Method and system for locating personnel in a closed area based on wireless communication

Abstract

This invention belongs to the field of wireless communication network technology and discloses a method and system for personnel positioning in closed areas based on wireless communication. It involves collecting wide-area satellite differential positioning data streams and received signal strength sequences from local short-range wireless networks; calculating the standard deviation of the received signal strength sequences to generate a channel instability index; executing a dynamic weight allocation procedure based on the inverse variance principle; generating master-slave positioning source fusion weights based on satellite signal observation variance and the channel instability index; and applying weighted expansion of the satellite signal observation variance using the channel instability index when the satellite data is in a floating-point solution state. Finally, the fusion weights are used to perform weighted fusion of satellite and Bluetooth coordinates. This invention addresses the problem of inaccurate weight allocation for heterogeneous positioning source fusion under high multipath fading environments by introducing a nonlinear correction factor based on the channel instability index into the weight allocation, thus achieving adaptive optimization of positioning accuracy.

Description

Technical Field

[0001] This invention relates to a method and system for locating people in a closed area based on wireless communication, belonging to the field of wireless communication network technology. Background Technology

[0002] In the current safety management system of high-risk enclosed areas such as ports, terminals, and large industrial parks, achieving all-weather high-precision positioning of workers is fundamental to ensuring production safety and scheduling efficiency. Currently, the industry generally adopts a heterogeneous network fusion positioning strategy. In open outdoor areas, the Global Navigation Satellite System is used in conjunction with carrier phase differential technology for positioning. In indoor or semi-enclosed areas where satellite signals are blocked, Bluetooth beacons or ultra-wideband base stations are deployed to provide auxiliary positioning data. The positioning source is switched through logical judgment on the mobile terminal or server. However, in typical complex electromagnetic environments such as container yards in port areas and large gantry crane operation areas, the space is filled with a large number of irregular metal reflective surfaces, which causes the propagation path of wireless signals to exhibit strong multipath effects and non-line-of-sight propagation characteristics. Under such conditions, the satellite signals received by outdoor high-precision positioning terminals often experience cycle slips in carrier phase observation values ​​due to metal blockage or reflection, causing disordered jumps between fixed and floating-point solutions in the solution state. At the same time, the radio frequency signal strength of indoor positioning systems will fluctuate drastically due to multiple reflections from metal surfaces, deteriorating the geometric accuracy factor of distance measurement based on signal strength.

[0003] Faced with the aforementioned physical layer channel impairments, the existing technology's processing logic, which relies on a single signal strength threshold or positioning status flag for hard handover, reveals significant limitations in practical applications. For example, the utility model patent CN207909202U discloses an LBS-based mobile attendance system. Although it integrates GPS positioning components and GSM components to achieve basic location data acquisition, its core logic focuses on simple physical integration of multi-source hardware, lacking deep adaptation to complex channel characteristics at the data processing level. This system does not construct a quantitative evaluation model for the discrete metric of received signal strength sequences, and cannot diagnose the current channel quality in real time. In high multipath fading environments, it lacks a dynamic weight allocation mechanism based on channel instability, and cannot suppress observation errors through nonlinear correction factors when satellite signals are in a non-convergent state. This static linear processing logic leads to the inability to achieve a smooth transition of positioning weights in the edge regions of heterogeneous networks, and is prone to coordinate drift and trajectory oscillation due to the inability to eliminate false strong signals generated by reflections from metal surfaces.

[0004] Therefore, the technical problem to be solved by this invention is how to construct a positioning method that can quantitatively evaluate the confidence level of heterogeneous channels in a multipath environment in real time and realize dynamic weighted fusion of satellite and Bluetooth positioning data based on the confidence level, thereby eliminating positioning drift and trajectory oscillation in complex metal environments. Summary of the Invention

[0005] To address the problems mentioned in the background art, the technical solution of the present invention is as follows: A method for locating personnel in a closed area based on wireless communication, comprising the following steps: In a pre-defined high multipath fading communication environment, the wide-area satellite differential positioning data stream and the received signal strength sequence of the local short-range wireless network within the current sampling time window are collected through the communication interface of the mobile terminal. The channel quality feature extraction program is executed to perform discrete statistical analysis on the received signal strength sequence and calculate the standard deviation of the sequence to generate a channel instability index that quantitatively characterizes the degree of multipath interference in the current short-range wireless channel. A dynamic weight allocation procedure based on the inverse variance principle is implemented. This procedure includes establishing a negative correlation mapping relationship between wide-area satellite positioning weights and satellite signal observation variance, and establishing a negative correlation mapping relationship between local short-range positioning weights and channel instability index. Based on the mapping relationship, the master-slave positioning source fusion weights at the current moment are generated. When it is identified that the wide-area satellite differential positioning data stream is in a non-convergent state of carrier phase floating-point solution, a nonlinear correction factor is constructed based on the channel instability index, and weighted expansion processing is performed on the satellite signal observation variance to update the value of the satellite signal observation variance. Furthermore, by utilizing fusion weights, the wide-area coordinate components parsed from the wide-area satellite differential positioning data stream are linearly weighted and fused with the local coordinate components calculated based on short-range signal trilateration logic, and the final positioning coordinates of the mobile terminal are output.

[0006] Preferably, the step of executing the channel quality feature extraction program and performing discrete statistical analysis on the received signal strength sequence includes: extracting discrete signal strength sample values ​​of the same short-range wireless reference node within the current sampling time window based on a preset communication protocol identifier; performing Gaussian filtering on the discrete signal strength sample values ​​and removing outliers exceeding the confidence interval according to a preset probability density function; calculating the arithmetic mean of the filtered discrete signal strength sample values ​​as the reference strength, and calculating the root mean square error of the discrete signal strength sample values ​​relative to the reference strength, and mapping the root mean square error to a channel instability index.

[0007] Preferably, the steps of executing the dynamic weight allocation procedure based on the inverse variance principle include: parsing the carrier phase observation data in the wide-area satellite differential positioning data stream and reading the solution status flag bit of the current communication link; in response to the solution status flag bit indicating a fixed solution status, extracting the diagonal elements of the covariance matrix in this status and assigning them as the satellite signal observation variance; in response to the solution status flag bit indicating a floating-point solution status, extracting the residual sum of squares in this status, converting the residual sum of squares into the initial value of the satellite signal observation variance based on a preset error propagation model, and performing weighted expansion processing based on the initial value.

[0008] Preferably, the step of generating the master-slave positioning source fusion weights at the current moment includes determining the local short-range positioning weights according to the following formula. : ,in, For satellite signal observation variance, It is a channel instability index, and wide-area satellite positioning weights satisfy The normalization constraints.

[0009] Preferably, the method further includes a hysteresis filtering determination step for suppressing frequent switching of positioning sources. This step includes: constructing a first-in-first-out queue to cache historical state data of satellite signal observation variance and channel instability indices for multiple consecutive sampling periods; calculating the time change rate of the historical state data and monitoring the symbol flip frequency of the time change rate; generating a weight update command to trigger a dynamic weight allocation procedure only when the symbol flip frequency is detected to be lower than a preset stability threshold of 0.5Hz; otherwise, locking the current weight update channel and forcibly maintaining the fused weights of the previous moment to lock the current master-slave positioning source configuration.

[0010] Preferably, the step of linearly weighting and fusing the wide-area coordinate components parsed from the wide-area satellite differential positioning data stream and the local coordinate components calculated based on short-range signal trilateration logic using fusion weights includes: extracting the three-dimensional spatial vectors of the wide-area coordinate components and the local coordinate components respectively; performing vector synthesis operations on the wide-area coordinate components and the local coordinate components according to the fusion weights in each independent spatial dimension to generate intermediate fused coordinates; performing Kalman filtering smoothing on the intermediate fused coordinates, predicting and correcting the system state based on the state transition matrix, and outputting the final positioning coordinates.

[0011] Preferably, the method further includes a channel quality early warning step for high-reflection communication environments, which includes: comparing a channel instability index with a preset multipath interference critical threshold; generating a channel quality degradation flag in response to the channel instability index continuously exceeding the multipath interference critical threshold within a preset time window; and triggering correction logic based on the channel quality degradation flag to introduce a preset attenuation factor into the dynamic weight allocation procedure to perform a forced weight reduction operation on the local short-range positioning weights.

[0012] Preferably, the method is applied to a restricted communication area where differential reference stations and wireless positioning beacons are deployed. The step of collecting wide-area satellite differential positioning data streams within the current sampling time window further includes: receiving carrier phase correction data packets sent by the differential reference station through a wireless communication link; using the carrier phase correction data packets to compensate for phase errors in the raw satellite observation data received by the mobile terminal; executing ambiguity resolution logic to verify whether the integer ambiguity of the data after error compensation has converged, and marking the confidence level of the data based on the convergence result.

[0013] Preferably, the step of executing the dynamic weight allocation procedure based on the inverse variance principle further includes the logic of handling the switching of signal coverage boundary areas: calculating the absolute value of the difference between the satellite signal observation variance and the channel instability index; in response to the absolute value of the difference being less than a preset ambiguity threshold, determining that the mobile terminal is in the heterogeneous network edge transition zone; in the heterogeneous network edge transition zone, applying a linear interpolation algorithm, based on the displacement velocity vector of the mobile terminal, to perform time-dimensional smoothing correction on the fusion weights, and outputting the final positioning coordinates of the mobile terminal, after the steps of: transmitting the final positioning coordinates to the remote data processing center via a wireless uplink; the remote data processing center constructing a motion trajectory model based on the time series of the final positioning coordinates; calculating the normal distance between the motion trajectory model and the preset spatial boundary; in response to the normal distance being less than a safety threshold of 1.5m, generating a tactile feedback control command and sending it to the mobile terminal to drive its actuator to generate physical vibration.

[0014] A personnel positioning system for a closed area based on wireless communication, comprising: The multi-source data acquisition module is configured to acquire wide-area satellite differential positioning data streams and received signal strength sequences of local short-range wireless networks within the current sampling time window through the communication interface of a mobile terminal in a preset high multipath fading communication environment. The channel quality assessment module is configured to execute a channel quality feature extraction program, perform discrete statistical analysis on the received signal strength sequence, and calculate the standard deviation of the sequence to generate a channel instability index that quantitatively characterizes the degree of multipath interference in the current short-range wireless channel. The dynamic weight allocation module is configured to execute a dynamic weight allocation procedure based on the inverse variance principle. This procedure includes establishing a negative correlation mapping relationship between wide-area satellite positioning weights and satellite signal observation variance, and establishing a negative correlation mapping relationship between local short-range positioning weights and channel instability index. Based on the mapping relationship, the module generates the master-slave positioning source fusion weights at the current moment. When it is identified that the wide-area satellite differential positioning data stream is in a non-convergent state of carrier phase floating-point solution, the module constructs a nonlinear correction factor based on the channel instability index and performs weighted expansion processing on the satellite signal observation variance to update the value of the satellite signal observation variance. The heterogeneous coordinate fusion module is configured to use fusion weights to linearly weight and fuse the wide-area coordinate components parsed from the wide-area satellite differential positioning data stream with the local coordinate components calculated based on short-range signal trilateration logic, and output the final positioning coordinates of the mobile terminal.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. In personnel positioning within enclosed areas, this invention suppresses positioning drift and false locking in highly dynamic metal multipath environments. It addresses positioning distortion caused by multipath effects in complex electromagnetic environments such as container yards in ports by constructing a time-sliding window-based channel statistical feature evaluation mechanism on the server side. Instead of relying solely on instantaneous signal strength or carrier-to-noise ratio for link selection, the system calculates the variance of the satellite horizontal accuracy factor and the standard deviation of the Bluetooth signal strength within a preset window. Utilizing the physical characteristic that multipath reflection signals, while energetic, have unstable phases, it identifies false strong signals generated by non-line-of-sight propagation and automatically reduces their confidence weight in location calculation. This allows mobile terminals to effectively filter out coordinate jumps caused by metal reflection when traversing container tunnels or approaching large metal quay cranes, ensuring consistency between the personnel's positioning trajectory and actual physical path in densely populated work areas and preventing false alarms triggered by false coordinate drift in the safety control system.

[0016] 2. To achieve seamless soft handover and trajectory smoothing in heterogeneous network edge areas, this invention utilizes a dynamic weighted fusion algorithm based on the inverse variance to establish a complementary mechanism between satellite positioning links and Bluetooth positioning links in indoor-outdoor transition areas. For critical areas such as warehouse entrances and transfer tower staircases where satellite and Bluetooth signals coexist but their quality is unstable, the system constructs a continuously changing weight function by real-time monitoring of the relationship between the RTK calculation status and the fluctuation rate of the Bluetooth signal. This avoids the repeated oscillations of the positioning source caused by traditional hard handover logic near the critical threshold, achieving a smooth transition of positioning coordinates from the absolute geographic coordinate system to the relative local coordinate system. Through this linear weighted processing, the system can maintain the spatiotemporal continuity of positioning data when the physical environment undergoes sudden changes, providing a stable data foundation for the continuous determination of the global electronic fence in the port area.

[0017] 3. Constructing blind zone adaptive compensation capability under semi-obstructed conditions: This invention overcomes the performance bottleneck of single technology in semi-obstructed areas by deeply coupling RTK differential data and indoor beacon ranging data. Under gantry cranes or in the shadow areas of high-rise buildings, when satellite signals are blocked and RTK cannot obtain a fixed solution, the system uses satellite data in a floating-point solution state to provide approximate position constraints, and at the same time uses the triangulation results of Bluetooth beacons for local fine correction. This collaborative processing of heterogeneous data uses the high-resolution characteristics of Bluetooth short-range ranging to compensate for the accuracy attenuation of satellite signals in weak coverage areas. Thus, without the need to deploy additional expensive anti-interference hardware, it ensures continuous observability of personnel in complex obstructed environments and establishes all-weather, blind-zone-free position awareness capability in medium- and high-risk enclosed areas. Attached Figure Description

[0018] Figure 1 A flowchart of dynamic weight allocation and coordinate fusion for introducing nonlinear correction factors in this invention; Figure 2 This is a system architecture diagram of multi-source data acquisition and back-end collaborative computing of the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0020] A method for locating people in a closed area based on wireless communication includes the following steps: In a pre-defined high multipath fading communication environment, the wide-area satellite differential positioning data stream and the received signal strength sequence of the local short-range wireless network within the current sampling time window are collected through the communication interface of the mobile terminal. The channel quality feature extraction program is executed to perform discrete statistical analysis on the received signal strength sequence and calculate the standard deviation of the sequence to generate a channel instability index that quantitatively characterizes the degree of multipath interference in the current short-range wireless channel. A dynamic weight allocation procedure based on the inverse variance principle is implemented. This procedure includes establishing a negative correlation mapping relationship between wide-area satellite positioning weights and satellite signal observation variance, and establishing a negative correlation mapping relationship between local short-range positioning weights and channel instability index. Based on the mapping relationship, the master-slave positioning source fusion weights at the current moment are generated. When it is identified that the wide-area satellite differential positioning data stream is in a non-convergent state of carrier phase floating-point solution, a nonlinear correction factor is constructed based on the channel instability index, and weighted expansion processing is performed on the satellite signal observation variance to update the value of the satellite signal observation variance. Furthermore, by utilizing fusion weights, the wide-area coordinate components parsed from the wide-area satellite differential positioning data stream and the local coordinate components calculated based on short-range signal trilateration logic are linearly weighted and fused to output the final positioning coordinates of the mobile terminal.

[0021] Preferably, the step of executing the channel quality feature extraction program and performing discrete statistical analysis on the received signal strength sequence includes: extracting discrete signal strength sample values ​​of the same short-range wireless reference node within the current sampling time window based on a preset communication protocol identifier; performing Gaussian filtering on the discrete signal strength sample values ​​and removing outliers exceeding the confidence interval according to a preset probability density function; calculating the arithmetic mean of the filtered discrete signal strength sample values ​​as the reference strength, and calculating the root mean square error of the discrete signal strength sample values ​​relative to the reference strength, and mapping the root mean square error to a channel instability index.

[0022] Preferably, the steps of executing the dynamic weight allocation procedure based on the inverse variance principle include: parsing the carrier phase observation data in the wide-area satellite differential positioning data stream and reading the solution status flag bit of the current communication link; in response to the solution status flag bit indicating a fixed solution status, extracting the diagonal elements of the covariance matrix in this status and assigning them as the satellite signal observation variance; in response to the solution status flag bit indicating a floating-point solution status, extracting the residual sum of squares in this status, converting the residual sum of squares into the initial value of the satellite signal observation variance based on a preset error propagation model, and performing weighted expansion processing based on the initial value.

[0023] Preferably, the step of generating the master-slave positioning source fusion weights at the current moment includes determining the local short-range positioning weights according to the following formula. : ,in, For satellite signal observation variance, It is a channel instability index, and wide-area satellite positioning weights satisfy The normalization constraints.

[0024] Preferably, the method further includes a hysteresis filtering determination step for suppressing frequent switching of positioning sources. This step includes: constructing a first-in-first-out queue to cache historical state data of satellite signal observation variance and channel instability indices for multiple consecutive sampling periods; calculating the time change rate of the historical state data and monitoring the symbol flip frequency of the time change rate; generating a weight update command to trigger a dynamic weight allocation procedure only when the symbol flip frequency is detected to be lower than a preset stability threshold of 0.5Hz; otherwise, locking the current weight update channel and forcibly maintaining the fused weights of the previous moment to lock the current master-slave positioning source configuration.

[0025] Preferably, the step of linearly weighting and fusing the wide-area coordinate components parsed from the wide-area satellite differential positioning data stream and the local coordinate components calculated based on short-range signal trilateration logic using fusion weights includes: extracting the three-dimensional spatial vectors of the wide-area coordinate components and the local coordinate components respectively; performing vector synthesis operations on the wide-area coordinate components and the local coordinate components according to the fusion weights in each independent spatial dimension to generate intermediate fused coordinates; performing Kalman filtering smoothing on the intermediate fused coordinates, predicting and correcting the system state based on the state transition matrix, and outputting the final positioning coordinates.

[0026] Preferably, the method further includes a channel quality early warning step for high-reflection communication environments, which includes: comparing a channel instability index with a preset multipath interference critical threshold; generating a channel quality degradation flag in response to the channel instability index continuously exceeding the multipath interference critical threshold within a preset time window; and triggering correction logic based on the channel quality degradation flag to introduce a preset attenuation factor into the dynamic weight allocation procedure to perform a forced weight reduction operation on the local short-range positioning weights.

[0027] Preferably, the method is applied to a restricted communication area where differential reference stations and wireless positioning beacons are deployed. The step of collecting wide-area satellite differential positioning data streams within the current sampling time window further includes: receiving carrier phase correction data packets sent by the differential reference station through a wireless communication link; using the carrier phase correction data packets to compensate for phase errors in the raw satellite observation data received by the mobile terminal; executing ambiguity resolution logic to verify whether the integer ambiguity of the data after error compensation has converged, and marking the confidence level of the data based on the convergence result.

[0028] Preferably, the step of executing the dynamic weight allocation procedure based on the inverse variance principle further includes the logic of handling the switching of signal coverage boundary areas: calculating the absolute value of the difference between the satellite signal observation variance and the channel instability index; in response to the absolute value of the difference being less than a preset ambiguity threshold, determining that the mobile terminal is in the heterogeneous network edge transition zone; in the heterogeneous network edge transition zone, applying a linear interpolation algorithm, based on the displacement velocity vector of the mobile terminal, to perform time-dimensional smoothing correction on the fusion weights, and outputting the final positioning coordinates of the mobile terminal, after the steps of: transmitting the final positioning coordinates to the remote data processing center via a wireless uplink; the remote data processing center constructing a motion trajectory model based on the time series of the final positioning coordinates; calculating the normal distance between the motion trajectory model and the preset spatial boundary; in response to the normal distance being less than a safety threshold of 1.5m, generating a tactile feedback control command and sending it to the mobile terminal to drive its actuator to generate physical vibration.

[0029] A personnel positioning system for a closed area based on wireless communication, comprising: The multi-source data acquisition module is configured to acquire wide-area satellite differential positioning data streams and received signal strength sequences of local short-range wireless networks within the current sampling time window through the communication interface of a mobile terminal in a preset high multipath fading communication environment. The channel quality assessment module is configured to execute a channel quality feature extraction program, perform discrete statistical analysis on the received signal strength sequence, and calculate the standard deviation of the sequence to generate a channel instability index that quantitatively characterizes the degree of multipath interference in the current short-range wireless channel. The dynamic weight allocation module is configured to execute a dynamic weight allocation procedure based on the inverse variance principle. This procedure includes establishing a negative correlation mapping relationship between wide-area satellite positioning weights and satellite signal observation variance, and establishing a negative correlation mapping relationship between local short-range positioning weights and channel instability index. Based on the mapping relationship, the module generates the master-slave positioning source fusion weights at the current moment. When it is identified that the wide-area satellite differential positioning data stream is in a non-convergent state of carrier phase floating-point solution, the module constructs a nonlinear correction factor based on the channel instability index and performs weighted expansion processing on the satellite signal observation variance to update the value of the satellite signal observation variance. The heterogeneous coordinate fusion module is configured to use fusion weights to linearly weight and fuse the wide-area coordinate components parsed from the wide-area satellite differential positioning data stream with the local coordinate components calculated based on short-range signal trilateration logic, and output the final positioning coordinates of the mobile terminal.

[0030] Example 1: In a high multipath fading communication environment in a port container yard, when a mobile terminal is located at the edge of a metal canyon formed by stacked containers, the multi-source data acquisition module collects the wide-area satellite differential positioning data stream and the received signal strength sequence of the local short-range wireless network within the current sampling time window through the communication interface. At this time, the satellite line-of-sight path is intermittently blocked, and the wireless signal is interfered with by reflection from the metal surface. The channel quality assessment module executes the channel quality feature extraction program and performs discrete statistical analysis on the received signal strength sequence. This module calculates the standard deviation of the received signal strength sequence within the preset sampling time window and defines it as a channel instability index that quantitatively characterizes the degree of interference from multipath effects on the current short-range wireless channel. This step is based on the physical property that the fluctuation amplitude of the received signal strength is positively correlated with the degree of non-line-of-sight propagation interference.

[0031] The dynamic weight allocation module executes a dynamic weight allocation procedure based on the inverse variance principle to establish wide-area satellite positioning weights. With satellite signal observation variance The negative correlation mapping relationship, and the local short-range positioning weights Channel instability index The negative correlation mapping relationship means that when the carrier phase solution status flag in the wide-area satellite differential positioning data stream is detected to have degraded from a fixed solution state to a floating-point solution state, the system performs weighted expansion processing, which is based on the channel instability index. A nonlinear correction factor is constructed and used to increase the observation variance of satellite signals. The value of the channel instability index When in the low value range, the increase Make local short-range positioning weights In the weight calculation formula The heterogeneous coordinate fusion module plays a dominant role in realizing the dynamic adjustment of the positioning source weight. The heterogeneous coordinate fusion module uses the fusion weight to linearly weight and fuse the wide-area coordinate components parsed from the wide-area satellite differential positioning data stream with the local coordinate components calculated based on the short-range signal trilateration logic. The final positioning coordinates of the mobile terminal output by this step suppress the coordinate jump caused by the quality degradation of a single signal source and maintain the spatial continuity of the positioning trajectory in the transition area of ​​the heterogeneous network.

[0032] Example 2: In a system-level verification test targeting the high-dynamic environment of a port container yard, a closed test platform including a metal shielding wall and a multipath reflection simulator was established to verify the anti-interference performance of the heterogeneous positioning source fusion logic under non-line-of-sight conditions. The test platform deployed an industrial-grade mobile positioning terminal whose GNSS receiving module had the ability to capture the carrier phase of the L1 and L2 frequency bands, with a sampling rate set to 10Hz. Its short-range communication module was configured to receive low-power Bluetooth beacon signals with a broadcast period of 100ms. Gaussian white noise with a signal-to-noise ratio of 15dB was injected into the original signal path, and a Rayleigh fading model was introduced to reproduce the metal surface... To investigate the multipath effect caused by surface reflection, a gradient optimization test was performed on the sampling time window length parameter in the channel quality feature extraction program. Under the condition that the mobile terminal passes through the obstructed area at a constant speed of 1.5 m / s, sampling time windows of 0.5 seconds, 3.0 seconds, and 6.0 seconds were compared. During this process, the sampling frequency of the mobile terminal's received signal strength data was set to 10 Hz, and the sliding window adopted a 50% time overlap rate, i.e., the statistical results were updated every 1.5 seconds to ensure the continuity and smoothness of the data stream. Data monitoring showed that when the window length was 0.5 seconds, the calculated channel instability index... The system exhibits high-frequency, violent oscillations, with a standard deviation coefficient of variation exceeding 40%, leading to frequent jumps in subsequent weight allocation instructions. When the window length is increased to 6.0 seconds, the response delay of the indicator to sudden changes in channel state reaches 1.2 seconds, making it impossible to track channel switching when the mobile terminal passes through in a timely manner. However, with a setting of 3.0 seconds, the coefficient of variation of the indicator converges to within 15%, and the response delay is controlled within 0.4 seconds, achieving an engineering balance between statistical stability and real-time performance. Based on this, the system fixes the sampling time window parameter to 3.0 seconds. A comparative experiment was constructed, including the sample group and control group of this invention, to verify the effectiveness of the dynamic weight allocation procedure and weighted expansion processing mechanism based on the inverse variance principle. The experimental scenario was set as a mobile terminal moving from an open area with good satellite signal to a semi-enclosed area where the satellite signal is blocked.

[0033] During this process, the carrier phase solution status flag in the wide-area satellite differential positioning data stream changes from a fixed solution status to a floating-point solution status, corresponding to the satellite signal observation variance. The increase was only slight and failed to accurately reflect the meter-level jump in actual positioning error. In the control group where the weighted expansion processing logic was not enabled, the local short-range positioning weights calculated by the system based on the original variance were... Maintaining a low value range of 0.3 to 0.4 causes the fused coordinates to be mainly driven by drifting satellite data, resulting in an average lateral deviation of 1.85 meters between the final output positioning trajectory and the actual path. However, in the sample of this invention with weighted expansion processing logic enabled, the system detects the floating-point solution state and simultaneously calculates the current channel instability index. A value of 2.5 indicates excellent local channel quality. The processor then triggers nonlinear correction logic, utilizing this low value. Generate correction factor pairs After performing multiplicative expansion, the variance values ​​of the satellites involved in the weighting calculation increase, thus affecting the calculated variance. The value rapidly increased and stabilized in the range of 0.85 to 0.92. This weight adjustment allowed the fusion algorithm to smoothly transfer positioning dominance to the local area network, ultimately reducing the average lateral deviation of the output positioning trajectory from the actual path to 0.42 meters. Further boundary stress tests showed that when environmental degradation led to channel instability indicators... When the preset degradation threshold of 25.0 is exceeded, even if the satellite is in floating-point solution state, the system automatically suppresses the trigger amplitude of the expansion logic to avoid misallocating weights to equally unreliable local channels. At this time, the system automatically enters the inertial holding mode, and the positioning deviation is maintained within a controllable range of 1.2 meters, which is better than the divergence error of more than 3.5 meters caused by the forced handover strategy. The above data logic chain confirms the adaptive adjustment capability of the weight allocation procedure in the scenario of asynchronous degradation of heterogeneous channel quality.

[0034] Example 3: During the engineering deployment phase of a heterogeneous positioning system, a standardized parameter calibration procedure is executed to determine the critical threshold for multipath interference in the channel quality early warning logic. The specific values ​​are determined by a radio frequency test environment with controllable multipath reflection simulation capabilities. This environment integrates a programmable phase attenuator and a signal reflection generator to inject simulated multipath interference of deterministic strength into the transmission path of the wireless positioning beacon. During calibration, the control system gradually increases the multipath interference strength in 1dB increments, while simultaneously collecting the channel instability index output by the mobile terminal. And the root mean square error (RMSE) of the positioning coordinates relative to the high-precision physical true value, and based on this set of discrete measured data, a performance degradation characteristic curve is constructed. Data analysis shows that when When the value is in the low range, the positioning error increases slowly and linearly with the interference intensity, but once... Beyond a certain inflection point, the error will exhibit an exponential divergence trend; therefore, the system calculates the extreme point of the second derivative of this characteristic curve to pinpoint the physical boundary where the positioning performance undergoes a qualitative change, and assigns the corresponding point to... The value is fixed as the critical threshold for multipath interference. This ensures that the triggering conditions of the early warning logic are anchored above the physical limits of system stability.

[0035] Based on a defined threshold parameter, the processor configures a calculation model for the nonlinear correction factor γ in the dynamic weight allocation module, employing a piecewise mapping mechanism based on the reliability boundary: when real-time monitoring... Less than or equal to the threshold When the correction factor γ is locked at a unit value of 1.0, the linear allocation logic of the original variance weights is maintained; when Greater than And if the safety limit is not exceeded, the processor follows the formula The correction is calculated in real time, where α is the sensitivity coefficient, the value of which is determined by the error divergence rate obtained during the calibration phase. This logarithmic nonlinear mapping mechanism ensures the accuracy of satellite signal observation variance. The expansion amplitude maintains a mathematical monotonic correspondence with the degree of degradation of the local channel quality, thus effectively suppressing positioning trajectory drift caused by weight skew in complex concurrent scenarios where satellite signal lock-up is lost and local signal degradation occurs synchronously. To further mitigate the risk of numerical overflow caused by extreme electromagnetic storms or sensor failures, the system incorporates mandatory saturation clamping logic at the end of the weight calculation link, which monitors the variance values ​​of each variable involved in the calculation in real time. Once the expanded variance is detected... The value exceeds the maximum representable range of the processor register, or the calculated local short-range positioning weight. A mathematical singularity jump will immediately trigger the circuit breaker protection mechanism. Force clamping to a preset saturation threshold, and ensure Maintaining a keep-alive range of no less than 0.05, this underlying protection measure ensures that the system can still maintain the most basic coordinate output capability under boundary conditions of extremely abnormal input data, realizing a complete closed-loop protection from algorithm logic to engineering implementation.

[0036] Example 4: Before the mobile positioning terminal is put into field operation, a static noise floor calibration procedure based on an electromagnetically silent environment is performed to determine the anti-singularity small constants in the weight calculation model. The physical reference value requires that the mobile terminal to be calibrated be placed in an electromagnetic shielding box, and in a zero-input state without external positioning signal excitation, the internal thermal noise data stream of the satellite receiving module and short-range communication module be continuously collected. The background noise level of the hardware is quantified by calculating the lower limit of the variance of the data stream in statistics, and then 1.5 times the value of the variance of the background noise is solidified into a small constant. This eliminates the risk of numerical divergence caused by the denominator approaching zero due to the extremely pure input signal at the physical level.

[0037] To address the multipath environmental baseline drift problem caused by dynamic changes in container stacking topology, the system continuously executes an online adaptive calibration procedure based on high-confidence anchor points during operation. When the wide-area satellite differential positioning data stream maintains a fixed solution state and the geometric accuracy factor is less than a preset quality threshold, the system marks the current satellite solution coordinates as a dynamic true reference and calculates the real-time deviation sequence of the local short-range positioning solution coordinates relative to this dynamic true reference. This calculation process includes a coordinate system alignment step: converting the latitude and longitude coordinates output by the wide-area satellite differential positioning into Cartesian coordinates using Gaussian projection. The system collects satellite and local coordinates of 10 consecutive sampling points, calculates the rotation matrix and translation vector between the two point sets using the singular value decomposition algorithm, and uses this rotation matrix and translation vector as the current coordinate transformation reference. It then maps all subsequent local short-range positioning coordinates to the wide-area coordinate system and uses the statistical trend of this deviation sequence to fine-tune the sensitivity coefficient α in the nonlinear correction factor calculation formula with a step size of 0.01. This ensures that the trigger sensitivity of the dynamic weight allocation logic can automatically follow the complex configuration changes of the external electromagnetic environment and maintain a constant suppression performance.

[0038] Example 5: To address the differences in motion characteristics among different work objects, the system executes a kinematic response matching calibration procedure during the deployment phase to determine the sampling time window in the channel quality feature extraction program. The optimal engineering values ​​were determined by using a linear motion guide rail to mount a mobile positioning terminal, which was then moved at a gradient speed from 0.5 m / s to 5.0 m / s. Traversing an electromagnetic boundary region where propagation abruptly shifts from line-of-sight to multipath-dominated propagation, simultaneously recording physical location trigger signals and channel instability indices. The step response waveform, the lag time required for the processor's computational performance response curve to reach 90% of its steady-state value. And based on the fitting formula Reverse calculation satisfies the security response delay threshold The maximum allowable window length under constraints, where β is the inherent delay coefficient determined by the filter order, ensures that the system can automatically shrink the sampling window to reduce the physical lag distance of multipath warning when facing high-speed automated guided vehicles (AGVs), and expand the window to improve the confidence of variance statistics when facing low-speed inspection personnel, thus achieving precise decoupling and matching of time-domain parameters and vehicle dynamic characteristics. To ensure the self-consistency of physical dimensions of the multi-source fusion positioning algorithm and the engineering stability under the dual adverse conditions of heterogeneous channels, the system performs a calibration procedure based on equivalent distance error mapping before formal operation. Based on the log-normal shadowing model of radio wave propagation, a deterministic quantitative transformation relationship is established between the statistical fluctuation characteristics of local received signal strength and the actual geometric positioning error, providing a unified input variable with physical meaning for the weight allocation formula.

[0039] Typical locations within a closed area that encompass both line-of-sight and non-line-of-sight propagation characteristics are selected as calibration points. The mobile terminal is placed stationary at these known, precise coordinate calibration points, and the system operates within a preset sampling time window. For example, within 3.0 seconds, the received signal strength sequence of a local short-range wireless network can be simultaneously acquired. Based on the sequence-based local positioning coordinates, the processor calculates the original standard deviation of the intensity sequence. And calculate the mean square error of the local positioning coordinates relative to the actual physical coordinates of the calibration point. The least squares method was used to analyze multiple groups. Data is subjected to nonlinear regression analysis to obtain a mapping coefficient κ with a definite physical dimension. In specific engineering implementation, this mapping coefficient is calibrated to 0.12 dB per square meter. When the processor executes the dynamic weight allocation procedure, it squares the channel instability index (i.e., the standard deviation of the received signal strength sequence) calculated in real time and multiplies it by this mapping coefficient, thereby converting the signal fluctuation characteristic value in dB into the equivalent distance error variance in square meters. At this time, both terms in the denominator of the formula are unified to the dimension of distance variance. When executing the dynamic weight allocation procedure, these terms are substituted into the formula. Mid-channel instability index Defined as the mapping equation The equivalent distance error variance after conversion ensures that both the numerator and denominator of the weight calculation formula represent the uncertainty of physical spatial distance, eliminating the risk of inaccurate weight allocation due to dimensional mismatch.

[0040] To address the extreme environment adaptability issue of the nonlinear correction factor γ, the system incorporates automatic circuit breaker protection logic based on confidence dead zone. During weighted expansion processing, the correction factor... Calculation based on formula The sensitivity coefficient α was determined through field stress testing: the terminal was placed in a region where the satellite signal was in a floating-point state and local multipath interference exhibited gradient enhancement and mixing characteristics. The α value was dynamically adjusted until the root mean square distance between the system output trajectory and the reference trajectory reached its minimum. To avoid the risk of system error amplification of weights when the local channel was extremely deteriorated, the processor preset an absolute circuit breaker threshold. The threshold corresponds to the system's maximum allowable positioning error boundary, such as... In real-time computation, after the mapping is detected If the circuit breaker threshold is exceeded, regardless of the satellite's solution status, the system will forcibly bypass the calculation logic of the correction factor γ, lock the value to 1.0, freeze the current weight allocation status, and start the Kalman filter-based inertial recursion mode. The protection mechanism ensures that the algorithm avoids divergent coordinate drift caused by the monotonicity of mathematical logic under the dual-blind conditions of satellite loss of lock and local storm.

[0041] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for locating people in a closed area based on wireless communication, characterized in that, Includes the following steps: In a pre-defined high multipath fading communication environment, the wide-area satellite differential positioning data stream and the received signal strength sequence of the local short-range wireless network within the current sampling time window are collected through the communication interface of the mobile terminal. The channel quality feature extraction program is executed to perform discrete statistical analysis on the received signal strength sequence and calculate the standard deviation of the sequence to generate a channel instability index that quantitatively characterizes the degree of multipath interference in the current short-range wireless channel. A dynamic weight allocation procedure based on the inverse variance principle is implemented. This procedure includes establishing a negative correlation mapping relationship between wide-area satellite positioning weights and satellite signal observation variance, and establishing a negative correlation mapping relationship between local short-range positioning weights and channel instability index. Based on the mapping relationship, the master-slave positioning source fusion weights at the current moment are generated. When it is identified that the wide-area satellite differential positioning data stream is in a non-convergent state of carrier phase floating-point solution, a nonlinear correction factor is constructed based on the channel instability index, and weighted expansion processing is performed on the satellite signal observation variance to update the value of the satellite signal observation variance. Furthermore, by utilizing fusion weights, the wide-area coordinate components parsed from the wide-area satellite differential positioning data stream and the local coordinate components calculated based on short-range signal trilateration logic are linearly weighted and fused to output the final positioning coordinates of the mobile terminal.

2. The method for locating people in a closed area based on wireless communication according to claim 1, characterized in that, The steps of executing the channel quality feature extraction program and performing discrete statistical analysis on the received signal strength sequence include: extracting discrete signal strength sample values ​​of the same short-range wireless reference node within the current sampling time window based on a preset communication protocol identifier; performing Gaussian filtering on the discrete signal strength sample values ​​and removing outliers exceeding the confidence interval according to a preset probability density function; calculating the arithmetic mean of the filtered discrete signal strength sample values ​​as the reference strength, and calculating the root mean square error of the discrete signal strength sample values ​​relative to the reference strength, mapping the root mean square error to a channel instability index.

3. The method for locating people in a closed area based on wireless communication according to claim 1, characterized in that, The steps for executing the dynamic weight allocation procedure based on the inverse variance principle include: parsing carrier phase observation data in the wide-area satellite differential positioning data stream and reading the solution status flag bit of the current communication link; in response to the solution status flag bit indicating a fixed solution status, extracting the diagonal elements of the covariance matrix in this status and assigning them as the satellite signal observation variance; in response to the solution status flag bit indicating a floating-point solution status, extracting the residual sum of squares in this status, converting the residual sum of squares into the initial value of the satellite signal observation variance based on a preset error propagation model, and performing weighted expansion processing based on the initial value.

4. The method for locating personnel in a closed area based on wireless communication according to claim 1, characterized in that, The steps for generating the master-slave positioning source fusion weights at the current moment include determining the local short-range positioning weights according to the following formula. : ,in, For satellite signal observation variance, It is a channel instability index, and wide-area satellite positioning weights satisfy The normalization constraints.

5. The method for locating personnel in a closed area based on wireless communication according to claim 1, characterized in that, The method also includes a hysteresis filtering decision step to suppress frequent switching of positioning sources. This step includes: constructing a first-in-first-out queue to cache historical state data of satellite signal observation variance and channel instability indices for multiple consecutive sampling periods; calculating the time change rate of the historical state data and monitoring the symbol flip frequency of the time change rate; generating a weight update command to trigger the dynamic weight allocation procedure only when the symbol flip frequency is detected to be lower than a preset stability threshold of 0.5Hz; otherwise, locking the current weight update channel and forcibly maintaining the fused weights of the previous moment to lock the current master-slave positioning source configuration.

6. The method for locating people in a closed area based on wireless communication according to claim 1, characterized in that, The steps of linearly weighting and fusing the wide-area coordinate components parsed from the wide-area satellite differential positioning data stream with the local coordinate components calculated based on short-range signal trilateration logic using fusion weights include: extracting the three-dimensional spatial vectors of the wide-area coordinate components and the local coordinate components respectively; performing vector synthesis operations on the wide-area coordinate components and the local coordinate components according to the fusion weights in each independent spatial dimension to generate intermediate fused coordinates; performing Kalman filtering smoothing on the intermediate fused coordinates; predicting and correcting the system state based on the state transition matrix; and outputting the final positioning coordinates.

7. The method for locating personnel in a closed area based on wireless communication according to claim 1, characterized in that, The method also includes a channel quality early warning step for high-reflection communication environments, which includes: comparing the channel instability index with a preset multipath interference critical threshold; generating a channel quality degradation flag in response to the channel instability index continuously exceeding the multipath interference critical threshold within a preset time window; and triggering correction logic based on the channel quality degradation flag to introduce a preset attenuation factor into the dynamic weight allocation procedure to perform a forced weight reduction operation on the local short-range positioning weights.

8. The method for locating people in a closed area based on wireless communication according to claim 1, characterized in that, The method is applied to a restricted communication area with differential reference stations and wireless positioning beacons. The steps of collecting wide-area satellite differential positioning data streams within the current sampling time window further include: receiving carrier phase correction data packets sent by the differential reference station through a wireless communication link; using the carrier phase correction data packets to compensate for phase errors in the raw satellite observation data received by the mobile terminal; executing ambiguity resolution logic to verify whether the integer ambiguity of the error-compensated data has converged, and marking the confidence level of the data based on the convergence result.

9. A method for locating people in a closed area based on wireless communication according to claim 1, characterized in that, The steps of executing the dynamic weight allocation procedure based on the inverse variance principle further include the logic of handling the switching of signal coverage boundary areas: calculating the absolute value of the difference between the satellite signal observation variance and the channel instability index; determining that the mobile terminal is in the heterogeneous network edge transition zone in response to the absolute value of the difference being less than a preset ambiguity zone threshold; and after the steps of applying a linear interpolation algorithm to smooth the fusion weights in the time dimension based on the displacement velocity vector of the mobile terminal within the heterogeneous network edge transition zone, and outputting the final positioning coordinates of the mobile terminal, the procedure further includes: transmitting the final positioning coordinates to a remote data processing center via a wireless uplink; constructing a motion trajectory model by the remote data processing center based on the time series of the final positioning coordinates; calculating the normal distance between the motion trajectory model and the preset spatial boundary; and generating a tactile feedback control command and sending it to the mobile terminal to drive its actuator to generate physical vibration in response to the normal distance being less than a safety threshold of 1.5m.

10. A personnel positioning system for a closed area based on wireless communication, used to implement the personnel positioning method for a closed area based on wireless communication as described in claim 1, characterized in that, include: The multi-source data acquisition module is configured to acquire wide-area satellite differential positioning data streams and received signal strength sequences of local short-range wireless networks within the current sampling time window through the communication interface of a mobile terminal in a preset high multipath fading communication environment. The channel quality assessment module is configured to execute a channel quality feature extraction program, perform discrete statistical analysis on the received signal strength sequence, and calculate the standard deviation of the sequence to generate a channel instability index that quantitatively characterizes the degree of multipath interference in the current short-range wireless channel. The dynamic weight allocation module is configured to execute a dynamic weight allocation procedure based on the inverse variance principle. This procedure includes establishing a negative correlation mapping relationship between wide-area satellite positioning weights and satellite signal observation variance, and establishing a negative correlation mapping relationship between local short-range positioning weights and channel instability index. Based on the mapping relationship, the module generates the master-slave positioning source fusion weights at the current moment. When it is identified that the wide-area satellite differential positioning data stream is in a non-convergent state of carrier phase floating-point solution, the module constructs a nonlinear correction factor based on the channel instability index and performs weighted expansion processing on the satellite signal observation variance to update the value of the satellite signal observation variance. The heterogeneous coordinate fusion module is configured to use fusion weights to linearly weight and fuse the wide-area coordinate components parsed from the wide-area satellite differential positioning data stream with the local coordinate components calculated based on short-range signal trilateration logic, and output the final positioning coordinates of the mobile terminal.

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