Two-channel unmanned aerial vehicle sight distance communication system

Abstract

The invention particularly relates to a two-channel unmanned aerial vehicle sight distance communication system, and relates to the technical field of unmanned aerial vehicle communication. A signal execution module; a retransmission module; a data processing module; and a receiving and displaying module. According to the invention, comprehensive analysis on a communication link comprises calculation of signal return time, data processing time consumption of a sending end and a receiving end, and determination of margin time by integrating a network packet loss rate and weather conditions, so that the retransmission duration of a timer is accurately determined; therefore, when facing a complex communication environment, the system can perform data retransmission operation more reasonably, data loss is reduced, the success rate and stability of data transmission are improved, a retransmission strategy can be adjusted according to actual conditions even in severe weather, and reliable data transmission is ensured.

Description

Technical Field

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

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

[0003] However, even with the support of a dual-channel communication system, once a data transmission problem is encountered during the data transmission process, the drone communication system needs to determine the sending and receiving status of the confirmation frame based on the timer retransmission duration. Currently, the setting of the timer retransmission duration is only based on an approximate range, lacking precise consideration and dynamic adjustment of the actual situation. For example, in different weather conditions and when the flight distance changes, the duration cannot be optimized accordingly. This leads to problems such as data packet loss and transmission delays during data transmission, which affects the quality of data transmission. It can be seen that there is a lot of room for improvement in the existing method of determining the timer retransmission duration; Therefore, a dual-channel UAV line-of-sight communication system is proposed to address the above-mentioned problems. Summary of the invention

[0004] The purpose of the present invention is to propose a dual-channel UAV line-of-sight communication system in order to solve the above-mentioned problem.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: A dual-channel UAV line-of-sight communication system includes the following parts: Command transmission module: After the ground control station personnel input the command, the command is converted into a digital signal and sent to the drone after corresponding modulation. The drone processes the received digital signal; Signal execution module: parses the received digital signal to determine the drone's action instructions and feeds back the execution of the instructions to the ground control station; Retransmission module: Analyzes the communication link to determine the timer retransmission duration, and the timer performs corresponding processing based on the retransmission duration; Data processing module: The drone will pre-process the acquired images, encode and package them, modulate them, and send them to the ground control station; Receiving and display module: The ground control station decodes the received digital data and displays the decoded data.

[0006] Preferably, the instruction transmission module specifically includes the following contents: The operator at the ground control station inputs instructions according to the mission requirements. The instructions are converted into digital signals that can be processed by the computer, encoded, and the encoded data is pre-processed to form a complete data frame; Determine the modulation method and calculate the transmission power based on the communication distance and link budget requirements; send the modulated signal to the drone in the form of electromagnetic waves through the antenna, and record the sent data frame sequence number and sending time; The drone receives the electromagnetic wave signal and amplifies it through a low-noise amplifier; The noise and interference signals are filtered out by a bandpass filter, and then demodulated to restore the modulated signal to a digital signal; the digital signal is verified and the sequence number is checked. If the data frame is correct and the sequence number is within the receiving window, it is stored in the buffer area and a confirmation frame is sent to the sender. The confirmation frame contains the sequence number of the correctly received data frame.

[0007] Preferably, the signal execution module specifically includes the following contents: The UAV's flight control system retrieves the correct control instructions from the cache and parses the instruction content; Control the flight attitude, position and movement of the drone according to the command parameters; The UAV can feed back the command execution status to the ground control station through the control channel.

[0008] Preferably, the data processing module specifically includes the following contents: The camera on the drone collects video image data and obtains image frames at a preset frame rate and resolution; After preprocessing the collected data such as denoising and compression, the image is compressed; Encode the preprocessed data; Pack the encoded data, add frame header, frame footer, sequence number, timestamp and other information to form a data frame, so as to perform correct decoding and data integrity verification at the receiving end; Confirm the modulation mode, calculate the transmission power and bandwidth, send the modulated signal through the drone data transmitting antenna, and record the sent data frame sequence number and sending time; The data receiving antenna of the ground control station receives the electromagnetic wave signal sent by the drone, and converts the high-frequency signal into an intermediate frequency or baseband signal through low-noise amplification, filtering, and down-conversion processing; Use the demodulation method corresponding to the sending end to demodulate the data signal from the carrier and restore it to digital data; perform verification and sequence number check 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 a confirmation frame to the sending end. If the data frame is wrong or the sequence number is not within the receiving window, discard the data frame and wait for the sending end to retransmit.

[0009] Preferably, the receiving and displaying module specifically includes the following contents: 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.

[0010] Preferably, the communication link is analyzed to determine the timer retransmission duration, and the specific process includes the following: Get the longest flight distance between the UAV and the ground station, and divide the longest flight distance by the propagation speed of the signal in the air to get the time between the signal sending end and the receiving end. Multiply the time by two to get the propagation time of the signal from the sending end to the receiving end and then back. Mark the propagation time as the return time. Obtain the return time corresponding to the several times when the drone performed tasks before the current time point, and calculate the average return time corresponding to each execution task to obtain the average return time; Obtain the data processing rate of the sender, and calculate the average length of the data frame processed by the sender each time when the drone performs tasks several times before the current time point to obtain the average data length; divide the average data length by the data processing rate of the sender to obtain the sending time; According to the above process of analyzing the data processing time of the sending end to obtain the sending time, the data processing time of the receiving end is analyzed to obtain the receiving time; The timer retransmission duration is calculated by summing up the average return time, the sending time, the receiving time and the remaining time.

[0011] Preferably, the method for obtaining the margin time includes the following parts: Obtain the network packet loss rate corresponding to each data transmission between the sender and the receiver when the drone performs tasks several times before the current time point, preset a packet loss rate threshold, record the signal transmission process with a packet loss rate greater than the packet loss rate threshold as the number of packet losses, and count all the packet losses, and divide all the packet losses by the total number of data transmissions to get the packet loss ratio; The weather conditions corresponding to the UAV's missions before the current time point are analyzed to obtain the delay ratio corresponding to each weather condition; The delay ratio is determined according to the weather conditions at the current moment when the UAV is performing the mission, and the weight factors corresponding to the delay ratio and the packet loss ratio are preset. The delay ratio and the packet loss ratio are multiplied by their corresponding weight factors and then summed to obtain the margin coefficient; and the margin time is determined according to the margin coefficient.

[0012] Preferably, the determining of the margin time according to the margin coefficient specifically includes the following contents: Three groups of threshold value ranges are preset, each group of threshold value ranges corresponds to a proportion level, and the residual coefficient is matched with the three groups of threshold value ranges to obtain the proportion level corresponding to the residual coefficient, wherein the proportion value includes a low proportion level, a medium proportion level, and a high proportion level, and each proportion level corresponds to a proportion value; The surplus duration is calculated by multiplying the ratio value corresponding to the surplus coefficient by the return average time.

[0013] Preferably, the timer performs corresponding processing according to the retransmission duration, and the specific contents include: Control channel: When the sender successfully sends a data frame, the corresponding timer is immediately started and starts timing. During the timer timing process, if the receiver does not receive an acknowledgment frame for the data frame within the retransmission time, it is considered to have timed out. Once the timer times out, the sender resends the data confirmation frame. During retransmission, the sender will encode and modulate the data frame again, then send it out through the antenna, and restart the timer to wait for the receiver's confirmation. If the sender receives duplicate confirmation frames, that is, receives confirmation frames for multiple data frames with the same sequence number, it will adopt corresponding strategies according to the specific situation.

[0014] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. The present invention conducts a comprehensive analysis of the communication link, including calculating the signal return time, the data processing time of the sender and the receiver, and determining the margin time based on the comprehensive 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 when facing a complex communication environment, reduce data loss, and improve the success rate and stability of data transmission. Even in bad weather, the retransmission strategy can be adjusted according to the actual situation to ensure reliable data transmission.

[0015] 2. The present invention closely links the entire data processing module and the receiving and display module process in an orderly manner, from the data collection of the UAV to the preprocessing, encoding, packaging, modulation and sending of the image and flight attitude data, and then to the reception, demodulation, verification and display at the ground control station. It adopts efficient modulation methods such as orthogonal frequency division multiplexing modulation, combined with the Shannon formula to calculate the transmission power and bandwidth, meets the requirements of different data transmission rates and signal quality, ensures the real-time communication, and enables the ground control station to obtain the information collected by the UAV in time and make accurate decisions. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Further details, features and advantages of the present application are disclosed in the following description of exemplary embodiments in conjunction with the accompanying drawings, in which: Figure 1 is a flow chart of the present invention; DETAILED DESCRIPTION

[0017] Several embodiments of the present application will be described in more detail below with reference to the accompanying 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.

[0018] 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 this 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 art and / or the context of this specification, and will not be interpreted in an idealized or overly formal sense unless explicitly defined as such herein.

[0019] See also Figure 1 As shown, the present invention provides a technical solution: A dual-channel UAV line-of-sight communication system includes the following parts: Command transmission module: After the ground control station personnel input the command, the command is converted into a digital signal and sent to the drone after corresponding modulation. The drone processes the received digital signal; The instruction transmission module specifically includes the following contents: The operator at the ground control station inputs instructions according to the task requirements. The instructions are converted into digital signals that can be processed by the computer, encoded, and pre-processed to form a complete data frame; pre-processing includes formatting the encoded instructions and adding frame headers, frame trailers, check bits and other information; Determine the modulation method and calculate the transmission power based on the communication distance and link budget requirements; send the modulated signal to the drone in the form of electromagnetic waves through the antenna, and record the sent data frame sequence number and sending time; If binary phase shift keying modulation is used, the expression is: ,in is the signal amplitude; is the carrier angular frequency, ,in is the carrier frequency; is the phase. When "1" is sent, , when sending "0", ; The formula used to calculate the transmit power is ,in is the minimum receiving power required by the receiving end; It is the path loss. The path loss model has the free space path loss model. ,in is the distance between the transmitter and the receiver, is the carrier frequency; is the transmit antenna gain, is the receiving antenna gain; The drone receives the electromagnetic wave signal and amplifies it through a low-noise amplifier, and its gain is , the amplified signal power ,in is the signal power input to the low noise amplifier; The noise and interference signals are filtered out by a bandpass filter, and then demodulated to restore the modulated signal to a digital signal; the digital signal is checked for verification and sequence number. If the data frame is correct and the sequence number is within the receiving window, it is stored in the buffer area and a confirmation frame is sent to the sender. The confirmation frame contains the sequence number of the correctly received data frame; Signal execution module: parses the received digital signal to determine the drone's action instructions and feeds back the execution of the instructions to the ground control station; The signal execution module specifically includes the following contents: The UAV's flight control system retrieves the correct control instructions from the cache and parses the contents of the instructions, such as the specific parameters such as the ascent height and the steering angle. Drive motors, servos and other actuators according to command parameters to control the flight attitude, position and movement of the drone; The UAV can feed back the command execution status to the ground control station through the control channel, and the feedback information is also encoded, modulated and sent; Retransmission module: Analyzes the communication link to determine the timer retransmission duration, and the timer performs corresponding processing based on the retransmission duration; The communication link is analyzed to determine the timer retransmission duration. The specific process includes the following: Get the longest flight distance between the UAV and the ground station, and divide the longest flight distance by the propagation speed of the signal in the air to get the time between the signal sending end and the receiving end. Multiply the time by two to get the propagation time of the signal from the sending end to the receiving end and then back. Mark the propagation time as the return time. Obtain the return time corresponding to the several times when the drone performed tasks before the current time point, and calculate the average return time corresponding to each execution task to obtain the average return time; Obtain the data processing rate of the sender, and calculate the average length of the data frame processed by the sender each time when the drone performs tasks several times before the current time point to obtain the average data length; divide the average data length by the data processing rate of the sender to obtain the sending time; According to the above process of analyzing the data processing time of the sending end to obtain the sending time, the data processing time of the receiving end is analyzed to obtain the receiving time; The timer retransmission duration is calculated by summing up the average return time, the sending time, the receiving time and the remaining time; The method of obtaining the margin time includes the following parts: Obtain the network packet loss rate corresponding to each data transmission between the sender and the receiver when the drone performs tasks several times before the current time point, preset a packet loss rate threshold, record the signal transmission process with a packet loss rate greater than the packet loss rate threshold as the number of packet losses, and count all the packet losses, and divide all the packet losses by the total number of data transmissions to get the packet loss ratio; The weather conditions corresponding to the UAV's missions before the current time point are analyzed to obtain the delay ratio corresponding to each weather condition; Obtain the weather conditions corresponding to the several drone missions before the current time point, and classify each drone mission according to the weather conditions; the weather conditions include sunny, rainy, snowy, windy, and thunder and lightning; Extract all execution tasks when the weather condition is sunny, as well as all data transmission times included in each execution task, and calculate the average of all data transmission times in all execution tasks to obtain the transmission reference time; Extract the execution tasks corresponding to the weather conditions other than the sunny weather condition respectively, and calculate the average of all the data transmission times included in the execution tasks corresponding to each weather condition, and obtain the transmission times corresponding to the weather conditions other than the sunny weather condition respectively; The transmission times corresponding to the weather conditions other than the sunny weather condition are respectively compared with the transmission reference time, and the transmission process corresponding to the transmission time greater than the transmission reference time is recorded as delayed transmission; Thus, the number of delayed transmissions corresponding to the weather conditions other than the sunny weather condition is counted, and the number of delayed transmissions corresponding to the weather conditions other than the sunny weather condition is divided by the total number of transmissions corresponding to each of the weather conditions, to obtain the delay ratios corresponding to the weather conditions other than the sunny weather condition; If there are multiple weather conditions when the drone performs a mission, the delay ratio corresponding to each weather condition will be summed up and used as the delay ratio for the mission. The delay ratio is determined according to the weather conditions at the current moment when the UAV is performing the mission, and the weight factors corresponding to the delay ratio and the packet loss ratio are preset. The delay ratio and the packet loss ratio are multiplied by their corresponding weight factors and then summed to obtain the margin coefficient; and the margin time is determined according to the margin coefficient; The margin time is determined based on the margin coefficient, which specifically includes the following: Three groups of threshold value ranges are preset, each group of threshold value ranges corresponds to a proportion level, and the residual coefficient is matched with the three groups of threshold value ranges to obtain the proportion level corresponding to the residual coefficient, wherein the proportion value includes a low proportion level, a medium proportion level, and a high proportion level, and each proportion level corresponds to a proportion value; The surplus time is calculated by multiplying the ratio value corresponding to the surplus coefficient by the average return time; The timer performs corresponding processing based on the retransmission duration, including: Control channel: When the sender successfully sends a data frame, the corresponding timer is immediately started and starts timing. During the timer timing process, if the receiver does not receive an acknowledgment frame for the data frame within the retransmission time, it is considered to have timed out. Once the timer times out, the sender resends the data confirmation frame. During retransmission, the sender will encode and modulate the data frame again, then send it out through the antenna, and restart the timer to wait for the receiver's confirmation. If the sender receives duplicate confirmation frames, that is, it receives confirmation frames for multiple data frames with the same sequence number, it will adopt the corresponding strategy according to the specific situation; For example, the sending window size can be adjusted to reduce the sending rate to avoid further aggravation of network congestion; the specific adjustment method can be made according to the network conditions and the provisions of the communication protocol, such as halving the sending window size to reduce the speed of sending data and observe whether the network conditions are improved; setting the maximum number of retransmissions, when the number of retransmissions reaches the upper limit and no confirmation frame is received, reporting the transmission failure to the upper layer; Data channel: The receiving end determines the sequence number of the data frame that can be received through the receiving window. When the receiving end receives the 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 is verified correctly, it will be stored in the buffer area and a confirmation frame will be sent to the sending end. The confirmation 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; If the receiving end finds that the received data frame has errors, or the received data frame sequence number is discontinuous, it indicates that the data frame 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 to be retransmitted; After receiving the request frame, the sender will find the corresponding data frame that was not received correctly according to the sequence number information in it, re-encode, package, modulate and other operations on it, and then send it out through the antenna; at the same time, the sender will also update the relevant sending status information, such as restarting the timer, to ensure that the data frame can be received correctly; To avoid wasting system resources and degrading performance due to infinite retransmissions, the system sets an upper limit on the number of retransmissions. When the sender reaches the upper limit for a data frame, if it still does not receive a correct confirmation from the receiver, the sender will consider that the data frame cannot be successfully transmitted and take other measures, such as discarding the data frame and reporting the transmission failure to the upper-layer application. According to the retransmission situation, the sender and receiver 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 sender can reduce the data transmission rate or use a more reliable encoding method to improve the success rate of data transmission; the receiver can also appropriately expand the receiving window size; Data processing module: The drone will pre-process the acquired images, encode and package them, modulate them, and send them to the ground control station; The data processing module specifically includes the following contents: The camera on the drone collects video image data and obtains image frames at a preset frame rate and resolution; Other sensors such as inertial measurement units collect flight attitude data, including acceleration, angular velocity, attitude angle, etc. The analog signals output by the sensors are converted into digital signals through analog-to-digital converters; After preprocessing the collected data such as denoising and compression, the image is compressed; Encoding the preprocessed data, such as encoding the video image data using the H.264 encoding standard; Pack the encoded data, add frame header, frame footer, sequence number, timestamp and other information to form a data frame, so as to perform correct decoding and data integrity verification at the receiving end; Confirm the modulation mode, calculate the transmission power and bandwidth, send the modulated signal through the drone data transmitting antenna, and record the sent data frame sequence number and sending time; The modulation method is orthogonal frequency division multiplexing modulation, and its signal expression is ,in It is The modulation symbols on the subcarriers are is the subcarrier spacing, is the number of subcarriers; The transmit power and bandwidth can be calculated based on the data transmission rate and signal quality requirements using the Shannon formula Calculate the required bandwidth ,in is the data transfer rate, is the signal power, is the noise power; The data receiving antenna of the ground control station receives the electromagnetic wave signal sent by the drone, and converts the high-frequency signal into an intermediate frequency or baseband signal through low-noise amplification, filtering, and down-conversion processing; Adopt the demodulation method corresponding to the sending end, demodulate the data signal from the carrier and restore it to digital data; check the digital data and the sequence number. If the data frame is correct and the sequence number is within the receiving window, store it in the buffer area and send a confirmation frame to the sending end. If the data frame is wrong or the sequence number is not within the receiving window, discard the data frame and wait for the sending end to retransmit; Receiving and display module: The ground control station decodes the received digital data and displays the decoded data; The receiving and display module specifically includes the following contents: The data processing system of the ground control station decodes the received digital data, such as decoding H.264-encoded video data, and restores it to the original image frame; it processes and displays the decoded data, displays the video image data on the display screen, and displays the UAV flight attitude data on the display screen in the form of charts, numbers, etc.

[0020] The above formulas are obtained by collecting a large amount of data and performing software simulation, and a formula close to the actual value is selected. The influencing weight factor and specific coefficient value in the formula are set by technical personnel in this field according to actual conditions, and can be adjusted and modified later.

[0021] The above description of the embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be 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. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to 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: Includes the following sections: Command transmission module: After the ground control station personnel input the command, the command is converted into a digital signal and sent to the drone after corresponding modulation. The drone processes the received digital signal; Signal execution module: parses the received digital signal to determine the drone's action instructions and feeds back the execution of the instructions to the ground control station; Retransmission module: Analyzes the communication link to determine the timer retransmission duration. The timer performs corresponding processing based on the retransmission duration. The specific contents include: Control channel: When the sender successfully sends a data frame, the corresponding timer is immediately started and starts timing. During the timer timing process, if the receiver does not receive an acknowledgment frame for the data frame within the retransmission time, it is considered to have timed out. Once the timer times out, the sender resends the data confirmation frame. During retransmission, the sender will encode and modulate the data frame again, then send it out through the antenna, and restart the timer to wait for the receiver's confirmation. If the sender receives duplicate confirmation frames, that is, it receives confirmation frames for multiple data frames with the same sequence number, it will adopt the corresponding strategy according to the specific situation; Data processing module: The drone will pre-process the acquired images, encode and package them, modulate them, and send them to the ground control station; Receiving and display module: The ground control station decodes the received digital data and displays the decoded data.

2. A dual-channel UAV line-of-sight communication system according to claim 1, characterized in that: The instruction transmission module specifically includes the following contents: The operator at the ground control station inputs instructions according to the mission requirements. The instructions are converted into digital signals that can be processed by the computer, encoded, and the encoded data is pre-processed to form a complete data frame; Determine the modulation method and calculate the transmission power based on the communication distance and link budget requirements; send the modulated signal to the drone in the form of electromagnetic waves through the antenna, and record the sent data frame sequence number and sending time; The drone receives the electromagnetic wave signal and amplifies it through a low-noise amplifier; The noise and interference signals are filtered out by a bandpass filter, and then demodulated to restore the modulated signal to a digital signal; the digital signal is verified and the sequence number is checked. If the data frame is correct and the sequence number is within the receiving window, it is stored in the buffer area and a confirmation frame is sent to the sender. The confirmation 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 contents: The UAV's flight control system retrieves the correct control instructions from the cache and parses the instruction content; Control the flight attitude, position and movement of the drone according to the command parameters; The UAV can feed back the command execution status to the ground control station through the control channel.

4. A dual-channel UAV line-of-sight communication system according to claim 1, characterized in that: The data processing module specifically includes the following contents: The camera on the drone collects video image data and obtains image frames at a preset frame rate and resolution; After denoising and compressing the collected data, the image is compressed; Encode the preprocessed data; Pack the encoded data, add frame header, frame footer, sequence number, and timestamp information to form a data frame, so that correct decoding and data integrity verification can be performed at the receiving end; Confirm the modulation mode, calculate the transmission power and bandwidth, send the modulated signal through the drone data transmitting antenna, and record the sent data frame sequence number and sending time; The data receiving antenna of the ground control station receives the electromagnetic wave signal sent by the drone, and converts the high-frequency signal into an intermediate frequency or baseband signal through low-noise amplification, filtering, and down-conversion processing; Use the demodulation method corresponding to the sending end to demodulate the data signal from the carrier and restore it to digital data; perform verification and sequence number check 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 a confirmation frame to the sending end. If the data frame is wrong or the sequence number is not within the receiving window, discard the data frame and wait for the sending end to retransmit.

5. The dual-channel UAV line-of-sight communication system according to claim 1 is characterized in that: The receiving and displaying module specifically includes the following contents: 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.

6. A dual-channel UAV line-of-sight communication system according to claim 1, characterized in that: The communication link is analyzed to determine the timer retransmission duration, and the specific process includes the following: Get the longest flight distance between the UAV and the ground station, and divide the longest flight distance by the propagation speed of the signal in the air to get the time between the signal sending end and the receiving end. Multiply the time by two to get the propagation time of the signal from the sending end to the receiving end and then back. Mark the propagation time as the return time. Obtain the return time corresponding to the several times when the drone performed tasks before the current time point, and calculate the average return time corresponding to each execution task to obtain the average return time; Obtain the data processing rate of the sender, and calculate the average length of the data frame processed by the sender each time when the drone performs tasks several times before the current time point to obtain the average data length; divide the average data length by the data processing rate of the sender to obtain the sending time; The sending time is obtained by analyzing the data processing time of the sending end, and the receiving time is obtained by analyzing the data processing time of the receiving end; The timer retransmission duration is calculated by summing up the average return time, the sending time, the receiving time and the remaining time.

7. A dual-channel UAV line-of-sight communication system according to claim 6, characterized in that: The method for obtaining the margin time includes the following parts: Obtain the network packet loss rate corresponding to each data transmission between the sender and the receiver when the drone performs tasks several times before the current time point, preset a packet loss rate threshold, record the signal transmission process with a packet loss rate greater than the packet loss rate threshold as the number of packet losses, and count all the packet losses, and divide all the packet losses by the total number of data transmissions to get the packet loss ratio; The weather conditions corresponding to the UAV's missions before the current time point are analyzed to obtain the delay ratio corresponding to each weather condition; The delay ratio is determined according to the weather conditions at the current moment when the UAV is performing the mission, and the weight factors corresponding to the delay ratio and the packet loss ratio are preset. The delay ratio and the packet loss ratio are multiplied by their corresponding weight factors and then summed to obtain the margin coefficient; and the margin time is determined according to the margin coefficient.

8. A dual-channel UAV line-of-sight communication system according to claim 7, characterized in that: Determining the margin time according to the margin coefficient specifically includes the following contents: Three groups of threshold value ranges are preset, each group of threshold value ranges corresponds to a proportion level, and the residual coefficient is matched with the three groups of threshold value ranges to obtain the proportion level corresponding to the residual coefficient, wherein the proportion value includes a low proportion level, a medium proportion level, and a high proportion level, and each proportion level corresponds to a proportion value; The surplus duration is calculated by multiplying the ratio value corresponding to the surplus coefficient by the return average time.

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