Clutter and interference-containing gate plot generation method based on radar model

Abstract

The invention discloses a method for generating a simulated trace point containing clutter and interference based on a radar model, and the method comprises the steps: constructing a trace point generation module based on a target tracking gate and a target truth value, carrying out the target trace point generation, clutter trace point generation and interference trace point generation, inputting the generated trace points into a data processing module of a radar, and carrying out the target trace point generation, the clutter trace point generation and the interference trace point generation. According to the method, the problem that a trace point module in a traditional function-level radar digital model is missing or the trace point module is inconsistent with an actual processing flow and an actual processing algorithm is solved, the accuracy of the radar digital model is improved, and tracking performance such as tracking stability and correlation correctness can be achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of radar simulation deduction, and particularly relates to a method for generating gate point traces with clutter and interference based on a radar model. Background Art

[0002] Electromagnetic attack and defense have the characteristics of being invisible and intangible, and are relatively abstract. In the process of scientific research and teaching, there is an urgent need to provide powerful electromagnetic attack and defense simulation software for simulating various electromagnetic attack and defense scenarios and tactical applications, and visually displaying the electromagnetic attack and defense process and effects through visualization means. Currently, general software such as MATLAB and some special electromagnetic analysis software often do not have the function of constructing a complete electronic warfare process, and only show the electromagnetic attack and defense effects of some links in a fragmented manner.

[0003] The planning and simulation verification system based on a digital model can realize functions such as scenario setting, operation planning, simulation deduction, effectiveness evaluation, data review and analysis, situation display, and resource management. In order to support the construction of a function-level planning and simulation verification system, it is necessary to design and develop a function-level radar digital model.

[0004] In addition to being able to simulate the calculation of the detection power of a radar and the detection data rate, etc., this digital model also needs to simulate the data processing function of the radar: simulating data processing functions such as point trace generation, point trace association, track establishment, and track update.

[0005] Therefore, the point trace module in the function-level radar digital model is the basis for simulating the data processing function, and the accuracy of its construction is related to the accuracy of the model.

[0006] In the traditional function-level radar digital model, when the true value is input to the simulation platform, the power is calculated through the radar power equation to evaluate the power performance of the radar, and the tracking performance of the radar for the target, such as tracking stability and association correctness, cannot be simulated. There are also problems where the processing flow is inconsistent with the actual algorithms and processes. Summary of the Invention

[0007] The purpose of the present invention is to provide a method for generating simulated point traces with clutter and interference based on a radar model, which can achieve tracking performance such as tracking stability and association correctness, and improve the accuracy of the radar digital model.

[0008] In order to achieve the purpose of the present invention, the present invention provides a method for generating simulated point traces with clutter and interference based on a radar model, including the following steps:

[0009] S1: Generation of target true value point traces: Generate target point traces according to the target position true value, target radar cross section, measurement error of the radar, and radar operating parameters;

[0010] S1-1: Effective detection airspace comparison: Determine whether the target is within the detection range by comparing the azimuth, distance, and elevation angle of the target with the azimuth range, distance range, and elevation angle range in the detection range of the current radar;

[0011] S1-2: Echo signal-to-noise ratio calculation: If the target is within the detection airspace in step S1-1, use the true value of the target position, target radar cross section, and radar operating parameters of the radar to calculate the signal-to-noise ratio of the target through the radar equation;

[0012] S1-3: Detection probability calculation: Use the signal-to-noise ratio to obtain the detection probability according to the detection probability and signal-to-noise ratio curve, and then simulate the probability based on the generated random number to determine whether to generate a trace;

[0013] S1-4: Error simulation: Based on the trace, add errors to the trace according to the measurement error of the radar.

[0014] S2: Generation of passive clutter traces: Includes generation of sea clutter traces, cloud clutter traces, and rain clutter traces;

[0015] S3: Generation of active interference traces: After receiving the radar interference data message output by the radar interference simulator, determine whether the antenna is aligned with the jammer according to the azimuth of the current scan and the azimuth of the jammer relative to the radar. Set the starting center frequency in the configuration file and obtain the current elevation frequency, and then determine whether the current scan frequency is within the frequency range where the jammer implements interference;

[0016] S4: Trace spatial matching: Perform spatial matching on the true target traces generated in step S1, the passive interference traces generated in step S2, and the active clutter traces generated in step S3 with the tracking gate of the target. If the matching is successful, add them to the gate trace library; if the matching is unsuccessful, delete the traces;

[0017] S5: Output of gate traces: Output the traces in the gate trace library to the data processing module of the radar for target track update association, and output the unassociated traces to the automatic start module for automatic start of new targets.

[0018] Compared with the prior art, the significant progress of the present invention lies in: The trace generation module of the present invention establishes a model based on the tracking prediction gate of the target and the target true value, and the data structure of the generated traces is consistent with that of the real equipment. Input the generated traces into the data processing module of the radar, which solves the problems of inconsistent data processing flow and incomplete simulation elements with coarse simulation granularity in the traditional simulation and deduction of the radar digital model, and can achieve tracking performance with tracking stability and association correctness, improving the accuracy of the radar digital model.

[0019] To more clearly illustrate the functional characteristics and structural parameters of the present invention, the following further elaborates in conjunction with the accompanying drawings and specific embodiments. Description of the Drawings

[0020] The drawings described herein are used to provide a further understanding of the present invention and form a part of this application. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0021] Figure 1 is the flowchart of the steps of the present invention;

[0022] Figure 2 is the curve of signal-to-noise ratio and detection probability of the present invention;

[0023] Figure 3 is a schematic diagram of target traces, clutter traces, and interference traces within the gate of the present invention;

[0024] Figure 4 is a schematic diagram for calculating the radar line-of-sight distance of the present invention. Specific Embodiments

[0025] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0026] A method for generating simulated traces containing clutter and interference based on a radar model of the present invention, in combination with Figure 1 and Figure 3 , includes the following steps:

[0027] S1: Generation of target true traces: Generate target traces according to the target position truth value, target radar cross section, radar measurement error, and radar operating parameters;

[0028] S1-1: Comparison of effective detection airspace: Determine whether the target is within the detection range by comparing the azimuth, distance, and elevation angle of the target with the azimuth range, distance range, and elevation angle range in the current radar detection range;

[0029] S1-1-1: Determine the current radar scanning range according to the masking angle, the start and end of the current radar scanning in azimuth and pitch;

[0030] S1-1-2: In combination with Figure 4 , calculate the radar line-of-sight distance d0 according to the radar height and target height;

[0031] d0 = 4.12 * (sqrt(ht) + sqrt(hr)), where sqrt is the square root function, hr is the radar installation height, and ht is the target height;

[0032] S1-1-3: Determine whether the target is outside the minimum operating distance based on the target distance, whether it is within the azimuth coverage range based on the target azimuth, whether it is within the elevation coverage range based on the target elevation, and whether it is within the corresponding line-of-sight distance based on the target type and target distance; if all conditions are met, it is determined that the target is within the effective detection airspace of the radar and a target trace is generated. If any condition is not met, no target trace is generated.

[0033] More specifically: According to the theory of electromagnetic fields, the influence of atmospheric refraction on the propagation of ultra-high frequency electromagnetic waves. On the sea surface at a temperature of +15°C and in a temperature gradient that changes with height of 0.0065° / m, under the standard condition where the temperature is constant, the gradient of atmospheric refraction is 0.039×10 -6 ° / m. At this time, the influence of the earth's curvature on propagation is equivalent to that of a spherical surface with a radius of R e : R e = 4R / 3 = 84490 km, R = 6370 km; The geometric figure representing the radar's line-of-sight distance, point A is the radar antenna array surface, point B is the sea surface target, point O is the earth's center, point G0 is the earth's surface, point C0 is the radar position, and point D0 is the vertical point of the target B to the ground.

[0034] Calculate the sea line-of-sight distance:

[0035] Rd = R1 + R2;

[0036] R1 2 = (Re + h1) 2 - Re 2 = 2Reh1 + h1 2 ;

[0037] R2 2 = (Re + h2) 2 - Re 2 = 2Reh2 + h2 2 ;

[0038] Where, h1 is the antenna installation height, h2 is the target height, R e is the equivalent earth curvature radius, the units of h1 and h2 are m, R1 is the distance from the radar to the horizontal plane on the line connecting the radar and the target, and R2 is the distance from the target to the horizontal plane:

[0039] Since Re >> h1, Re >> h2, then R1 and R2 are simplified to:

[0040]

[0041] Among them, Rd is the direct viewing distance of the radar;

[0042] Calculate the visual range of ultra-low altitude targets:

[0043]

[0044] The letters in the formula are the same as those in calculating the sea visual range;

[0045] Set the target incident angle to [-B, A]. For targets with elevation angles greater than A, they all enter the over-the-top blind area, and the near-field blind area is [0, Rm], where Rm = h1 / sin(B * pi / 180). Due to the limitation of the minimum operating distance of the radar, the near-field blind area is not considered, that is, only the minimum operating distance needs to be considered.

[0046] The over-the-top blind area of the radar simulator is related to the operating mode. It is >18° in operating mode 1, >45° in operating mode 2, and >70° in operating mode 3.

[0047] S1-2: Echo signal-to-noise ratio calculation: If the target is within the detection airspace in step S1-1, then use the true value of the target position, the target scattering cross-section area, and the radar operating parameters of the radar to calculate the signal-to-noise ratio of the target through the radar equation;

[0048] Judge according to the azimuth and elevation angles covered by the beam in the current operating mode. If the target is within the azimuth and elevation angle range covered by the beam, calculate the signal-to-noise ratio S / N of the target of the current scanning beam according to the following formula:

[0049]

[0050] Among them, P t is the peak power of radar transmission, G t , G r are the gains of the radar transmitting and receiving antennas; λ is the radar wavelength; σ is the radar cross-section area of the target; D is the pulse compression ratio; k is the Boltzmann constant, which is 1.38x10 -23 ; T 0 is the equivalent noise temperature, taking 290; B n is the receiver bandwidth; R is the distance from the target to the radar; F n is the receiver noise factor; L is the sum of various losses.

[0051] S1-3: Combine Figure 2 , Detection probability calculation: Use the signal-to-noise ratio to obtain the detection probability according to the detection probability and signal-to-noise ratio curve, and then simulate the probability according to the generated random number to determine whether to generate a trace; Compare the target signal-to-noise ratio with the minimum detectable signal-to-noise ratio of the radar. If the target signal-to-noise ratio is greater than the minimum detectable signal-to-noise ratio of the radar, then look up the table and interpolate according to the signal-to-noise ratio to obtain the detection probability P D, then generate a random number that follows a uniform distribution on [0, 1], and compare the random number with the detection probability P D , if the random number is less than the detection probability P D then output the target for the next step, otherwise remove the target.

[0052] S1-4: Error simulation: Based on the traces, add errors to the traces according to the measurement errors of the radar;

[0053] S1-4-1: Superimpose systematic errors on the target azimuth, distance, and elevation angle according to the currently set mean distance error, mean azimuth error, and mean elevation angle error;

[0054] S1-4-2: Call the real-time calculation dynamic library function of the radio wave propagation refraction effect error provided by the overall system to superimpose on the target based on the previous step.

[0055] S2: Generation of passive clutter traces: including generation of sea clutter traces, generation of cloud clutter traces, and generation of rain clutter traces;

[0056] S2-1: Generation of sea clutter: Obtain the sea state of the environmental area of the platform according to the longitude and latitude information of the ship platform where the radar is located, and determine each sea clutter trace in each beam scanned by the antenna according to the number of sea clutter points corresponding to each sea state in the local configuration file;

[0057] S2-2: Generation of cloud clutter: If the "obstacle type" in the obstacle data message is "6 cloud", determine the area range of the cylinder centered on the obstacle relative to the radar origin according to the number of cloud clutter points set in the local configuration file. When the antenna scans this area, generate cloud clutter traces in the current beam according to the foregoing method and output them to the data processing module;

[0058] S2-3: Generation of rain clutter: If the "obstacle type" in the obstacle data message is "3 light rain, 4 moderate rain, 5 heavy rain", determine the area range of the cylinder centered on the obstacle relative to the radar origin according to the number of rain clutter points set in the local configuration file. When the antenna scans this area, generate rain clutter traces in the current beam according to the foregoing method and output them to the data processing module.

[0059] S3: Generation of active interference traces: After receiving the radar interference data message output by the radar interference simulator, determine whether the antenna is aligned with the jammer according to the current scanned azimuth and the azimuth of the jammer relative to the radar. Set the starting center frequency in the configuration file, and obtain the current elevation angle frequency, and then determine whether the currently scanned frequency is within the frequency range where the jammer implements interference;

[0060] The data processing module is the data processing module of the radar, which is used to perform correlation processing on the received traces and tracks to update the tracks, and the remaining correlated traces are used for automatic initiation;

[0061] Set the starting center frequency in the configuration file, and calculate according to the frequency-elevation angle correspondence relationship of the radar to obtain the current elevation angle frequency; if the currently scanned frequency is within the frequency range where the jammer jams, calculate the received radar interference data according to different working modes to obtain interference traces on different range cells, and output them to the back-end data processing module; if the currently scanned frequency is not within the frequency range where the jammer jams, the radar is not interfered and no processing is performed.

[0062] S4: Trace spatial matching: Perform spatial matching on the target true value traces generated in step S1, the passive interference traces generated in step S2, and the active clutter traces generated in step S3 with the tracking gate of the target. If the matching is successful, add them to the gate trace library; if the matching is unsuccessful, delete the traces.

[0063] S5: Gate trace output: Output the traces in the gate trace library to the data processing module of the radar for target track update association, and output the unassociated traces to the automatic initiation module for automatic initiation of new targets.

[0064] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device.

[0065] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for generating simulated point traces containing clutter and interference based on a radar model, characterized in that: The following steps are involved: S1: Target true value point trace generation: Generate target point trace according to the target position true value, target scattering cross-sectional area, radar measurement error, and radar operating parameters; S2: Passive clutter point trace generation: including sea clutter point trace generation, cloud clutter point trace generation, and rain clutter point trace generation; S3: Active jamming point trace generation: After receiving the radar jamming data message output by the radar jamming simulator, determine whether the antenna is aligned with the jammer according to the current scanning direction and the direction of the jammer relative to the radar, set the starting center frequency in the configuration file, and obtain the current elevation frequency, and then determine whether the current scanning frequency is within the frequency range of the jammer's interference; S4: spatial matching of traces: spatially matching the target true value traces generated in step S1, the passive interference traces generated in step S2, and the active clutter traces generated in step S3 with the target tracking gate. If the match is successful, the traces are added to the gate trace library. If the match is unsuccessful, the traces are deleted. S5: Wave gate point track output: output the points of the wave gate point track library to the data processing module of the radar to update the target track association, and output the unassociated points to the automatic start module for automatic start of new targets.

2. The method for generating gate traces containing clutter and interference based on a radar model according to claim 1, characterized in that: The step S1 of generating the target point trace comprises the following steps: S1-1: Effective detection airspace comparison: Determine whether the target is within the detection range by comparing the target's azimuth, distance, and elevation with the azimuth range, distance range, and elevation range in the current radar's detection range; S1-2: Echo signal-to-noise ratio calculation: If the target is within the detection airspace of step S1-1, the target signal-to-noise ratio is calculated by using the radar's target position true value, target scattering cross-sectional area, and radar operating parameters through the radar equation; S1-3: Detection probability calculation: using the signal-to-noise ratio, according to the detection probability and the signal-to-noise ratio curve, the detection probability is obtained, and then the probability is simulated by generating random numbers to determine whether to generate a point trace; S1-4: Error simulation: Based on the point trace, an error is added to the point trace according to the measurement error of the radar.

3. The method for generating gate traces containing clutter and interference based on a radar model according to claim 2, characterized in that: The effective detection of airspace comparison in step S1-1 is specifically as follows: S1-1-1: Determine the current radar scanning range based on the shielding angle, the azimuth and elevation of the radar's current scanning; S1-1-2: Calculate the radar line-of-sight distance d0 based on the radar height and target height; d0 = 4.12*(sqrt(ht)+sqrt(hr)), where sqrt is the square root function, hr is the radar installation height, and ht is the target height; S1-1-3: Determine whether the target is beyond the minimum effective distance based on the target distance, determine whether it is within the azimuth coverage range based on the target azimuth, determine whether it is within the elevation coverage range based on the target elevation, and determine whether it is within the corresponding line of sight based on the target type and target distance. If all conditions are met, the target is judged to be within the effective detection airspace of the radar and a target point trace is generated. If any condition is not met, no target point trace is generated.

4. The method for generating gate traces containing clutter and interference based on a radar model according to claim 3, characterized in that: The step S1-1 is: Calculate sea sight distance: Rd=R1+R2: R1 2 =(Re+h1) 2 -Re 2 =2Reh1+h1 2 ; R22=(Re+h2) 2 -Re 2 =2Reh2+h2 2 ; Among them, h1 is the antenna height, h2 is the target height, R e is the equivalent radius of curvature of the earth, h1 and h2 are in meters, R1 is the distance from the radar to the horizontal plane on the line connecting the radar and the target, and R2 is the distance from the target to the horizontal plane: Since Re>>h1, Re>>h2, R1 and R2 are simplified to: Where Rd is the radar direct line of sight distance; Calculate the sight distance of ultra-low altitude targets:

5. The method for generating gate traces containing clutter and interference based on a radar model according to claim 2, characterized in that: The echo signal-to-noise ratio detection in step S1-2 is specifically as follows: judging according to the azimuth and elevation angle covered by the beam in the current working mode, if the target is within the range of the azimuth and elevation angle covered by the beam, calculating the target signal-to-noise ratio S / N of the current scanning beam according to the following formula: Among them, P t is the radar transmission peak power, G t , G r is the radar transmitting and receiving antenna gain; λ is the radar wavelength; σ is the radar cross-sectional area of ​​the target; D is the pulse compression ratio; k is the Boltzmann constant; T0 is the equivalent noise temperature; B n is the receiver bandwidth; R is the distance from the target to the radar; F n is the receiver noise coefficient; L is the sum of various losses.

6. The method for generating gate traces containing clutter and interference based on a radar model according to claim 2, characterized in that: The detection probability calculation feature of step S1-3 is: compare the target signal-to-noise ratio and the radar minimum detectable signal-to-noise ratio. If the target signal-to-noise ratio is greater than the radar minimum detectable signal-to-noise ratio, then interpolate the detection probability P according to the signal-to-noise ratio table lookup. D , then generate a random number that obeys the uniform distribution of [0, 1], and compare the random number with the detection probability P D , if the random number is less than the detection probability P D Then output the target to proceed to the next step, otherwise remove the target.

7. The method for generating gate traces containing clutter and interference based on a radar model according to claim 2, characterized in that: The error simulation characteristics of step S1-4 are: S1-4-1: Superimpose the system error on the target azimuth, distance and elevation according to the currently set mean value of distance error, mean value of azimuth error and mean value of elevation error; S1-4-2: Call the overall provided dynamic library function for real-time calculation of radio wave propagation refraction effect error to superimpose the target based on the previous step.

8. The method for generating gate traces containing clutter and interference based on a radar model according to claim 1, characterized in that: The passive clutter point trace generation step S2 is specifically as follows: S2-1: Sea clutter generation: The sea conditions of the environment area of ​​the platform are obtained according to the latitude and longitude information of the platform, and the sea clutter points are determined in each beam scanned by the antenna according to the number of sea clutter points corresponding to each level of sea conditions in the local configuration file; S2-2: Cloud clutter generation: If the obstacle type in the obstacle data message is cloud, the area range of the cylinder with the obstacle as the center point relative to the radar origin is determined according to the number of cloud clutter points set in the local configuration file. If the antenna scans this area, the cloud clutter point traces in the current beam are generated according to the above method and then output to the data processing module; S2-3: Rain clutter generation: If the obstacle type in the obstacle data message is light rain, moderate rain, or heavy rain, the area range of the cylinder with the obstacle as the center point relative to the radar origin is determined according to the number of rain clutter points set in the local configuration file. If the antenna scans this area, the rain clutter point traces in the current beam are generated according to the aforementioned method and then output to the data processing module.

9. The method for generating gate traces containing clutter and interference based on a radar model according to claim 1, characterized in that: The step S3 sets the starting center frequency in the configuration file, and calculates according to the frequency-elevation correspondence of the radar to obtain the current elevation frequency; if the current scanning frequency is within the frequency range of the jammer, the received radar interference data is calculated according to different working modes to obtain interference point traces on different distance units, and output to the backward data processing module; if the current scanning frequency is not within the frequency range of the jammer, the radar is not interfered and no processing is performed.

10. The method for generating gate traces containing clutter and interference based on a radar model according to claim 5, characterized in that: The equivalent noise temperature T0 is 290°C.

Images