A method for representing targets in radar simulated terrain environment

Abstract

The present invention discloses a method for representing a target in a radar simulation terrain environment, including: S1, establishing a target information database; S2, constructing a target-terrain unit mapping relationship table; S3, retrieving target information; S4, retrieving target radar reflection characteristic information in a target radar reflection characteristic database; S5, simulating the radar echo of the terrain unit according to the target radar reflection characteristic information to obtain a simulation image; S6, judging whether the environment has changed, and updating the target decoration information according to the environmental change: if the environment has changed, the dynamic information of the target is updated, and the above steps are repeated; if the environment has not changed, the simulation image is output. The present invention establishes a target-terrain relationship mapping table to improve computing efficiency; with decoration information, it can represent and dynamically update the coverage of media such as rain and snow, can dynamically reflect the influence of meteorological conditions on simulation results, and improve simulation fidelity.

Description

Technical Field

[0001] The invention relates to the field of radar system simulation, and in particular to a method for representing a target in a radar simulation terrain environment. Background Art

[0002] For airborne radars, targets such as terrain and buildings within the radar field of view have a key impact on terrain imaging and downward target detection. The use of digital terrain-based methods to simulate radar echoes can not only realistically reproduce the real ground echo image, but also be used as a clutter environment for real signals in the research of algorithms such as target detection and tracking, making the clutter simulation signal output by the simulation system closer to the real clutter environment, which has important engineering application value.

[0003] The point scattering model method is based on the following assumptions: the ground consists of homogeneous areas, each of which covers one or more resolution units. This means that the size of a homogeneous area is at least one resolution unit. Complex targets are non-homogeneous, with different reflection characteristics; the size may be smaller than one resolution unit; and in some cases the reflectivity is extremely large, dominating the echo. The point scattering model method is not suitable for complex target echo calculations. The target echo needs to be calculated separately, so the target needs to be represented separately in the terrain model. Therefore, when performing radar simulation, in addition to using a digital terrain model, the target also needs to be modeled separately. The echo calculations of the two models are performed independently, resulting in a waste of computing resources. Using only static target information representation methods cannot reflect the impact of weather changes on radar simulation, and can easily cause distortion of simulated radar images under special meteorological conditions. Summary of the invention

[0004] The present invention provides a method for representing a target in a radar simulated terrain environment to overcome the above problems.

[0005] The present invention comprises the following steps:

[0006] S1. Establish a target information database to store target information; establish a target radar reflection characteristic database to store target radar reflection characteristic information;

[0007] The target radar reflection characteristic information is radar reflection characteristic parameters of different target types corresponding to different dynamic information; the target information includes: static information and dynamic information;

[0008] S2, constructing a target-terrain unit mapping relationship table between terrain units and target information according to the mapping relationship between terrain unit data and target information, targets and terrain units;

[0009] The target-terrain unit mapping table includes: a terrain unit index, a target on the terrain unit, and a target number corresponding to the target;

[0010] S3. Retrieve target information:

[0011] Retrieving target information according to the target-terrain unit mapping relationship table: according to the index number of the terrain unit, retrieving the target number of the target on the terrain unit in the mapping data structure, and retrieving the static information and dynamic information of the target in the target information database according to the target number;

[0012] S4, according to the static information and dynamic information of the target, retrieving the target radar reflection characteristic information from the target radar reflection characteristic database;

[0013] S5. According to the target radar reflection characteristic information, the radar echo of the terrain unit is simulated to obtain a simulated image;

[0014] S6. Determine whether the environment has changed, and update the target decoration information according to the change of the environment:

[0015] If the environment changes, the target dynamic information update instruction is called to update the target dynamic information, the updated target dynamic information is stored in the target information database, and S3 is executed;

[0016] If the environment has not changed, the simulation image in S5 is output.

[0017] Furthermore, the target information database in S1 includes the following data:

[0018] Static information includes: target number, target type, and target posture information;

[0019] Dynamic information includes: decorative information.

[0020] Furthermore, the target number is a target identifier manually assigned during modeling. The target number is the identifier of the target in the terrain environment. The target number corresponds one-to-one to each target in the environment.

[0021] The target type is a target type identification code, which corresponds to the target type one by one. The target type is used to retrieve the target reflection characteristics in the target radar reflection feature library;

[0022] The attitude information is the attitude of the target relative to the terrain. The attitude information includes: the three-dimensional information of the target, that is, the pitch, roll, and yaw information of the target;

[0023] The decoration information includes: the type of medium covering the target surface and the degree of target coverage;

[0024] Further, S4 includes the following steps:

[0025] S41, calculating the observation angle of the beam to the target according to the target posture information and the terrain information of the target location;

[0026] S42, obtaining the target coverage degree according to the target decoration information;

[0027] S43, retrieving target radar reflection characteristic information from a target radar reflection characteristic database according to the target type, coverage degree, and beam observation angle.

[0028] Furthermore, the attitude information refers to the attitude angle of the target model relative to the terrain: the initial pitch, roll, and yaw angles of the target model are all 0 degrees, and the attitude information is the change in pitch, roll, and yaw angles when the target model is placed in the terrain unit.

[0029] The present invention establishes a target-terrain relationship mapping table to improve the computational efficiency. The target model of the present invention has decorative information, can represent and dynamically update the coverage of media such as rain and snow, can dynamically reflect the impact of meteorological conditions on simulation results, and improve the fidelity of the simulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0031] Figure 1 It is a flow chart of the present invention;

[0032] Figure 2 It is the principle diagram of the present invention;

[0033] Figure 3 It is a schematic diagram of the radar ground object echo simulation method of the present invention;

[0034] Figure 4 It is a flow chart of the method of the present invention. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] Example 1

[0037] like Figure 1-Figure 4 As shown, the present invention includes:

[0038] S1. Establish a target information database to store target information; establish a target radar reflection characteristic database to store target radar reflection characteristic information; the target radar reflection characteristic information is radar reflection characteristic parameters of different target types corresponding to different dynamic information;

[0039] Specifically, the target information representation includes:

[0040] 1) Static information: created offline and stored in ROM as a file, and loaded into RAM when used;

[0041] 2) Dynamic information: It is created in RAM when static information is loaded. The initial value is the default value. The data is set according to the meteorological environment control instructions received by the program in the simulation.

[0042] Specifically, when the meteorological environment control command issues the command "Raining within range a", the system receives the command, selects all targets within the terrain unit range a, and changes the dynamic information of all targets therein to "covered by rain".

[0043] Preferably, the target information database in S1 includes the following data:

[0044] Target information includes: static information and dynamic information;

[0045] Static information includes: target number, target type, and target posture information;

[0046] Dynamic information includes: decorative information.

[0047] Preferably, the target number is a target identifier manually assigned during modeling, the target number is an identifier of the target in the terrain environment, and the target number corresponds one-to-one to each target in the environment;

[0048] The target type is a target type identification code, which corresponds to the target type one by one. The target type is used to retrieve the target reflection characteristics in the target radar reflection feature library;

[0049] The attitude information is the attitude of the target relative to the terrain. The attitude information includes: the three-dimensional information of the target, that is, the pitch, roll, and yaw information of the target;

[0050] Specifically, the reflection characteristics of the target are related to the relative attitude relationship between the incident beam and the target, so the target attitude information needs to be described. The pitch, roll, and yaw of the target refer to the attitude angle of the target metamodel relative to the terrain. Assuming that the pitch, roll, and yaw angles of the target metamodel are all 0 degrees, the pitch, roll, and yaw of the target in the terrain information refer to the change in position along the attitude axis when the original model is placed in the terrain.

[0051] The decoration information includes: the type of medium covering the target surface and the degree of target coverage;

[0052] Specifically, the decoration information is called dynamic information because the information data may change during the simulation. The decoration information represents information such as water accumulation and snow cover. Natural phenomena such as rain and snow have an important impact on the radar reflection characteristics of the target. This information can be updated as needed during the simulation. The decoration information contains two fields, which separately identify the type of medium covering the target surface (rain accumulation, snow) and the degree of target coverage.

[0053] Specifically, the coverage degree is set based on experience. For example, when it rains heavily, the target's external surface is 100% covered with rain. When it snows, the target coverage degree is determined based on the preset target structure. For example, if target A is set to have a water surface (such as a swimming pool), the coverage degree is 0% when it snows; if target B is set to be wood, the coverage degree is 100% when it snows.

[0054] S2, constructing a target-terrain unit mapping relationship table between terrain units and target information according to the mapping relationship between terrain unit data and target information, targets and terrain units;

[0055] The target-terrain unit mapping table includes: terrain unit index, target on the terrain unit and target number;

[0056] Specifically, the target-terrain unit mapping method includes:

[0057] According to the mapping relationship between terrain unit data and target information, targets and terrain units, a target-terrain unit mapping relationship table between terrain units and target information is constructed, and a target-terrain unit mapping relationship table is established for each LoD level. The key is the index of the LoD terrain unit, and the value is the reference of the target information. During the simulation process, the complex target information on the terrain unit can be quickly found according to the mapping table.

[0058] The target-terrain unit mapping relationship table is a way to implement the data structure of "mapping". Mapping is a data structure that stores key-value data pairs, and searches for values ​​according to the key.

[0059] Here the key is the index of the LoD terrain unit and the value is the reference to the target information.

[0060] Here, the mapping relationship table is a mapping data structure, whose key is the index number of the terrain unit, and its value is the target number in the target information. According to the index number of the terrain unit, the target number (part of the static information) of the target on the unit can be retrieved in the mapping data structure, and the static and dynamic information of the target can be retrieved from the target information database according to the target number.

[0061] S3. Retrieve target information:

[0062] Retrieving target information according to the target-terrain unit mapping relationship table: according to the index number of the terrain unit, retrieving the target number of the target on the terrain unit in the mapping data structure, and retrieving the static information and dynamic information of the target in the target information database according to the target number;

[0063] Specifically, if Figure 3 As shown in Figure 1, the target information retrieval process includes:

[0064] 1) According to the radar beam scanning (such as Figure 3 The four solid lines 3C in the figure are used to obtain the beam coverage area 3B (i.e. Figure 3 The coverage area is divided into several ground units in terms of the incident direction distance and azimuth. Suppose the number of distance resolution units in the beam coverage area is N r , the number of azimuth resolution units is N a .

[0065] 2) Traverse the ground unit and perform Terrain on the ground unit ij 3A, determine the terrain data LoD level according to its size n , get the index value x of the corresponding terrain grid cell Cellij ij ,y ij .

[0066] 3) With l n , x ij ,y ij As a terrain index, according to the target-terrain cell mapping cellTargetMap, call the find method to find the target information {targetInfo1,…,targetInfo k}.

[0067] Use: Targeted Information Retrieval Method

[0068] According to the geographical location of the terrain unit illuminated by the radar beam and the required LoD level, the index of the corresponding terrain unit is calculated, and then the target information is retrieved according to the target-terrain unit target-terrain unit mapping relationship table.

[0069] S4, according to the static information and dynamic information of the target, retrieving the target radar reflection characteristic information from the target radar reflection characteristic database;

[0070] (5) Calculation of target radar reflection characteristic information

[0071] Traversing the retrieved targets, for target k, the calculation method of its radar reflection characteristic information is:

[0072] 1) Beam observation angle calculation: Calculate the target’s beam observation angle (thetak, phik, psi) based on the target’s attitude information, the target’s geographic data, and the beam incidence information.

[0073] 2) Read the decoration information decoratork.

[0074] 3) According to the target type typeIDk, beam observation angle (thetak, phik, psi), decoration information decoratork, and beam carrier frequency, polarization mode and other information, the target radar reflection characteristic information is retrieved from the target reflection characteristic database.

[0075] Specifically, in the target reflection characteristic database, according to the dynamic information and static information of the target, the database table is queried to obtain the corresponding target radar reflection characteristic information.

[0076] Preferably, S4 calculating the target radar reflection characteristic information comprises the following steps:

[0077] S41, calculating the observation angle of the beam to the target according to the target posture information and the terrain information of the target location;

[0078] S42, obtaining the target coverage degree according to the target decoration information;

[0079] S43, retrieving target radar reflection characteristic information from a target radar reflection characteristic database according to the target type, coverage degree, and beam observation angle.

[0080] Preferably, the attitude information refers to the attitude angle of the target model relative to the terrain: the initial pitch, roll and yaw angles of the target model are all 0 degrees, and the attitude information is the change in pitch, roll and yaw angles when the target model is placed in the terrain unit.

[0081] Specifically, the posture information in the terrain information is the change in position along the posture axis when the target model is placed in the terrain.

[0082] S5. According to the target radar reflection characteristic information, the radar echo of the terrain unit is simulated to obtain a simulated image;

[0083] Specifically, the target radar reflection characteristic information calculation method includes the following steps:

[0084] 1) Calculate the viewing angle of the beam to the target based on the target posture information and the terrain information of the target location. Calculation method description: This calculation is a geographic calculation method in the prior art.

[0085] 2) Obtain the coverage degree of the target by precipitation / snow etc. according to the target decoration information.

[0086] 3) According to the target type, the coverage degree of precipitation / snow, etc., and the beam observation angle, the target radar reflection characteristic information is retrieved from the target radar reflection characteristic database. Description of the retrieval method: The general associated data retrieval method is used.

[0087] The target radar reflection characteristic database should be able to represent the situation where the target is affected by rainfall, snow, etc. The method for constructing the target radar reflection characteristic database does not belong to the content of the present invention.

[0088] S6. Determine whether the environment has changed, and update the target decoration information according to the change of the environment:

[0089] If the environment changes, the target dynamic information update instruction is called to update the target dynamic information, the updated target dynamic information is stored in the target information database, and S3 is executed;

[0090] If the environment has not changed, the simulation image in S5 is output.

[0091] Specifically, the simulation program receives the meteorological environment control command and updates the target decoration information according to the command. During the simulation, when the meteorological environment rains, snows, etc., causing the target to be covered by water or snow, the target decoration information needs to be updated. Update method: The decoration information is a dynamic information, and the data is set according to the meteorological environment control command received by the program during the simulation.

[0092] Specifically, during the simulation process, when the meteorological environment experiences rain, snow, etc., causing the target to be covered by water or snow, the target decoration information needs to be updated.

[0093] Update method: The decoration information is a dynamic information. The decoration information is updated in real time through the real-time update interface. During the simulation process, the meteorological environment control instructions issued by the environmental simulation system (this system is a component of the simulation training system and is a prior art) are received to update the target decoration information.

[0094] Beneficial effects:

[0095] The present invention establishes a target-terrain relationship mapping table to improve computational efficiency. The target model of the present invention has decorative information, can represent and dynamically update the coverage of media such as rain and snow, can dynamically reflect the impact of meteorological conditions on simulation results, and improve the fidelity of simulation.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for representing a target in a radar simulated terrain environment, characterized in that: The following steps are involved: S1. Establish a target information database to store target information; Establish a target radar reflection characteristic database to store target radar reflection characteristic information; The target radar reflection characteristic information is the radar reflection characteristic parameters of different target types corresponding to different dynamic information; the target information includes: static information and dynamic information; the static information includes: target number, target type, target attitude information; wherein the target number is a target identifier manually specified during modeling, the target number is an identifier of the target in the terrain environment, and the target number corresponds one-to-one with each target in the environment; the target type is a target type identification code, which corresponds one-to-one with the target type, and the target type is used to retrieve the target reflection characteristics in the target radar reflection feature library; the target attitude information is the attitude of the target relative to the terrain, and the target attitude information includes: three-dimensional information of the target, that is, the pitch, roll, and yaw information of the target; The dynamic information includes: decoration information; the decoration information includes: the type of medium covering the target surface and the degree of target coverage; S2, constructing a target-terrain unit mapping relationship table between terrain units and target information according to the mapping relationship between terrain unit data and target information, targets and terrain units; The target-terrain unit mapping table includes: a terrain unit index, a target on the terrain unit, and a target number corresponding to the target; S3. Retrieve target information: Retrieving target information according to the target-terrain unit mapping relationship table: according to the index number of the terrain unit, retrieving the target number of the target on the terrain unit in the mapping data structure, and retrieving the static information and dynamic information of the target in the target information database according to the target number; S4, according to the static information and dynamic information of the target, retrieving the target radar reflection characteristic information from the target radar reflection characteristic database; S5. According to the target radar reflection characteristic information, the radar echo of the terrain unit is simulated to obtain a simulated image; S6. Determine whether the environment has changed, and update the target decoration information according to the change of the environment: If the environment changes, the dynamic information of the target is updated, the updated dynamic information of the target is stored in the target information database, and S3 is executed; If the environment has not changed, the simulation image in S5 is output.

2. The method for representing a target in a radar simulation terrain environment according to claim 1, characterized in that: The S4 comprises the following steps: S41, calculating the observation angle of the beam to the target according to the target posture information and the terrain information of the target location; S42, obtaining the target coverage degree according to the target decoration information; S43, retrieving target radar reflection characteristic information from a target radar reflection characteristic database according to the target type, coverage degree, and beam observation angle.

3. The method for representing a target in a radar simulation terrain environment according to claim 1, characterized in that: The attitude information refers to the attitude angle of the target model relative to the terrain: the initial pitch, roll, and yaw angles of the target model are all 0 degrees, and the attitude information is the change in pitch, roll, and yaw angles when the target model is placed in the terrain unit.

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