A dual-channel drone line-of-sight communication system

Abstract

The present invention specifically relates to a dual-channel drone line-of-sight communication system, which belongs to the field of drone communication technology and includes the following parts: an instruction transmission module; a signal execution module; a retransmission module; a data processing module; a receiving and displaying module. In the present invention, a comprehensive analysis of the communication link is carried out, including calculating the signal return time, the data processing time consumption at the sending end and the receiving end, and determining the margin time by integrating the network packet loss rate and weather conditions, so as to accurately determine the timer retransmission duration; this enables the system to perform data retransmission operations more reasonably in the face of a complex communication environment, reduce data loss, improve the success rate and stability of data transmission, and even in bad weather, it can adjust the retransmission strategy according to the actual situation to ensure reliable data transmission.

Description

Technical Field

[0001] The present invention relates to the technical field of UAV communication, and in particular to a dual-channel UAV line-of-sight communication system. Background Art

[0002] In order to address communication quality issues, current UAVs have emerged with dual-channel communication systems.

[0003] However, even with the support of a dual-channel communication system, during data transmission, once a data transmission problem occurs, the UAV communication system needs to determine the sending and receiving status of the acknowledgment frame based on the timer retransmission duration. Currently, the setting of the timer retransmission duration is only based on a rough range, lacking precise consideration and dynamic adjustment of the actual situation. For example, in different weather conditions and when the flight distance changes, this duration cannot be optimized accordingly. This leads to frequent problems such as data packet loss and transmission delay during data transmission, thus affecting the data transmission quality. It can be seen that there is a large room for improvement in the existing method for determining the timer retransmission duration;

[0004] Therefore, a dual-channel UAV line-of-sight communication system is proposed to address the above-mentioned problems. Summary of the Invention

[0005] The purpose of the present invention is to propose a dual-channel UAV line-of-sight communication system to solve the above problems.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions:

[0007] A dual-channel UAV line-of-sight communication system includes the following parts:

[0008] Instruction Transmission Module: After the ground control station personnel input an instruction, the instruction is converted into a digital signal and sent to the UAV after corresponding modulation, and the UAV processes the received digital signal;

[0009] Signal Execution Module: Parses the received digital signal to determine the action instruction of the UAV, and feeds back the instruction execution status to the ground control station;

[0010] Retransmission Module: Analyzes the communication link to determine the timer retransmission duration, and the timer performs corresponding processing based on the retransmission duration;

[0011] Data Processing Module: The UAV preprocesses the acquired image, encodes and packs it, modulates it, and sends it to the ground control station;

[0012] Receiving and Display Module: The ground control station decodes the received digital data and displays the decoded data.

[0013] Preferably, the instruction transmission module specifically includes the following:

[0014] Operators at the ground control station input instructions according to mission requirements. The instructions are converted into digital signals that can be processed by a computer, encoded, and the encoded data is preprocessed to form a complete data frame.

[0015] Determine the modulation method, and calculate the transmission power according to the communication distance and link budget requirements; transmit the modulated signal to the UAV in the form of electromagnetic waves through an antenna, and record the sequence number and transmission time of the transmitted data frame at the same time.

[0016] The UAV receives the electromagnetic wave signal and amplifies it through a low-noise amplifier.

[0017] Filter out noise and interference signals through a band-pass filter, and then demodulate to restore the modulated signal to a digital signal; check the checksum and sequence number of the digital signal. If the data frame is correct and the sequence number is within the receiving window, store it in the buffer area and send an acknowledgment frame to the sending end. The acknowledgment frame contains the sequence number of the correctly received data frame.

[0018] Preferably, the signal execution module specifically includes the following:

[0019] The flight control system of the UAV retrieves the correct control instructions from the buffer area and parses the instruction content.

[0020] Control the flight attitude, position, and actions of the UAV according to the instruction parameters.

[0021] The UAV can feedback the instruction execution status to the ground control station through the control channel.

[0022] Preferably, the data processing module specifically includes the following:

[0023] The camera on the UAV collects video image data and obtains image frames at a preset frame rate and resolution.

[0024] Perform preprocessing such as denoising and compression on the collected data.

[0025] Encode the preprocessed data.

[0026] Pack the encoded data, add information such as a frame header, frame tail, sequence number, and timestamp to form a data frame for correct decoding and data integrity verification at the receiving end.

[0027] Confirm the modulation method, calculate the transmission power and bandwidth, and send the modulated signal through the UAV data transmission antenna, while recording the sequence number and transmission time of the transmitted data frame.

[0028] The data receiving antenna of the ground control station receives the electromagnetic wave signal sent by the UAV, and through low-noise amplification, filtering, and down-conversion processing, the high-frequency signal is converted into an intermediate-frequency or baseband signal;

[0029] Adopt the demodulation method corresponding to the sending end to demodulate the data signal from the carrier and restore it to digital data; check the checksum and sequence number of the digital data. If the data frame is correct and the sequence number is within the receiving window, store it in the buffer area and send an acknowledgment frame to the sending end. If the data frame is incorrect or the sequence number is not within the receiving window, discard the data frame and wait for the sending end to retransmit.

[0030] Preferably, the receiving and displaying module specifically includes the following:

[0031] The data processing system of the ground control station decodes the received digital data to restore the original image frame; processes and displays the decoded data, and displays the video image data on the display screen.

[0032] Preferably, the process of analyzing the communication link to determine the timer retransmission duration specifically includes the following:

[0033] Obtain the farthest flight distance between the UAV and the ground station, divide the farthest flight distance by the propagation speed of the signal in the air to obtain the time between the sending end and the receiving end of the signal, and multiply the time by two to obtain the propagation time from the sending end to the receiving end and then back, and mark this propagation time as the return time;

[0034] Obtain the return times corresponding to several previous UAV missions before the current time point, and calculate the average value of the obtained return times corresponding to each mission to obtain the average return time;

[0035] Obtain the data processing rate of the sending end, and calculate the average value of the data frame lengths processed by the sending end each time during several previous UAV missions before the current time point to obtain the average data length per time; divide the average data length per time by the data processing rate of the sending end to obtain the sending time consumption;

[0036] Based on the process of analyzing the data processing time of the sending end to obtain the sending time consumption, analyze the data processing time of the receiving end to obtain the receiving time consumption;

[0037] Sum up the average return time, sending time consumption, receiving time consumption, and margin time to obtain the timer retransmission duration.

[0038] Preferably, the method for obtaining the margin time includes the following parts:

[0039] Obtain the network packet loss rate corresponding to each data transmission between the sender and the receiver during several previous drone missions before the current time point, and a preset packet loss rate threshold. Record the signal transmission processes with packet loss rates greater than the packet loss rate threshold as the number of packet losses, and count all the numbers of packet losses. Divide the total number of all packet losses by the total number of data transmissions to obtain the packet loss ratio;

[0040] Analyze the weather conditions corresponding to several previous drone missions before the current time point, so as to obtain the delay ratio corresponding to each weather condition;

[0041] Determine the delay ratio according to the weather condition when the drone performs the mission at the current moment, and preset the weight factors corresponding to the delay ratio and the packet loss ratio. Multiply the delay ratio and the packet loss ratio by their corresponding weight factors respectively and then sum them to obtain the margin coefficient; and determine the margin time according to the margin coefficient.

[0042] Preferably, the determination of the margin time according to the margin coefficient specifically includes the following content:

[0043] Preset three groups of threshold value ranges, each group of threshold value ranges corresponding to a ratio level. Match the margin coefficient with the three groups of threshold value ranges to obtain the ratio level corresponding to the margin coefficient, where the ratio levels include low ratio level, medium ratio level, and high ratio level, and each ratio level corresponds to a ratio value respectively;

[0044] Multiply the ratio value corresponding to the margin coefficient by the average return time to obtain the margin time.

[0045] Preferably, the timer performs corresponding processing according to the retransmission duration, and the specific content includes:

[0046] Control channel: When the sender successfully sends a data frame, immediately start the corresponding timer to start timing; during the timer timing process, if the acknowledgment frame for this data frame sent by the receiver is not received within the retransmission duration, it is determined as a timeout;

[0047] Once the timer times out, the sender resends this data frame; during retransmission, the sender will encode and modulate the data frame again, and then send it out through the antenna, and at the same time restart the timer to wait for the receiver's acknowledgment;

[0048] If the sender receives a duplicate acknowledgment frame, that is, receives acknowledgment frames for multiple data frames with the same sequence number, corresponding strategies will be adopted according to the specific situation.

[0049] In summary, due to the adoption of the above technical solutions, the beneficial effects of the present invention are:

[0050] 1. Through a comprehensive analysis of the communication link, including calculating the signal round-trip time, the data processing time at the transmitter and receiver, and determining the margin time by integrating the network packet loss rate and weather conditions, the present invention accurately determines the timer retransmission duration. This enables the system to perform data retransmission operations more reasonably in the face of complex communication environments, reducing data loss and improving the success rate and stability of data transmission. Even in adverse weather conditions, the retransmission strategy can be adjusted according to the actual situation to ensure reliable data transmission.

[0051] 2. From the data collection of the drone to the preprocessing, encoding, packaging, modulation, and transmission of image and flight attitude data, and then to the reception, demodulation, verification, and display at the ground control station, the entire data processing module and the reception and display module are closely connected and proceed in an orderly manner. By using efficient modulation methods such as orthogonal frequency division multiplexing modulation and calculating the transmit power and bandwidth in combination with the Shannon formula, different data transmission rate and signal quality requirements are met, ensuring the real-time nature of communication and enabling the ground control station to obtain the information collected by the drone in a timely manner and make accurate decisions. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In the following description of exemplary embodiments with reference to the drawings, more details, features, and advantages of the present application are disclosed. In the drawings:

[0053] Figure 1 is a flowchart of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0054] The following will describe several embodiments of the present application in more detail with reference to the drawings so that those skilled in the art can implement the present application. The present application can be embodied in many different forms and purposes and should not be limited to the embodiments described herein. These embodiments are provided to make the present application comprehensive and complete and to fully convey the scope of the present application to those skilled in the art. The embodiments do not limit the present application.

[0055] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present application belongs. It will be further understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the relevant field and / or the context of this specification and will not be interpreted in an idealized or overly formal sense unless clearly defined herein.

[0056] Please refer to Figure 1 as shown, the present invention provides a technical solution:

[0057] A dual-channel drone line-of-sight communication system, including the following parts:

[0058] Instruction Transmission Module: After the ground control station personnel input an instruction, the instruction is converted into a digital signal and sent to the UAV after corresponding modulation. The UAV processes the received digital signal;

[0059] The instruction transmission module specifically includes the following:

[0060] The operator of the ground control station inputs an instruction according to the mission requirements. The instruction is converted into a digital signal that can be processed by a computer, encoded, and the encoded data is preprocessed to form a complete data frame; The preprocessing includes formatting the encoded instruction and adding information such as a frame header, frame tail, and check bits;

[0061] Determine the modulation method and calculate the transmit power according to the communication distance and link budget requirements; Send the modulated signal to the UAV in the form of electromagnetic waves through an antenna, and record the sequence number and transmission time of the sent data frame;

[0062] If binary phase shift keying modulation is used, its expression is , where is the signal amplitude; is the carrier angular frequency, , where is the carrier frequency; is the phase. When sending "1", , when sending "0", ;

[0063] The formula used to calculate the transmit power is , where is the minimum receive power required at the receiving end;

[0064] is the path loss. The path loss model has a free space path loss model , where is the distance between the transmitting end and the receiving end, is the carrier frequency;

[0065] is the transmitting antenna gain, is the receiving antenna gain;

[0066] The UAV receives the electromagnetic wave signal and amplifies it through a low-noise amplifier, and its gain is . The power of the amplified signal , where is the signal power input to the low-noise amplifier;

[0067] After filtering out noise and interference signals through a band-pass filter, demodulation is then performed to restore the modulated signal to a digital signal; the digital signal is checked for parity and sequence number. If the data frame is correct and the sequence number is within the receiving window, it is stored in the buffer, and an acknowledgment frame is sent to the sending end. The acknowledgment frame contains the sequence number of the correctly received data frame.

[0068] Signal execution module: Analyze the received digital signal to determine the action instructions of the drone, and feedback the instruction execution status to the ground control station.

[0069] The signal execution module specifically includes the following:

[0070] The flight control system of the drone retrieves the correct control instructions from the buffer and analyzes the instruction content; specific parameters such as the rising height and steering angle are parsed.

[0071] Drive actuators such as motors and servos according to the instruction parameters to control the flight attitude, position, and actions of the drone.

[0072] The drone can feedback the instruction execution status to the ground control station through the control channel. The feedback information is also encoded, modulated, etc. before being sent.

[0073] Retransmission module: Analyze the communication link to determine the timer retransmission duration, and the timer performs corresponding processing based on the retransmission duration.

[0074] Analyze the communication link to determine the timer retransmission duration. The specific process includes the following:

[0075] Obtain the maximum flight distance between the drone and the ground station, divide the maximum flight distance by the propagation speed of the signal in the air to get the time from the sending end to the receiving end of the signal, and multiply the time by two to get the propagation time from the sending end to the receiving end and back. Mark this propagation time as the round-trip time.

[0076] Obtain the round-trip times corresponding to several previous drone mission executions before the current time point, and calculate the average value of the obtained round-trip times corresponding to each mission execution to get the average round-trip time.

[0077] Obtain the data processing rate of the sending end, and calculate the average value of the data frame lengths processed by the sending end each time during several previous drone mission executions before the current time point to get the average data length per time; divide the average data length per time by the data processing rate of the sending end to get the sending time consumption.

[0078] Based on the process of analyzing the data processing time of the sending end to obtain the sending time consumption, analyze the data processing time of the receiving end to obtain the receiving time consumption.

[0079] Sum up the feedback equalization time, transmission time, reception time, and remaining time to obtain the timer retransmission duration;

[0080] The method for obtaining the remaining time includes the following parts:

[0081] Obtain the network packet loss rate corresponding to each data transmission between the sender and the receiver during several previous drone missions before the current time point, a preset packet loss rate threshold. Record the signal transmission processes with a packet loss rate greater than the packet loss rate threshold as the number of packet losses, and count all the numbers of packet losses. Divide all the numbers of packet losses by the total number of data transmissions to obtain the packet loss ratio;

[0082] Analyze the weather conditions corresponding to several previous drone missions before the current time point to obtain the delay ratio corresponding to each weather condition;

[0083] Obtain the weather conditions corresponding to several previous drone missions before the current time point, and classify each drone mission according to the weather conditions; where the weather conditions include sunny, rainy, snowy, windy, and thunderstorm;

[0084] Extract all the missions with sunny weather conditions and all the data transmission times included in each mission, and calculate the average value of all the data transmission times within all the missions to obtain the transmission reference time;

[0085] Extract the missions corresponding to weather conditions other than sunny weather respectively, and for each weather condition, calculate the average value of all the data transmission times included in the corresponding missions, and obtain the transmission times corresponding to the weather conditions other than sunny weather respectively;

[0086] Compare the transmission times corresponding to the weather conditions other than sunny weather respectively with the transmission reference time, and record the transmission processes with transmission times greater than the transmission reference time as delayed transmissions;

[0087] Thus, count the number of delayed transmissions corresponding to the weather conditions other than sunny weather respectively, and divide the number of delayed transmissions corresponding to the weather conditions other than sunny weather respectively by their respective total number of transmissions to obtain the delay ratios corresponding to the weather conditions other than sunny weather respectively;

[0088] If there are multiple weather conditions during a drone mission, calculate the sum of the delay ratios corresponding to each weather condition as the delay ratio for this mission;

[0089] Determine the delay ratio based on the weather conditions when the UAV executes tasks at the current moment, preset the weight factors corresponding to the delay ratio and the packet loss ratio, calculate the product of the delay ratio and the packet loss ratio with their corresponding weight factors respectively, and then sum them to obtain the margin coefficient; and determine the margin time based on the margin coefficient.

[0090] Determine the margin time based on the margin coefficient, which specifically includes the following content:

[0091] Preset three groups of threshold value ranges, each group of threshold value ranges corresponding to a ratio level. Match the margin coefficient with the three groups of threshold value ranges to obtain the ratio level corresponding to the margin coefficient, where the ratio levels include low ratio level, medium ratio level, and high ratio level, and each ratio level corresponds to a ratio value respectively.

[0092] Calculate the product of the ratio value corresponding to the margin coefficient and the average return time to obtain the margin time.

[0093] The timer performs corresponding processing according to the retransmission duration, and the specific content includes:

[0094] Control channel: When the sending end successfully sends a data frame, immediately start the corresponding timer to start timing; during the timer timing process, if the acknowledgment frame for this data frame sent by the receiving end is not received within the retransmission duration, it is determined as a timeout.

[0095] Once the timer times out, the sending end re-sends the data frame; during retransmission, the sending end will encode and modulate the data frame again, and then send it out through the antenna, while restarting the timer and waiting for the acknowledgment from the receiving end.

[0096] If the sending end receives duplicate acknowledgment frames, that is, receives acknowledgment frames for multiple data frames with the same sequence number, corresponding strategies will be adopted according to the specific situation.

[0097] For example, the sending window size can be adjusted to reduce the sending rate to avoid further exacerbation of network congestion; the specific adjustment method can be carried out according to the network conditions and the regulations of the communication protocol, such as halving the sending window size to reduce the speed of sending data and observing whether the network conditions improve; set the maximum retransmission times, and when the retransmission times reach the upper limit and the acknowledgment frame has not been received yet, report the transmission failure to the upper layer.

[0098] Data channel: The receiving end determines the sequence numbers of data frames that can be received through the receiving window. When the receiving end receives a data frame, it will first check the sequence number of the data frame. If the sequence number is within the receiving window and the data frame verification is correct, it will be stored in the buffer area, and an acknowledgment frame will be sent to the sending end, and the acknowledgment frame contains the sequence number of the correctly received data frame; if the sequence number is not within the receiving window, the receiving end will discard the data frame and wait for the sending end to retransmit.

[0099] If the receiving end finds that the received data frame has an error or the sequence numbers of the received data frames are not continuous, it indicates that data frames may be lost; at this time, the receiving end will send a retransmission request frame to the sending end, and the request frame contains information such as the sequence number of the data frame that needs to be retransmitted;

[0100] After receiving the request frame, the sending end will find the corresponding data frame that has not been correctly received according to the sequence number information therein, re-encode, pack, modulate it, etc., and then send it out through the antenna; at the same time, the sending end will also update relevant sending status information, such as restarting the timer, etc., to ensure that the data frame can be correctly received;

[0101] To avoid wasting system resources and degrading performance due to infinite retransmissions, the system will set an upper limit on the number of retransmissions; when the number of retransmissions of a certain data frame by the sending end reaches the upper limit, if the correct acknowledgment from the receiving end has still not been received, the sending end will consider that the data frame cannot be successfully transmitted, and then take some other measures, such as discarding the data frame and reporting the transmission failure to the upper-layer application;

[0102] According to the retransmission situation, the sending end and the receiving end can dynamically adjust the communication strategy; for example, if the number of retransmissions is frequent, it may mean that the network condition is poor. The sending end can reduce the data transmission rate or adopt a more reliable coding method to improve the success rate of data transmission; the receiving end can also appropriately increase the size of the receiving window;

[0103] Data processing module: The drone preprocesses the acquired images, encodes and packs them, modulates them, and sends them to the ground control station;

[0104] The data processing module specifically includes the following:

[0105] The camera on the drone collects video image data and obtains image frames at a preset frame rate and resolution;

[0106] Other sensors such as the inertial measurement unit collect flight attitude data, including acceleration, angular velocity, attitude angle, etc. The analog signals output by the sensors are converted into digital signals through an analog-to-digital converter;

[0107] Perform preprocessing such as denoising and compression on the collected data;

[0108] Encode the preprocessed data, such as encoding the video image data using the H.264 encoding standard;

[0109] Pack the encoded data, add information such as a frame header, a frame tail, a sequence number, a timestamp, etc., to form a data frame for correct decoding and data integrity verification at the receiving end;

[0110] Confirm the modulation method, calculate the transmission power and bandwidth, and send the modulated signal through the UAV data transmission antenna. At the same time, record the sequence number of the transmitted data frame and the transmission time;

[0111] The modulation method is orthogonal frequency division multiplexing modulation, and its signal expression is , where is the modulation symbol on the th subcarrier, is the subcarrier spacing, is the number of subcarriers;

[0112] Calculate the transmission power and bandwidth. According to the data transmission rate and signal quality requirements, the required bandwidth can be calculated by the Shannon formula where is the data transmission rate, is the signal power, is the noise power; is the noise power;

[0113] The data receiving antenna of the ground control station receives the electromagnetic wave signal sent by the UAV, and through low-noise amplification, filtering, and down-conversion processing, converts the high-frequency signal into an intermediate-frequency or baseband signal;

[0114] Adopt the demodulation method corresponding to the sending end to demodulate the data signal from the carrier and restore it to digital data; check the checksum and sequence number of the digital data. If the data frame is correct and the sequence number is within the receiving window, store it in the buffer area and send an acknowledgment frame to the sending end. If the data frame is incorrect or the sequence number is not within the receiving window, discard the data frame and wait for the sending end to retransmit;

[0115] Receiving and displaying module: The ground control station decodes the received digital data and displays the decoded data;

[0116] The receiving and displaying module specifically includes the following content:

[0117] The data processing system of the ground control station decodes the received digital data, such as decoding the H.264-encoded video data to restore the original image frames; processes and displays the decoded data, displays the video image data on the display screen, and displays the UAV flight attitude data and other data in the form of charts, numbers, etc. on the display screen.

[0118] The above formulas are all obtained by collecting a large amount of data for software simulation and selecting a formula close to the true value. The influence weight factors and specific coefficient values in the formulas are set by those skilled in the art according to the actual situation and can be adjusted and modified later.

[0119] The foregoing description of the embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A dual-channel UAV line-of-sight communication system, characterized in that, It includes the following parts: Instruction transmission module: After the ground control station personnel input instructions, the instructions are converted into digital signals, modulated accordingly and sent to the UAV. The UAV processes the received digital signals; Signal execution module: Analyze the received digital signals to determine the action instructions of the UAV, and feedback the execution status of the instructions to the ground control station; Retransmission module: Analyze the communication link to determine the timer retransmission duration. The timer performs corresponding processing according to the retransmission duration. The specific content includes: Obtain the maximum flight distance between the UAV and the ground station, divide the maximum flight distance by the propagation speed of the signal in the air to obtain the time from the sending end to the receiving end of the signal, multiply the time by two to obtain the propagation time from the sending end to the receiving end and then back, and mark this propagation time as the return time; Obtain the return times corresponding to several previous UAV missions before the current time point, and calculate the average value of the obtained return times corresponding to each mission to obtain the average return time; Obtain the data processing rate of the sending end, and calculate the average value of the data frame lengths processed by the sending end each time during several previous UAV missions before the current time point to obtain the average data length per time; Divide the average data length per time by the data processing rate of the sending end to obtain the sending time consumption; Based on the process of analyzing the data processing time of the sending end to obtain the sending time consumption, analyze the data processing time of the receiving end to obtain the receiving time consumption; Sum up the average return time, sending time consumption, receiving time consumption and margin time to obtain the timer retransmission duration; The method for obtaining the margin time includes the following parts: Obtain the network packet loss rate corresponding to each data transmission by the sending end and the receiving end during several previous UAV missions before the current time point, preset the packet loss rate threshold, record the signal transmission processes with packet loss rate greater than the packet loss rate threshold as the number of packet losses, count all the numbers of packet losses, and divide all the numbers of packet losses by the total number of data transmissions to obtain the packet loss ratio; Analyze the weather conditions corresponding to several previous UAV missions before the current time point to obtain the delay ratio corresponding to each weather condition; Determine the delay ratio according to the weather condition when the UAV performs the mission at the current moment, preset the weight factors corresponding to the delay ratio and the packet loss ratio, multiply the delay ratio and the packet loss ratio by their corresponding weight factors respectively and then sum them up to obtain the margin coefficient; And determine the margin time according to the margin coefficient, which specifically includes the following content: Preset three groups of threshold value ranges, each group of threshold value ranges corresponds to a ratio level, match the margin coefficient with the three groups of threshold value ranges to obtain the ratio level corresponding to the margin coefficient, where the ratio levels include low ratio level, medium ratio level, high ratio level, and each ratio level corresponds to a ratio value respectively; Multiply the ratio value corresponding to the margin coefficient by the average return time to obtain the margin time; Control Channel: When the sender successfully sends a data frame, it immediately starts the corresponding timer to start timing; during the timer timing process, if an acknowledgment frame for this data frame sent by the receiver is not received within the retransmission duration, it is determined as a timeout; Once the timer times out, the sender re-sends the data frame; during retransmission, the sender will encode and modulate the data frame again, and then send it out through the antenna, while restarting the timer and waiting for the receiver's acknowledgment; If the sender receives duplicate acknowledgment frames, that is, receives acknowledgment frames for multiple data frames with the same sequence number, it will adopt corresponding strategies according to the specific situation; Data Processing Module: The drone preprocesses the acquired images, encodes and packs them, modulates them, and sends them to the ground control station; Receiving and Displaying Module: The ground control station decodes the received digital data and displays the decoded data.

2. The dual-channel UAV line-of-sight communication system according to claim 1, wherein The instruction transmission module specifically includes the following: The operator of the ground control station inputs instructions according to the mission requirements. The instructions are converted into digital signals that can be processed by a computer, encoded, and preprocessed on the encoded data to form a complete data frame; Determine the modulation method and calculate the transmit power according to the communication distance and link budget requirements; send the modulated signal to the drone in the form of electromagnetic waves through the antenna, and at the same time record the sequence number and transmission time of the sent data frame; The drone receives the electromagnetic wave signal and amplifies it through a low-noise amplifier; Filter out noise and interference signals through a band-pass filter, and then demodulate to restore the modulated signal to a digital signal; perform a checksum and sequence number check on the digital signal. If the data frame is correct and the sequence number is within the receiving window, store it in the buffer area and send an acknowledgment frame to the sender. The acknowledgment frame contains the sequence number of the correctly received data frame.

3. A dual-channel UAV line-of-sight communication system according to claim 1, characterized in that, The signal execution module specifically includes the following: The flight control system of the drone takes out the correct control instructions from the buffer area and parses the instruction content; Control the flight attitude, position, and actions of the drone according to the instruction parameters; The drone can feedback the instruction execution situation to the ground control station through the control channel.

4. A two-channel UAV line-of-sight communication system according to claim 1, characterized in that, The data processing module specifically includes the following: The camera on the drone collects video image data and obtains image frames at a preset frame rate and resolution; Perform denoising and compression preprocessing on the collected data; Encode the preprocessed data; Pack the encoded data, add frame headers, frame tails, sequence numbers, and timestamp information to form a data frame for correct decoding and data integrity verification at the receiving end; Confirm the modulation method, calculate the transmit power and bandwidth, and send the modulated signal through the drone data transmission antenna, while recording the sequence number and transmission time of the sent data frame; The data receiving antenna of the ground control station receives the electromagnetic wave signal sent by the drone, and after low-noise amplification, filtering, and down-conversion processing, converts the high-frequency signal into an intermediate-frequency or baseband signal; Adopt the demodulation method corresponding to the sending end to demodulate the data signal from the carrier wave and restore it to digital data; perform checksum and sequence number checks on the digital data. If the data frame is correct and the sequence number is within the receiving window, store it in the buffer area and send an acknowledgment frame to the sending end. If the data frame is incorrect or the sequence number is not within the receiving window, discard the data frame and wait for the sending end to retransmit.

5. A dual-channel UAV line-of-sight communication system according to claim 1, characterized in that, The receiving and displaying module specifically includes the following: The data processing system of the ground control station decodes the received digital data and restores it to the original image frame; processes and displays the decoded data, and displays the video image data on the display screen.

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