Method and medium for realizing multi-link switching and redundancy transmission of low-altitude aircraft

Abstract

The invention discloses a method for realizing multi-link switching and redundancy transmission of a low-altitude aircraft and a medium, and belongs to the technical field of low-altitude aircrafts, and the method comprises the steps: constructing communication links between the low-altitude aircraft and a ground control center, and dynamically detecting the quality index of each communication link; calculating a comprehensive quality evaluation value of the communication link according to the detected quality index; determining the state of the communication link according to the comprehensive quality evaluation value of the communication link; and performing multi-link switching and redundancy transmission according to the communication link state. According to the method, link state grading, dynamic strategy switching and key data redundancy guarantee are achieved, communication stability and system resource optimization are both considered, and robustness and real-time performance of aircraft communication are improved.

Description

Technical Field

[0001] The present invention relates to a method and medium for realizing multi-link switching and redundant transmission of low-altitude aircraft, belonging to the technical field of low-altitude aircraft. Background Art

[0002] With the rapid development of low-altitude aircraft, especially electric vertical takeoff and landing aircraft, in the fields of urban air transportation, emergency rescue, etc., higher requirements are put forward for the reliability and real-time performance of their communication systems. To ensure flight safety and mission continuity, low-altitude aircraft are usually equipped with multiple communication links to achieve stable backhaul of flight data, system status, and environmental perception information.

[0003] In the prior art, multi-link communication strategies are mainly divided into two categories: one is to adopt a pure redundant transmission mechanism, that is, the same data is simultaneously sent to the ground end through multiple links; the other is to adopt a link switching mechanism, that is, switch to the backup link when the main link fails or the performance drops to a certain threshold. The pure redundant mechanism can improve the reliability of data transmission, but it will cause waste of bandwidth resources, increase in energy consumption, and increase in system processing overhead. The pure switching mechanism can optimize resource utilization, but there is a risk of data loss during the gradual deterioration of link quality, and the switching delay may affect the timeliness of flight control data, bringing potential safety hazards.

[0004] Some technical solutions dynamically allocate data streams based on link performance weights. Although they can achieve a certain degree of resource optimization, they usually lack a clear link state classification standard and cannot adopt targeted transmission strategies for different quality conditions. At the same time, existing multi-link management solutions generally ignore the distinction processing of the importance of data packets, and all data adopts a unified transmission strategy, resulting in the inability to effectively guarantee the transmission reliability of key control data in resource-constrained or link-deteriorated environments.

[0005] In summary, the existing multi-link communication technologies for low-altitude aircraft still have deficiencies in dynamic link state perception, strategy switching accuracy, key data guarantee, and system resource utilization efficiency. There is an urgent need for a multi-link management method that can perform refined state division according to real-time link quality changes, and accordingly flexibly adjust transmission strategies, while taking into account communication reliability and resource optimization utilization, so as to improve the stability and flight safety of low-altitude aircraft in complex communication environments. Summary of the Invention

[0006] The purpose of the present invention is to overcome the deficiencies in the prior art, provide a method for realizing multi-link switching and redundant transmission of low-altitude aircraft, solve the problem of the lack of intelligent switching and differential transmission mechanisms in multi-link communication of low-altitude aircraft, and improve its communication reliability and resource utilization efficiency in complex network environments.

[0007] To achieve the above object, the present invention is implemented by the following technical solutions:

[0008] In a first aspect, the present invention provides a low-latency data conversion method based on a low-altitude aircraft, including:

[0009] Construct a communication link between the low-altitude aircraft and the ground control center, and dynamically detect the quality indicators of each communication link;

[0010] Calculate the comprehensive quality evaluation value of the communication link according to the detected quality indicators;

[0011] Determine the communication link status according to the comprehensive quality evaluation value of the communication link;

[0012] Perform multi-link switching and redundant transmission according to the communication link status.

[0013] Further, the link types of the communication link include ad hoc network, cellular communication link, and low-earth orbit satellite link;

[0014] Assign a unique link identifier LinkID to each communication link, and register the information of the communication link in the link pool, where the link pool is used to manage the status and parameters of the communication link;

[0015] During the operation of the system, periodically monitor the survival status of the communication link. When it is detected that the communication link has continuous timeouts or the packet loss rate increases abnormally, cancel the corresponding communication link and remove it from the link pool.

[0016] Further, the dynamic detection of the quality indicators of each communication link includes:

[0017] Periodically send probe data packets to each communication link according to a preset sampling period;

[0018] Record the sending timestamp and receiving timestamp of the probe data packet, and calculate the one-way round-trip delay :

[0019] ;

[0020] In the formula: represents the sending time, represents the receiving time;

[0021] Statistically count the number of sent and received probe packets within a set time window, and calculate the packet loss rate of the communication link :

[0022] ;

[0023] In the formula: represents the number of sent probe packets, represents the number of received probe packets;

[0024] Based on continuous measurement results, calculate the jitter value of the communication link :

[0025] ;

[0026] where: n represents the number of measurements, represents the round-trip delay measured at the (i + 1)-th time, represents the round-trip delay measured at the i-th time;

[0027] Take the collected round-trip delay , packet loss rate and jitter value as quality indicators.

[0028] Furthermore, the calculation of the comprehensive quality evaluation value of the communication link includes:

[0029] According to the preset weight coefficients , , calculate the comprehensive quality evaluation value Q of each communication link as shown in the following formula:

[0030] ;

[0031] ;

[0032] where: , , respectively represent the preset weight coefficients corresponding to the round-trip delay, packet loss rate, and jitter value, represents the maximum round-trip delay received, represents the maximum packet loss rate received, represents the maximum jitter received, represents the maximum reference value preset for the round-trip delay, represents the maximum reference value preset for the packet loss rate, represents the maximum reference value preset for the jitter value.

[0033] Furthermore, determining the communication link state according to the comprehensive quality evaluation value of the communication link includes:

[0034] Compare the comprehensive quality evaluation value Q of the communication link with the preset first threshold T1 and second threshold T2 respectively, and divide the communication link state into multiple levels, where:

[0035] When Q < T1, it indicates that the communication link quality is good;

[0036] When T1 ≤ Q < T2, it indicates that the communication link is slightly degraded;

[0037] When Q ≥ T2, it indicates that the communication link is severely degraded.

[0038] Furthermore, multi-link switching and redundant transmission according to the communication link status include:

[0039] When the communication link quality is good, directly transmit data through the current communication link;

[0040] When the communication link is slightly degraded, start the redundant transmission strategy for critical data packets;

[0041] When the communication link is severely degraded, immediately trigger the pre-establishment of a connection to the backup link and complete the switching of the data stream to the backup link.

[0042] Furthermore, when the communication link is slightly degraded, starting the redundant transmission strategy for critical data packets includes:

[0043] Select data packets with high importance as critical data packets and mark critical attributes;

[0044] When normally sending data packets on the current main link, synchronously and redundantly send the critical data packets on the backup link;

[0045] The critical data packets carry data sequence numbers and timestamp information for the receiving end to remove duplicate data and reconstruct the data of the critical data packets.

[0046] Furthermore, when the communication link is severely degraded, immediately triggering the pre-establishment of a connection to the backup link and completing the switching of the data stream to the backup link includes:

[0047] Complete the pre-establishment of the connection on the backup link in advance and keep the backup link in a ready state;

[0048] When the switching condition is triggered, quickly migrate the data stream to the backup link, and at the same time send data on both the main link and the backup link during the switching window period to ensure that the data is not interrupted;

[0049] After the backup link confirms that the data is received correctly, disconnect the connection to the original main link.

[0050] Furthermore, the receiving end receives multiple data packets transmitted from different communication links;

[0051] According to the sequence number information carried by the data packets, use the hash table duplicate removal algorithm to remove duplicate data packets;

[0052] According to the order of the sequence numbers, reconstruct the continuous data stream to ensure the consistency of the data order;

[0053] Provide the de-duplicated and reorganized data stream to the application layer for business processing.

[0054] In a second aspect, the present invention provides a computer-readable storage medium, on which a computer program is stored, and when the program is executed by a processor, the steps of the method for realizing multi-link switching and redundant transmission of a low-altitude aircraft according to any one of claims 1 to 9 are realized.

[0055] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0056] The method for multi-link switching and redundant transmission provided by the present invention realizes link state grading, dynamic policy switching and key data redundancy guarantee, takes into account communication stability and system resource optimization, and improves the robustness and real-time performance of aircraft communication. Description of the Drawings

[0057] Figure 1 It is a flowchart of a method for realizing multi-link switching and redundant transmission of a low-altitude aircraft provided by the present invention. Detailed Embodiments

[0058] The technical solution of the present invention will be described in detail below through the drawings and specific embodiments. It should be understood that the specific features in the embodiments of the present application and the embodiments are detailed descriptions of the technical solution of the present application, rather than limitations on the technical solution of the present application. Without conflict, the technical features in the embodiments of the present application and the embodiments can be combined with each other.

[0059] The terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present disclosure / this application, unless otherwise stated, the meaning of "a plurality" is two or more.

[0060] Embodiment 1:

[0061] This embodiment provides a method for realizing multi-link switching and redundant transmission of a low-altitude aircraft, which is applicable to the intelligent management of multiple communication links during the flight of eVTOL aircraft. The method is jointly completed by the aircraft end and the ground station end. By constructing multiple communication links, dynamically evaluating the communication link quality and performing hierarchical management, the optimization of communication link selection and the reliable transmission of key data are realized, as Figure 1 shown, including:

[0062] Build a communication link and initialize the system; when the aircraft system starts, establish three communication channels: 4G cellular communication link, ad-hoc network communication link, and low-earth orbit satellite link respectively. The system assigns a unique link identifier LinkID to each communication link and registers it in the link pool for unified management. The link pool is used to record the current status, interface information, and last measurement data of each communication link, which serves as the basis for subsequent scheduling management. The status of each communication link is initialized to "available" during registration.

[0063] In this embodiment, the sampling period at the aircraft end is set to 100 ms, and probe packets are periodically sent to each communication link. The system records the timestamps of each transmission and response for calculating the one-way round-trip delay. , as shown in the following formula:

[0064] ;

[0065] In the formula: represents the transmission time, represents the reception time;

[0066] Statistically count the number of probe packets transmitted and received within a set time window, and calculate the packet loss rate of the communication link , as shown in the following formula:

[0067] ;

[0068] In the formula: represents the number of probe packets transmitted, represents the number of probe packets received;

[0069] Based on consecutive measurement results, calculate the jitter value of the communication link :

[0070] ;

[0071] In the formula: n represents the number of measurements, represents the round-trip delay measured at the (i + 1)-th time, represents the round-trip delay measured at the i-th time;

[0072] Take the collected round-trip delay , packet loss rate and jitter value as quality indicators.

[0073] According to the preset weight coefficients , , calculate the comprehensive quality evaluation value Q of each communication link. In this embodiment, set = 0.4, = 0.4, = 0.2, as shown in the following formula:

[0074] ;

[0075] ;

[0076] In the formula: , , respectively represent the preset weight coefficients corresponding to the round-trip delay, packet loss rate, and jitter value, represents the maximum round-trip delay received, represents the maximum packet loss rate received, represents the maximum jitter received, represents the maximum reference value preset for the round-trip delay, represents the maximum reference value preset for the packet loss rate, represents the maximum reference value preset for the jitter value.

[0077] Compare the comprehensive quality evaluation value Q of the communication link with the preset first threshold T1 and second threshold T2 respectively. The system sets the first threshold T1 = 0.4 and the second threshold T2 = 0.7, and divides the communication link status into multiple levels, where:

[0078] When Q < T1, it is determined that the communication link is in the green state, indicating that the communication link quality is good, and data can be directly transmitted through the current communication link without redundancy;

[0079] When T1 ≤ Q < T2, it is determined that the communication link is in the yellow state, indicating that the communication link is slightly deteriorated. The system identifies the packets marked as critical in the current data to be sent, such as flight control instructions, attitude control commands, etc., and performs dual-link redundancy transmission on the primary link and the backup link;

[0080] When Q ≥ T2, it is determined that the communication link is in the red state, indicating that the communication link is severely deteriorated. Immediately start the pre-establishment process of the backup link connection, perform a handshake using the QUIC protocol to ensure that the backup link enters the "connection available" state in advance, and complete the seamless switching of the data stream. During the switching period, critical data is still transmitted redundantly on the primary link and the backup link simultaneously to ensure that data is not lost during the switching.

[0081] The ground - end receiving module supports multi - link input, and all received data packets carry sequence number information. The system constructs a hash table, using the sequence number as the index field, to perform redundant data identification and deduplication operations: when the sequence number of a data packet appears for the first time, it is written into the hash table and the data is retained; if a data packet with the same sequence number appears again, it is regarded as a duplicate packet and is directly discarded. To prevent the hash table from growing infinitely, the system sets up a cleaning mechanism to periodically clear expired records.

[0082] After deduplication, the data packets are recombined according to the sequence number order to form a continuous data stream. After buffer processing, the data stream is input into the aircraft application layer system for subsequent processing by the flight control calculation module, telemetry display module, mission scheduling module, etc., to ensure data integrity, sequentiality, and real - time performance.

[0083] Embodiment 2:

[0084] The embodiment of the present invention also provides a computer - readable storage medium, on which a computer program is stored. When the program is executed by a processor, it first implements the steps of the method for realizing multi - link switching and redundant transmission of low - altitude aircraft in the above - mentioned Embodiment 1.

[0085] The computer - readable storage medium includes: various media that can store program codes, such as USB flash drives, mobile hard disks, read - only memory (ROM), random access memory (RAM), magnetic disks, or optical discs.

[0086] Those skilled in the art should understand that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer - usable storage media (including but not limited to disk storage, CD - ROM, optical storage, etc.) containing computer - usable program codes.

[0087] This application is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram, as well as the combination of flows and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general - purpose computer, a special - purpose computer, an embedded processor, or other programmable data - processing devices to generate a machine, such that the instructions executed by the processor of the computer or other programmable data - processing devices generate for implementing in the process Figure 1 one process or multiple processes and / or blocks Figure 1means for the functions specified in one or more boxes.

[0088] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, such that the instructions stored in the computer-readable memory produce a manufactured article including an instruction means that implements the functions specified in one Figure 1 process or more processes and / or boxes Figure 1 means for the functions specified in one or more boxes.

[0089] These computer program instructions can also be loaded onto a computer or other programmable data processing device, such that a series of operation steps are executed on the computer or other programmable device to produce a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one Figure 1 process or more processes and / or boxes Figure 1 means for the functions specified in one or more boxes.

[0090] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art of the present technology, without departing from the technical principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A method for realizing multi-link switching and redundant transmission of a low-altitude aircraft, characterized in that Including: Establish a communication link between the low-altitude aircraft and the ground control center, and dynamically detect the quality indicators of each communication link; Calculate the comprehensive quality evaluation value of the communication link according to the detected quality indicators; Determine the communication link status according to the comprehensive quality evaluation value of the communication link; Perform multi-link switching and redundant transmission according to the communication link status.

2. The method for realizing multi-link switching and redundant transmission of a low-altitude aircraft according to claim 1, characterized in that, The link types of the communication link include ad hoc network, cellular communication link, and low-earth orbit satellite link; Assign a unique link identifier LinkID to each communication link, and register the information of the communication link in the link pool, which is used to manage the status and parameters of the communication link; During the operation of the system, periodically monitor the survival status of the communication link. When it is detected that the communication link has continuous timeouts or the packet loss rate increases abnormally, cancel the corresponding communication link and remove it from the link pool.

3. The method for implementing multi-link switching and redundant transmission of a low-altitude aircraft according to claim 1, wherein The dynamic detection of the quality indicators of each communication link includes: Periodically send probe data packets to each communication link according to a preset sampling period; Record the sending timestamp and receiving timestamp of the detection data packet, and calculate the one-way round-trip delay : ； Wherein: represents the sending time, represents the receiving time; Count the number of probe packets sent and received within the set time window, and calculate the packet loss rate of the communication link : ； In the formula: represents the number of sent probe packets, represents the number of received probe packets; Based on continuous measurement results, calculate the communication link jitter value : ； In the formula: n represents the number of measurements, represents the round-trip delay measured at the (i + 1)-th time, represents the round-trip delay measured at the i-th time; Use the collected round-trip delay , packet loss rate and jitter value as quality indicators.

4. The method for implementing multi-link switching and redundant transmission of a low-altitude aircraft according to claim 1, characterized in that, The calculation of the comprehensive quality evaluation value of the communication link includes: According to the preset weight coefficient , , calculate the comprehensive quality evaluation value Q of each communication link as shown in the following formula: ； ； Wherein: , , respectively represent the preset weight coefficients corresponding to the round-trip delay, packet loss rate, and jitter value, represents the maximum round-trip delay received, represents the maximum packet loss rate received, represents the maximum jitter received, represents the maximum reference value preset for the round-trip delay, represents the maximum reference value preset for the packet loss rate, represents the maximum reference value preset for the jitter value.

5. The method for realizing multi-link switching and redundant transmission of a low-altitude aircraft according to claim 1, wherein Determining the communication link status according to the comprehensive quality evaluation value of the communication link includes: Compare the comprehensive quality evaluation value Q of the communication link with the preset first threshold T1 and second threshold T2 respectively, and divide the communication link status into multiple levels, where: When Q < T1, it means that the communication link quality is good; When T1 ≤ Q < T2, it means that the communication link is slightly deteriorated; When Q ≥ T2, it means that the communication link is severely deteriorated.

6. The method for implementing multi-link switching and redundant transmission of a low-altitude aircraft according to claim 5, wherein Performing multi-link switching and redundant transmission according to the communication link status includes: When the communication link quality is good, directly transmit data through the current communication link; When the communication link is slightly deteriorated, start the redundant transmission strategy for critical data packets; When the communication link is severely deteriorated, immediately trigger the pre-establishment of a connection for the standby link and complete the data flow switch to the standby link.

7. The method for realizing multi-link switching and redundant transmission of a low-altitude aircraft according to claim 6, wherein When the communication link is slightly deteriorated, starting the redundant transmission strategy for critical data packets includes: Select the data packets with high importance as critical data packets and mark the critical attributes; When normally sending data packets on the current main link, synchronously and redundantly send the critical data packets on the standby link; The critical data packets carry data sequence numbers and timestamp information, which are used for the receiving end to remove duplicates and reorganize the data of the critical data packets.

8. The method for implementing multi-link switching and redundant transmission of a low-altitude aircraft according to claim 6, characterized in that, When the communication link is severely deteriorated, immediately trigger the pre-establishment of a connection for the standby link and complete the data flow switch to the standby link includes: Complete the pre-establishment of the connection on the standby link in advance and keep the standby link in a ready state; When the switching condition is triggered, quickly migrate the data flow to the standby link, and at the same time send data on both the main link and the standby link during the switching window period to ensure that the data is not interrupted; After the standby link confirms that the data is received correctly, disconnect the connection of the original main link.

9. The method for realizing multi-link switching and redundant transmission of a low-altitude aircraft according to claim 1, wherein It also includes: The receiving end receives multiple data packets transmitted from different communication links; Remove duplicate data packets using the hash table deduplication algorithm according to the sequence number information carried by the data packets; Reorganize the continuous data flow according to the order of the sequence numbers to ensure the consistency of the data order; Provide the deduplicated and reorganized data flow to the application layer for service processing.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by a processor, it implements the steps of the method for implementing multi-link switching and redundant transmission of a low-altitude aircraft according to any one of claims 1 to 9.

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