UAV formation communication method based on packet loss compensation

Abstract

The present invention discloses a UAV formation communication method based on packet loss compensation, which belongs to the field of UAV communication technology. The method includes: each UAV in the UAV formation obtains the status information of other UAVs through inter-machine communication; when inter-machine communication generates packet loss, the position information is compensated by using the speed information at the historical moment; the minimum inter-machine communication frequency is determined by the compensated position information, and the maximum value of the minimum communication frequency of the i-th UAV to other UAVs is used as the information broadcast frequency of the i-th UAV for communication. The present invention can reduce the communication burden during large-scale formation.

Description

Technical Field

[0001] The present invention belongs to the technical field of unmanned aerial vehicle communication, and in particular relates to a unmanned aerial vehicle formation communication method based on packet loss compensation. Background Art

[0002] When the size of the UAV flight formation is large, the UAVs using distributed formations need to communicate with each other to ensure functions such as formation maintenance, transformation, and obstacle avoidance. Any UAV in the formation needs to broadcast its position and speed information at a certain frequency, and needs to receive the position and speed information released by other UAVs in the formation. However, due to platform limitations, airborne communication equipment has problems such as electromagnetic interference and low reliability. On the one hand, there is a problem of communication packet loss during the transmission of UAV formation status information, and there will be information loss or information update delay at certain moments when UAVs receive status information from other UAVs. On the other hand, with the increase in the number of formations, the communication volume between UAVs in the formation increases exponentially, greatly increasing the communication burden between formations. This has a very adverse effect on the coordinated control of the formation.

[0003] Reducing the communication frequency between drones can effectively reduce the communication burden, but the method of directly reducing the communication frequency has obvious defects. On the one hand, the limitation of the position update frequency in satellite navigation is ignored. The satellite navigation position update frequency limits the effective position in communication, and the satellite navigation position update frequency needs to be considered in the communication frequency. On the other hand, due to the limitation of airborne equipment, electromagnetic interference, etc., there is a problem of packet loss of varying lengths in communication between drones, and the impact of packet loss needs to be considered in the communication frequency. Summary of the invention

[0004] The purpose of the present invention is to provide a UAV formation communication method based on packet loss compensation to overcome the defects of the prior art. The status information of other UAVs is obtained through inter-machine communication. When packet loss occurs in inter-machine communication, it is determined whether packet loss occurs based on historical status information. If there is no packet loss, the information of other UAVs is updated normally. If packet loss occurs, the position is compensated by the integration method using the speed at the historical moment.

[0005] The object of the present invention is achieved through the following technical solutions:

[0006] A UAV formation communication method based on packet loss compensation, the method comprising:

[0007] Each drone in the drone formation obtains the status information of other drones through inter-machine communication;

[0008] When packet loss occurs in inter-machine communication, the speed information at the historical moment is used to compensate for the location information;

[0009] The minimum communication frequency between drones is determined by the compensated position information, and the maximum value of the minimum communication frequencies of the i-th drone to other drones is used as the information broadcast frequency of the i-th drone for communication.

[0010] Furthermore, each drone in the drone formation obtains status information of other drones through inter-drone communication specifically including:

[0011] Obtaining the current position information and speed information of each drone in the drone formation, and converting the position information and speed information into a north-east rectangular coordinate system;

[0012] Calculating the relative position relationship and relative speed relationship between the drones in the drone formation in the north-east rectangular coordinate system;

[0013] The relative position relationship and relative velocity relationship are converted to a launch coordinate system.

[0014] Furthermore, the compensating the position information by using the speed information at the historical moment specifically includes:

[0015] ;

[0016] in, Indicates the current moment, Indicates the last moment, represents the relative position of the i-th UAV and the j-th UAV compensated at the current moment, is the relative position of the i-th UAV and the j-th UAV at the previous moment, is the relative speed between the i-th UAV and the j-th UAV at the previous moment.

[0017] Further, the determining the minimum communication frequency between machines based on the compensated position information specifically includes:

[0018] Calculate the deviation between the true relative position and the compensated relative position:

[0019] ;

[0020] Available

[0021] ;

[0022] in, represents the deviation at the current moment, represents the relative position of the i-th UAV and the j-th UAV at the current moment, Indicates the relative speed between the i-th UAV and the j-th UAV at the current moment;

[0023] According to the integral limit theorem, let We can get:

[0024] ;

[0025] in, It represents the average value of the difference between the real relative speed and the compensated relative speed;

[0026] set up Time to The maximum relative speed is:

[0027] ;

[0028] We can get:

[0029] ;

[0030] After compensation, you can get

[0031] ;

[0032] Among them, the operator is the two-norm, For safe distance;

[0033] The minimum communication frequency after compensation is:

[0034] ;

[0035] represents the minimum communication frequency between the i-th and j-th UAVs, It represents the average value of the difference between the real relative speed and the compensated relative speed of the i-th and j-th UAVs.

[0036] Furthermore, the safety distance is calculated as follows:

[0037] ;

[0038] in, They are the heading safety distance, lateral safety distance and safety height between UAVs respectively.

[0039] Furthermore, the maximum value of the minimum communication frequency of the i-th UAV to other UAVs is calculated as follows:

[0040] When the UAVs i and j are flying at the same altitude, According to the relative lateral safety distance and relative heading safety distance, we can get

[0041] ;

[0042] make , , so take

[0043] ;

[0044] The maximum value of the minimum communication frequency of the i-th UAV to other UAVs is , ;

[0045] in, Indicates Frame and The packet loss rate between drones, and is the intermediate variable, represents the relative heading distance between the i-th and j-th UAVs, represents the relative lateral distance between the i-th and j-th UAVs, express The component in the direction relative to the course, express Component in the direction perpendicular to the course.

[0046] The beneficial effects of the present invention are:

[0047] The present invention discloses a compensation scheme for the state information of a UAV formation under the condition of communication packet loss. The state information of other UAVs is obtained through inter-machine communication. When inter-machine communication packet loss occurs, it is determined whether packet loss occurs based on historical state information. If there is no packet loss, the information of other UAVs is updated normally. If there is packet loss, the position is compensated by the integration method using the speed at the historical moment. In addition, the compensation frequency can be kept consistent with the inner loop control frequency to improve the control accuracy. Through the compensation optimization method, the frequency of inter-machine communication in the UAV formation can be effectively reduced, reducing the communication burden. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is a flowchart of a UAV formation communication method based on packet loss compensation according to an embodiment of the present invention. DETAILED DESCRIPTION

[0049] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0050] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making any creative work shall fall within the scope of protection of the present invention.

[0051] Reducing the communication frequency between drones can effectively reduce the communication burden, but the method of directly reducing the communication frequency has obvious defects. On the one hand, the limitation of the position update frequency in satellite navigation is ignored. The satellite navigation position update frequency limits the effective position in communication, and the satellite navigation position update frequency needs to be considered in the communication frequency. On the other hand, due to the limitation of airborne equipment, electromagnetic interference, etc., there is a problem of packet loss of varying lengths in communication between drones, and the impact of packet loss needs to be considered in the communication frequency.

[0052] In order to solve the above technical problems, the following embodiments of the UAV formation communication method based on packet loss compensation of the present invention are proposed.

[0053] Reference Figure 1 ,like Figure 1 The figure is a flowchart of the UAV formation communication method based on packet loss compensation in this embodiment, and the method specifically includes the following steps:

[0054] Step 1: Get the current position and speed information of the drone through satellite navigation.

[0055] Specifically, the aircraft obtains its own position information and speed information through the onboard GPS. The position information includes longitude, latitude and altitude, and the speed information includes three speed components: north, east and celestial.

[0056] Step 2: Convert the directly obtained information into the north-east coordinate system.

[0057] Specifically, a location near the take-off point of the UAV formation is selected as the reference point of the north-east celestial rectangular coordinate system, and the GPS information is converted to the north-east terrestrial rectangular coordinate system. Drone location ,speed ,in, are the northing coordinate, easting coordinate and ground coordinate respectively. They are the north velocity, east velocity and celestial velocity respectively. The positions and speeds of the UAVs in the formation form a position matrix With the speed matrix .

[0058] Step 3: Calculate the relative position and relative speed information between each drone and convert it to the launch coordinate system.

[0059] Specifically, no. The first drone The relative position vector between the two drones is , ,in,

[0060] ；

[0061] ；

[0062] ；

[0063] No. The first drone The relative velocity vector between the two drones is , ,in,

[0064] ；

[0065] ；

[0066] ；

[0067] The relative position relationship between all drones in the formation is expressed as a relative position vector matrix ,

[0068] ;

[0069] The relative velocity relationship between all UAVs in the formation is expressed as a relative velocity vector matrix ,

[0070] ;

[0071] Step 4: Calculate the drone's information broadcast frequency based on the relative position and relative speed information.

[0072] Specifically, suppose that at a certain moment, GPS measures the Frame and The relative position vector between the two drones is , assuming that Frame and The packet loss rate between drones is , the minimum communication frequency between the two is ,When packet loss compensation is not performed, Frame and The effective communication frequency between UAVs is , No. Frame and The safe distance between drones satisfies the following inequality

[0073] ;

[0074] In the formula, For a safe distance, ,in, Respectively , The heading safety distance, lateral safety distance and safety height between the two drones. is the two-norm.

[0075] By calculating the above formula, the minimum communication frequency , ;

[0076] Step 5: Broadcast the drone information that needs to be broadcast according to the information broadcast frequency and the last drone information broadcast time.

[0077] Specifically, the minimum communication compensation frequency under compensation conditions is calculated according to the anti-packet loss compensation method. First, the position information is compensated by the speed information:

[0078] ;

[0079] In the formula, , Represent the previous moment and the current moment respectively. , is the relative position and relative speed of the i-th UAV and the j-th UAV at the previous moment, is the relative position of the i-th UAV and the j-th UAV to be compensated.

[0080] There is a deviation between the true relative position and the compensated position:

[0081] ;

[0082] Available

[0083] ;

[0084] According to the integral limit theorem, we can

[0085] ;

[0086] Here, Δv represents the average value of the difference between the real relative speed and the compensated relative speed.

[0087] Available

[0088] ;

[0089] set up Time to The maximum relative speed

[0090] ;

[0091] Available

[0092] ;

[0093] After compensation, you can get

[0094] ;

[0095] The minimum communication frequency after compensation is

[0096] ;

[0097] in, It represents the average value of the difference between the real relative speed and the compensated relative speed of the i-th and j-th UAVs.

[0098] Therefore, it is possible to The value of

[0099] ;

[0100] When the formation drones fly at the same altitude, According to the relative lateral safety distance and the relative heading safety distance, we can get:

[0101] ;

[0102] make , , so it is advisable

[0103] ;

[0104] For the first The frequency of information sent by a drone to other drones , ,… , select the maximum value as the The information broadcast frequency of the frame, that is

[0105] ;

[0106] The information broadcast frequency matrix of all UAVs in the formation is:

[0107] .

[0108] in, and is the intermediate variable, represents the relative heading distance between the i-th and j-th UAVs, represents the relative lateral distance between the i-th and j-th UAVs, express The component in the direction relative to the course, express Component in the direction perpendicular to the course.

[0109] This embodiment provides a compensation scheme for the state information of a UAV formation under the condition of communication packet loss. The state information of other UAVs is obtained through inter-machine communication. When inter-machine communication packet loss occurs, it is determined whether packet loss occurs based on historical state information. If there is no packet loss, the information of other UAVs is updated normally. If there is packet loss, the position is compensated by the integration method using the speed at the historical moment. In addition, the compensation frequency can be kept consistent with the inner loop control frequency to improve control accuracy. Through the compensation optimization method, the frequency of inter-machine communication in the UAV formation can be effectively reduced, reducing the communication burden.

[0110] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A UAV formation communication method based on packet loss compensation, characterized in that: The method comprises: Each drone in the drone formation obtains the status information of other drones through inter-machine communication; When packet loss occurs in inter-machine communication, the speed information at the historical moment is used to compensate for the location information; The method of compensating the position information by using the speed information at the historical moment specifically includes: ； in, Indicates the current moment, Indicates the last moment, represents the relative position of the i-th UAV and the j-th UAV compensated at the current moment, is the relative position of the i-th UAV and the j-th UAV at the previous moment, is the relative speed between the i-th UAV and the j-th UAV at the previous moment; The minimum communication frequency between drones is determined based on the compensated position information, and the maximum value of the minimum communication frequencies of the i-th drone to other drones is used as the information broadcast frequency of the i-th drone for communication; The minimum communication frequency after compensation is: ； represents the minimum communication frequency between the i-th and j-th UAVs, represents the average value of the difference between the real relative speed and the compensated relative speed of the i-th and j-th UAVs; The maximum value of the minimum communication frequency of the i-th UAV to other UAVs is , the calculation methods include: When the UAVs i and j are flying at the same altitude, According to the relative lateral safety distance and relative heading safety distance, we can get ； make , , so take ； The maximum value of the minimum communication frequency of the i-th UAV to other UAVs is , ; in, Indicates Frame and The packet loss rate between drones, and is the intermediate variable, represents the relative heading distance between the i-th and j-th UAVs, represents the relative lateral distance between the i-th and j-th UAVs, express The component in the direction relative to the course, express The component in the direction perpendicular to the course, Indicates the safe height between drones. represents the relative speed between the i-th UAV and the j-th UAV.

2. The UAV formation communication method based on packet loss compensation according to claim 1, characterized in that: The specific method for each drone in the drone formation to obtain status information of other drones through inter-drone communication includes: Obtaining the current position information and speed information of each drone in the drone formation, and converting the position information and speed information into a north-east rectangular coordinate system; Calculating the relative position relationship and relative speed relationship between the drones in the drone formation in the north-east rectangular coordinate system; The relative position relationship and relative velocity relationship are converted to a launch coordinate system.

3. The UAV formation communication method based on packet loss compensation according to claim 1, characterized in that: Determining the minimum communication frequency between machines by using the compensated position information specifically includes: Calculate the deviation between the true relative position and the compensated relative position: ； Available ； in, represents the deviation at the current moment, represents the relative position of the i-th UAV and the j-th UAV at the current moment, Indicates the relative speed between the i-th UAV and the j-th UAV at the current moment; According to the integral limit theorem, let We can get: ； in, It represents the average value of the difference between the real relative speed and the compensated relative speed; set up Time to The maximum relative speed is: ； We can get: ； After compensation, you can get ； Among them, the operator is the two-norm, For a safe distance.

4. The UAV formation communication method based on packet loss compensation according to claim 3, characterized in that: The safety distance is calculated as follows: ； in, They are the heading safety distance, lateral safety distance and safety height between UAVs respectively.

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