An airborne radar terrain fusion method and apparatus

Abstract

The present application relates to airborne radar signal processing technical field, provide a kind of airborne radar terrain fusion method and equipment, the method is based on false alarm filtering and grid matching mechanism, using airborne radar detection terrain point and map database pre-stored elevation data are fused;The airborne radar detection terrain point is converted with coordinates, with the map database pre-stored elevation data uniform spatial reference system, and determine corresponding terrain grid;The terrain grid filters the airborne radar detection terrain point that causes false alarm;Airborne radar terrain fusion result is stored back to map database.The present application can significantly improve radar terrain fusion efficiency on the basis of not accumulating radar detection terrain point error, improves data processing speed.

Description

Technical Field

[0001] This invention relates to the field of airborne radar signal processing technology, and in particular to an airborne radar terrain fusion method and device. Background Technology

[0002] Obstacle avoidance technology relies on matching and fusing 3D terrain information stored in a computer with terrain information detected by radar along the flight path. The advent of large-scale memory, microprocessors, and high-speed CPUs has significantly improved aircraft obstacle avoidance systems. Large-scale memory makes it possible to store as much real-time terrain altitude information as possible, providing aircraft with accurate terrain information and laying a solid foundation for low-altitude flight capabilities. When the aircraft receives radar data, the microprocessor and high-speed CPU can perform faster calculations and send flight control commands, improving the real-time performance and reliability of the commands. Moreover, the combination of these new technologies and specific algorithms can reduce radar operating time, thereby lowering the possibility of controlled flight crashes.

[0003] Traditional methods for matching and fusing radar-detected terrain information with pre-stored 3D terrain information typically employ Kalman filtering, which can achieve optimal accuracy. However, the algorithm is highly complex and cannot guarantee real-time processing. Summary of the Invention

[0004] In view of this, embodiments of the present invention provide an airborne radar terrain fusion method and device to solve the technical problems of complex information processing and low processing efficiency in obstacle avoidance technology in the prior art.

[0005] The first aspect of this invention provides an airborne radar terrain fusion method, specifically including:

[0006] Airborne radar terrain fusion software receives a radar detection point;

[0007] The two-dimensional coordinates and elevation values ​​of the radar detection point are calculated based on the attributes of the grid map in the airborne radar terrain fusion software.

[0008] The rules for initially determining whether a radar detection point is valid include: if the two-dimensional coordinates of the radar detection point exceed the representation range of the grid map, the radar detection point is initially determined to be invalid; otherwise, the radar detection point is initially determined to be valid.

[0009] If a radar detection point is initially determined to be valid, the cell corresponding to the radar detection point in the grid map is calculated to obtain the pre-stored elevation and fused elevation within the cell. If the elevation value of the radar detection point is greater than the pre-stored elevation and less than the sum of the pre-stored elevation and the preset error upper limit, then the radar detection point is ultimately determined to be valid; otherwise, the radar detection point is ultimately determined to be invalid.

[0010] When the radar detection point is finally determined to be valid, if the fused elevation is equal to the pre-stored elevation, then the elevation value is used as the new fused elevation; if the fused elevation is not equal to the pre-stored elevation, the average of the elevation value and the fused elevation is used as the new fused elevation.

[0011] The new fused elevation is stored in the data of the raster map, thus completing the fusion of the radar detection point and the raster map.

[0012] Furthermore, before receiving a radar detection point, the airborne radar terrain fusion software initializes the grid map in the software. The method includes:

[0013] The center point coordinates of the grid map are initialized using the aircraft's position;

[0014] Create a pre-stored elevation layer and a merged elevation layer based on the preset map length, width, and resolution;

[0015] Elevation data is loaded from the map database and written into each cell of the pre-stored elevation layer and the merged elevation layer, respectively.

[0016] Furthermore, after initializing the grid map in the airborne radar terrain fusion software, the method further includes:

[0017] The difference between the center point coordinates of the grid map and the aircraft position is checked in real time. If the difference exceeds a preset threshold, the grid map is updated with the aircraft position as the new center point coordinates, and then the elevation data is loaded from the map database.

[0018] Furthermore, the data receiving task and the data processing task are divided. The data receiving task includes the operation of the airborne radar terrain fusion software receiving the radar detection points, and the data processing task includes various fusion operations of the radar detection points and the grid map. The data receiving task and the data processing task are performed asynchronously.

[0019] Furthermore, after obtaining the new fused elevation, a notification is sent to the terrain warning task in the airborne radar terrain fusion software.

[0020] Furthermore, after receiving a radar detection point, the airborne radar terrain fusion software also includes converting the polar coordinates of the radar detection point into global coordinates in the format of (longitude, latitude, altitude).

[0021] A second aspect of the present invention provides an airborne radar terrain fusion operation device, the device comprising a processor and a program memory, wherein when the program in the program memory is loaded by the processor, the various steps of the airborne radar terrain fusion method according to any one of claims 1 to 6 are executed sequentially.

[0022] Compared with the prior art, the beneficial effects that can be achieved by at least one of the above-mentioned technical solutions adopted in the embodiments of this specification include: the present invention provides an airborne radar terrain fusion method, which is based on false alarm filtering and grid matching mechanism, meets the technical requirements of radar terrain fusion, and can significantly improve the efficiency of radar terrain fusion while ensuring that the error of radar detection terrain points is not accumulated. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of a grid map provided in an embodiment of the present invention;

[0025] Figure 2 This is a schematic diagram of the processing steps of the airborne radar terrain fusion operation method provided in the embodiments of the present invention. Detailed Implementation

[0026] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0027] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0028] This invention provides an airborne radar terrain fusion method based on false alarm filtering and grid matching mechanisms, which meets the technical requirements of radar terrain fusion and can significantly improve the efficiency of radar terrain fusion while ensuring that the error of radar detection terrain points is not accumulated.

[0029] according to Figure 1 and Figure 2 As shown in the figure, the airborne radar terrain fusion method provided in this embodiment specifically includes:

[0030] Step S100: The airborne radar terrain fusion software receives a radar detection point;

[0031] Furthermore, in step S100, before the airborne radar terrain fusion software receives a radar detection point, it initializes the grid map in the airborne radar terrain fusion software. The method includes:

[0032] Step S110: Initialize the center point coordinates of the grid map using the aircraft position;

[0033] Step S120: Create a pre-stored elevation layer and a merged elevation layer based on the preset map length, width, and resolution;

[0034] Step S130: Load elevation data from the map database and write the elevation data into each cell of the pre-stored elevation layer and the fused elevation layer respectively.

[0035] Specifically, such as Figure 1 As shown, the raster map has two layers: a pre-stored elevation layer and a fused elevation layer, along with attributes such as width, height, resolution, and center point coordinates. Each cell in the pre-stored elevation layer records elevation data pre-stored in the map database, and each cell in the fused elevation layer records the elevation data after radar terrain fusion. The cells in the pre-stored elevation layer and the cells in the fused elevation layer correspond one-to-one. When initializing the raster map in the airborne radar terrain fusion software, firstly, the center point coordinates of the raster map are initialized using the aircraft's position; secondly, the pre-stored elevation layer and the fused elevation layer are created according to the given map length, width, and resolution; finally, elevation data is loaded from the map database and written to each cell of the pre-stored elevation layer and the fused elevation layer.

[0036] Step S200: Calculate the two-dimensional coordinates and elevation values ​​of the radar detection point based on the attributes of the grid map in the airborne radar terrain fusion software;

[0037] Specifically, after receiving a radar detection point, the radar detection point is converted from polar coordinates to global coordinates, and the two-dimensional coordinates and elevation values ​​of the radar point are calculated using the grid map attributes.

[0038] Step S300: Preliminarily determine whether the radar detection point is valid. The rules include: if the two-dimensional coordinates of the radar detection point exceed the representation range of the grid map, the radar detection point is preliminarily determined to be invalid; otherwise, the radar detection point is preliminarily determined to be valid.

[0039] Step S400: If the radar detection point is initially determined to be valid, calculate the cell corresponding to the radar detection point in the grid map to obtain the pre-stored elevation and fused elevation in the cell. If the elevation value of the radar detection point is greater than the pre-stored elevation and less than the sum of the pre-stored elevation and the preset error upper limit, then the radar detection point is finally determined to be valid; otherwise, the radar detection point is finally determined to be invalid.

[0040] Step S500: When the radar detection point is finally determined to be valid, if the fused elevation is equal to the pre-stored elevation, then the elevation value is used as the new fused elevation; if the fused elevation is not equal to the pre-stored elevation, the average of the elevation value and the fused elevation is used as the new fused elevation.

[0041] Step S600: Store the new fused elevation into the data of the grid map to complete the fusion of the radar detection point and the grid map.

[0042] Specifically, the validity of the two-dimensional coordinates of the radar detection point is first determined. If the two-dimensional coordinates of the radar point are valid, the corresponding cell in the raster map is calculated to obtain the pre-stored elevation and the fused elevation. By checking the validity of the elevation value of the radar point, a new fused elevation is obtained. The raster map is reorganized according to the new fused elevation, and the required elevation data is loaded from the map database to complete the fusion of the radar detection point and the raster map.

[0043] Preferably, after obtaining the new fused elevation, the new fused elevation data is stored in the map database.

[0044] Furthermore, after initializing the grid map in the airborne radar terrain fusion software, the method further includes:

[0045] The difference between the center point coordinates of the grid map and the aircraft position is checked in real time. If the difference exceeds a preset threshold, the grid map is updated with the aircraft position as the new center point coordinates, and then the elevation data is loaded from the map database.

[0046] Specifically, the difference between the center coordinates of the raster map and the position of the aircraft is checked in real time. If it exceeds a certain threshold, the raster map is reorganized with the position of the aircraft as the new center coordinates, and the required elevation data is loaded from the map database.

[0047] Preferably, the data receiving task and the data processing task are divided. The data receiving task includes the operation of the airborne radar terrain fusion software receiving the radar detection points. The data processing task includes various fusion operations of the radar detection points and the grid map. The data receiving task and the data processing task are performed asynchronously.

[0048] Specifically, the processing of the airborne radar terrain fusion method is implemented by two tasks: Task 1 is the data receiving task, which executes step S100; Task 2 is the data processing task, which executes steps S200 to S600. Task 1 and Task 2 transmit radar detection point information through a multi-task concurrent operation queue.

[0049] Preferably, after obtaining the new fused elevation, a notification is sent to the terrain warning task in the airborne radar terrain fusion software.

[0050] Furthermore, after receiving a radar detection point, the airborne radar terrain fusion software also includes converting the polar coordinates of the radar detection point into global coordinates in the format of (longitude, latitude, altitude).

[0051] The present invention also proposes a radar terrain fusion operation device, including a processor and a program memory, wherein when the program in the program memory is loaded by the processor, the various steps of the above-described airborne radar terrain fusion method are executed sequentially.

[0052] Example 1

[0053] This embodiment uses radar terrain fusion, an airborne digital map application based on the osgEarth map rendering engine, as an example to illustrate the specific application scenario of this embodiment.

[0054] First, create a raster map with a width and height of 1024 and a resolution of 0.00027°. The center point coordinates are taken as the current latitude and longitude of the aircraft.

[0055] Next, create two tasks and a message queue. Task 1 will perform the following steps:

[0056] 1. Receive a radar detection point;

[0057] 2. Convert the radar detection points from polar coordinates to (longitude, latitude, altitude) coordinates;

[0058] 3. Add the radar detection point coordinates (longitude, latitude, altitude) to the message queue;

[0059] Task 2 involves the following steps:

[0060] (1) Retrieve a radar point data from the message queue;

[0061] (2) Calculate the two-dimensional coordinates and elevation values ​​of the radar point using the grid map attributes;

[0062] (3) Check the validity of the two-dimensional coordinates of the radar point. If the two-dimensional coordinates of the radar point are outside the representation range of the grid map, then the radar point is invalid.

[0063] (4) If the two-dimensional coordinates of the radar point are valid, calculate the corresponding cell in the grid map to obtain the pre-stored elevation and the fused elevation;

[0064] (5) Check the validity of the elevation value of the radar point. The upper limit of error is M = 50 meters. If the elevation value of the radar point is less than the pre-stored elevation or greater than the sum of the pre-stored elevation and M, then the radar point is invalid.

[0065] (6) If the elevation value of the radar point is valid, and the fused elevation is equal to the pre-stored elevation, then the elevation value of the radar point is used as the new fused elevation; otherwise, the average value of the elevation value of the radar point and the original fused elevation is used as the new fused elevation; the change in fused elevation is notified to the drawing task.

[0066] (7) Check the difference between the center coordinates of the grid map and the position of the aircraft. If it exceeds a certain threshold, then use the position of the aircraft as the new center coordinates of the grid map, reorganize the grid map, and load the required elevation data from the map database.

[0067] (8) Finally, create a drawing task, read elevation data from the raster map and draw the map; receive the notification from Task 2 and update the drawn map according to the changes in the merged elevation.

[0068] This airborne digital map application features short reconstruction time and high real-time performance. The airborne radar terrain fusion method, utilizing grid matching and multi-task processing, enables rapid updates of pre-stored terrain data from airborne radar information.

[0069] The embodiments of the present invention achieve the following technical effects:

[0070] 1. Based on false alarm filtering and grid matching mechanisms, it meets the technical requirements of radar terrain fusion and can significantly improve the efficiency of radar terrain fusion while ensuring that the error of radar detection terrain points is not accumulated.

[0071] 2. Based on the preferred embodiment of the present invention, by dividing the data receiving task and the data processing task, it conforms to the working mode of airborne radar interval radiation and makes full use of the parallel processing capability of multi-core processors.

[0072] 3. Based on the preferred embodiment of the present invention, by timely issuing integrated elevation change notifications, the flight visual system can adjust the corresponding terrain prompts, thereby improving the aircraft's ability to report dangerous terrain ahead;

[0073] 4. Based on the preferred embodiment of the present invention, by storing the updated fused elevation data into the map database, the errors in the map database are corrected, and a certain terrain detection and recording capability is provided.

[0074] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, various modifications and variations can be made to the embodiments of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for terrain fusion using airborne radar, characterized in that, The method includes: Airborne radar terrain fusion software receives a radar detection point; The two-dimensional coordinates and elevation values ​​of the radar detection point are calculated based on the attributes of the grid map in the airborne radar terrain fusion software. The rules for initially determining whether a radar detection point is valid include: if the two-dimensional coordinates of the radar detection point exceed the representation range of the grid map, the radar detection point is initially determined to be invalid; otherwise, the radar detection point is initially determined to be valid. If a radar detection point is initially determined to be valid, the cell corresponding to the radar detection point in the grid map is calculated to obtain the pre-stored elevation and fused elevation within the cell. If the elevation value of the radar detection point is greater than the pre-stored elevation and less than the sum of the pre-stored elevation and the preset error upper limit, then the radar detection point is ultimately determined to be valid; otherwise, the radar detection point is ultimately determined to be invalid. When the radar detection point is finally determined to be valid, if the fused elevation is equal to the pre-stored elevation, then the elevation value is used as the new fused elevation; if the fused elevation is not equal to the pre-stored elevation, the average of the elevation value and the fused elevation is used as the new fused elevation. The new fused elevation is stored in the data of the raster map, thus completing the fusion of the radar detection point and the raster map.

2. The airborne radar terrain fusion method according to claim 1, characterized in that, Before receiving a radar detection point, the airborne radar terrain fusion software initializes the grid map in the airborne radar terrain fusion software. The method includes: The center point coordinates of the grid map are initialized using the aircraft's position; Create a pre-stored elevation layer and a merged elevation layer based on the preset map length, width, and resolution; Elevation data is loaded from the map database and written into each cell of the pre-stored elevation layer and the merged elevation layer, respectively.

3. The airborne radar terrain fusion method according to claim 2, characterized in that, After initializing the grid map in the airborne radar terrain fusion software, the method further includes: The difference between the center point coordinates of the grid map and the aircraft position is checked in real time. If the difference exceeds a preset threshold, the grid map is updated with the aircraft position as the new center point coordinates, and then the elevation data is loaded from the map database.

4. The airborne radar terrain fusion method according to claim 1, characterized in that, The method includes: The system divides data reception into data reception and data processing tasks. The data reception task includes the operation of the airborne radar terrain fusion software receiving the radar detection points, and the data processing task includes various fusion operations between the radar detection points and the grid map. The data reception and data processing tasks are performed asynchronously.

5. The airborne radar terrain fusion method according to claim 1, characterized in that, The method includes: After obtaining the new fused elevation, a notification is sent to the terrain warning task in the airborne radar terrain fusion software.

6. The airborne radar terrain fusion method according to claim 1, characterized in that, After receiving a radar detection point, the airborne radar terrain fusion software also includes converting the polar coordinates of the radar detection point into global coordinates that include longitude, latitude, and altitude.

7. An airborne radar terrain fusion operation device, characterized in that, The device includes a processor and a program memory, wherein when the program in the program memory is loaded by the processor, the various steps of the airborne radar terrain fusion method according to any one of claims 1 to 6 are executed sequentially.

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