission signal generated. This ensures the safety of the delivery or retrieval operation from both physical state and positioning accuracy perspectives, effectively preventing cargo damage or collision accidents caused by the hatch not being in place or positioning deviation. In summary, this invention significantly improves the environmental adaptability, communication robustness, and handover security of the collaborative operation of logistics UAVs and intelligent turnover cabinets. Attached Figure Description

[0014] Figure 1 This is a flowchart of the communication and linkage scheduling method between a logistics drone and an intelligent turnover cabinet according to Embodiment 1 of the present invention. Figure 2 This invention provides a logic diagram for dynamically adjusting the modulation and coding scheme and transmit power of the bidirectional communication link in Embodiment 1 of the present invention. Figure 3 The bidirectional communication link logic diagram is reconstructed using the communication frequency band reselected in Embodiment 1 of the present invention. Detailed Implementation

[0015] Example 1 Please see Figure 1 The present invention provides an embodiment of a communication and linkage scheduling method between a logistics drone and a smart turnover cabinet, the steps of which include: S1. Obtain the real-time flight position information of the drone and the preset location information of the smart turnover cabinet, and calculate the real-time straight-line distance between the drone and the smart turnover cabinet, specifically including: S101. Continuously acquire multi-source positioning data of the UAV at a preset sampling period. The multi-source positioning data includes at least the raw latitude, longitude, and altitude coordinate data output by the Global Navigation Satellite System (GNSS) receiver, the three-axis acceleration and three-axis angular velocity data output by the Inertial Measurement Unit (INS), and the relative displacement data output by the Visual Odometry (VAI). After performing timestamp synchronization and alignment based on the UAV flight control main system clock on all acquired multi-source positioning data, the data is input into a pre-constructed Extended Kalman Filter (EKF) for multi-source data fusion processing. The EKF's state vector includes at least the UAV's three-dimensional position, three-dimensional velocity, and three attitude angles in the navigation coordinate system, while the observation vector includes at least the single-point positioning result from the GNSS, the integral displacement increment from the INS, and the keyframe relative displacement from the VAI. Through prediction and update iteration calculations of the EKF, the real-time flight position information of the UAV after fusion filtering is output. The real-time flight position information of the UAV is three-dimensional coordinate data in the navigation coordinate system.

[0016] The iteration and operation logic specifically includes: For the current sampling time k, obtain the posterior state estimate x̂_{k-1|k-1} and the posterior error covariance matrix P_{k-1|k-1} after fusion from the previous time k-1; The prediction step involves constructing the system state transition matrix F_{k-1} and control input model based on the triaxial acceleration and triaxial angular velocity data collected by the inertial measurement unit, and calculating the prior state estimate x̂_{k|k-1} and prior error covariance matrix P_{k|k-1} at the current time k. This process represents the recursive prediction of the UAV's motion state by the inertial navigation system. The observation acquisition and linearization steps are performed. The single-point positioning results of the global navigation satellite system and the key frame relative displacement of the visual odometry are read. The observation z_k at the current time k is constructed, and the observation matrix H_k is calculated to map the state space to the observation space. When the observation model is nonlinear, its Jacobian matrix is ​​calculated for first-order linearization. The update step involves calculating the Kalman gain K_k, which is determined jointly by the prior error covariance matrix P_{k|k-1}, the observation matrix H_k, and the observation noise covariance matrix R_k. The difference between the observed value z_k and the predicted value H_k·x̂_{k|k-1} is used as innovation. This innovation is weighted by the Kalman gain K_k, and the weighted result is added to the prior state estimate x̂_{k|k-1} to calculate the posterior state estimate x̂_{k|k} after fusion at the current time k. This posterior state estimate is the real-time flight position information of the UAV after fusion filtering. The posterior error covariance matrix P_{k|k} is updated synchronously for use in the next iteration. Innovation is a core concept in the Kalman filter update stage, representing the deviation between the actual observed value at the current time and the predicted value based on the state equation of the Kalman filter.

[0017] In this embodiment, the preset sampling period is preferably 50 milliseconds. This sampling period is matched with the output sampling rate of the inertial measurement unit, ensuring that the temporal resolution of the positioning data meets the accuracy requirements of high-speed approach scenarios while avoiding redundant use of the onboard processor's computing power due to excessively high sampling frequencies. The process noise covariance matrix and observation noise covariance matrix of the extended Kalman filter are determined after on-site calibration based on the nominal accuracy of each positioning sensor. They are used to suppress data jumps and high-frequency noise caused by multipath effects, satellite obstruction, or electromagnetic interference from a single positioning source, thereby improving the stability and confidence of the positioning data.

[0018] S102. Read the preset point information stored in the local non-volatile memory of the intelligent turnover cabinet. The preset point information is the latitude, longitude, and altitude coordinate data in the geocentric coordinate system. At the same time, read the static deviation correction parameter uniquely associated with the preset point information. The static deviation correction parameter is the deviation components in three directions in the northeast-sky coordinate system generated after the intelligent turnover cabinet is installed and calibrated on site.

[0019] In this embodiment, the calibration method for the static deviation correction parameter is as follows: After the intelligent turnover cabinet is installed, a differential global navigation satellite system receiver is used to collect three-dimensional coordinate data of the actual installation point of the cabinet at no less than four measurement points with different azimuth angles around the cabinet. Coordinate data for no less than 300 epochs are continuously collected at each measurement point, and the arithmetic mean is taken to obtain the actual installation coordinates of the cabinet. The difference between the actual installation coordinates and the preset point information is decomposed into components in three directions of the northeast-northeast coordinate system to generate the static deviation correction parameter. The update cycle for the static deviation correction parameter is six months, or it is recalibrated immediately after the cabinet is moved and reinstalled, to ensure the long-term effectiveness of the correction accuracy and eliminate the static position deviation introduced by installation measurement errors from the root.

[0020] S103. The real-time flight position information of the UAV obtained after fusion filtering is transformed from the reference ellipsoid coordinate system corresponding to the global navigation satellite system to the station center northeast-sky coordinate system with the preset position of the smart turnover cabinet as the coordinate origin. The station center northeast-sky coordinate system is defined as follows: with the coordinate origin as the reference, the X-axis points due east along the tangent of the reference ellipsoid's east-west circle, the Y-axis points due north along the tangent of the reference ellipsoid's meridian circle, and the Z-axis points to the zenith along the normal of the reference ellipsoid.

[0021] The conversion operation specifically includes: Read the preset location information of the smart turnover cabinet, call the static deviation correction parameter uniquely associated with the preset location information to perform deviation compensation processing on the preset location information, and generate the precise latitude, longitude and elevation coordinates of the smart turnover cabinet; perform the first coordinate transformation operation on the precise latitude, longitude and elevation coordinates to transform the precise latitude, longitude and elevation coordinates from the reference ellipsoid coordinate system to the geocentric rectangular coordinate system, and obtain the initial geocentric rectangular coordinates of the smart turnover cabinet.

[0022] Simultaneously, the real-time latitude, longitude, and altitude coordinates corresponding to the UAV's real-time flight position information at the current sampling time are obtained. A second coordinate transformation operation is performed on the real-time latitude, longitude, and altitude coordinates to transform them from the reference ellipsoidal coordinate system to the geocentric rectangular coordinate system, thus obtaining the initial geocentric rectangular coordinates of the UAV.

[0023] After obtaining the initial geocentric rectangular coordinates of the intelligent turnover cabinet and the UAV, the pre-calibrated seven-parameter Bursa model is called to perform coordinate datum unification transformation on the initial geocentric rectangular coordinates of the intelligent turnover cabinet and the UAV, unifying the initial geocentric rectangular coordinates of the intelligent turnover cabinet and the UAV to the same geocentric rectangular coordinate datum, thus obtaining the datum-unified geocentric rectangular coordinates of the intelligent turnover cabinet and the UAV respectively.

[0024] The seven transformation parameters of the seven-parameter Bursa model are pre-determined and fixed in the system based on local surveying control points. The seven transformation parameters specifically include: translation parameters along the X-axis of the geocentric geostationary rectangular coordinate system, translation parameters along the Y-axis of the geocentric geostationary rectangular coordinate system, translation parameters along the Z-axis of the geocentric geostationary rectangular coordinate system, rotation angle parameters around the X-axis of the geocentric geostationary rectangular coordinate system, rotation angle parameters around the Y-axis of the geocentric geostationary rectangular coordinate system, rotation angle parameters around the Z-axis of the geocentric geostationary rectangular coordinate system, and a scale factor parameter.

[0025] The coordinate datum unification transformation process specifically includes: scaling the input initial geocentric rectangular coordinates using a scale scaling factor parameter to obtain the scale-corrected intermediate geocentric rectangular coordinates; constructing a three-dimensional rotation matrix using three rotation angle parameters, applying the three-dimensional rotation matrix to the scale-corrected intermediate geocentric rectangular coordinates, and performing a spatial rotation transformation to obtain the rotation-corrected intermediate geocentric rectangular coordinates; superimposing the translation parameters along the X-axis, Y-axis, and Z-axis of the geocentric rectangular coordinate system onto the X-axis, Y-axis, and Z-axis components of the rotation-corrected intermediate geocentric rectangular coordinates, respectively, performing a spatial translation transformation, and outputting the datum-unified geocentric rectangular coordinates.

[0026] The coordinate reference unification transformation process is used to completely avoid systematic deviations caused by the inconsistency between the initial geocentric rectangular coordinates of the smart turnover cabinet and the initial geocentric rectangular coordinates of the UAV, and to ensure that the position data of the smart turnover cabinet and the UAV have reference uniformity under the same geocentric rectangular coordinate reference.

[0027] Based on the unified geocentric rectangular coordinates of the intelligent turnover cabinet and the unified geocentric rectangular coordinates of the UAV, the geocentric coordinate difference between the UAV and the intelligent turnover cabinet is calculated.

[0028] The system calls a preset rotation matrix with the precise latitude and longitude of the smart turnover cabinet as construction parameters, and uses the difference between the geocentric and Earth-fixed coordinates as the input of the preset rotation matrix. It performs a matrix rotation transformation operation to transform the difference between the geocentric and Earth-fixed coordinates from the geocentric Earth-fixed rectangular coordinate system to the station-centric Northeast-Sky coordinate system, and outputs the three-dimensional relative position vector of the UAV relative to the smart turnover cabinet. The three-dimensional relative position vector is composed of the eastward coordinate component, the northward coordinate component, and the skyward coordinate component.

[0029] Perform vector magnitude operation on the three-dimensional relative position vector, calculate the arithmetic square root of the sum of the squares of the eastward coordinate components, the northward coordinate components, and the celestial coordinate components, and determine the arithmetic square root as the original straight-line distance value between the UAV and the intelligent turnover cabinet.

[0030] S104. For the raw straight-line distance values ​​calculated from multiple consecutive sampling periods, construct a historical distance queue with a preset sliding window length. Perform median filtering and outlier removal processing on the raw straight-line distance values ​​in the historical distance queue. Specifically, sort the distance values ​​in the historical distance queue in ascending order of numerical value, and take the value in the middle of the queue after sorting as the median; at the same time, calculate the interquartile range of the queue, and remove outlier values ​​that are less than the difference between the first quartile and 1.5 times the interquartile range, and greater than the sum of the third quartile and 1.5 times the interquartile range; perform an arithmetic mean operation between the remaining effective distance values ​​after removing outlier values ​​and the median, and output the real-time straight-line distance at the current sampling time.

[0031] In this embodiment, the preset sliding window length is preferably 11, meaning the historical distance queue retains the original straight-line distance values ​​from the most recent 11 sampling periods. This window length is used to maintain the ability to quickly track changes in the actual distance of the UAV while filtering out abnormal jumps in single-point or two consecutive points. In the historical distance queue, the ratio of the difference in original straight-line distance between adjacent sampling times to the sampling time interval serves as the basis for calculating the radial relative approach speed. This ratio is only called as needed in the subsequent two-way communication link establishment step; this step does not perform redundant output to reduce system data processing overhead. The real-time straight-line distance processed in this step serves as the sole basis for subsequent comparison with the first preset distance threshold.

[0032] S105. Determine whether the real-time straight-line distance is less than or equal to the first preset distance threshold. If yes, trigger the subsequent two-way communication link establishment steps; otherwise, return to step S101, continue to collect multi-source positioning data for the next sampling period and update the real-time straight-line distance.

[0033] In this embodiment, the setting method of the first preset distance threshold is specifically configured as follows: the first preset distance threshold is jointly determined by the typical cruise speed of the UAV, the preset maximum allowable establishment time of the two-way communication link, and the preset mechanical response delay required for the smart turnover cabinet to complete the mechanical action from receiving the instruction; the value of the first preset distance threshold is configured to be no less than the product of the typical cruise speed and the time parameter, where the time parameter is the sum of the preset maximum allowable establishment time and the preset mechanical response delay.

[0034] Among them, the typical cruise speed is defined as the horizontal flight speed of the UAV when it does not perform deceleration during the approach phase; the preset maximum allowable establishment time is defined as the upper limit of the time required from the time the UAV enters the first preset distance threshold range until the two-way communication link is successfully established; the preset mechanical response delay is defined as the upper limit of the time required for the intelligent turnover cabinet to complete the pre-opening preparation of the door from receiving the approach warning signal.

[0035] In a preferred implementation of this embodiment, the typical cruising speed of the UAV is 10 meters per second, the preset maximum allowable establishment time is 300 milliseconds, and the preset mechanical response delay is 2 seconds. Therefore, the value of the time parameter is 2.3 seconds, and the product of the typical cruising speed and the time parameter is 23 meters. Based on this, a first preset distance threshold of 100 meters is configured. The value of 100 meters is greater than the product, which is used to reserve a sufficient time window for the establishment of a two-way communication link, and at the same time reserve a sufficient operating distance range for subsequent phased linkage scheduling, so as to avoid resource waste caused by establishing the link too early or instruction delay caused by establishing the link too late.

[0036] This embodiment eliminates the impact of positioning signal accuracy fluctuations, data jumps, and static coordinate deviations on distance calculation in complex outdoor environments through multi-source data fusion filtering, static deviation correction, unified coordinate transformation, and sliding window midpoint filtering. This significantly improves the accuracy and stability of real-time straight-line distance, thereby avoiding premature or delayed link establishment due to distance errors. It should be further noted that the preset sampling period, sliding window length, interquartile range multiple, and first preset distance threshold parameters in this embodiment are preferred examples. Those skilled in the art can adaptively adjust these parameters based on the interference intensity of the actual operating environment and the dynamic characteristics of the UAV through specific simulation experiments. Such adjustments do not constitute a limitation on the scope of protection of this invention.

[0037] S2. Determine whether the real-time straight-line distance is less than or equal to the first preset distance threshold; S21. If so, a two-way communication link is established between the drone and the intelligent turnover cabinet, and real-time status data of the intelligent turnover cabinet is obtained. The real-time status data includes the door opening / closing status, the position status of the cargo receiving mechanism, and the cabinet communication quality indicator parameters. It should be further explained that establishing a two-way communication link between the drone and the intelligent turnover cabinet in this embodiment includes: S211. Obtain the real-time straight-line distance D and the real-time flight speed vector of the UAV at the current moment. Calculate the radial relative approach speed between the drone and the smart turnover cabinet. ,in The position vector of the drone pointing towards the smart turnover cabinet; The modulo symbol; S212. Determine whether the real-time straight-line distance D is less than or equal to the first preset distance threshold D. th ; If not, continue waiting and reacquire the real-time straight-line distance D at the preset detection cycle and perform the judgment again until the real-time straight-line distance D is less than or equal to the first preset distance threshold D. th Then, the establishment of a two-way communication link is triggered; If so, then determine the radial relative approach velocity. Is it greater than the preset speed threshold? ; like Greater than If the condition is met, the fast link establishment mode is triggered. In the fast link establishment mode, the maximum number of handshake retransmissions during the link establishment process is set to the first retransmission number threshold, the initial transmit power is set to the first initial transmit power value, and the handshake response waiting timer duration is set to the first waiting duration. Among these, the first retransmission number threshold is less than the default retransmission number in the standard link establishment mode, the first initial transmit power value is greater than the default initial transmit power in the standard link establishment mode, and the first waiting duration is less than the default waiting duration in the standard link establishment mode. like Less than or equal to If so, the standard link establishment mode is triggered, using the default maximum number of handshake retransmissions, default initial transmit power, and default waiting time; It should be further explained that, after triggering the fast link establishment mode in this embodiment, the specific methods for determining the first retransmission count threshold, the first initial transmit power value, and the first waiting time include: When the radial relative approach speed is greater than a preset speed threshold but less than or equal to a first speed upper limit, the first retransmission count threshold is set to half of the default retransmission count in standard link establishment mode, rounded down. The first initial transmit power value is set to the default initial transmit power value in standard link establishment mode plus a first power increment. The first waiting time is set to half of the default waiting time in standard link establishment mode. In this embodiment, as a specific implementation method, the preset speed threshold is set according to the typical approach speed of the UAV and the response delay requirements of the smart turnover cabinet. During the UAV's approach to cargo handover, there is a speed upper limit that allows the two-way communication link to be successfully established with standard parameters without command delay. The preset speed threshold is configured as this speed upper limit. When the radial relative approach speed is less than or equal to the preset speed threshold, the UAV is in a low-speed approach state, and the two-way communication link establishment operation has sufficient time to be completed with conservative parameter configuration, thus triggering the standard link establishment mode. When the radial relative approach speed exceeds a preset speed threshold, the UAV is in a high-speed approach state, and the available establishment time of the two-way communication link is compressed. More aggressive parameter configurations are needed to further reduce link establishment time, thus triggering a fast link establishment mode. In this embodiment, the preset speed threshold is preferably two meters per second.

[0038] In this embodiment, the fast link establishment mode is further divided into at least two parameter configuration levels. Each parameter configuration level corresponds to a radial relative approach speed range, and the higher the radial relative approach speed, the more aggressive the link establishment parameters of the corresponding parameter configuration level. Specifically, the fast link establishment mode is divided into a first speed level and a second speed level. The radial relative approach speed range corresponding to the first speed level is greater than a preset speed threshold and less than or equal to a first speed upper limit value. The radial relative approach speed range corresponding to the second speed level is greater than the first speed upper limit value; wherein, the first speed upper limit value is greater than the preset speed threshold.

[0039] In this embodiment, the first speed upper limit is set based on the following specific configuration: the first speed upper limit is an engineering empirical value of the maximum radial relative approach speed that the UAV can achieve in a typical approach scenario, used to distinguish between medium-speed and extremely fast approach states; when the radial relative approach speed is less than or equal to the first speed upper limit, the establishment operation of the two-way communication link still allows a limited number of handshake retransmissions; when the radial relative approach speed is greater than the first speed upper limit, the available establishment time of the two-way communication link is drastically compressed, and handshake retransmission is only allowed to be performed once to complete the link establishment in the shortest possible time. In this embodiment, the first speed upper limit is preferably five meters per second.

[0040] In this embodiment, when the radial relative approach speed is within the speed range corresponding to the first speed level, the fast link establishment mode adopts the first set of link establishment parameters. The first set of link establishment parameters includes: setting the maximum number of handshake retransmissions to half of the default maximum number of handshake retransmissions in the standard link establishment mode and rounding it down; setting the initial transmit power to the default initial transmit power in the standard link establishment mode plus the first power increment; and setting the handshake response waiting timer duration to half of the default waiting time in the standard link establishment mode.

[0041] In this embodiment, when the radial relative approach speed is within the speed range corresponding to the second speed level, the fast link establishment mode adopts the second set of link establishment parameters. The second set of link establishment parameters includes: setting the maximum number of handshake retransmissions to one, setting the initial transmit power to the default initial transmit power in the standard link establishment mode plus the second power increment, wherein the second power increment is greater than the first power increment, and setting the handshake response waiting timer duration to one-third of the default waiting time in the standard link establishment mode.

[0042] Both the first power increment and the second power increment are preset positive values.

[0043] For example, in this embodiment, the values ​​of the first power increment and the second power increment are specifically configured as follows: the default initial transmit power in the standard link establishment mode is 10 milliwatts, corresponding to a power spectral density of 10 milliwatts per megahertz; the first power increment is 6 milliwatts, making the first initial transmit power value reach 16 milliwatts; the second power increment is 14 milliwatts, making the second initial transmit power value reach 24 milliwatts. The above power increment values ​​are selected based on the following: for every 6 milliwatts increase in transmit power, the link budget can theoretically be improved by about 3 dB under the free space propagation model, which can compensate for the additional signal-to-noise ratio loss introduced by the rapid fading of the channel or the Doppler frequency shift caused by the high-speed approach of the UAV; the second power increment of 14 milliwatts corresponds to an improvement of about 7 dB in link margin, which is suitable for extreme high-speed approach scenarios to ensure that the link establishment is completed within a single handshake cycle.

[0044] For example, the specific calculation method for rounding down half of the default maximum handshake retransmission count in the standard link establishment mode is as follows: if the default maximum handshake retransmission count in the standard link establishment mode is 5 times, then half of it is 2.5 times, which is rounded down to 2 times; if the default maximum handshake retransmission count in the standard link establishment mode is 3 times, then half of it is 1.5 times, which is rounded down to 1 time. In this embodiment, the default maximum handshake retransmission count in the standard link establishment mode is preferably 5 times, therefore the first retransmission threshold corresponding to the first speed level in the fast link establishment mode is 2 times.

[0045] For example, the default waiting time in the standard link establishment mode is preferably 200 milliseconds in this embodiment. This value corresponds to the upper limit of the typical round-trip latency of a single handshake request and response between the drone and the smart turnover cabinet. Based on this, the first waiting time corresponding to the first speed level in the fast link establishment mode is half of the default waiting time in the standard link establishment mode, i.e., 100 milliseconds; the first waiting time corresponding to the second speed level in the fast link establishment mode is one-third of the default waiting time in the standard link establishment mode, i.e., approximately 66.67 milliseconds, rounded down to 70 milliseconds. The aforementioned shortened waiting time can adapt to the fast link establishment requirements in high-speed approach scenarios, avoiding delays in subsequent command issuance due to waiting for the standard time.

[0046] In this embodiment, the specific values ​​and calculation rules described above are preferred examples and not limitations on the present invention. In other embodiments, adjustments can be made by those skilled in the art based on specific simulation experiments, according to the UAV model, the performance of the wireless communication module of the intelligent turnover cabinet, and the electromagnetic compatibility requirements of the operating environment. For example, in high-density urban operating areas, the default initial transmission power can be adjusted to 5 milliwatts to reduce mutual interference, or for long-endurance UAVs, the first power increment and the second power increment can be set to smaller values ​​to save energy. The above values ​​and calculation rules are only used to enable those skilled in the art to implement the present invention and do not constitute a limitation on the scope of the claims.

[0047] In existing technologies, the establishment of communication links between UAVs and ground equipment typically employs a single-mode handshake protocol with fixed parameters. This protocol establishes the link with uniform transmission power, retransmission count, and waiting time after detecting a distance threshold. This fails to detect the dynamic approach speed of the UAV, leading to excessively long link establishment times when the UAV approaches at high speeds due to multiple retransmissions, insufficient power, or prolonged response waits. This delays the issuance of approach warning signals or door opening commands, affecting the timing accuracy of subsequent phased scheduling. Conversely, when the UAV approaches at low speeds, overly conservative parameter configurations result in unnecessary energy waste and spectrum occupation. To address these issues, this application proposes an adaptive fast link establishment mode based on radial relative approach speed. Furthermore, it refines parameter configuration according to speed ranges, halving the retransmission count, moderately increasing power, and shortening the waiting time during medium-to-high speed approaches, thus ensuring... While ensuring link reliability, this application compresses link establishment time; during extremely high-speed approach, it reduces retransmissions to once, significantly increases power, and reduces waiting time to one-third, aiming to complete link establishment within a single handshake cycle to the greatest extent possible. Compared to existing static methods, this application introduces a dynamic variable, radial relative approach speed, to achieve speed-adaptive adjustment of handshake parameters. It upgrades the link establishment strategy from static distance triggering to speed-driven dynamic parameter matching. Its beneficial effects are that it significantly reduces link establishment latency in high-speed approach scenarios, avoids command loss or handover misalignment due to link establishment timeout, and maintains default parameters for energy saving and low interference in medium- and low-speed scenarios, realizing on-demand allocation of communication resources and energy consumption. This improves the timeliness, environmental adaptability, robustness of communication establishment, and predictability of collaborative timing of logistics drones and intelligent turnover cabinets in complex approach conditions.

[0048] S213. During the link establishment process, the signal-to-noise ratio (SNR) of the received first handshake response frame is collected in real time, and it is determined whether the SNR is less than a preset handshake SNR threshold. In this embodiment, the preset handshake SNR threshold is specifically configured as follows: the preset handshake SNR threshold is determined based on the minimum demodulation SNR of the basic modulation and coding scheme used in the bidirectional communication link under the preset bit error rate requirement. Specifically, firstly, the basic modulation and coding scheme used in the handshake phase of the bidirectional communication link is determined, and the theoretical minimum demodulation SNR corresponding to the basic modulation and coding scheme under the preset target bit error rate is obtained; a preset SNR protection margin is superimposed on the theoretical minimum demodulation SNR, and the superposition result is used as the preset handshake SNR threshold. For example, in this embodiment, the basic modulation and coding scheme used in the handshake phase is quadrature phase shift keying (QPSK). The theoretical minimum demodulation signal-to-noise ratio (SNR) of QPSK at a preset target bit error rate of 10^-6 is approximately 11 dB. The preset SNR protection margin is 4 dB, used to compensate for instantaneous SNR degradation caused by channel fluctuations, hardware noise, and interference. Therefore, the preset handshake SNR threshold is 15 dB. When the SNR of the first handshake response frame acquired in real-time is less than 15 dB, it indicates that the current channel quality is insufficient to support reliable demodulation of the basic modulation and coding scheme, requiring a power boost operation. When the SNR is greater than or equal to 15 dB, it indicates that the current channel quality meets the requirements for reliable transmission of the handshake frame, and the current transmission power remains unchanged. The specific values ​​and modulation and coding schemes mentioned above are preferred examples of this embodiment and are not intended to limit the invention. In other embodiments, the theoretical minimum demodulation SNR and the preset SNR protection margin can be adaptively adjusted by those skilled in the art based on specific simulation experiments, according to the actual modulation and coding scheme used and the system's reliability requirements.

[0049] If it is less than, the current transmit power will be increased by a preset step value, and the handshake request frame will be resent. This process will be repeated until a valid handshake response frame is received or the maximum number of retransmissions in the current mode is reached. It should be further explained that the process of increasing the current transmit power by a preset step value and retransmitting the handshake request frame in this embodiment specifically includes: Set the maximum number of retransmissions in the current mode to the current retransmission limit value, and set the maximum allowable transmit power value to the preset power limit value; Each time the transmission power is increased, the current transmission power is increased by a fixed power step value, and it is determined whether the increased transmission power exceeds the preset power limit; if it does, the transmission power is clamped to the preset power limit. In this embodiment, the fixed power step value is set based on the following: the fixed power step value is configured as a minimum power increment value that allows the receiver of the smart turnover cabinet to clearly perceive changes in signal strength. This increment value, in the link budget of the bidirectional communication link, generates a change in received signal strength that is greater than the minimum change in received signal strength that the receiver of the smart turnover cabinet can distinguish. This is to ensure that each power increase operation can effectively improve the reception success rate of the handshake response frame. At the same time, the fixed power step value is configured to be less than the maximum power jump value allowed to avoid excessive electromagnetic interference to adjacent channels caused by excessively large single power increase, and to avoid excessive adjustment times and excessive link establishment time caused by excessively small single power increase.

[0050] For example, in this embodiment, the fixed power step value is a linear power increment corresponding to 3 dB, that is, the current transmission power value is multiplied by 2 each time the transmission power is increased. For example, when the initial transmission power is 10 milliwatts, the transmission power after a fixed power step value is 20 milliwatts; when the transmission power is 20 milliwatts, the transmission power after the next fixed power step value is 40 milliwatts, but due to the preset power limit of 30 milliwatts, the actual increased transmission power is clamped to 30 milliwatts; if further increase is needed, it remains unchanged at 30 milliwatts.

[0051] It should be noted that the specific values ​​mentioned above are preferred examples of this embodiment and are not intended to limit the present invention. In other embodiments, the fixed power step value can be adaptively adjusted by those skilled in the art based on specific simulation experiments, according to the transmitting capability of the UAV's onboard communication module, the receiving sensitivity of the intelligent turnover cabinet, and the electromagnetic background noise level of the operating environment. For example, in scenarios where the channel fading changes gradually, the fixed power step value can be reduced to 1 dB to achieve finer power adjustment, or in scenarios where the channel fading changes drastically, the fixed power step value can be increased to 6 dB to quickly compensate for channel degradation.

[0052] In this embodiment, the preset power limit is set as follows: the preset power limit is configured as the maximum allowable transmit power value of the UAV onboard communication module under the constraints of electromagnetic compatibility regulations and the linear operating range of the hardware RF front-end. This provides the maximum possible link margin under extremely harsh channel conditions, while ensuring that the transmit power does not exceed the regulatory limit and device ratings to avoid excessive interference to surrounding electronic equipment or damage to the RF front-end. For example, in this embodiment, the preset power limit is set to 30 milliwatts. This value complies with the regulatory limit for transmit power of civilian UAV communication modules in the 2.4 GHz band and provides sufficient link margin in strong outdoor electromagnetic interference environments to ensure reliable establishment of a two-way communication link.

[0053] In this embodiment, the specific values ​​and parameter values ​​mentioned above are preferred examples of this embodiment and are not intended to limit the present invention. In other embodiments, the fixed power step value and preset power upper limit can be adaptively adjusted by those skilled in the art based on specific simulation experiments, according to the transmitting capability of the UAV's airborne communication module, the receiving sensitivity of the intelligent turnover cabinet, and the electromagnetic background noise level of the working environment.

[0054] If a valid handshake response frame is not received within the updated waiting time after resending the handshake request frame, the signal-to-noise ratio judgment, power boost and retransmission operation will be performed again until any of the following termination conditions occur: a valid handshake response frame is received, the cumulative number of retransmissions reaches the current retransmission limit, or the current transmit power has reached the preset power limit and two consecutive retransmissions have failed. When link establishment fails due to the latter two termination conditions, a link establishment failure flag is generated, and an uplink notification is triggered to instruct the drone to hover or return to base. In this embodiment, the specific determination method for using two consecutive retransmission failures as a termination condition is configured as follows: If, under the premise that the current transmit power has reached the preset power limit, a complete signal-to-noise ratio (SNR) judgment and retransmission operation is performed, but no valid handshake response frame is received, and a complete SNR judgment and retransmission operation is performed again under this state, but still no valid handshake response frame is received, then it is determined that two consecutive retransmissions have failed, the bidirectional communication link establishment process is terminated, a link establishment failure flag is generated, and an uplink notification is triggered to instruct the drone to hover or return to base. The reason for setting this termination condition is that when the transmit power has reached the preset power limit and two consecutive retransmissions fail at the same power limit, it indicates that the current channel conditions have severely deteriorated to the point that even at the maximum power allowed by regulations and hardware, a reliable connection cannot be established. If retransmission is continued at this time, it will only waste communication resources and time, delay subsequent hovering or return-to-base decisions, and increase the safety risk of the drone remaining in a poor channel environment for a long time.

[0055] It should be further explained that the preset step value in this embodiment is set as follows: the preset step value is configured as a fixed transmit power increment value. This increment value, in the link budget of the bidirectional communication link, generates a change in received signal strength that is greater than the minimum change in received signal strength that the receiver of the smart turnover cabinet can distinguish, and less than the maximum power jump value allowed to avoid excessive electromagnetic interference to adjacent channels caused by excessive single power increase. This is to ensure that each transmit power increase operation can produce a detectable improvement in the reception success rate of the handshake response frame, while avoiding excessive adjustments required to reach the required link margin and excessive link establishment time due to excessively small single power increase, and avoiding unnecessary power consumption and electromagnetic interference to adjacent channels due to excessively large single power increase. For example, in this embodiment, the preset step value is a linear power increment corresponding to 3 dB, that is, the current transmit power value is multiplied by 2 each time the transmit power is increased. For example, when the initial transmit power is 10 milliwatts, the transmit power is increased to 20 milliwatts after a preset step value; when the transmit power is 20 milliwatts, the transmit power is increased to 40 milliwatts after the next preset step value, but due to the preset power limit, the actual increased transmit power is clamped to the preset power limit; and so on, until the preset power limit is reached.

[0056] It should be further explained that, in this embodiment, the specific configuration of the multiple relationship between the adaptive extension of the waiting time and the number of retransmissions is as follows: As the number of retransmissions increases, the channel of the bidirectional communication link may be in a state of continuous deep fading or sudden interference. If a fixed waiting time is maintained, the handshake response frame may not be able to reach the receiving end within the waiting time because the channel has not yet recovered or the processing delay has not been completed, resulting in premature judgment of retransmission failure and triggering unnecessary retransmission, thereby increasing the number of invalid retransmissions and the total link establishment time. By gradually extending the waiting time with the number of retransmissions, a more sufficient time window can be provided for channel recovery and response processing, thereby increasing the success probability of a single retransmission without significantly increasing the total link establishment time. The specific values ​​for the multiple relationship are based on the following: During the first retransmission, the channel is in a slightly abnormal state, so the waiting time is extended to 1.5 times the initial waiting time to cover the processing overhead and additional time for channel recovery introduced by the first transmission failure; During the second and subsequent retransmissions, the channel may be in a state of continuous deep fading, so the waiting time is further extended to twice the initial waiting time to provide the maximum time window for channel recovery and response processing. At the same time, the upper limit of the waiting time is set at twice the initial waiting time to avoid the total link establishment time becoming uncontrollable due to the infinite extension of the waiting time.

[0057] For example, in this embodiment, the initial waiting time in the standard link establishment mode is 200 milliseconds, then the waiting time after the first retransmission is 300 milliseconds, and the waiting time after the second and subsequent retransmissions is 400 milliseconds; in the fast link establishment mode, the initial waiting time corresponding to the first speed level is 100 milliseconds, then the waiting time after the first retransmission is 150 milliseconds, and the waiting time after the second and subsequent retransmissions is 200 milliseconds; in the fast link establishment mode, the initial waiting time corresponding to the second speed level is 70 milliseconds, then the waiting time after the first retransmission is 105 milliseconds, and the waiting time after the second and subsequent retransmissions is 140 milliseconds.

[0058] In this embodiment, the specific numerical values ​​and multiples are preferred examples and not limitations on the invention. In other embodiments, the fixed power step value, preset power limit, and the multiple relationship of adaptive extension of waiting time with retransmission count can be adaptively adjusted by those skilled in the art based on specific simulation experiments, according to the transmitting capability of the UAV's onboard communication module, the receiving sensitivity of the intelligent turnover cabinet, and the electromagnetic background noise level of the operating environment. For example, in low-noise suburban scenarios, the preset power limit can be reduced to 20 milliwatts to save energy, or in industrial areas with strong interference, the fixed power step value can be increased to 6 dB to quickly improve link quality. Alternatively, the extension multiple of the waiting time can be adjusted to a non-linear increasing relationship according to the channel fading characteristics to adapt to different channel recovery times. The above numerical values ​​and rules are only used to enable those skilled in the art to implement the invention and do not constitute a limitation on the scope of the claims.

[0059] In existing technologies, the link establishment phase typically employs a fixed transmit power and a fixed retransmission waiting time. When channel quality deteriorates instantaneously due to environmental interference or the dynamic movement of drones, it cannot adaptively adjust, leading to either repeated retransmissions due to insufficient power until timeout failure, or unnecessary energy consumption and electromagnetic interference due to excessive power. To address this issue, this application collects the signal-to-noise ratio (SNR) of the first handshake response frame in real time during link establishment and compares it with a preset handshake SNR threshold. When the SNR is lower than the threshold, it indicates that the current channel quality is insufficient for reliable handshake response transmission. At this point, the transmit power is immediately increased by a preset step value, and the handshake request frame is retransmitted. The core of this operation lies in rapidly compensating for channel attenuation through closed-loop power control, avoiding invalid retransmissions due to insufficient power. Furthermore, this application sets a maximum allowable transmit power value as a preset power upper limit and checks whether the upper limit is exceeded each time the power is increased. If it is exceeded, the power is clamped back to the upper limit. This ensures that the maximum power allowed by regulations can be achieved in scenarios with strong interference or long distances to secure the link. This approach establishes a reliable connection while preventing violations of electromagnetic compatibility standards or damage to the RF front-end due to unlimited power increases. Furthermore, this application introduces a waiting time mechanism that adaptively extends with the number of retransmissions. The initial handshake uses the current mode's initial waiting time, which is increased to 1.5 times after the first retransmission and to twice after the second and subsequent retransmissions. This is because, as the number of retransmissions increases, the channel may be in a state of continuous deep fading or interference. A fixed waiting time is insufficient to accommodate the additional processing delays or channel recovery time introduced by retransmissions. Appropriately extending the waiting time can increase the probability of successful retransmission and avoid premature failure due to the lack of response. In addition, this application sets one of the termination conditions as the current transmit power reaching a preset power limit and two consecutive retransmission failures. The technical significance of this is that when the transmit power cannot be further increased, and two consecutive retransmissions at the same power limit fail to receive a valid response, it indicates that the channel conditions have severely deteriorated to the point that even at maximum power, a reliable link cannot be established. Continuing to retransmit at this point would only waste time and energy, delaying subsequent hovering or return-to-home decisions.Therefore, timely generation of link establishment failure flags and triggering uplink notifications for the drone to hover or return can prevent the drone from blindly waiting or making erroneous approaches, ensuring operational safety. Compared to the simple mechanism in existing technologies that relies on a fixed number of retransmissions before declaring failure or infinite retransmission, this application significantly improves the success rate and timeliness of link establishment in complex electromagnetic environments and dynamic approach speeds through multiple refined controls, such as signal-to-noise ratio-guided stepwise power enhancement, power upper limit clamping, adaptive extension of waiting time, and termination after two consecutive upper limit failures. At the same time, it reduces the energy consumption and spectrum occupation caused by invalid retransmissions. Its beneficial effects are that it can quickly complete link establishment with the minimum necessary power in weak signal or sudden interference scenarios, and can promptly terminate invalid attempts and trigger safety protection actions under extreme conditions, thereby enhancing the robustness and mission continuity of the communication linkage between logistics drones and intelligent turnover cabinets.

[0060] S214. After the link is successfully established, record the actual time taken for this link establishment and determine whether the actual time taken is greater than the preset maximum allowed establishment time. S2141. If the value is greater than the specified value, a delay establishment flag is generated and set to a valid state. The delay establishment flag is then fed back to the phased linkage scheduling strategy to instruct the phased linkage scheduling strategy to send an approach warning signal one scheduling cycle in advance or adjust the timing of the door opening command. Specifically, this includes: The scheduling cycle is pre-set to a fixed duration, and a phased, coordinated scheduling strategy is executed once per cycle for status updates and command issuance. In this embodiment, the preferred scheduling cycle length is 200 milliseconds. This length matches the main control cycle of the UAV flight control system and the minimum response time of the mechanical movements of the turnover cabinet, ensuring both the timeliness of scheduling commands and avoiding excessive communication load. When the UAV is in the first stage of scheduling, i.e., the long-distance approach stage, the ground scheduling system or the onboard computing unit performs a unified distance judgment, status update, and command issuance operation once per scheduling cycle.

[0061] When the delayed establishment flag is in a valid state, the difference between the actual link establishment time and the preset maximum allowable establishment time is calculated and recorded as the excess time. In this embodiment, the preset maximum allowable establishment time is 300 milliseconds, which is determined based on the longest acceptable time for link establishment under a typical handshake retransmission mechanism. If the actual link establishment time is 420 milliseconds, then the excess time is 120 milliseconds. This excess time reflects the subsequent scheduling timing offset caused by the link establishment delay and needs to be compensated in the next scheduling cycle.

[0062] The start time of the next scheduling cycle is advanced by an excess time, and an approach warning signal is immediately sent at the advanced start time. Simultaneously, the second preset distance threshold is temporarily reduced by a correction distance value, which is equal to the excess time multiplied by the average radial relative approach speed of the UAV, thus advancing the timing of the door opening command. In this embodiment, the specific configuration for adjusting the timing of the door opening command is as follows: when the delay establishment flag is in a valid state, the difference between the actual link establishment time and the preset maximum allowable establishment time is calculated, and this difference is recorded as the excess time; the second preset distance threshold is temporarily reduced by a correction distance value, which is equal to the product of the excess time and the average radial relative approach speed of the UAV during the delay establishment period.

[0063] The correction distance value is set based on the following: During the time period corresponding to the excess time consumption, the UAV continuously approaches the smart turnover cabinet at the average radial relative approach speed. The actual distance flown by the UAV during this time period is the correction distance value. By reducing the correction distance value by the second preset distance threshold, the trigger distance of the door opening command is advanced accordingly to compensate for the distance the UAV has already approached the smart turnover cabinet during the link establishment delay. This ensures that the timing of the door opening command is synchronized with the time when the UAV actually reaches the expected hovering position, avoiding the door opening command being issued too late due to link establishment delay.

[0064] In this embodiment, the average radial relative approach velocity is specifically configured as follows: the arithmetic mean of three consecutive radial relative approach velocity samples within the delay setup period is taken. These three consecutive radial relative approach velocity samples correspond to three temporally consecutive and equally spaced sampling times within the delay setup period, with the time interval between two adjacent sampling times equal to a preset sampling period of 50 milliseconds. Using the arithmetic mean of three consecutive equally spaced samples eliminates the influence of single-sample fluctuations on the calculated correction distance value, while also avoiding an increase in calculation delay due to excessive sampling.

[0065] For example, in this embodiment, the preset maximum allowable establishment time is set to 300 milliseconds, the actual link establishment time is set to 420 milliseconds, and the excess time is 120 milliseconds; the average radial relative approach speed is set to 3 meters per second; the corrected distance is 0.12 seconds multiplied by 3 meters per second equals 0.36 meters; the original second preset distance threshold was 10 meters, and the temporary reduction value of the second preset distance threshold is 10 meters minus 0.36 meters equals 9.64 meters. When the real-time straight-line distance between the drone and the smart turnover cabinet is less than or equal to 9.64 meters for the first time, the door opening command is triggered, which is triggered earlier than the original second preset distance threshold of 10 meters, to compensate for the 0.36-meter distance the drone has already approached the smart turnover cabinet within the 120-millisecond excess time.

[0066] It should be noted that the temporary reduction of the second preset distance threshold is only effective within the current scheduling cycle; once the cargo handover is completed or the drone leaves the current scheduling process, the second preset distance threshold will revert to its original value.

[0067] In this embodiment, the specific values ​​mentioned above are preferred examples and are not intended to limit the invention. In other embodiments, the preset maximum allowable establishment time and the second preset distance threshold can be adaptively adjusted by those skilled in the art based on specific simulation experiments, according to the actual link establishment time, UAV approach speed and turnover cabinet response characteristics.

[0068] When the delayed establishment flag is invalid, the original scheduling cycle start time and the original second preset distance threshold remain unchanged. In this embodiment, if the actual link establishment time is 250 milliseconds, which is less than the preset maximum allowed establishment time of 300 milliseconds, the delayed establishment flag is invalid, the scheduling cycle still starts from the original zero point, the second preset distance threshold remains unchanged at 10 meters, and no timing correction is performed.

[0069] In this embodiment, the specific values ​​and calculation methods described above are preferred examples and are not intended to limit the invention. In other embodiments, the scheduling cycle length, maximum allowable establishment time, and speed averaging method in the distance correction calculation can be adaptively adjusted by those skilled in the art based on specific simulation experiments, according to the typical approach speed of the UAV, the mechanical response delay of the turnover cabinet, and the expected establishment time of the communication link. The above content is only intended to enable those skilled in the art to implement the invention and does not constitute a limitation on the scope of the claims.

[0070] S2142. If the actual time consumption is less than or equal to the preset maximum allowable establishment time, the delayed establishment flag will be set to an invalid state, and the original scheduling sequence will remain unchanged. S215. After the link is established, read the real-time status data of the intelligent turnover cabinet. The real-time status data includes the door opening / closing status, the position status of the cargo receiving mechanism, and the cabinet communication quality indicator parameters. Store the real-time status data and the delay establishment flag together in the link context cache for subsequent phased linkage scheduling strategy calls, specifically including: The link context cache contains at least the following fields: hatch opening / closing status value, cargo receiving mechanism position status value, cabinet communication quality indicator parameter value, delay establishment flag value, link establishment timestamp, and the initial transmit power value and retransmission count used for this link establishment. In this embodiment, the link context cache adopts a circular buffer structure with a capacity of ten data entries. The field length of each entry is fixed. The hatch opening / closing status value is represented by two bits, corresponding to three states: closed, pre-opening, and fully opened, as well as a reserved state. The cargo receiving mechanism position status value is represented by four bits, used to indicate eight possible states of the receiving mechanism, including extension, retraction, positioning, and failure. The cabinet communication quality indicator parameter value is represented by eight bits, with a value range of zero to 255, mapped to the normalized value of the received signal strength indicator. The delay establishment flag value occupies one bit, with a valid state of logic one. The link establishment timestamp is a 32-bit unsigned integer recording the millisecond count since system startup. The initial transmit power value and retransmission count each occupy one byte. The encoding method and storage format of the above fields can be adjusted according to the resource constraints of the actual embedded system. This embodiment is only an example.

[0071] During subsequent execution of the first or second phase of scheduling, the coordinated scheduling strategy first reads the delay establishment flag value from the link context cache. If the flag is valid, the conventional initial link quality detection step is skipped, and the cabinet communication quality indicator parameter value in the cache is directly used as the initial communication quality basis. The actual transmit power value recorded during link establishment is used as the starting power reference for subsequent dynamic adjustments. In this embodiment, the conventional initial link quality detection step includes sending three probe frames consecutively at the beginning of each scheduling cycle and taking the average signal-to-noise ratio, a process that takes approximately 150 milliseconds. When the delay establishment flag is valid, skipping this detection step directly saves 150 milliseconds of scheduling overhead, thus partially compensating for the timing offset caused by the link establishment delay. Simultaneously, the actual transmit power value recorded during link establishment is used as the starting power reference. For example, if the transmit power used for a successful handshake during link establishment is 16 milliwatts, subsequent dynamic adjustments will not start from the default 10 milliwatts and gradually increase, but will directly start from 16 milliwatts and continue adjusting according to the real-time packet loss rate to avoid repeated power ramp-up processes.

[0072] If the door opening / closing status value in the cache indicates pre-opening or fully opened, the coordinated scheduling strategy will not repeatedly send the proximity warning signal and will directly enter the second stage of scheduling waiting. In this embodiment, after the bidirectional communication link between the UAV and the smart turnover cabinet is established, if the door opening / closing status value in the cache is read as pre-opening, it indicates that the smart turnover cabinet has previously received the proximity warning signal and started the door pre-opening preparation. If the coordinated scheduling strategy sends the proximity warning signal again at this time, it will lead to duplicate instructions and wasted communication resources. Therefore, the first stage of scheduling is skipped and the second stage of scheduling waiting is entered. Similarly, if the door opening / closing status value is fully opened, it indicates that the door has been opened. The coordinated scheduling strategy can directly wait for the hovering positioning accuracy to meet the conditions to generate a cargo handover permission signal without sending the door opening instruction again. In this embodiment, the definition and judgment method of hovering positioning accuracy are specifically configured as follows: In this embodiment, hovering positioning accuracy is used to characterize the degree of deviation between the actual spatial position of the UAV and the target hovering point when the UAV performs hovering and positioning operations; the target hovering point is defined as the spatial coordinate point at a preset distance directly above the door of the smart turnover cabinet.

[0073] In this embodiment, the hovering positioning accuracy is quantified by the three-dimensional position deviation of the UAV relative to the target hovering point. The three-dimensional position deviation includes a horizontal lateral deviation component, a horizontal longitudinal deviation component, and a vertical height deviation component. The value of the hovering positioning accuracy is the maximum value among the absolute values ​​of the horizontal lateral deviation component, the horizontal longitudinal deviation component, and the vertical height deviation component.

[0074] In this embodiment, hovering positioning accuracy greater than a preset accuracy threshold means that the maximum value among the absolute values ​​of the horizontal lateral deviation component, the horizontal longitudinal deviation component, and the vertical height deviation component is greater than the preset accuracy threshold.

[0075] In this embodiment, the preset accuracy threshold is determined based on a combination of the door opening size of the smart turnover cabinet and the external dimensions of the goods. For example, when the door opening of the smart turnover cabinet is a square opening with a side length of 0.5 meters, and the maximum cross-sectional dimension of the goods is 0.3 meters, in order to ensure that the goods can pass through the door opening without obstruction to complete the delivery or retrieval action, the preset accuracy threshold is configured to 0.1 meters; that is, when the maximum value of the position deviation of the UAV in the three directions of horizontal lateral, horizontal longitudinal, and vertical height does not exceed 0.1 meters, it is determined that the hovering positioning accuracy meets the requirements, and a goods handover permission signal is generated.

[0076] In this embodiment, the specific values ​​mentioned above are preferred examples and are not intended to limit the invention. In other embodiments, the preset accuracy threshold can be adaptively adjusted by those skilled in the art based on specific simulation experiments, according to the actual door opening size of the intelligent turnover cabinet and the actual external dimensions of the goods.

[0077] In this embodiment, the specific field definitions, numerical examples, and operation procedures described above are preferred examples and not limitations on the present invention. In other embodiments, the bit allocation of the cache field, the number of probe frames, and the power adjustment initiation strategy can be adaptively modified according to the actual communication protocol, processor word length, and storage resource limitations. The above content is only intended to enable those skilled in the art to implement the present invention and does not constitute a limitation on the scope of the claims.

[0078] After a two-way communication link is successfully established, this application compares the actual time taken to establish the link with the preset maximum allowable time. When the time exceeds the limit, a delayed establishment flag is generated, and the start time of the scheduling cycle is advanced by an excess time. Simultaneously, the second preset distance threshold is temporarily reduced by a correction distance value related to the excess time and radial relative approach speed. The fundamental reason for this is that the UAV has been continuously approaching the smart turnover cabinet during the link establishment process. If the approach warning signal or door opening command is sent according to the original sequence, the timing of the command issuance will lag behind the actual position of the UAV, resulting in late door opening or prolonged hovering waiting time, or even triggering an incorrect scheduling phase due to distorted distance judgment. By advancing the start time of the scheduling cycle and dynamically reducing the second preset distance threshold, the distance already flown by the UAV during the link establishment delay can be accurately compensated, ensuring that the door opening command remains synchronized with the actual approach position. Meanwhile, this application stores real-time status data and delay establishment identifiers in the link context cache. During subsequent scheduling, if the delay establishment identifier is valid, the conventional initial link quality detection step is skipped, and the cabinet communication quality indicator parameter value in the cache and the actual transmit power value used for successful link establishment are directly used as the starting benchmark. This is because conventional detection steps require multiple probe frames, which is time-consuming, while the handshake just completed during link establishment has already verified the current channel quality and effective transmit power. Reusing this information avoids repeated measurements and power ramp-ups, thereby further compensating for timing offsets and reducing communication overhead. Furthermore, if the door opening / closing status value in the cache indicates pre-opening or fully opened, the scheduling strategy will not repeatedly send proximity warning signals or door opening commands. This is because during the link establishment delay, the intelligent turnover cabinet may have already completed a state switch through other means or previous commands; repeated transmission not only wastes bandwidth but may also cause state conflicts. The beneficial effects of the above operations are as follows: by advancing the timing and dynamically correcting the distance threshold, the cumulative deviation of the link establishment delay on the subsequent staged scheduling timing is completely eliminated; by reusing cached information, the link quality detection time and power adjustment time are saved; and by skipping redundant instructions with state awareness, invalid communication and mechanical repetitive actions are avoided. Compared with the crude mode of fixed timing, starting from scratch for each scheduling and not utilizing historical states in the existing technology, this application realizes closed-loop compensation for link establishment delay and scheduling timing, as well as a context-aware intelligent skipping mechanism, which significantly improves the collaborative timing accuracy, response speed and communication efficiency of logistics drones and intelligent turnover cabinets in high-speed approach and complex electromagnetic environments, and effectively prevents instruction loss or handover misalignment caused by link establishment timeout.

[0079] S3. Based on the distance interval of the real-time straight-line distance, execute a phased linkage scheduling strategy, specifically including: S31. Using a scheduling execution period that is synchronized with the preset sampling period, acquire the real-time straight-line distance after filtering at the current sampling time, the delay establishment flag stored in the link context cache, the real-time status data of the intelligent turnover cabinet, and the link quality parameters of the current communication link. Use this information as the sole input for phased scheduling. In this embodiment, the scheduling execution period is preferably 50 milliseconds, completely synchronized with the preset sampling period, to ensure that the timing of distance data updates and scheduling command issuance is perfectly aligned, avoiding scheduling timing deviations caused by data asynchrony. The link quality parameters are from the same source as the parameters monitored in the dynamic adjustment stage of the communication link in this application, ensuring the adaptability of the scheduling strategy to the link quality status. In this embodiment, the scheduling execution period and the preset sampling period have the same duration and are driven by the same clock source, maintaining phase synchronization.

[0080] The specific configuration for setting the scheduling execution cycle is as follows: the scheduling execution cycle and the preset sampling cycle adopt a common source synchronization mechanism, that is, the scheduling execution cycle and the preset sampling cycle share the main system clock of the UAV flight control system as the clock source, and the trigger time of the scheduling execution cycle and the sampling time of the preset sampling cycle are completely aligned on the time axis; this is to ensure that the update of real-time straight-line distance data and the issuance of scheduling instructions are strictly synchronized in time, and to avoid the data used as the basis for scheduling decisions not being the latest collected real-time straight-line distance data due to phase deviation between data updates and instruction issuance.

[0081] For example, in this embodiment, the preset sampling period is 50 milliseconds, and the scheduling execution period is also configured to be 50 milliseconds. At the beginning of each 50-millisecond period, the UAV flight control system synchronously performs multi-source positioning data acquisition operation and scheduling status update operation, so that the real-time straight-line distance data used in each scheduling period is the latest data after filtering at the current sampling time.

[0082] In this embodiment, the specific values ​​and synchronization methods described above are preferred examples and are not intended to limit the invention. In other embodiments, the scheduling execution cycle can be adaptively adjusted by those skilled in the art based on specific simulation experiments according to the processing capacity and communication load of the UAV flight control system, but the synchronous relationship between the scheduling execution cycle and the preset sampling cycle must be maintained.

[0083] S32. State machine initialization and one-way jump during the scheduling phase are as follows: The scheduling phase state machine is initialized, which includes four mutually exclusive operating states: pending trigger state, first-phase execution state, second-phase execution state, and scheduling exception state. Based on the current real-time straight-line distance and the preset distance threshold range, the state machine performs a one-way jump judgment. The one-way jump judgment means that the state machine can only flow in the order of pending trigger state → first-phase execution state → second-phase execution state, and reverse backtracking jump is prohibited.

[0084] In this embodiment, the specific execution rules for the one-way jump judgment of the state machine are as follows: When the real-time straight-line distance is greater than the first preset distance threshold, the state machine remains in the pending trigger state and does not execute any scheduling instruction issuance operation. When the real-time straight-line distance meets the condition of being greater than the second preset distance threshold and less than or equal to the first preset distance threshold for two consecutive scheduling cycles, the state machine will unidirectionally jump from the pending state to the first stage execution state. After the jump is completed, regardless of whether the real-time straight-line distance fluctuates back to the range greater than the first preset distance threshold, it will not return to the pending state. When the real-time straight-line distance is less than or equal to the second preset distance threshold for two consecutive scheduling cycles for the first time, the state machine jumps unidirectionally from the first stage execution state to the second stage execution state. After the jump is completed, regardless of whether the real-time straight-line distance fluctuates back to the range greater than the second preset distance threshold, it will not return to the first stage execution state.

[0085] The above steps, through a unidirectional, non-reversible state machine design, are used to solve the technical problems of frequent switching of scheduling states and repeated issuance of instructions caused by fluctuations in positioning data and instantaneous changes in distance calculation. This avoids frequent start-stop and action conflicts of the intelligent turnover cabinet's mechanical mechanism, ensuring the stability and security of the scheduling process.

[0086] S33, the first phase of scheduling execution, specifically: When the real-time straight-line distance is greater than the second preset distance threshold and less than or equal to the first preset distance threshold, the first stage of scheduling is executed, which specifically includes: S331, The first stage of entry judgment and proximity warning anti-redundancy transmission is as follows: Determine whether the current scheduling system is already in the first stage of execution; If it is not in the first stage of execution, it is determined to be the first time entering the first stage of scheduling. Immediately send an approach warning signal with a unique frame number to the intelligent turnover cabinet, instructing the intelligent turnover cabinet to enter the standby state and start the door pre-opening preparation. At the same time, write the time of the first entry into the first stage of scheduling and the corresponding real-time straight-line distance value into the link context cache. If it is already in the first stage of execution, it is further determined whether the time elapsed since the last valid transmission of the proximity warning signal is greater than the preset warning repetition period threshold. If it is greater than the preset warning repetition period threshold, the proximity warning signal is transmitted again to refresh the standby status of the smart turnover cabinet. Otherwise, the repetition operation is not performed to avoid invalid communication data occupying the link bandwidth. Furthermore, if the delay establishment flag stored in the link context cache is in a valid state, then when entering the first stage of scheduling for the first time, two proximity warning signals with consecutive frame numbers are sent simultaneously, and the intelligent turnover cabinet is instructed to perform the mechanical unlocking operation of the hatch during the hatch pre-opening preparation, in order to compensate for the timing deviation caused by the link establishment delay.

[0087] S332, the first stage of hysteresis stabilization is as follows: To suppress frequent switching of scheduling states caused by distance measurement noise or minor fluctuations in the UAV's position, this step sets a hysteresis comparison mechanism at the trigger boundary of the first-stage scheduling, specifically: When the real-time straight-line distance decreases from an interval greater than the first preset distance threshold to less than or equal to the first preset distance threshold for two consecutive scheduling cycles, the first stage of scheduling is triggered. If the real-time straight-line distance briefly exceeds the first preset distance threshold during the first stage of scheduling and operation, and the duration is less than the preset hysteresis time threshold, the first stage execution state will be maintained, and the operation will exit without execution. The first-stage scheduling exit operation is only executed when the real-time straight-line distance is continuously greater than the first preset distance threshold for a duration exceeding the preset hysteresis time threshold. This stops the transmission of the proximity warning signal and synchronizes the status exit information to the link context cache.

[0088] In this embodiment, the preset warning repetition cycle threshold is preferably 2 seconds, and the preset hysteresis time threshold is preferably 500 milliseconds. The preset warning repetition cycle threshold is used to match the duration of the standby state of the intelligent turnover cabinet, so as to avoid resource occupation caused by frequent refreshes. The preset hysteresis time threshold corresponds to 10 consecutive scheduling cycles, which is used to filter out high-frequency noise in distance measurement and instantaneous position fluctuations of the UAV, so as to avoid frequent changes in the scheduling state.

[0089] S34. The second phase of scheduling and execution is as follows: When the real-time straight-line distance is less than or equal to the second preset distance threshold, the second stage of scheduling is executed, which specifically includes: S341, Second-stage entry judgment and hatch opening timeout fault tolerance control, specifically: Determine whether the current scheduling system is already in the second stage of execution; If it is not in the second stage of execution, it is determined to be the first time to enter the second stage of scheduling. First, the first stage scheduling execution completion flag in the link context cache is read. After confirming that the flag is valid, a door opening command with a unique frame sequence number is sent to the intelligent turnover cabinet. At the same time, the door opening waiting timer is started. The timer duration is the preset maximum allowed duration of door opening. If the system is already in the second stage of execution and the smart turnover cabinet has not yet reported the door opening status, the system will detect in real time whether the door opening waiting timer has expired. If the timer expires, the door opening command will be resent and the timer will be reset. The cumulative number of resentments of the door opening command shall not exceed the preset maximum number of resentments. If the cumulative number of retransmissions exceeds the preset maximum number of retransmissions and no feedback is received that the hatch is in place, a hatch opening failure alarm is generated, synchronized to the link context cache, and approach abort and hovering waiting commands are sent to the UAV.

[0090] In this embodiment, the maximum allowable duration for opening the hatch is preferably 3 seconds, and the maximum number of retransmissions is preferably 3 times. These parameters are used to match the maximum action response time of the intelligent turnover cabinet hatch drive mechanism, while reserving a sufficient time window for command retransmission to ensure reliable transmission of the hatch opening command.

[0091] S342, Door status confirmation and hovering in place command issued, specifically as follows: After the hatch opening command is issued, the system continuously receives real-time status data reported by the intelligent turnover cabinet in units of scheduling execution cycle, and analyzes the hatch opening and closing status parameters in real time. When the hatch opening / closing status obtained from parsing for three consecutive scheduling cycles is all "open in place" and no cabinet fault indicator is reported, it is determined that the hatch is effectively opened in place, and the hatch opening waiting timer is immediately stopped. In this embodiment, the specific configuration for confirming the hatch opening in place for three consecutive scheduling cycles is as follows: after the hatch opening command is issued, the real-time status data reported by the intelligent turnover cabinet is continuously received in units of scheduling execution cycles, and the hatch opening / closing status parameters are parsed in real time; when the hatch opening / closing status obtained from parsing for three consecutive scheduling execution cycles is all "open in place" and no cabinet fault indicator is reported, it is determined that the hatch is effectively opened in place. The three consecutive scheduling cycles are based on the following: During the transmission of the intelligent turnover cabinet's door opening / closing status via the two-way communication link, wireless interference may cause single or two consecutive momentary status feedback errors. If the judgment is based solely on the status information from a single or two consecutive scheduling cycles, it may be mistakenly determined that the door is fully open due to momentary errors. The confirmation mechanism of three consecutive scheduling cycles effectively filters out momentary status feedback errors while ensuring timely judgment, preventing premature issuance of subsequent hovering and positioning commands due to misjudgments. If the confirmation conditions for three consecutive scheduling cycles are not met and the door opening waiting timer has not expired, the system continues to wait and monitor; if the door opening waiting timer expires, the door opening timeout retransmission mechanism is triggered.

[0092] Further read the current hovering positioning accuracy data of the UAV to determine whether the hovering positioning accuracy meets the preset hovering accuracy requirements. If the requirements are met, immediately send a hovering position signal with a timestamp synchronized with the main system clock to the UAV flight control system. At the same time, write the hovering position signal sending time and the corresponding positioning accuracy data into the link context cache. If the hovering accuracy requirement is not met, the hovering positioning accuracy will be waited for until it reaches the standard before the hovering positioning signal is issued. At the same time, a deceleration adjustment command will be issued to the UAV flight control system to control the UAV to reduce its radial relative approach speed.

[0093] In this embodiment, the preset hovering accuracy requirement is completely consistent with the hovering positioning accuracy threshold used to generate the subsequent cargo handover permission signal, so as to ensure the consistency of the positioning accuracy judgment benchmark throughout the entire process.

[0094] S343, Second-stage distance backoff tolerance handling, specifically: During the second phase of scheduling and operation, the changes in real-time straight-line distance were continuously monitored; If the real-time straight-line distance unexpectedly increases to a level greater than the second preset distance threshold due to drone attitude adjustment or environmental wind disturbance, but does not exceed the first preset distance threshold, and the duration of the excess is less than the preset distance rollback tolerance time, then the second stage execution state remains unchanged, and the rollback operation to the first stage is not performed. If the real-time straight-line distance exceeds the second preset distance threshold for a duration that exceeds the preset distance backoff tolerance time, then the second-stage scheduling exit operation is executed, and the system re-enters the first-stage execution state, while simultaneously resending the proximity warning signal and refreshing the standby status of the intelligent turnover cabinet.

[0095] In this embodiment, the preset distance backoff tolerance time is preferably 1 second, corresponding to 20 consecutive scheduling cycles. This is used to accommodate the instantaneous position shift caused by normal attitude adjustment of the UAV and wind disturbance, avoid invalid backoff in the scheduling phase due to non-subjective distance fluctuations, and ensure the continuity of the scheduling process.

[0096] S35, Stage State Synchronization and Context Update, specifically: Each time a scheduling phase switch occurs, the current scheduling phase identifier, the type and corresponding timestamp of the most recently valid command sent, the remaining duration of the door opening waiting timer, and the reason for the phase switch are immediately updated in the link context cache. The cached status information is used for subsequent communication frequency band reselection decisions and cargo handover permission signal generation, providing a unified status judgment benchmark for subsequent processes.

[0097] Meanwhile, when a state change occurs, such as reverting from the second stage to the first stage or exiting the first stage of scheduling, the state change information is immediately synchronized to the intelligent turnover cabinet through a two-way communication link. This ensures that the scheduling state machine on the UAV side and the intelligent turnover cabinet side are fully synchronized, avoiding command conflicts and abnormal mechanical actions caused by inconsistent states.

[0098] Through the aforementioned phased scheduling execution process, this embodiment addresses the frequent switching of scheduling states caused by distance measurement fluctuations using a hysteresis comparison mechanism, avoids unnecessary redundancy in communication links using a periodically controllable early warning sending mechanism, fills the gap in handling unresponsive door opening commands using a fault-tolerant mechanism with timeout retransmission and fault alarms, ensures the continuity of the scheduling process using a distance backoff tolerance mechanism, and guarantees the consistency of the state machines of the UAV and the turnover cabinet using a full-process state synchronization mechanism. Compared with existing technologies, this embodiment significantly improves the robustness, timing accuracy, and environmental adaptability of collaborative operations between logistics UAVs and intelligent turnover cabinets, providing a stable and reliable scheduling foundation for subsequent cargo handover operations.

[0099] All preset parameters and threshold values ​​in the above steps are preferred examples of this embodiment. Depending on the drone model, the mechanical performance of the intelligent turnover cabinet, and the characteristics of the operating environment, those skilled in the art can make adaptive adjustments based on specific simulation tests. Such adjustments do not constitute a limitation on the scope of protection of this invention.

[0100] In this embodiment, the phased linkage scheduling strategy employs a series of refined operations, including state machine unidirectional jump, hysteresis anti-shake, early warning anti-redundancy transmission, delay compensation, door opening timeout retransmission and multi-cycle confirmation, hovering accuracy waiting and deceleration adjustment, distance backoff tolerance, and phase state synchronization. The fundamental reason for this is that the real-time straight-line distance of the UAV is subject to instantaneous fluctuations due to positioning noise, environmental interference, and its own attitude adjustment. If the phase switching is triggered directly based on a single distance judgment, it will lead to frequent changes in scheduling state, repeated issuance of instructions, and repeated start-stop of the intelligent turnover cabinet's mechanical mechanism. At the same time, the door opening instruction may wait indefinitely due to wireless packet loss and lack of response. Furthermore, if the UAV issues the positioning signal too early when the hovering positioning accuracy is insufficient, it may cause the risk of cargo collision. To address these issues, this application employs a one-way state machine to ensure the irreversibility of the scheduling process, resolving state rollback and oscillations caused by distance fluctuations. Hysteresis comparison and continuous periodic confirmation filter out distance measurement noise, switching states only when the threshold is stably crossed, thus avoiding invalid start-stop of mechanical actions. Controllable periodic warning transmission and dual-frame encryption / unlocking compensation under delayed establishment markers prevent communication bandwidth waste and compensate for timing deviations caused by link establishment delays. Door opening timeout retransmission and multi-period opening confirmation resolve fault tolerance issues in scenarios of lost or unresponsive instructions, ensuring subsequent actions only proceed after the door is actually in position. Hovering accuracy judgment and deceleration adjustment ensure that hovering positioning signals are only sent when positioning is achieved, physically guaranteeing the safety of cargo handover. A distance rollback tolerance mechanism accommodates brief distance exceedances caused by instantaneous wind disturbances or attitude adjustments, preventing meaningless rollbacks in the scheduling process. Stage state synchronization ensures consistency between the state machines on both sides of the UAV and the turnover cabinet, preventing instruction conflicts. The beneficial effects of the above operations are: significantly improved anti-interference capability, timing accuracy, and continuity of mechanical actions in the scheduling process, while reducing communication redundancy and energy consumption. Compared with the extensive scheduling methods in the prior art that rely solely on single distance comparisons, lack state maintenance, fault tolerance, and synchronization, this application achieves high robustness, high reliability, and high security in the collaborative scheduling of logistics drones and intelligent turnover cabinets in complex outdoor environments through multi-level anti-shake, closed-loop timeout retransmission, accuracy threshold linkage, and state machine solidification mechanisms, solving the scheduling disorder problem caused by distance fluctuations and unreliable communication.

[0101] S4. During the coordinated scheduling of the drone and the intelligent turnover cabinet, the interference parameters of the current working environment are collected in real time. The interference parameters include at least one of electromagnetic interference intensity, signal attenuation and signal-to-noise ratio. S5. Based on the interference parameters and the preset interference level mapping table, dynamically adjust the modulation and coding scheme and transmit power of the bidirectional communication link, and record the packet loss rate and retransmission count of the current communication link. Please refer to [link to relevant documentation]. Figure 2 Specifically, it includes: S51. Collect the interference parameters of the current working environment in real time. The interference parameters include the electromagnetic interference intensity value E, the signal reception power value P_rx, and the signal-to-noise ratio SNR. S52. Determine whether the electromagnetic interference intensity value E is greater than the preset electromagnetic interference threshold E_th. If E > E_th, directly determine that the current interference level is the high interference level, and execute step S54. If E ≤ E_th, execute step S53. S53. Determine whether the signal reception power value P_rx is less than the preset signal reception power lower limit threshold P_min, or whether the signal-to-noise ratio SNR is less than the preset signal-to-noise ratio lower limit threshold SNR_min. If P_rx < P_min or SNR < SNR_min, determine that the current interference level is the medium interference level. If P_rx ≥ P_min and SNR ≥ SNR_min, determine that the current interference level is the low interference level. In this embodiment, the setting methods of the preset electromagnetic interference threshold, the preset signal reception power lower limit threshold, and the preset signal-to-noise ratio lower limit threshold are specifically configured as follows: The setting basis of the preset electromagnetic interference threshold is: the preset electromagnetic interference threshold is configured to determine whether the electromagnetic interference intensity of the current working environment has reached the critical value that can independently cause serious deterioration of the reliability of the two-way communication link; when the electromagnetic interference intensity value is greater than the preset electromagnetic interference threshold, it indicates that there is a strong electromagnetic interference source in the current working environment. Regardless of whether the signal reception power value and the signal-to-noise ratio are within the normal range, the two-way communication link faces a high packet loss risk. Therefore, directly determine that the current interference level is the high interference level to prioritize ensuring the reliability of link transmission.

[0102] The setting basis of the preset signal reception power lower limit threshold is: the preset signal reception power lower limit threshold is configured as the minimum reception power value required for the receiver of the intelligent turnover cabinet to correctly demodulate the signal under the basic modulation and coding scheme adopted by the two-way communication link; when the signal reception power value is less than the preset signal reception power lower limit threshold, it indicates that the signal attenuates too much during transmission and the link margin of the two-way communication link is insufficient.

[0103] The setting basis of the preset signal-to-noise ratio lower limit threshold is: the preset signal-to-noise ratio lower limit threshold is configured as the minimum signal-to-noise ratio required for the basic modulation and coding scheme adopted by the two-way communication link to meet the preset bit error rate requirement; when the signal-to-noise ratio is less than the preset signal-to-noise ratio lower limit threshold, it indicates that the noise and interference level in the channel has exceeded the tolerance range of the basic modulation and coding scheme.

[0104] For example, in this embodiment, the preset lower limit threshold for signal receiving power is set to -80 dBmW. This value is the typical receiving sensitivity value of the receiver of the intelligent turnover cabinet when using a quadrature phase shift keying modulation and coding scheme in the 2.4 GHz band to meet the preset bit error rate requirement. The preset lower limit threshold for signal-to-noise ratio is set to 10 dB. This value is the theoretical minimum demodulation signal-to-noise ratio required by the quadrature phase shift keying modulation and coding scheme when the preset target bit error rate is 10 to the power of -6. The preset electromagnetic interference threshold is set according to the electromagnetic background noise survey results of the working environment where the two-way communication link is located, and is set to 15 dB above the receiver noise floor for example.

[0105] In this embodiment, the combination of the above three thresholds constitutes a complete interference level determination logic: when the electromagnetic interference intensity value is greater than the preset electromagnetic interference threshold, it is directly determined to be a high-level interference level; when the electromagnetic interference intensity value is less than or equal to the preset electromagnetic interference threshold, but the signal received power value is less than the preset lower limit threshold for signal received power or the signal-to-noise ratio is less than the preset lower limit threshold for signal-to-noise ratio, it is determined to be a medium-level interference level; when the electromagnetic interference intensity value is less than or equal to the preset electromagnetic interference threshold, and the signal received power value is greater than or equal to the preset lower limit threshold for signal received power, and the signal-to-noise ratio is greater than or equal to the preset lower limit threshold for signal-to-noise ratio, it is determined to be a low-level interference level.

[0106] In this embodiment, the specific values ​​and judgment logic described above are preferred examples of this embodiment and are not intended to limit the present invention. In other embodiments, the preset electromagnetic interference threshold, preset signal receiving power lower limit threshold, and preset signal-to-noise ratio lower limit threshold can be adaptively adjusted by those skilled in the art based on specific simulation experiments, according to the actual modulation and coding scheme adopted by the bidirectional communication link, the receiver sensitivity of the intelligent turnover cabinet, and the actual electromagnetic background noise level of the working environment.

[0107] S54. Based on the current interference level, match the corresponding modulation and coding scheme and transmit power level from the preset interference level mapping table, specifically: When the current interference level is low interference level, select the first modulation and coding scheme MCS_1 and the first transmit power level PWR_1, where MCS_1 is a high-order modulation and coding scheme and PWR_1 is a low power level; When the current interference level is medium interference level, select the second modulation and coding scheme MCS_2 and the second transmit power level PWR_2, where MCS_2 is a medium-order modulation and coding scheme and PWR_2 is a medium power level; When the current interference level is high-level interference, select the third modulation and coding scheme MCS_3 and the third transmit power level PWR_3, where MCS_3 is a low-order modulation and coding scheme and PWR_3 is a high-power level. In this embodiment, the preset interference level mapping table is specifically configured as follows: the preset interference level mapping table is used to establish the corresponding mapping relationship between the current interference level and the modulation and coding scheme and the transmit power level. The basis for constructing the corresponding mapping relationship is that the better the channel quality, the higher the spectral efficiency of the modulation and coding scheme and the lower the transmit power level are selected, and the worse the channel quality, the stronger the anti-interference capability of the modulation and coding scheme and the higher the transmit power level are selected. Specifically, the preset interference level mapping table contains at least three sets of mapping records: When the current interference level is low, it is mapped to the first modulation and coding scheme and the first transmit power level. The first modulation and coding scheme is a high-order modulation and coding scheme with a modulation order of not less than 16 quadrature amplitude modulation, and the first transmit power level is a low-power level, used to achieve high data transmission rate with low power consumption in scenarios with good channel quality; When the current interference level is medium, it is mapped to the second modulation and coding scheme and the second transmit power level. The second modulation and coding scheme is a medium-order modulation and coding scheme with a modulation order between quadrature phase shift keying and 16 quadrature amplitude modulation, and the second transmit power level is a medium-power level, used to balance data transmission rate and anti-interference capability in scenarios with average channel quality; When the current interference level is high, it is mapped to the third modulation and coding scheme and the third transmit power level. The third modulation and coding scheme is a low-order modulation and coding scheme with a modulation order of not more than quadrature phase shift keying, and the third transmit power level is a high-power level, used to prioritize the transmission reliability of the communication link in scenarios with poor channel quality. The above-mentioned interference level classification methods, modulation and coding scheme selection, and transmit power level settings are all preferred examples of this embodiment and are not intended to limit the present invention. In other embodiments, the number of mapping records in the preset interference level mapping table and the parameters corresponding to each mapping record can be adaptively adjusted by those skilled in the art based on specific simulation experiments, according to the actual communication module support capabilities and operating environment characteristics.

[0108] In this embodiment, the threshold setting method for selecting and switching between high-order modulation and coding schemes, mid-order modulation and coding schemes, and low-order modulation and coding schemes is specifically configured as follows: The preset electromagnetic interference threshold is set based on the following criteria: It is configured to determine whether the electromagnetic interference intensity of the current working environment has reached a critical value that can independently cause severe degradation of the reliability of the two-way communication link. The preset threshold is set according to the electromagnetic background noise survey results of the working environment where the two-way communication link is located; for example, it is set to 15 dB above the receiver noise floor of the intelligent turnover cabinet. When the electromagnetic interference intensity value is greater than the preset threshold, it indicates the presence of a strong electromagnetic interference source in the current working environment. Regardless of whether the signal received power and signal-to-noise ratio are within the normal range, the two-way communication link faces a high risk of packet loss. Therefore, the current interference level is directly determined to be a high-level interference level, and a low-order modulation and coding scheme is selected to prioritize the reliability of the link transmission.

[0109] The preset signal receiving power lower limit threshold is set based on the following: the preset signal receiving power lower limit threshold is configured as the minimum receiving power value required for the receiver of the smart turnover cabinet to correctly demodulate the signal under the basic modulation and coding scheme adopted in the two-way communication link; for example, in this embodiment, the preset signal receiving power lower limit threshold is set to -80 milliwatt decibels. This value is the typical receiving sensitivity value of the receiver of the smart turnover cabinet when adopting the quadrature phase shift keying modulation and coding scheme in the 2.4 GHz band to meet the preset bit error rate requirement, and is used to determine whether the signal attenuates too much or the link margin is insufficient during transmission.

[0110] The preset signal-to-noise ratio (SNR) lower limit threshold is set based on the following: the preset SNR lower limit threshold is configured as the minimum SNR value required by the basic modulation and coding scheme used in the bidirectional communication link to meet the preset bit error rate requirement; for example, in this embodiment, the preset SNR lower limit threshold is set to 10 dB, which is the theoretical minimum demodulation SNR required by the quadrature phase shift keying (QPSK) modulation and coding scheme when the preset target bit error rate is 10 to the power of -6, and is used to determine whether the noise and interference levels in the channel have exceeded the tolerance range of the basic modulation and coding scheme.

[0111] Based on the hierarchical judgment logic composed of the above three thresholds, the specific rules for selecting the modulation and coding scheme are as follows: when the electromagnetic interference intensity value is less than or equal to the preset electromagnetic interference threshold, the signal received power value is greater than or equal to the preset lower limit threshold for signal received power, and the signal-to-noise ratio is greater than or equal to the preset lower limit threshold for signal-to-noise ratio, the current interference level is determined to be a low-level interference level. At this time, the channel is in a clean state with low interference and high signal-to-noise ratio, and a high-order modulation and coding scheme is selected. The high-order modulation and coding scheme is a modulation and coding scheme with a modulation order of not less than 16 orthogonal amplitude modulation. Each symbol can carry at least 4 bits of information. Under the premise of ensuring that the bit error rate is lower than the preset target bit error rate, the data transmission rate is maximized to meet the needs of high-bandwidth services such as real-time status synchronization and airborne image transmission between UAVs and smart turnover cabinets during the approach stage or cargo handover process.

[0112] When the electromagnetic interference intensity value is greater than the preset electromagnetic interference threshold, or the signal received power value is less than the preset lower limit threshold for signal received power, or the signal-to-noise ratio is less than the preset lower limit threshold for signal-to-noise ratio, the current interference level is determined to be a high-level interference level. At this time, the channel has adverse factors such as strong electromagnetic interference, severe signal attenuation, or severe degradation of signal-to-noise ratio, and a low-order modulation and coding scheme is selected. The low-order modulation and coding scheme is a modulation and coding scheme with a modulation order no higher than four-phase shift keying, with four-phase shift keying or two-phase shift keying as typical representatives. Each symbol can carry 2 bits or 1 bit of information. Its demodulation threshold is low, and it has high noise and interference resistance capabilities. It is used to ensure that key commands such as hatch opening command and hovering positioning signal can still be reliably transmitted with an extremely low bit error rate in weak signal and strong interference environments.

[0113] When the electromagnetic interference intensity is less than or equal to the preset electromagnetic interference threshold, but the received signal power is less than the preset lower limit of received signal power or the signal-to-noise ratio is less than the preset lower limit of signal-to-noise ratio, the current interference level is determined to be medium-level interference. At this time, the channel state is between clean and bad, and a medium-order modulation and coding scheme is selected. The medium-order modulation and coding scheme is a modulation and coding scheme with a modulation order between quadrature phase shift keying and 16 quadrature amplitude modulation. 8-phase shift keying or low-code-rate 16 quadrature amplitude modulation are typical examples. Each symbol can carry 3 bits of information, achieving a balance between spectral efficiency and anti-interference capability. It is used to adapt to channel fluctuations in medium-level interference environments, avoid frequent switching of modulation and coding schemes caused by small fluctuations in channel state, and reduce the probability of link oscillation.

[0114] In this embodiment, the specific values ​​and modulation coding scheme selections mentioned above are preferred examples of this embodiment and are not intended to limit the present invention. In other embodiments, the preset electromagnetic interference threshold, preset signal receiving power lower limit threshold, and preset signal-to-noise ratio lower limit threshold can be adaptively adjusted by those skilled in the art based on specific simulation experiments, according to the actual modulation coding scheme used in the bidirectional communication link, the receiver sensitivity of the intelligent turnover cabinet, and the actual electromagnetic background noise level of the working environment.

[0115] To further clarify, in this embodiment, the low-power setting corresponds to a transmit power value of 10dBm, the medium-power setting corresponds to a transmit power value of 20dBm, and the high-power setting corresponds to a transmit power value of 30dBm. The principle and basis for the graded transmission power setting in this embodiment is based on the balance between link budget, energy consumption control, and electromagnetic compatibility. When the UAV has flown to the near-field area of ​​the smart turnover cabinet and the real-time straight-line distance is less than or equal to the second preset distance threshold, and the channel is at a low interference level, the low-power setting, i.e., 10dBm corresponding to 10mW of transmit power, is adopted. This power level is sufficient to maintain reliable communication under good channel conditions at close range, which can effectively reduce the UAV's energy consumption to extend its flight time and reduce electromagnetic radiation interference to surrounding equipment, meeting the electromagnetic compatibility requirements of outdoor multi-device coexistence scenarios. When the drone is in the approach phase (i.e., the real-time straight-line distance is greater than the second preset distance threshold but less than or equal to the first preset distance threshold), or when the channel is at a medium interference level, the medium power setting (20dBm corresponding to 100mW of transmit power) is used. This power value is the typical operating power of civilian drone data radios, providing approximately 10 to 20 dB of link margin. It can penetrate general building obstructions or overcome moderate-intensity co-channel interference, achieving a common trade-off between transmission rate and communication reliability. When the electromagnetic interference intensity exceeds the preset electromagnetic interference threshold or the signal-to-noise ratio is severely degraded, the high power setting (30dBm corresponding to 1W of transmit power) is used. This power value is the legal power limit for civilian communication equipment in some countries and regions. Theoretically, every 6 dB increase in transmit power can double the effective communication distance or increase the anti-interference margin by approximately 6 dB. This ensures uninterrupted link transmission even under extreme conditions such as proximity to high-voltage towers, severe weather, or severe signal attenuation, guaranteeing reliable transmission of critical commands such as door opening commands and hovering positioning signals. Through the above-mentioned hierarchical settings, adaptive matching between transmission power and channel status is achieved, ensuring communication reliability while taking into account energy consumption optimization and electromagnetic compatibility requirements.

[0116] S55. Configure a bidirectional communication link based on the selected modulation and coding scheme and transmit power level, and continuously monitor the current packet loss rate L_loss and retransmission count N_retrans at a preset period. Further, in this embodiment, the preset period is 100ms to 500ms, the first preset packet loss threshold L_th1 is 5%, and the first preset retransmission count threshold N_th1 is 3 times. In this embodiment, in the scenario of collaborative operation between a drone and a smart turnover cabinet, the communication link needs to balance real-time performance, reliability, and anti-interference capability. The preset period is set to 100ms to 500ms because a period that is too short will cause the system to frequently collect link status parameters, increasing communication overhead and processing burden, and is prone to misjudgment due to instantaneous fluctuations; a period that is too long will fail to detect link degradation in a timely manner, especially in the second stage when the drone approaches the cabinet or performs cargo handover, where sudden changes in link status may lead to the loss of critical instructions; a period of 100ms to 500ms can balance the millisecond-level response requirements and system overhead, and effectively filter short-term interference, ensuring the stability and timeliness of link monitoring. The first preset packet loss threshold L_th1 is set to 5%. This is based on the fact that in complex outdoor electromagnetic environments, it's difficult for wireless communication links to achieve zero packet loss. A 5% packet loss rate is a generally accepted critical value in engineering; below this value, the link is considered basically stable, while above it indicates that interference has significantly affected communication quality, requiring the triggering of a link adjustment mechanism. The first preset retransmission threshold N_th1 is set to 3 times. This is based on the fact that while retransmission is an important means of ensuring reliability, excessive retransmissions can introduce latency accumulation. For time-sensitive commands such as door opening and hovering, three consecutive retransmission failures mean the link has severely degraded or is interrupted. Continuing to wait for retransmissions will delay cargo handover. In this case, higher-level link compensation measures such as frequency band reselection or power boosting should be decisively triggered. The combination of these parameters enables accurate monitoring and timely response to the link status, avoiding excessive adjustments while ensuring reliability, and meeting the dual requirements of timeliness and robustness for collaborative operation between UAVs and intelligent turnover cabinets.

[0117] S56. Determine whether the current packet loss rate L_loss is greater than the first preset packet loss threshold L_th1, or whether the number of retransmissions N_retrans is greater than the first preset retransmission number threshold N_th1. If L_loss>L_th1 or N_retrans>N_th1, then proceed to step S57; If L_loss≤L_th1 and N_retrans≤N_th1, then maintain the current configuration; S57. Increase the current interference level by one level and return to step S54 to reselect the modulation and coding scheme and transmit power level. Specifically: if the current interference level is low, increase it to medium interference level; if the current interference level is medium interference level, increase it to high interference level; if the current interference level is high interference level, maintain the high interference level and trigger a link anomaly alarm. Further, this embodiment combines a gradual principle of link adaptive adjustment with a system fault tolerance mechanism. When the packet loss rate L_loss is greater than the first preset packet loss threshold L_th1 or the retransmission count N_retrans is greater than the first preset retransmission count threshold N_th1, it indicates that the current combination of modulation and coding scheme and transmit power level under the current interference level can no longer guarantee reliable communication and needs to be adjusted towards a higher anti-interference capability. Using a step-by-step increase rather than a jump across levels avoids link oscillations or over-adjustment caused by sudden parameter changes, enabling the system to smoothly transition in an environment of gradually changing interference intensity and ensuring the stability of the communication link. When the current interference level is low, it is upgraded to medium level. The modulation and coding scheme is downgraded from mid-high order to medium order, and the transmit power is increased from low to medium level. This sacrifices some transmission rate to achieve a moderate improvement in anti-interference capability. When the current interference level is medium, it is upgraded to high level. The modulation and coding scheme is further downgraded to low order, and the transmit power is increased to high level to ensure the reliable transmission of critical commands to the greatest extent. When the current interference level has reached high level and the link quality still cannot meet the requirements, it indicates that simply relying on modulation and coding and power adjustment is insufficient to compensate for the extremely harsh channel environment. At this time, maintaining the high interference level and triggering a link anomaly alarm can avoid ineffective repeated adjustments that would waste resources and cause response delays. At the same time, the abnormal status is reported to the flight control system or ground dispatch system in a timely manner, providing a basis for decision-making for subsequent frequency band reselection, mission abortion, or manual intervention. Thus, while ensuring communication reliability, the rational allocation of system resources and rapid identification of abnormal status are achieved.

[0118] S6. Determine whether the packet loss rate is greater than the first preset packet loss threshold or whether the number of retransmissions is greater than the first preset retransmission number threshold. S61. If so, then reselect the communication frequency band based on the interference parameters, and rebuild the bidirectional communication link based on the reselected communication frequency band. Please refer to [link to relevant documentation]. Figure 3 Specifically, it includes: S611. When it is determined that the packet loss rate L_loss is greater than the first preset packet loss threshold L_th1 or the number of retransmissions N_retrans is greater than the first preset retransmission number threshold N_th1, the current flight phase identifier Phase_current is obtained. The flight phase identifier includes the first phase identifier Phase_1 and the second phase identifier Phase_2. The first phase identifier Phase_1 corresponds to the state where the real-time straight distance D is greater than the second preset distance threshold D2 and less than or equal to the first preset distance threshold D1. The second phase identifier Phase_2 corresponds to the state where the real-time straight distance D is less than or equal to the second preset distance threshold D2. S612. Determine whether the current flight phase identifier Phase_current is the second phase identifier Phase_2; If Phase_current is Phase_2, the frequency band reselection operation is delayed, and a delay timer T_delay is started. Step S613 is executed only after the real-time straight-line distance D is greater than the second preset distance threshold D2 or after the timer T_delay times out. In this embodiment, the delay timer T_delay is specifically configured as follows: the duration of the delay timer T_delay is determined based on the longest time required for the UAV to complete the cargo handover action in the second stage of scheduling. This ensures that after the delay timer T_delay times out, the frequency band reselection operation can be executed in a timely manner regardless of whether the UAV has moved away from the smart turnover cabinet. This avoids continuous degradation of link quality and inability to restore communication due to indefinitely waiting for the real-time straight-line distance to be greater than the second preset distance threshold. For example, in this embodiment, the duration of the delay timer T_delay is 10 seconds. This value is greater than the longest time required for the UAV to complete the handover from entering the second stage in the normal cargo handover process. This is used to set an overtime protection limit for link recovery while ensuring the continuity of communication during the cargo handover process. When the real-time straight-line distance is greater than the second preset distance threshold before the delay timer T_delay expires, it indicates that the UAV has safely moved away and the frequency band reselection operation can be safely performed. When the delay timer T_delay expires and the real-time straight-line distance is still less than or equal to the second preset distance threshold, it indicates that the UAV's dwell time in the second stage is abnormal. At this time, the frequency band reselection operation is forcibly performed to prioritize the restoration of communication quality and avoid the continued deterioration of link quality.

[0119] In this embodiment, the specific values ​​mentioned above are preferred examples and are not intended to limit the invention. In other embodiments, the duration of the delay timer T_delay can be adaptively adjusted by those skilled in the art based on specific simulation experiments, according to the longest actual cargo handover process and the system's requirements for communication recovery timeliness.

[0120] If Phase_current is Phase_1, then proceed to step S613 immediately; S613. Obtain the preset list of available frequency bands F_list={F1,F2,F3}, where F1 is the 2.4GHz band, F2 is the 5.8GHz band, and F3 is the 4G cellular band; S614. For each candidate frequency band Fi in the available frequency band list F_list, perform the following quality evaluation operation in sequence: S6141. Temporarily switch the current bidirectional communication link to candidate frequency band Fi, and continuously send N_probe link quality probe frames on candidate frequency band Fi, where N_probe is the preset number of probes. In this embodiment, the preset number of probes is specifically configured as follows: the preset number of probes is configured to be the number of probe frames sent that balances the statistical confidence level of candidate frequency band quality assessment with the time overhead of assessment operation. The value of the preset number of probes must meet two constraints: First, the preset number of probes is large enough so that the statistical results of the measured average received power, measured average signal-to-noise ratio, and measured average round-trip delay of the candidate frequency band can effectively filter out the instantaneous random fluctuations of the channel and truly reflect the steady-state channel quality of the candidate frequency band at the current moment. Second, the preset number of probes is small enough so that the total time for completing the quality assessment operation for all candidate frequency bands in sequence does not exceed the maximum assessment time allowed by the frequency band reselection operation, avoiding delays in the timely reconstruction of the bidirectional communication link due to excessive assessment operation time. For example, in this embodiment, the preset number of detections is 10. This value has been verified by engineering tests and can complete the quality assessment of a single candidate frequency band within 100 milliseconds under typical outdoor electromagnetic conditions, while ensuring that the deviation between the measured statistical results and the long-term steady-state measurement results does not exceed the preset evaluation error tolerance. The above specific values ​​are preferred examples of this embodiment and are not intended to limit the invention. In other embodiments, the preset number of detections can be adaptively adjusted by those skilled in the art based on specific simulation experiments, according to the number of candidate frequency bands in the available frequency band list, the response time of the communication module switching frequency bands in the bidirectional communication link, and the maximum evaluation time allowed for the frequency band reselection operation.

[0121] S6142. Receive the link quality feedback information returned from candidate frequency band Fi, and calculate the measured average received power RSSI_avg_i, the measured average signal-to-noise ratio SNR_avg_i, and the measured average round-trip time RTT_avg_i of candidate frequency band Fi. In this embodiment, the specific method for calculating the measured average received power, measured average signal-to-noise ratio, and measured average round-trip time of the candidate frequency band is configured as follows: after continuously sending a preset number of link quality detection frames on the candidate frequency band, receive the link quality feedback information returned by the intelligent turnover cabinet for each link quality detection frame. Each link quality feedback information includes at least... This includes the instantaneous values ​​of received signal power, signal-to-noise ratio (SNR), and round-trip time (RTD) corresponding to each detection. The instantaneous values ​​of received signal power from each of the preset number of detections are arithmetically averaged, and this arithmetic mean is determined as the average measured received signal power for the candidate frequency band. Similarly, the instantaneous values ​​of SNR from each of the preset number of detections are arithmetically averaged, and this arithmetic mean is determined as the average measured RTD for the candidate frequency band. The instantaneous RTD corresponding to successfully received link quality feedback information during the preset number of detections is arithmetically averaged, and this arithmetic mean is determined as the average measured RTD for the candidate frequency band. Arithmetic averaging is used to statistically process the results of multiple detections to filter out the influence of instantaneous random fluctuations in the channel on single measurements, ensuring that the average measured received signal power, average measured SNR, and average measured RTD accurately reflect the steady-state channel quality of the candidate frequency band at the current moment.

[0122] S6143. Calculate the comprehensive quality score Q_i of candidate frequency band Fi according to the preset frequency band quality scoring formula, where Fi represents the i-th candidate frequency band; Q_i=(RSSI_avg_i / RSSI_max)×0.4+(SNR_avg_i / SNR_max)×0.4+(1-RTT_avg_i / RTT_max)×0.2; Where RSSI_max is the preset maximum signal received power, SNR_max is the preset maximum signal-to-noise ratio, and RTT_max is the preset maximum round-trip time delay. In this embodiment, the weights of 0.4 for the signal received power and SNR scores, and 0.2 for the round-trip time score, are set as follows: Signal received power and SNR are core indicators for measuring the transmission quality of a two-way communication link. They jointly determine the upper limit of the data transmission rate and the bit error rate of the two-way communication link, and have a decisive impact on the reliable transmission of key instructions between the UAV and the smart turnover cabinet. Therefore, they are given a high weight in the comprehensive quality score. Round-trip time delay reflects the real-time response of the two-way communication link. Its fluctuation has a relatively small impact on the overall availability of the link. Therefore, it is given a low weight in the comprehensive quality score. The weights of 0.4, 0.4, and 0.2 are a set of normalized weight values, and the sum of the three is 1. This is used to ensure that the weighted contribution of each score item to the comprehensive quality score can be directly quantified.

[0123] In this embodiment, the preset maximum signal received power, preset maximum signal-to-noise ratio, and preset maximum round-trip delay are set as follows: the preset maximum signal received power is configured as the maximum input signal received power that the receiver of the intelligent turnover cabinet can stably operate under the current hardware platform, and is exemplarily set to -20 milliwatt decibels in this embodiment; the preset maximum signal-to-noise ratio is configured as the saturation signal-to-noise ratio corresponding to the highest modulation and coding scheme that the bidirectional communication link can utilize under the current communication system, and is exemplarily set to 30 decibels in this embodiment; the preset maximum round-trip delay is configured as the upper limit of the round-trip delay that the bidirectional communication link can guarantee the normal execution of the phased linkage scheduling strategy on the current candidate frequency band, and is exemplarily set to 100 milliseconds in this embodiment; by dividing the average measured signal received power, the average measured signal-to-noise ratio, and the average measured round-trip delay by their respective preset maximum values, the dimensions of the three scoring items are normalized, and the values ​​of each scoring item are mapped to the range of 0 to 1, which is used to eliminate the incomparability of different dimension parameters in the comprehensive quality score.

[0124] In this embodiment, the specific values ​​and weight allocations mentioned above are preferred examples of this embodiment and are not intended to limit the present invention. In other embodiments, the weight allocation, preset maximum signal receiving power, preset maximum signal-to-noise ratio, and preset maximum round-trip delay can be adaptively adjusted by those skilled in the art based on specific simulation experiments, according to the actual communication system of the bidirectional communication link, the receiver hardware characteristics of the intelligent turnover cabinet, and the sensitivity of the phased linkage scheduling strategy to real-time performance.

[0125] S6144. Record the candidate frequency band Fi and its comprehensive quality score Q_i into the frequency band evaluation result table; S615. Traverse the frequency band evaluation result table and select the candidate frequency band with the highest comprehensive quality score Q_i as the target frequency band F_target; if there are multiple candidate frequency bands with the same Q_i and all of them are the highest, then the current working frequency band shall be selected first. S616. Before switching frequency bands, save the context status information of the current communication link. The context status information includes at least the current door opening / closing status value Door_status and the current hovering positioning accuracy value Pos_accuracy. The door opening / closing status value Door_status includes three states: closed, pre-opening, and fully opened. The hovering positioning accuracy value Pos_accuracy is the maximum value among the lateral deviation, longitudinal deviation, height deviation, and attitude angle deviation in the current real-time relative pose deviation. S617. Switch the bidirectional communication link from the current operating frequency band to the target frequency band F_target, and rebuild the bidirectional communication link based on the target frequency band F_target; S618. On the reconstructed two-way communication link, synchronize the door opening / closing status value Door_status and the hovering positioning accuracy value Pos_accuracy to both the UAV and the smart turnover cabinet, and restore the communication link status. S619. On the reconstructed bidirectional communication link, the modulation and coding scheme is reset to the preset default modulation and coding scheme MCS_default, the transmit power level is reset to the preset default transmit power level PWR_default, and the process returns to the step of dynamically adjusting the modulation and coding scheme and transmit power level. In this embodiment, the setting rule for the preset default modulation and coding scheme is as follows: obtain the set of all modulation and coding schemes supported by the bidirectional communication link, select the basic modulation and coding scheme used by the standard link establishment mode from the set of all modulation and coding schemes, and determine the selection result as the preset default modulation and coding scheme. The preset default modulation and coding scheme includes at least modulation mode parameters and channel coding mode parameters. The modulation mode parameters are used to determine the symbol mapping method used by the bidirectional communication link when transmitting data on the newly established frequency band, and the channel coding mode parameters are used to determine the forward error correction coding method and its code rate used by the bidirectional communication link when transmitting data on the newly established frequency band. For example, in this embodiment, the basic modulation and coding scheme adopted by the standard link establishment mode is quadrature phase shift keying modulation and convolutional coding with a coding rate of one-half. Therefore, the preset default modulation and coding scheme is quadrature phase shift keying and convolutional coding with a coding rate of one-half.

[0126] In this embodiment, the preset default transmit power level is set as follows: the default initial transmit power value in the standard link establishment mode is obtained, and the obtained result is determined as the preset default transmit power level. The preset default transmit power level includes at least a transmit power value parameter and a power spectral density parameter. The transmit power value parameter is used to determine the total transmit power of the radio frequency front-end of the UAV onboard communication module in the newly established frequency band, and the power spectral density parameter is used to determine the transmit power distribution per unit bandwidth. For example, in this embodiment, the default initial transmit power in the standard link establishment mode is 10 milliwatts, corresponding to a power spectral density of 10 milliwatts per megahertz. Therefore, the preset default transmit power level is set to a transmit power of 10 milliwatts and a power spectral density of 10 milliwatts per megahertz.

[0127] In this embodiment, the specific values ​​and modulation coding schemes described above are preferred examples of this embodiment and are not intended to limit the present invention. In other embodiments, the modulation method and channel coding method included in the preset default modulation coding scheme, as well as the transmission power value and power spectral density value included in the preset default transmission power level, can be adaptively adjusted according to the set of all modulation coding schemes supported by the bidirectional communication link and the transmission capability of the UAV's onboard communication module.

[0128] In this embodiment, the triggering conditions and execution logic of the frequency band reselection and link reconstruction process are specifically configured as follows: when the detected packet loss rate is greater than the first preset packet loss threshold or the number of retransmissions is greater than the first preset retransmission number threshold, the frequency band reselection and link reconstruction process is triggered. The first preset packet loss threshold and the first preset retransmission number threshold are set based on the following: the first preset packet loss threshold is configured as the maximum allowable packet loss rate that the bidirectional communication link can guarantee the reliable transmission of key instructions in the phased linkage scheduling strategy. Exceeding this packet loss rate will cause the transmission success rate of key instructions such as the hatch opening command or hovering positioning signal to be lower than the preset safety threshold. For example, in this embodiment, the first preset packet loss threshold is set to 5%. The first preset retransmission number threshold is configured as the maximum number of retransmissions allowed for a single instruction transmission in the bidirectional communication link. Exceeding this number of retransmissions will cause the cumulative delay of instruction transmission to exceed the upper limit of the delay that can be tolerated in a single scheduling cycle in the phased linkage scheduling strategy. For example, in this embodiment, the first preset retransmission number threshold is set to 3 times.

[0129] In this embodiment, after triggering the frequency band reselection and link reconstruction process, the current flight stage identifier is first obtained: if the current flight stage identifier is the second stage identifier, that is, the UAV has entered the critical stage of close-range cargo handover, the frequency band reselection operation is delayed and a delay timer is started. The frequency band reselection operation is then performed after the real-time straight-line distance is greater than the second preset distance threshold or the delay timer expires; if the current flight stage identifier is the first stage identifier, that is, the UAV is in the long-distance approach stage, the frequency band reselection operation is performed immediately. The fundamental reason for the above-mentioned phased delayed reselection strategy is that the second stage is the core window for door opening, hovering and positioning, and cargo delivery or retrieval. At this time, the two-way communication link carries critical instructions that cannot be interrupted. If the frequency band is switched rashly, it will cause the link to be interrupted momentarily, the handshake reconnection will take a long time, the hovering signal may be lost or the abnormal protection may be triggered, resulting in handover failure or even collision accident; while the first stage has a longer distance and more time, and timely reselection can eliminate link risks in advance.

[0130] In the frequency band reselection operation, a preset list of available frequency bands is obtained, and a quality assessment operation is performed sequentially for each candidate frequency band in the list: the current bidirectional communication link is temporarily switched to the candidate frequency band, and a preset number of link quality probe frames are continuously sent on the candidate frequency band. The link quality feedback information returned from the candidate frequency band is received, and the average measured signal received power, average measured signal-to-noise ratio, and average measured round-trip delay of the candidate frequency band are calculated. Based on the average measured signal received power, average measured signal-to-noise ratio, and average measured round-trip delay, combined with a preset frequency band quality scoring formula, a comprehensive quality score for the candidate frequency band is calculated. The candidate frequency band with the highest comprehensive quality score is selected as the target frequency band. If multiple candidate frequency bands have the same and the highest comprehensive quality score, the current working frequency band is selected first to avoid invalid switching. This active detection and weighted scoring mechanism replaces the traditional passive monitoring or random frequency hopping method, which can accurately identify the optimal frequency band in the current environment and avoid selecting the wrong frequency band due to instantaneous fluctuations or misleading single indicators.

[0131] Before frequency band switching, the context state information of the current communication link is saved. The context state information includes at least the current hatch opening / closing status value and the current hovering positioning accuracy value. The two-way communication link is switched from the current operating frequency band to the target frequency band, and the two-way communication link is rebuilt based on the target frequency band. On the rebuilt two-way communication link, the hatch opening / closing status value and the hovering positioning accuracy value are synchronized to both the UAV and the smart turnover cabinet to restore the communication link status, thereby avoiding additional delays caused by status loss or re-query due to link reconstruction. After the switch is completed, the modulation and coding scheme is reset to the preset default modulation and coding scheme, the transmit power level is reset to the preset default transmit power level, and the process returns to the step of dynamically adjusting the modulation and coding scheme and transmit power level. The purpose is to clear the aggressive parameters left over from the previous frequency band and re-adapt the channel conditions on the new frequency band with a conservative standard starting point, preventing excessive conservatism or excessive aggressiveness.

[0132] In this embodiment, the beneficial effects of the frequency band reselection and link reconstruction process are as follows: The flight-phase-aware delay reselection strategy ensures communication continuity and command reliability during critical cargo handover stages; proactive detection and weighted scoring achieve precise selection of the optimal frequency band, improving link quality; context state saving and recovery reduces switching overhead and the risk of state asynchrony; and parameter reset ensures smooth adaptation to the new frequency band. Compared to the existing coarse-grained frequency band switching methods that passively trigger based solely on packet loss rate, disregard flight phases, indiscriminately switch immediately, do not save context, and do not perform proactive quality assessments, this application significantly improves the anti-interference capability, handover security, and collaborative continuity of communication between logistics drones and intelligent turnover cabinets in complex outdoor environments, effectively avoiding the loss of critical commands or operational interruptions due to improper frequency band switching.

[0133] In this embodiment, the specific values ​​and threshold settings mentioned above are preferred examples of this embodiment and are not intended to limit the present invention. In other embodiments, the first preset packet loss threshold, the first preset retransmission number threshold, and the timing duration of the delay timer can be adaptively adjusted by those skilled in the art based on specific simulation experiments, according to the specific requirements of the phased linkage scheduling strategy for the reliability and delay of instruction transmission, the actual communication system of the two-way communication link, and the operating environment characteristics of the UAV and the intelligent turnover cabinet.

[0134] The core of the frequency band reselection and link reconstruction strategy in this embodiment lies in the following: when the packet loss rate or retransmission count exceeds the limit, the decision on whether to immediately perform reselection is made based on the current flight phase. That is, in the second phase of close-range cargo handover, it is preferable to tolerate temporary channel degradation rather than interrupt the link, because any momentary communication interruption caused by frequency band switching at this time may result in the loss of hovering positioning signals or door status feedback, thereby causing cargo collision or handover failure. In the first phase of long-distance approach, there is ample time and latency is not a major concern, so immediate reselection can eliminate potential link risks in advance and prevent degradation from accumulating to the critical stage. This phase-aware delay reselection mechanism fundamentally ensures the communication continuity and command reliability of the core cargo handover window. Upon determining the need for reselection, this application does not employ a passive approach of waiting for packet loss or random frequency hopping. Instead, it proactively switches the link temporarily to various candidate frequency bands, continuously transmitting probe frames to measure the average received signal power, average signal-to-noise ratio, and average round-trip time for each band. Then, a weighted scoring method is used to accurately evaluate the overall quality of each band, selecting the optimal band while retaining the current band simultaneously to avoid invalid oscillations. This proactive detection and weighted scoring method accurately reflects the steady-state performance of each frequency band under the current electromagnetic environment, avoiding misjudgments caused by instantaneous fluctuations or single indicators. Before switching, the hatch opening / closing status and hovering positioning accuracy are saved and immediately restored after switching, eliminating state loss or re-query delays caused by link reconstruction. Simultaneously, the modulation coding and transmit power are reset to default values, and dynamic adjustments are restarted on the new frequency band, preventing aggressive parameters left over from the previous band from causing interference or efficiency loss on the new band. Compared to the simple strategies in existing technologies that rely solely on passive triggering based on packet loss thresholds, immediate switching without phase differentiation, lack of active detection, failure to save context, and failure to reset parameters, this application significantly improves the accuracy of link reselection in complex electromagnetic environments, the security of the handover phase, and the adaptation efficiency after reconstruction through flight phase-aware delay protection, multi-dimensional active detection scoring, state synchronization recovery, and parameter reset mechanisms. It completely avoids command loss, state disorder, and coordination interruption caused by blind or improper frequency band switching.

[0135] S7. During the second phase of scheduling and execution, continuously monitor the opening and closing status of the smart turnover cabinet door and the hovering positioning accuracy of the UAV. In this embodiment, the setting method of the preset accuracy threshold is specifically configured as follows: the preset accuracy threshold is used to define whether the hovering positioning accuracy of the UAV meets the upper limit of the spatial position deviation required to perform the cargo handover action. When the hovering positioning accuracy is greater than the preset accuracy threshold, it indicates that the deviation of the current actual spatial position of the UAV relative to the target hovering point has exceeded the allowable range. If the cargo delivery or retrieval action is forcibly performed, there is a risk that the cargo will collide with the edge of the smart turnover cabinet door.

[0136] In this embodiment, the specific value of the preset accuracy threshold is determined based on the size of the smart turnover cabinet door opening and the maximum cross-sectional size of the goods. The setting basis is: the preset accuracy threshold is configured to be no greater than half the difference between the minimum side length of the door opening and the maximum cross-sectional side length of the goods, so as to ensure that when the position deviation of the UAV in the horizontal, vertical and vertical directions does not exceed the preset accuracy threshold, a preset safety gap is maintained between the goods and any edge of the door opening during the delivery or retrieval process.

[0137] For example, in this embodiment, the door opening of the intelligent turnover cabinet is a square opening with a side length of 0.5 meters, and the maximum cross-section of the cargo is a square cross-section with a side length of 0.3 meters. Therefore, the difference between the minimum side length of the door opening and the maximum cross-section of the cargo is 0.2 meters, and half of this difference is 0.1 meters. Accordingly, the preset accuracy threshold is configured to 0.1 meters. When the maximum value of the position deviation of the UAV in the three directions of horizontal lateral, horizontal longitudinal, and vertical height does not exceed 0.1 meters, it is determined that the hovering positioning accuracy meets the requirements. At least a safety gap of 0.1 meters is maintained between the outer edge of the cargo and any edge of the door opening. At this time, a cargo handover permission signal is generated, triggering the cargo delivery or retrieval action.

[0138] In this embodiment, the specific values ​​mentioned above are preferred examples and are not intended to limit the invention. In other embodiments, the preset accuracy threshold can be adaptively adjusted by those skilled in the art based on specific simulation experiments, according to the actual door opening size of the intelligent turnover cabinet, the actual external dimensions of the goods, and the safety clearance required for the handover of goods.

[0139] S71. When the hatch is in the open position and the hovering positioning accuracy is greater than the preset accuracy threshold, a cargo handover permission signal is generated and sent to the drone and the smart turnover cabinet respectively to trigger the cargo delivery or retrieval action.

[0140] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments under the guidance of the present invention without departing from the spirit and scope of the claims. All of these variations are within the protection scope of the present invention.

[0141] If the technical solution disclosed herein involves personal information, the product using this technical solution has clearly informed the user of the personal information processing rules and obtained the user's voluntary consent before processing the personal information. If the technical solution disclosed herein involves sensitive personal information, the product using this technical solution has obtained the user's separate consent before processing the sensitive personal information, and also meets the requirement of explicit consent. For example, at personal information collection devices such as cameras, clear and prominent signs are set up to inform users that they have entered the scope of personal information collection and that personal information will be collected. If an individual voluntarily enters the collection scope, it is deemed that they have agreed to the collection of their personal information; or on the personal information processing device, with clear signs / information informing users of the personal information processing rules, authorization is obtained from the individual through pop-up information or by asking the individual to upload their personal information; wherein, the personal information processing rules may include information such as the personal information processor, the purpose of personal information processing, the processing method, and the types of personal information processed.

Claims

1. A communication and linkage scheduling method for logistics drones and intelligent turnover cabinets, characterized in that, include: The real-time flight location information of the drone and the preset location information of the smart turnover cabinet are obtained, and the real-time straight-line distance between the drone and the smart turnover cabinet is calculated. Determine whether the real-time straight-line distance is less than or equal to a first preset distance threshold. If so, establish a two-way communication link between the drone and the smart turnover cabinet, and obtain the real-time status data of the smart turnover cabinet, specifically: S211. Obtain the real-time straight-line distance D and the real-time flight speed vector of the UAV at the current moment. Calculate the radial relative approach speed between the drone and the smart turnover cabinet. ,in The position vector of the drone pointing towards the smart turnover cabinet; The modulo symbol; S212. Determine whether the real-time straight-line distance D is less than or equal to the first preset distance threshold D. th ; If not, continue to wait and periodically check the distance; If so, then determine the radial relative approach velocity. Is it greater than the preset speed threshold? ; The real-time status data includes the hatch opening and closing status, the cargo receiving mechanism position status, and the cabinet communication quality indicator parameters. Based on the distance range of the real-time straight-line distance, a phased linkage scheduling strategy is executed. When the real-time straight-line distance is within the first distance range, the first phase of scheduling is executed, and an approach warning signal is sent to the intelligent turnover cabinet. When the real-time straight-line distance is within the second distance range, the second phase of scheduling is executed, and a door opening command is sent to the intelligent turnover cabinet. After confirming that the door is open in place based on the real-time status data, a hovering positioning signal is sent to the UAV. The first distance range is greater than a second preset distance threshold and less than or equal to the first preset distance threshold, and the second distance range is less than or equal to the second preset distance threshold. During the coordinated scheduling process, interference parameters of the current working environment are collected in real time; The modulation and coding scheme and transmission power of the bidirectional communication link are dynamically adjusted according to the interference parameters, and the packet loss rate and retransmission count of the current communication link are recorded. When the packet loss rate exceeds a first preset packet loss threshold or the number of retransmissions exceeds a first preset retransmission number threshold, the communication frequency band is reselected and the bidirectional communication link is rebuilt, specifically as follows: S611. When it is determined that the packet loss rate L_loss is greater than the first preset packet loss threshold L_th1 or the retransmission count N_retrans is greater than the first preset retransmission count threshold N_th1, the current flight phase identifier Phase_current is obtained. The flight phase identifier includes a first phase identifier Phase_1 and a second phase identifier Phase_2. The first phase identifier Phase_1 corresponds to the state where the real-time straight-line distance D is greater than the second preset distance threshold D2 and less than or equal to the first preset distance threshold D1. The second phase identifier Phase_2 corresponds to the state where the real-time straight-line distance D is less than or equal to the second preset distance threshold D2. S612. Determine whether the current flight phase identifier Phase_current is the second phase identifier Phase_2; If Phase_current is Phase_2, the frequency band reselection operation is delayed, and a delay timer T_delay is started. Step S613 is executed after the real-time straight-line distance D is greater than the second preset distance threshold D2 or after the timer T_delay times out. If Phase_current is Phase_1, then proceed to step S613 immediately; S613. Obtain the preset list of available frequency bands.

2. The communication and coordination scheduling method between logistics drones and intelligent turnover cabinets as described in claim 1, characterized in that, The communication linkage scheduling method further includes: During the execution of the second-stage scheduling, continuously monitor the opening and closing state of the hatch of the intelligent turnover cabinet and the hovering positioning accuracy of the UAV. When the opening and closing state of the hatch is fully opened and the hovering positioning accuracy is greater than the preset accuracy threshold, generate a goods transfer permission signal.

3. The communication and coordination scheduling method between logistics drones and intelligent turnover cabinets as described in claim 2, characterized in that, The dynamic adjustment of the modulation coding method and transmission power of the bidirectional communication link includes: S51. Real-time collect the interference parameters of the current operating environment, where the interference parameters include the electromagnetic interference intensity value E, the signal reception power value P_rx, and the signal-to-noise ratio SNR; S52. Determine whether the electromagnetic interference intensity value E is greater than the preset electromagnetic interference threshold E_th; If E > E_th, directly determine that the current interference level is the high interference level, and execute step S54; If E ≤ E_th, execute step S53; S53. Determine whether the signal reception power value P_rx is less than the preset signal reception power lower threshold P_min, or whether the signal-to-noise ratio SNR is less than the preset signal-to-noise ratio lower threshold SNR_min; If P_rx < P_min or SNR < SNR_min, determine that the current interference level is the medium interference level; If P_rx ≥ P_min and SNR ≥ SNR_min, determine that the current interference level is the low interference level.

4. The communication and linkage scheduling method between logistics drones and intelligent turnover cabinets as described in claim 3, characterized in that, The dynamic adjustment of the modulation coding method and transmission power of the bidirectional communication link includes: S54. According to the current interference level, match the corresponding modulation coding scheme and transmission power level from the preset interference level mapping table; S55. Configure the bidirectional communication link based on the selected modulation coding scheme and transmission power level, and continuously monitor the current packet loss rate L_loss and the number of retransmissions N_retrans at a preset period; S56. Determine whether the current packet loss rate L_loss is greater than the first preset packet loss threshold L_th1, or whether the number of retransmissions N_retrans is greater than the first preset number of retransmissions threshold N_th1; If L_loss > L_th1 or N_retrans > N_th1, execute step S57; If L_loss ≤ L_th1 and N_retrans ≤ N_th1, maintain the current configuration; S57. Upgrade the current interference level by one level, and return to step S54 to reselect the modulation coding scheme and transmission power level.

5. The communication and linkage scheduling method between logistics drones and intelligent turnover cabinets as described in claim 4, characterized in that, The reselecting the communication frequency band and reconstructing the bidirectional communication link further includes: S614. For each candidate frequency band in the available frequency band list F_list, sequentially perform a quality assessment operation, specifically: S6141. Temporarily switch the current bidirectional communication link to the candidate frequency band, and continuously send N_probe link quality detection frames on the candidate frequency band, where N_probe is the preset detection number; S6142. Receive the link quality feedback information returned under the candidate frequency band, and calculate the average measured signal reception power, the average measured signal-to-noise ratio, and the average measured round-trip delay of the candidate frequency band; S6143. Calculate the comprehensive quality score of the candidate frequency band based on the average measured signal received power, the average measured signal-to-noise ratio, and the average measured round-trip delay, combined with the preset frequency band quality scoring formula. S6144. Record the candidate frequency bands and their comprehensive quality scores in the frequency band evaluation result table.

6. The communication and linkage scheduling method between logistics drones and intelligent turnover cabinets as described in claim 5, characterized in that, The process of reselecting the communication frequency band and rebuilding the bidirectional communication link further includes: S615. Traverse the frequency band evaluation result table and select the candidate frequency band with the highest comprehensive quality score as the target frequency band F_target; if there are multiple candidate frequency bands with the same comprehensive quality score and all of them are the highest, then the current working frequency band shall be selected first. S616. Before switching frequency bands, save the context state information of the current communication link, the context state information including the current door opening / closing state value and the current hovering positioning accuracy value; S617. Switch the bidirectional communication link from the current operating frequency band to the target frequency band, and rebuild the bidirectional communication link based on the target frequency band; S618. On the reconstructed two-way communication link, the door opening / closing status value and hovering positioning accuracy value are synchronized to both the UAV and the smart turnover cabinet to restore the communication link status.

7. The communication and linkage scheduling method between logistics drones and intelligent turnover cabinets as described in claim 6, characterized in that, The establishment of a two-way communication link between the drone and the smart turnover cabinet also includes: like Greater than If the condition is met, the fast link establishment mode is triggered. In the fast link establishment mode, the maximum number of handshake retransmissions during the link establishment process is set to the first retransmission number threshold, the initial transmit power is set to the first initial transmit power value, and the handshake response waiting timer duration is set to the first waiting duration. The first retransmission number threshold is less than the default retransmission number in the standard link establishment mode, the first initial transmit power value is greater than the default initial transmit power in the standard link establishment mode, and the first waiting duration is less than the default waiting duration in the standard link establishment mode. like Less than or equal to If this is not the case, the standard link establishment mode will be triggered, using the default maximum number of handshake retransmissions, default initial transmit power, and default waiting time.

8. The communication and linkage scheduling method between logistics drones and intelligent turnover cabinets as described in claim 7, characterized in that, The establishment of a two-way communication link between the drone and the smart turnover cabinet includes: S213. During the link establishment process, the signal-to-noise ratio of the received first handshake response frame is collected in real time, and it is determined whether the signal-to-noise ratio is less than the preset handshake signal-to-noise ratio threshold. If it is less than, the current transmit power will be increased by a preset step value, and the handshake request frame will be resent. This process will be repeated until a valid handshake response frame is received or the maximum number of retransmissions in the current mode is reached. S214. After the link is successfully established, record the actual time taken for this link establishment, and determine whether the actual time taken is greater than the preset maximum allowed establishment time. If the value is greater than the specified value, a delay establishment flag is generated and set to a valid state. The delay establishment flag is then fed back to the phased linkage scheduling strategy to instruct the phased linkage scheduling strategy to send an approach warning signal one scheduling cycle in advance or to adjust the timing of sending the hatch opening command. If the actual time taken is less than or equal to the preset maximum allowable establishment time, the delayed establishment flag will be set to invalid, and the original scheduling sequence will remain unchanged.

9. The communication and linkage scheduling method between logistics drones and intelligent turnover cabinets as described in claim 8, characterized in that, After triggering the fast link establishment mode, the methods for determining the first retransmission count threshold, the first initial transmit power value, and the first waiting time include: when Greater than However, when the first speed limit is less than or equal to the first speed limit, the first retransmission number threshold is set to half of the default retransmission number in the standard link establishment mode, rounded down. The first initial transmit power value is set to the default initial transmit power value in the standard link establishment mode plus the first power increment. The first waiting time is set to half of the default waiting time in the standard link establishment mode. when When the speed exceeds the first speed limit, the first retransmission threshold is set to one, the first initial transmit power value is set to the default initial transmit power value in standard link establishment mode plus the second power increment, where the second power increment is greater than the first power increment, and the first waiting time is set to one-third of the default waiting time in standard link establishment mode. Among them, the first speed upper limit is greater than the preset speed threshold, and the first power increment and the second power increment are both preset positive values.

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