An island-shore suppression method that utilizes radar detection information and geographic information matching

Abstract

This invention relates to an island-shore suppression method that utilizes radar detection information and geographic information matching. The method first detects targets, then converts the detected targets back into geographic information for matching, determining whether they are island-shore targets. It only needs to calculate a limited number of detected targets, avoiding the need to traverse and judge the geographic information of the entire search area before searching, and calculating the distance and angle distribution of the entire island-shore area. By utilizing radar single-pulse angle measurement information, targets within the same beam are separated, solving the problem of aliasing and indistinguishability when targets are very close to islands. It fully utilizes radar detection information, geographic information, and carrier position and attitude information for matching. The computational load of this method is independent of the map range, dynamically adapting to each search result, with limited and controllable computational load, reducing the complexity of use.

Description

Technical Field

[0001] This invention relates to the field of radar seeker-based maritime detection, specifically to island and shore target suppression technology that utilizes radar-detected target information and geographic information for matching. Background Technology

[0002] When radar detects naval targets, especially those near the coast or islands, it often faces the risk of false detection due to strong reflections from the coastline, islands, buildings, and large undulating terrain such as cliffs. Therefore, suppressing and filtering radar targets against a coastal or island background is a prerequisite for accurate target acquisition.

[0003] Previously, echo suppression of islands and shores in target areas was mainly achieved by using geographic information to plan radar search maps, that is, controlling the range search range at different angles to exclude islands and shores from the search range. Because radar beam angle resolution is poor, while range resolution is relatively high due to bandwidth, the workflow is as follows... Figure 1 As shown, the radar first imports geographical information containing the distribution of islands and shores in the sea area, such as digital maps; according to the search instructions issued by the control unit, the radar calculates whether there are island or reef targets within the radar search range based on the range and angle range; if the target exists, the angle and range of the island or shore are calculated and saved, and the range gate within the radar beam of the corresponding angle range is restricted during the search to exclude the island or reef target from the radar search range; if there are no islands or reefs, the target search is performed directly. This method is described in detail in the references and has achieved a certain effect in suppressing island and shore targets, but it has the following shortcomings: Before the search, the geographical information of the entire search area, mainly the coastline, must be traversed to confirm whether there are islands and reefs within the search range; if islands and shores are found during the search, the angle range and distance range of all islands and shores relative to their own positions within the search range must be calculated in real time, so that island and shore targets can be excluded by controlling the range gate of different angle beams. As the map size increases, the amount of computation increases quadratically, but the computing resources are limited. The limited map range means that a large-scale approximate digital map cannot be bound in advance. A precise digital map of a limited area near the target must be bound, which imposes certain limitations on the use of the system; the radar beam angle resolution is poor. If the target and islands and shores are in the same beam, it is easy to mix the target and islands and shores together and make it impossible to distinguish them. Summary of the Invention

[0004] Technical problems to be solved

[0005] To avoid the shortcomings of existing technologies, it is necessary to traverse the entire search area, primarily the coastline, to confirm the existence of islands and reefs. If islands and reefs exist, it is also necessary to calculate the angle and distance ranges of all islands and reefs relative to their own positions within the search area. As the map size increases, the computational load increases quadratically, which limits the system's usability. This invention provides an island and reef suppression method that utilizes radar detection information and geographic information matching.

[0006] Technical solution

[0007] An island-shore suppression method that utilizes radar detection information and geographic information matching is characterized by the following steps:

[0008] Step 1: The radar can directly start searching the target area without reading or traversing the digital map within the search range before searching, obtain the angles and distances of multiple targets within the area, and improve the accuracy of target angles by using single-pulse angle measurement results, separating different targets within the same beam. At this time, the targets obtained in the search area may include islands, coastlines, and sea surface targets.

[0009] Step 2: Based on the carrier's position and attitude angle information, and combined with the target angle information obtained in the previous step, calculate the latitude, longitude, and altitude information of the multiple targets detected in the area.

[0010] Step 3: Based on the latitude, longitude and altitude information of multiple targets, match the corresponding location in the digital map stored by the seeker head, and read only the geographical information of that point. Each target corresponds to one matching point, that is, only the digital map containing the target location needs to be read, without having to calculate or judge the distribution of islands and shores in the entire area.

[0011] Step 4: Determine whether the target is located on land or belongs to an island / shore target based on the matching points in the digital map; remove targets identified as island / shore targets within the search area, and save sea targets for subsequent calculations.

[0012] Beneficial effects

[0013] This invention provides a method for suppressing island and shore targets by combining radar monopulse angle measurement and geographic information matching. The method first detects targets, then converts the detected targets into geographic information for matching to determine whether they are island or shore targets. This method only needs to calculate a limited number of detected targets, avoiding the need to traverse and judge the geographic information of the entire search range and calculate the distance and angle distribution of the entire island and shore before the search. By utilizing radar monopulse angle measurement information, targets within the same beam are separated, solving the problem of aliasing and indistinguishability when targets are very close to the island or shore. It fully utilizes radar detection information, geographic information, and carrier position and attitude information for matching.

[0014] Experimental results show that the computational load of the method of this invention is independent of the map range, dynamically adapts to each search result, and has a limited and controllable computational load, reducing the complexity of use. It can effectively suppress and filter background targets on islands and shores without traversing the search range or calculating the angular positional relationship between all islands and shores and itself, thus improving the radar's interception performance of near-island and shore targets on the sea surface while significantly reducing the requirements for computational resources. Attached Figure Description

[0015] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0016] Figure 1 Flowchart of traditional geographic information-based island and shore target suppression methods;

[0017] Figure 2 Flowchart of an island-shore suppression method that uses radar detection information to match geographic information;

[0018] Figure 3 Comparison of radar target distribution maps in the same sea area;

[0019] Figure 4 Satellite map of the island and shore background detection test;

[0020] Figure 5 Detection results after implementing this invention (left image shows identified island and shore targets, right image shows sea surface targets);

[0021] Figure 6 Implementation examples. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0023] The flowchart of the island and shore target suppression method that uses radar detection information and geographic information matching is as follows: Figure 2 As shown:

[0024] First, the radar can directly search the target area without reading or traversing the digital map within the search range before the search begins. It obtains the angles and distances of multiple targets within the area and uses single-pulse angle measurement results to improve target angle accuracy, separating different targets within the same beam. The targets within the search area at this point may include islands, coastlines, and sea targets. Based on the carrier's position and attitude angle information, combined with the target angle information obtained in the previous step, the latitude, longitude, and altitude information of the multiple detected targets within the area are calculated. The seeker matches the corresponding locations in the digital map stored with the latitude, longitude, and altitude information of multiple targets, and only reads the geographical information of that single point. Each target corresponds to one matching point; that is, only the digital map containing the target's location needs to be read, without calculating or judging the distribution of islands and coastlines throughout the entire area. Based on the matching point in the digital map, it is determined whether the target is located on land or belongs to an island or coastline target. Targets identified as islands or coastlines within the search area are removed, while sea targets are saved for subsequent calculations.

[0025] The number of times the digital map geographic information is read in the above method depends on the actual number of targets in the search area, which changes dynamically and is limited in number, thus significantly reducing the number of calculations related to the digital map. Taking a search area of ​​20km×20km as an example, with a map accuracy of 50m, there are 160,000 points containing geographic information in the area. Identifying coastlines for such a huge amount of data puts a lot of pressure on computing resources, especially since the power consumption and size of high-mobility vehicles limit computing power. Using the method of this invention, only the corresponding calculations and identifications are performed on the locations of detected targets, generally on the order of less than 100. Areas where no targets are found are not calculated, greatly freeing up computing resources. The methods used in the prior art are limited by the map range. As the map size increases, the amount of computation increases quadratically, but computing resources are limited. The limited map range also means that a large-scale approximate digital map cannot be bound in advance. A precise digital map of a limited area near the target being detected must be bound, which limits the use of the system. With this method, the amount of computation is unrelated to the map range, dynamically adapts to each search result, the amount of computation is limited and controllable, and a large-scale map can be bound in advance, reducing the complexity of use. In the background technology, when the target and the island / shore are in the same beam, aliasing is very likely to occur, making it impossible to distinguish between the target and the island / shore. Furthermore, the angular resolution does not change with distance; at greater distances, the indistinguishable distance is very large, forcing the missile to approach the target again for re-discrimination. Using the method in the background technology, the indistinguishable distance between island / shore targets and ship targets in the same beam is constrained by beamwidth. This method utilizes radar monopulse angle measurement information to separate targets within the same beam with an accuracy of 1 / 10 of the beamwidth. At the same missile-target distance, the indistinguishable distance between island / shore targets and ship targets is reduced to one-tenth, representing a significant improvement over the background technology. Figure 3To search for and map targets in the same sea area using radar, the vertical axis represents the distance between the radar and the target, and the horizontal axis represents the target's angle relative to the radar. The left figure shows the method used in the background technology, and the right figure shows the improved method using monopulse angle measurement. It can be seen that this method effectively separates targets within the same beam.

[0026] Using the present invention Figure 4 Multiple detection tests were conducted on sea surface targets in the nearshore waters shown, and the detection results are as follows: Figure 5 As shown, this invention can effectively separate island / shore targets from sea surface targets. In this scenario, 84 search and capture tests were conducted, and sea surface targets were correctly captured in all 84 tests. The test results demonstrate that the method of this invention can effectively suppress and filter island / shore background targets without traversing the search range or calculating the angular positional relationship between all coastlines and the radar itself, significantly improving the radar's interception performance against near-island / shore targets on the sea surface.

[0027] To enable those skilled in the art to better understand the present invention, the invention will be described in detail below with reference to specific embodiments. For example... Figure 6 As shown:

[0028] 1. The radar is activated based on the information programmed into the control unit to search the designated sea area;

[0029] 2. The radar saves the search targets it has obtained, and calculates the latitude, longitude and altitude information of multiple targets detected in the area based on the carrier's position and attitude angle information, combined with the target angle and distance information obtained in the previous step.

[0030] 3. Read the geographic information of the target point from the digital map. Each target corresponds to only one matching point, that is, only the digital map containing the target location needs to be read.

[0031] 4. Determine whether the target is located on land or belongs to an island / shore target based on the matching points in the digital map; remove targets identified as island / shore targets within the search area, and save targets on the sea surface.

[0032] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the scope of the technology disclosed in the present invention, and such modifications or substitutions should all be covered within the scope of protection of the present invention.

Claims

1. A method for island-shore suppression using radar detection information and geographic information matching, characterized in that... The steps are as follows: Step 1: The radar can directly search the target area without reading or traversing the digital map within the search range before the search, obtaining the angles and distances of multiple targets within the area. The single-pulse angle measurement results are used to improve the accuracy of the target angles and separate different targets within the same beam. At this time, the targets in the search area may include island and coastal targets and sea targets. In this step, the radar single-pulse angle measurement information is used to separate targets within the same beam with an accuracy of 1 / 10 of the beamwidth. Under the same missile-target distance, the indistinguishable distance between island and coastal targets and ship targets is reduced to one-tenth. Step 2: Based on the carrier's position and attitude angle information, combined with the target angle information obtained in the previous step, calculate the latitude, longitude, and altitude information of the multiple targets detected in the area. Step 3: Based on the latitude, longitude and altitude information of multiple targets, match the corresponding location in the digital map stored by the seeker head, and read only the geographical information of that point. Each target corresponds to one matching point, that is, only the digital map containing the target location needs to be read, without having to calculate or judge the distribution of islands and shores in the entire area. Step 4: Determine whether the target is located on land or belongs to an island / shore target based on the matching points in the digital map; remove targets identified as island / shore targets within the search area, and save sea targets for subsequent calculations.

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