A method for obtaining a two-dimensional analysis graph of radar detection capability

Abstract

The application discloses a method for obtaining a radar detection capability two-dimensional analysis graph, and belongs to the technical field of radar imaging. The method solves the problem that the radar detection capability in the prior art can only be analyzed by data, which is not conducive to the intuitive understanding of the detection capability of the radar by an operator. The method screens the range resolution in a range resolution matrix, the azimuth resolution in an azimuth resolution matrix and the ground reflection coefficient in a ground reflection coefficient matrix according to the threshold range of the range resolution, the azimuth resolution and the ground reflection coefficient. If the range resolution, the azimuth resolution and the ground reflection coefficient are all within the threshold range, the corresponding multiple grid points simultaneously satisfy the range resolution, the azimuth resolution and the ground reflection coefficient. The multiple grid points simultaneously satisfying the range resolution, the azimuth resolution and the ground reflection coefficient are graphically displayed, and a two-dimensional analysis graph is obtained. The method can be used to obtain a two-dimensional analysis graph of the radar elasticity capability.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of radar imaging, and particularly relates to a method for obtaining a radar detection capability two-dimensional analysis diagram. BACKGROUND

[0002] The radar can be installed on a flight platform such as an airplane, a satellite, a spacecraft, etc., and can implement observation on the ground at all times and in all weathers.

[0003] In order to meet the increasing demand for high-precision detection, the detection capability of the radar needs to be known before the radar performs actual detection.

[0004] However, the radar detection capability can only be analyzed by data at present, and this way is not intuitive and is not conducive to the operator to intuitively understand the detection capability of the radar. SUMMARY

[0005] In view of the above analysis, the present application aims to provide a method for obtaining a radar detection capability two-dimensional analysis diagram, which solves the problem that the radar detection capability can only be analyzed by data in the prior art and is not conducive to the operator to intuitively understand the detection capability of the radar.

[0006] The purpose of the present application is mainly achieved by the following technical solutions:

[0007] The present application provides a method for obtaining a radar detection capability two-dimensional analysis diagram, comprising the following steps:

[0008] The ground beam coverage range is determined, and a grid point coordinate matrix in the beam coverage range is obtained, and a ground reflection coefficient matrix corresponding to the grid points at different distance resolutions, a distance resolution matrix and an azimuth resolution matrix are calculated;

[0009] The distance resolution in the distance resolution matrix, the azimuth resolution in the azimuth resolution matrix and the ground reflection coefficient in the ground reflection coefficient matrix of the grid points are screened according to the threshold range of the distance resolution, the threshold range of the azimuth resolution and the threshold range of the ground reflection coefficient respectively;

[0010] If the distance resolution is within the threshold range of the distance resolution, the azimuth resolution is within the threshold range of the azimuth resolution, and the ground reflection coefficient is within the threshold range of the ground reflection coefficient, then the distance resolution, the azimuth resolution and the ground reflection coefficient of the corresponding multiple grid points are simultaneously satisfied, the multiple grid points simultaneously satisfying the distance resolution, the azimuth resolution and the ground reflection coefficient are graphically displayed, and a two-dimensional analysis diagram is obtained.

[0011] Further, the ground beam coverage range is determined by using the flight parameters of the carrier and the antenna installation angle and scanning range of the radar, the grid is drawn in the beam coverage range, and the grid point coordinate matrix in the beam coverage range is obtained.

[0012] Further, the carrier is an airplane, a satellite or a spacecraft.

[0013] Further, the flight parameters of the carrier include coordinates, a pitch attitude, a yaw attitude, a roll attitude and a three-dimensional velocity of the carrier in a navigation coordinate system.

[0014] Further, the screening of the range resolution, the azimuth resolution and the ground reflection coefficient in the range resolution matrix, the azimuth resolution matrix and the ground reflection coefficient matrix of the grid points according to the threshold range of the range resolution, the threshold range of the azimuth resolution and the threshold range of the ground reflection coefficient respectively comprises the following steps:

[0015] Step a: judging whether the range resolution in the range resolution matrix is within the threshold range of the range resolution, if yes, judging that the grid point corresponding to the range resolution meets the condition, and obtaining a plurality of grid points meeting the range resolution;

[0016] Step b: judging whether the azimuth resolution in the plurality of grid points meeting the range resolution is within the threshold range of the azimuth resolution, if yes, judging that the grid point corresponding to the azimuth resolution meets the condition, and obtaining a plurality of grid points meeting both the range resolution and the azimuth resolution;

[0017] Step c: judging whether the ground reflection coefficient in the plurality of grid points meeting both the range resolution and the azimuth resolution is within the threshold range of the ground reflection coefficient, if yes, judging that the grid point corresponding to the ground reflection coefficient meets the condition, and obtaining a plurality of grid points meeting all of the range resolution, the azimuth resolution and the ground reflection coefficient.

[0018] Further, the screening of the range resolution, the azimuth resolution and the ground reflection coefficient in the range resolution matrix, the azimuth resolution matrix and the ground reflection coefficient matrix of the grid points according to the threshold range of the range resolution, the threshold range of the azimuth resolution and the threshold range of the ground reflection coefficient respectively comprises the following steps:

[0019] Step a': judging whether the azimuth resolution in the azimuth resolution matrix is within the threshold range of the azimuth resolution, if yes, judging that the grid point corresponding to the azimuth resolution meets the condition, and obtaining a plurality of grid points meeting the azimuth resolution;

[0020] Step b': judging whether the range resolution in the plurality of grid points meeting the azimuth resolution is within the threshold range of the range resolution, if yes, judging that the grid point corresponding to the range resolution meets the condition, and obtaining a plurality of grid points meeting both the azimuth resolution and the range resolution;

[0021] Step c: judging whether the ground reflection coefficients in the multiple grid points satisfying the azimuth resolution and the distance resolution are within the threshold range of the ground reflection coefficients, if yes, judging that the grid points corresponding to the ground reflection coefficients satisfy the condition, and obtaining multiple grid points satisfying the distance resolution, the azimuth resolution and the ground reflection coefficient.

[0022] Further, the screening of the distance resolution in the distance resolution matrix, the azimuth resolution in the azimuth resolution matrix and the ground reflection coefficient in the ground reflection coefficient matrix of the grid points according to the threshold range of the distance resolution, the threshold range of the azimuth resolution and the threshold range of the ground reflection coefficient respectively comprises the following steps:

[0023] Step a: judging whether the ground reflection coefficients in the ground reflection coefficient matrix are within the threshold range of the ground reflection coefficients, if yes, judging that the grid points corresponding to the ground reflection coefficients satisfy the condition, and obtaining multiple grid points satisfying the ground reflection coefficient;

[0024] Step b: judging whether the azimuth resolutions in the multiple grid points satisfying the ground reflection coefficient are within the threshold range of the azimuth resolution, if yes, judging that the grid points corresponding to the azimuth resolutions satisfy the condition, and obtaining multiple grid points satisfying the ground reflection coefficient and the azimuth resolution;

[0025] Step c: judging whether the distance resolutions in the multiple grid points satisfying the ground reflection coefficient and the azimuth resolution are within the threshold range of the distance resolution, if yes, judging that the grid points corresponding to the distance resolutions satisfy the condition, and obtaining multiple grid points satisfying the distance resolution, the azimuth resolution and the ground reflection coefficient.

[0026] Further, the screening of the distance resolution in the distance resolution matrix, the azimuth resolution in the azimuth resolution matrix and the ground reflection coefficient in the ground reflection coefficient matrix of the grid points according to the threshold range of the distance resolution, the threshold range of the azimuth resolution and the threshold range of the ground reflection coefficient respectively comprises the following steps:

[0027] Step A: judging whether the ground reflection coefficients in the ground reflection coefficient matrix are within the threshold range of the ground reflection coefficients, if yes, judging that the grid points corresponding to the ground reflection coefficients satisfy the condition, and obtaining multiple grid points satisfying the ground reflection coefficient;

[0028] Step B: judging whether the distance resolutions in the multiple grid points satisfying the ground reflection coefficient are within the threshold range of the distance resolution, if yes, judging that the grid points corresponding to the distance resolutions satisfy the condition, and obtaining multiple grid points satisfying the ground reflection coefficient and the distance resolution;

[0029] Step C: judging whether the azimuth resolution of the multiple grid points satisfying the ground reflection coefficient and the distance resolution simultaneously is within the threshold range of the azimuth resolution, if yes, judging that the grid point corresponding to the azimuth resolution satisfies the condition, and obtaining multiple grid points satisfying the distance resolution, the azimuth resolution and the ground reflection coefficient simultaneously.

[0030] Further, the screening of the distance resolution in the distance resolution matrix, the azimuth resolution in the azimuth resolution matrix and the ground reflection coefficient in the ground reflection coefficient matrix of the grid points according to the threshold range of the distance resolution, the threshold range of the azimuth resolution and the threshold range of the ground reflection coefficient respectively comprises the following steps:

[0031] Step A': judging whether the azimuth resolution in the azimuth resolution matrix is within the threshold range of the azimuth resolution, if yes, judging that the grid point corresponding to the azimuth resolution satisfies the condition, and obtaining multiple grid points satisfying the azimuth resolution;

[0032] Step B': judging whether the distance resolution in the multiple grid points satisfying the azimuth resolution is within the threshold range of the ground reflection coefficient, if yes, judging that the grid point corresponding to the ground reflection coefficient satisfies the condition, and obtaining multiple grid points satisfying the azimuth resolution and the ground reflection coefficient simultaneously;

[0033] Step C': judging whether the distance resolution in the multiple grid points satisfying the azimuth resolution and the ground reflection coefficient simultaneously is within the threshold range of the distance resolution, if yes, judging that the grid point corresponding to the distance resolution satisfies the condition, and obtaining multiple grid points satisfying the distance resolution, the azimuth resolution and the ground reflection coefficient simultaneously.

[0034] Further, the screening of the distance resolution in the distance resolution matrix, the azimuth resolution in the azimuth resolution matrix and the ground reflection coefficient in the ground reflection coefficient matrix of the grid points according to the threshold range of the distance resolution, the threshold range of the azimuth resolution and the threshold range of the ground reflection coefficient respectively comprises the following steps:

[0035] Step A": judging whether the distance resolution in the distance resolution matrix is within the threshold range of the distance resolution, if yes, judging that the grid point corresponding to the distance resolution satisfies the condition, and obtaining multiple grid points satisfying the distance resolution;

[0036] Step B": judging whether the azimuth resolution in the multiple grid points satisfying the distance resolution is within the threshold range of the ground reflection coefficient, if yes, judging that the grid point corresponding to the ground reflection coefficient satisfies the condition, and obtaining multiple grid points satisfying the distance resolution and the ground reflection coefficient simultaneously;

[0037] Step C": judging whether the azimuth resolution of the multiple grid points satisfying the distance resolution and the ground reflection coefficient is in the azimuth resolution threshold range, if yes, judging that the grid point corresponding to the azimuth resolution satisfies the condition, and obtaining the multiple grid points satisfying the distance resolution, the azimuth resolution and the ground reflection coefficient.

[0038] Compared with the prior art, the present application can achieve at least one of the following beneficial effects:

[0039] The radar detection capability two-dimensional analysis diagram acquisition method provided by the present application can comprehensively calculate and screen the indexes such as distance resolution, azimuth resolution and ground reflection coefficient which are respectively calculated in the past according to the radar detection capability analysis requirement, present the radar capability boundary in a two-dimensional image multidimensional manner, correspond the position, three-dimensional speed and three-dimensional attitude of the carrier to multiple dimensions such as the action distance, squint angle and off-axis angle of the radar, and give the distribution characteristics of the resolution in the ground beam coverage range, so that the radar detection capability can be more intuitively displayed, and the operator can intuitively understand the detection capability of the radar.

[0040] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent to those skilled in the art from the description, or can be learned by practice of the present application. The objects and other advantages of the present application can be realized and achieved by the structure particularly pointed out in the written description and the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0041] The accompanying drawings are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the principles of the application.

[0042] Figure 1 The memory and the shell are connected in the radar detection capability two-dimensional analysis diagram acquisition method provided by the embodiment one of the present application.

[0043] Figure 2 The first arc-shaped rod and the connecting rod are connected in the radar detection capability two-dimensional analysis diagram acquisition method provided by the embodiment one of the present application.

[0044] Reference signs:

[0045] 1 - shell; 2 - memory; 3 - first arc-shaped rod; 4 - second arc-shaped rod; 5 - connecting pipe; 6 - outer ring; 7 - first inner ring; 8 - second inner ring; 9 - baffle. DETAILED DESCRIPTION

[0046] The preferred embodiments of the present application will be specifically described below in combination with the drawings, wherein the drawings constitute a part of the present application, and are used together with the embodiments of the present application to explain the principles of the present application.

[0047] Embodiment one

[0048] The embodiment provides an acquisition method of a radar detection capability two-dimensional analysis diagram, and the radar can be a synthetic aperture radar, for example. The acquisition method comprises the following steps:

[0049] Determine a ground beam coverage range, and acquire a grid point coordinate matrix in the beam coverage range, calculate a squint angle matrix and a slant range matrix corresponding to the grid points, an actual transmitting gain matrix of an antenna to the grid points and an actual receiving gain matrix of the antenna to the grid points;

[0050] According to the squint angle matrix and the slant range matrix, the actual transmitting gain matrix of the antenna to the grid points and the actual receiving gain matrix of the antenna to the grid points, calculate a ground reflection coefficient matrix, a distance resolution matrix and an azimuth resolution matrix of the grid points under different distance resolutions respectively;

[0051] According to a threshold range of the distance resolution, a threshold range of the azimuth resolution and a threshold range of the ground reflection coefficient, screen the distance resolution in the distance resolution matrix, the azimuth resolution in the azimuth resolution matrix and the ground reflection coefficient in the ground reflection coefficient matrix of the grid points respectively;

[0052] If the distance resolution is in the threshold range of the distance resolution, the azimuth resolution is in the threshold range of the azimuth resolution and the ground reflection coefficient is in the threshold range of the ground reflection coefficient, then the distance resolution, the azimuth resolution and the ground reflection coefficient of the corresponding multiple grid points satisfy simultaneously, perform graphical display on the multiple grid points which satisfy the distance resolution, the azimuth resolution and the ground reflection coefficient simultaneously, and obtain a two-dimensional analysis diagram.

[0053] According to the two-dimensional analysis diagram obtained by the above system, the beam coverage range can be divided into multiple areas, and the resolution distribution characteristics in the ground beam coverage range under different squint angles are obtained, for example, 1m x 1m x sigma (ground reflection coefficient) =-12, 3m x 3m x sigma (ground reflection coefficient) =-12 and 5m x 5m x sigma (ground reflection coefficient) =-12. In practical applications, for example, the grid points marked with circles are grid points that satisfy the distance resolution and azimuth resolution of 1m x 1m x sigma (ground reflection coefficient) =-12, the grid points marked with m-shaped characters are grid points that satisfy the distance resolution and azimuth resolution of 3m x 3m x sigma (ground reflection coefficient) =-12, and the grid points marked with triangles are grid points that satisfy the distance resolution and azimuth resolution of 5m x 5m x sigma (ground reflection coefficient) =-12. When the carrier needs to perform image detection with a distance resolution and azimuth resolution of 1m x 1m x sigma (ground reflection coefficient) =-12, the parameters of the carrier and the radar can be controlled to be consistent with the parameters corresponding to the grid points marked with circles, so that image detection with a distance resolution and azimuth resolution of 1m x 1m x sigma (ground reflection coefficient) =-12 can be realized, thereby guiding radar image detection.

[0054] Compared with the prior art, the method for obtaining a radar detection capability two-dimensional analysis diagram provided in the embodiment comprehensively calculates and screens the indexes such as distance resolution, azimuth resolution and ground reflection coefficient which are respectively calculated in the past, presents the radar capability boundary in multiple dimensions through a two-dimensional image, corresponds the position, three-dimensional velocity and three-dimensional attitude of the carrier to multiple dimensions such as the action distance, squint angle and off-axis angle of the radar, and gives the distribution characteristics of the resolution in the ground beam coverage range, so that the radar detection capability can be more intuitively displayed, and an operator can intuitively understand the detection capability of the radar.

[0055] Specifically, the method for obtaining a radar detection capability two-dimensional analysis diagram includes the following steps:

[0056] Step 1: determining the ground beam coverage range by using the flight parameters of the carrier and the antenna installation angle and scanning range of the radar, drawing a grid in the beam coverage range, and obtaining a grid point coordinate matrix in the beam coverage range;

[0057] Step 2: calculating a squint angle matrix and a slant distance matrix corresponding to the grid points in the beam coverage range according to the flight parameters of the carrier and the grid point coordinate matrix;

[0058] Step 3: calculating an actual transmitting gain matrix of the antenna to the grid points and an actual receiving gain matrix of the antenna to the grid points according to the off-axis angle, and it should be noted that the off-axis angle refers to the angle between the target direction of the carrier and the direction of the antenna;

[0059] Step 4: According to the actual transmitting gain matrix of the antenna to the grid points, the actual receiving gain matrix of the antenna to the grid points, the squint angle matrix, the slant range matrix, the system loss of the radar (it is to be noted that the system loss of the radar is a fixed value, and each model of radar has a fixed system loss, which usually includes waveform loss or transmission loss, etc.) and the average power, the radar equation is calculated to obtain the ground reflection coefficient matrix of the grid points at different distance resolutions;

[0060] According to the bandwidth of the radar, the height of the carrier and the slant range matrix, the distance resolution matrix of the grid points is obtained;

[0061] According to the speed of the carrier (which can be obtained by three-dimensional speed calculation of the carrier), the wavelength, the synthetic aperture time, the squint angle matrix and the slant range matrix, the azimuth resolution matrix of the grid points is obtained;

[0062] According to the threshold range, the distance resolution in the distance resolution matrix of the grid points, the azimuth resolution in the azimuth resolution matrix and the ground reflection coefficient in the ground reflection coefficient matrix are screened to obtain multiple grid points that simultaneously satisfy the distance resolution, the azimuth resolution and the ground reflection coefficient, which are graphically displayed to obtain a two-dimensional analysis graph.

[0063] Exemplarily, in the above steps 1 and 2, the flight parameters of the carrier include the coordinates of the carrier in the navigation coordinate system, the pitch attitude, the yaw attitude, the roll attitude and the three-dimensional speed.

[0064] It is to be noted that the carrier refers to a base body for loading the radar, such as an aircraft, a satellite, a spacecraft and the like.

[0065] In the above step 1, the following method is used to obtain the grid point coordinate matrix in the beam coverage range:

[0066] T x =[x1,x2,…,x M ]

[0067] T z =[z1,z2,…,z N ]

[0068] Wherein, x1, x M , z1, z N are the intersection coordinate values of the maximum coverage range of the beam and the two-dimensional coordinate axes of the ground, T x , T z are the two-dimensional coordinate matrices of the grid points, x is an integer from 1 to M, and z is an integer from 1 to N.

[0069] In step 2 above, the slant angle matrix θ and the slant distance matrix R corresponding to the grid points in the beam coverage are calculated according to the flight parameters of the carrier and the grid point coordinate matrix by using the following formulas:

[0070] θ v = arctan(v z / v x )

[0071] θ p = arctan(T z -P z ) / (T x -P z )

[0072] θ = θ p - θ v

[0073]

[0074] wherein θ is the slant angle matrix, R is the slant distance matrix, v x is the north speed of the carrier in the navigation coordinate system, v z is the east speed of the carrier in the navigation coordinate system, (P x , P y , P z ) is the coordinate of the carrier in the navigation coordinate system, T x , T z are the two-dimensional coordinate matrices of the grid points, x is an integer from 1 to M, and z is an integer from 1 to N.

[0075] In step 3 above, the actual transmitting gain matrix G tT of the antenna to the grid points and the actual receiving gain matrix G rT of the antenna to the grid points are calculated according to the off-axis angle matrix by using the following formulas:

[0076]

[0077]

[0078] wherein G t is the antenna transmitting gain, G r is the antenna receiving gain, each type of GAR has fixed G t and G r , both of which are known values, G tT is the actual transmitting gain matrix of the antenna to the grid points, G rT is the actual receiving gain matrix of the antenna to the grid points, and is the off-axis angle matrix.

[0079] In step 4 above, the radar equations are calculated based on the actual transmit gain matrix from the antenna to the grid point, the actual receive gain matrix from the antenna to the grid point, the slant angle matrix, the slant range matrix, the radar system loss, and the average power. The ground reflection coefficient matrix of the grid point at different resolutions is obtained using the following formula:

[0080]

[0081] Where σ is the ground reflection coefficient matrix, R is the slant range matrix, and K = 1.38 × 10⁻⁶. -23 Here, T0 is the Boltzmann constant, T0 is the 350K sound temperature, and F is the noise level. n The noise coefficient is 4.5 dB, L is the system loss, v is the sum of the vehicle's velocities in the northeast plane in the navigation coordinate system, θ is the oblique angle matrix, and P is the noise coefficient. av For average power, G tT G is the actual transmit gain matrix from the antenna to the grid points. rT The actual receive gain matrix from the antenna to the grid points, SNR is the image signal-to-noise ratio, λ is the wavelength, and D... r Where is the distance resolution (in this formula, is a specified value), and k = 1.4 is the azimuth broadening factor.

[0082] In step 4 above, based on the radar bandwidth B r The distance resolution matrix D is calculated from the carrier's height and slant range R matrix. r The following formula is used:

[0083]

[0084]

[0085] Among them, D r R is the range resolution matrix, and B is the slant range matrix. r For the bandwidth of the radar, (P) x ,P y ,P z ) represents the coordinates of the carrier in the navigation coordinate system, k is a 1.4-dimensional expansion factor, c is the speed of light, and β is the ground grazing angle.

[0086] The azimuth resolution matrix D is calculated based on the carrier's velocity, wavelength, synthetic aperture time, slant angle matrix, and slant range matrix. a The following formula is used:

[0087]

[0088] Among them, D awhere R is the slant range matrix, v is the and velocity of the platform in the navigation coordinate system, Θ is the slant angle matrix, T is the time matrix, k is the 1.4 azimuth broadening factor, and λ is the wavelength. a is the synthetic aperture time.

[0089] Exemplarily, the screening of the range resolution in the range resolution matrix, the azimuth resolution in the azimuth resolution matrix and the ground reflection coefficient in the ground reflection coefficient matrix of the grid points according to the threshold range of the range resolution, the threshold range of the azimuth resolution and the threshold range of the ground reflection coefficient respectively includes the following steps:

[0090] Step a: judging whether the range resolution in the range resolution matrix is within the threshold range of the range resolution, if yes, judging that the grid point corresponding to the range resolution meets the condition, and obtaining a plurality of grid points meeting the range resolution;

[0091] Step b: judging whether the azimuth resolution in the plurality of grid points meeting the range resolution is within the threshold range of the azimuth resolution, if yes, judging that the grid point corresponding to the azimuth resolution meets the condition, and obtaining a plurality of grid points meeting both the range resolution and the azimuth resolution;

[0092] Step c: judging whether the ground reflection coefficient in the plurality of grid points meeting both the range resolution and the azimuth resolution is within the threshold range of the ground reflection coefficient, if yes, judging that the grid point corresponding to the ground reflection coefficient meets the condition, and obtaining a plurality of grid points meeting the range resolution, the azimuth resolution and the ground reflection coefficient.

[0093] Alternatively, the screening of the range resolution in the range resolution matrix, the azimuth resolution in the azimuth resolution matrix and the ground reflection coefficient in the ground reflection coefficient matrix of the grid points according to the threshold range of the range resolution, the threshold range of the azimuth resolution and the threshold range of the ground reflection coefficient respectively includes the following steps:

[0094] Step a': judging whether the azimuth resolution in the azimuth resolution matrix is within the threshold range of the azimuth resolution, if yes, judging that the grid point corresponding to the azimuth resolution meets the condition, and obtaining a plurality of grid points meeting the azimuth resolution;

[0095] Step b': judging whether the range resolution in the plurality of grid points meeting the azimuth resolution is within the threshold range of the range resolution, if yes, judging that the grid point corresponding to the range resolution meets the condition, and obtaining a plurality of grid points meeting both the azimuth resolution and the range resolution;

[0096] Step c': judging whether the ground reflection coefficients in the multiple grid points satisfying the azimuth resolution and the distance resolution simultaneously are within the threshold range of the ground reflection coefficient, if yes, judging that the grid point corresponding to the ground reflection coefficient satisfies the condition, and obtaining the multiple grid points satisfying the distance resolution, the azimuth resolution and the ground reflection coefficient simultaneously.

[0097] Alternatively, the screening of the distance resolution in the distance resolution matrix, the azimuth resolution in the azimuth resolution matrix and the ground reflection coefficient in the ground reflection coefficient matrix of the grid points according to the threshold range of the distance resolution, the threshold range of the azimuth resolution and the threshold range of the ground reflection coefficient respectively comprises the following steps:

[0098] Step a": judging whether the ground reflection coefficient in the ground reflection coefficient matrix is within the threshold range of the ground reflection coefficient, if yes, judging that the grid point corresponding to the ground reflection coefficient satisfies the condition, and obtaining the multiple grid points satisfying the ground reflection coefficient;

[0099] Step b": judging whether the azimuth resolution in the multiple grid points satisfying the ground reflection coefficient is within the threshold range of the azimuth resolution, if yes, judging that the grid point corresponding to the azimuth resolution satisfies the condition, and obtaining the multiple grid points satisfying the ground reflection coefficient and the azimuth resolution simultaneously;

[0100] Step c": judging whether the distance resolution in the multiple grid points satisfying the ground reflection coefficient and the azimuth resolution simultaneously is within the threshold range of the distance resolution, if yes, judging that the grid point corresponding to the distance resolution satisfies the condition, and obtaining the multiple grid points satisfying the distance resolution, the azimuth resolution and the ground reflection coefficient simultaneously.

[0101] Alternatively, the screening of the distance resolution in the distance resolution matrix, the azimuth resolution in the azimuth resolution matrix and the ground reflection coefficient in the ground reflection coefficient matrix of the grid points according to the threshold range of the distance resolution, the threshold range of the azimuth resolution and the threshold range of the ground reflection coefficient respectively comprises the following steps:

[0102] Step A: judging whether the ground reflection coefficient in the ground reflection coefficient matrix is within the threshold range of the ground reflection coefficient, if yes, judging that the grid point corresponding to the ground reflection coefficient satisfies the condition, and obtaining the multiple grid points satisfying the ground reflection coefficient;

[0103] Step B: judging whether the distance resolution in the multiple grid points satisfying the ground reflection coefficient is within the threshold range of the distance resolution, if yes, judging that the grid point corresponding to the distance resolution satisfies the condition, and obtaining the multiple grid points satisfying the ground reflection coefficient and the distance resolution simultaneously;

[0104] Step C: judging whether the azimuth resolution of the multiple grid points satisfying the ground reflection coefficient and the distance resolution simultaneously is within the threshold range of the azimuth resolution, if yes, judging that the grid point corresponding to the azimuth resolution satisfies the condition, and obtaining the multiple grid points satisfying the distance resolution, the azimuth resolution and the ground reflection coefficient simultaneously.

[0105] Alternatively, the screening of the distance resolution in the distance resolution matrix, the azimuth resolution in the azimuth resolution matrix and the ground reflection coefficient in the ground reflection coefficient matrix of the grid points according to the threshold range of the distance resolution, the threshold range of the azimuth resolution and the threshold range of the ground reflection coefficient respectively comprises the following steps:

[0106] Step A': judging whether the azimuth resolution in the azimuth resolution matrix is within the threshold range of the azimuth resolution, if yes, judging that the grid point corresponding to the azimuth resolution satisfies the condition, and obtaining the multiple grid points satisfying the azimuth resolution;

[0107] Step B': judging whether the distance resolution in the multiple grid points satisfying the azimuth resolution is within the threshold range of the ground reflection coefficient, if yes, judging that the grid point corresponding to the ground reflection coefficient satisfies the condition, and obtaining the multiple grid points satisfying the azimuth resolution and the ground reflection coefficient simultaneously;

[0108] Step C': judging whether the distance resolution in the multiple grid points satisfying the azimuth resolution and the ground reflection coefficient simultaneously is within the threshold range of the distance resolution, if yes, judging that the grid point corresponding to the distance resolution satisfies the condition, and obtaining the multiple grid points satisfying the distance resolution, the azimuth resolution and the ground reflection coefficient simultaneously.

[0109] Alternatively, the screening of the distance resolution in the distance resolution matrix, the azimuth resolution in the azimuth resolution matrix and the ground reflection coefficient in the ground reflection coefficient matrix of the grid points according to the threshold range of the distance resolution, the threshold range of the azimuth resolution and the threshold range of the ground reflection coefficient respectively comprises the following steps:

[0110] Step A": judging whether the distance resolution in the distance resolution matrix is within the threshold range of the distance resolution, if yes, judging that the grid point corresponding to the distance resolution satisfies the condition, and obtaining the multiple grid points satisfying the distance resolution;

[0111] Step B": judging whether the azimuth resolution in the multiple grid points satisfying the distance resolution is within the threshold range of the ground reflection coefficient, if yes, judging that the grid point corresponding to the ground reflection coefficient satisfies the condition, and obtaining the multiple grid points satisfying the distance resolution and the ground reflection coefficient simultaneously;

[0112] Step C'': judging whether the azimuth resolution of the multiple grid points satisfying the distance resolution and the ground reflection coefficient simultaneously is within the threshold range of the azimuth resolution, if yes, judging that the grid point corresponding to the azimuth resolution satisfies the condition, and obtaining the multiple grid points satisfying the distance resolution, the azimuth resolution and the ground reflection coefficient simultaneously.

[0113] Alternatively, the screening of the distance resolution in the distance resolution matrix, the azimuth resolution in the azimuth resolution matrix and the ground reflection coefficient in the ground reflection coefficient matrix of the grid points according to the threshold range of the distance resolution, the threshold range of the azimuth resolution and the threshold range of the ground reflection coefficient respectively comprises the following steps:

[0114] simultaneously judging whether the distance resolution in the distance resolution matrix is within the threshold range of the distance resolution, whether the azimuth resolution in the azimuth resolution matrix is within the threshold range of the azimuth resolution, and whether the ground reflection coefficient in the ground reflection coefficient matrix is within the threshold range of the ground reflection coefficient;

[0115] if the distance resolution, the azimuth resolution and the ground reflection coefficient are all within the respective threshold range, judging that the grid point corresponding to the distance resolution, the azimuth resolution and the ground reflection coefficient satisfies the condition, and obtaining the multiple grid points satisfying the distance resolution, the azimuth resolution and the ground reflection coefficient simultaneously.

[0116] It is worth noting that in actual application, the velocity error and the height error of the carrier will also affect the detection capability of the radar, therefore, the above step 4 further comprises the following steps:

[0117] calculating the distortion rate according to the velocity error and the height error of the carrier;

[0118] screening the multiple grid points satisfying the distance resolution, the azimuth resolution and the ground reflection coefficient simultaneously according to the threshold range, and performing graphical display on the grid points after the distortion screening as the grid points satisfying the condition.

[0119] Specifically, the above calculation of the distortion rate according to the velocity error and the height error of the carrier comprises the following steps:

[0120] obtaining the theoretical two-dimensional positions of the four edge points of the ground beam coverage range according to the ground beam coverage range;

[0121] adding the three-dimensional velocity error and the height error of the carrier into the ground beam coverage range to obtain the actual ground beam coverage range and the actual two-dimensional positions of the four edge points of the actual beam coverage range;

[0122] calculating the maximum value of the ratio of the difference between the actual two-dimensional position and the theoretical two-dimensional position to the two-dimensional width of the actual beam coverage range, which is the distortion rate.

[0123] Exemplarily, the radar detection capability two-dimensional analysis chart acquisition method can adopt a radar detection capability two-dimensional analysis chart acquisition system, which comprises a data calculation unit, a threshold comparison unit and an image display unit.

[0124] The data calculation unit is configured to determine a ground beam coverage range, and acquire a grid point coordinate matrix within the beam coverage range, calculate a slant angle matrix and a slant distance matrix corresponding to the grid points, an actual transmission gain matrix of the antenna to the grid points and an actual reception gain matrix of the antenna to the grid points; calculate a ground reflection coefficient matrix, a distance resolution matrix and an azimuth resolution matrix of the grid points at different distance resolutions according to the slant angle matrix and the slant distance matrix, respectively.

[0125] The threshold comparison unit receives the distance resolution matrix, the azimuth resolution matrix and the ground reflection coefficient matrix respectively, and compares them with the threshold range of the distance resolution, the threshold range of the azimuth resolution and the threshold range of the ground reflection coefficient stored in the threshold comparison unit, to obtain a plurality of grid points that simultaneously satisfy the distance resolution, the azimuth resolution and the ground reflection coefficient, and send them to the graphical display unit to display a two-dimensional analysis chart.

[0126] Specifically, in the data calculation unit, the grid point coordinate matrix adopts the following formula:

[0127] T x =[x1,x2,…,x M ]

[0128] T z =[z1,z2,…,z N ]

[0129] Wherein, x1, x M , z1, z N are the intersection coordinate values of the beam maximum coverage range and the two-dimensional coordinate axes of the ground, T x , T z are the two-dimensional coordinate matrix of the grid points.

[0130] In the data calculation unit, the slant angle matrix θ and the slant distance matrix R are calculated by the following formula:

[0131] θ v =arctan(v z / v x )

[0132] θ p =arctan(T z -P z ) / (T x -Pz )

[0133] θ = θ p - θ v

[0134]

[0135] wherein, θ is the angle of sight matrix, R is the slant distance matrix, v x is the north speed of the carrier in the navigation coordinate system, v z is the east speed of the carrier in the navigation coordinate system, (P x , P y , P z ) is the coordinate of the carrier in the navigation coordinate system, T x , T z is the two-dimensional coordinate matrix of the grid points.

[0136] In the above data calculation unit, the calculation of the actual transmitting gain matrix G tT of the antenna to the grid points and the actual receiving gain matrix G rT of the antenna to the grid points uses the following formula:

[0137]

[0138]

[0139] wherein, G t is the antenna transmitting gain, G r is the antenna receiving gain, each type of GAR has fixed G t and G r , both of which are known values, G tT is the actual transmitting gain matrix of the antenna to the grid points, G rT is the actual receiving gain matrix of the antenna to the grid points, is the off-axis angle matrix.

[0140] In the above data calculation unit, the calculation of the ground reflection coefficient matrix uses the following formula:

[0141]

[0142] wherein, σ is the ground reflection coefficient matrix, R is the slant distance matrix, K = 1.38 x 10 -23 is the Boltzmann constant, T0 is the noise temperature, F n is the noise coefficient, L is the system loss, v is the north-east plane speed of the carrier in the navigation coordinate system, θ is the angle of sight matrix, P av is the average power, G tT is the actual transmitting gain matrix of the antenna to the grid points, G rTis the actual received gain matrix of the antenna to the grid points, SNR is the image signal-to-noise ratio, λ is the wavelength, D r is the range resolution (in this formula, D z = 1.4 is the azimuth broadening factor.

[0143] In the above data calculation unit, the calculation of the range resolution matrix D r uses the following formula:

[0144]

[0145]

[0146] where D r is the range resolution matrix, R is the slant range matrix, B r is the bandwidth of the radar, (P x , P y , P z ) are the coordinates of the carrier in the navigation coordinate system, k is the azimuth broadening factor, c is the speed of light, and β is the grazing angle.

[0147] In the above data calculation unit, the calculation of the azimuth resolution matrix D a uses the following formula:

[0148]

[0149] where D a is the azimuth resolution matrix, k is the azimuth broadening factor, λ is the wavelength, R is the slant range matrix, v is the north-east plane speed of the carrier in the navigation coordinate system, θ is the squint angle matrix, and T a is the synthetic aperture time.

[0150] It is worth noting that in actual application, the speed error and height error of the carrier will also affect the detection capability of the radar, so the above radar detection capability two-dimensional analysis diagram acquisition system also includes a distortion rate acquisition unit;

[0151] The threshold comparison unit receives the distortion rate and compares the distortion rates corresponding to the multiple grid points that simultaneously satisfy the range resolution, the azimuth resolution, and the ground reflection coefficient with the threshold stored in the threshold comparison unit, to obtain multiple grid points that simultaneously satisfy the range resolution, the azimuth resolution, the ground reflection coefficient, and the distortion rate and send them to the graphical display unit to display the two-dimensional analysis diagram.

[0152] It can be understood that in order to realize the storage of the above various units, the above radar detection capability two-dimensional analysis diagram acquisition system also includes a memory 2 for storing the data calculation unit, the threshold comparison unit, and the graphical display unit. Illustratively, the memory 2 can be a chip.

[0153] In order to effectively protect the memory 2, the above-mentioned radar detection capability two-dimensional analysis diagram acquisition system further comprises a shell 1, the memory 2 is arranged in the shell 1, and the memory 2 can be effectively protected through the shell 1, thereby prolonging the service life.

[0154] In actual application, considering that the memory 2 is an electronic device, when the carrier is an airplane, the memory 2 will inevitably be impacted when the carrier lands, and the above-mentioned radar detection capability two-dimensional analysis diagram acquisition system further comprises a buffer, the memory 2 is detachably connected with the shell 1 through the buffer, and the buffer is shown in Figure 1 .

[0155] Exemplarily, the buffer comprises a first arc-shaped rod 3, a connecting pipe 5 and a second arc-shaped rod 4, one end of the first arc-shaped rod 3 is slidably connected with one end of the second arc-shaped rod 4 through the connecting pipe 5, the other end of the first arc-shaped rod 3 and the other end of the second arc-shaped rod 4 are connected with the shell 1, and the memory 2 is arranged on the connecting pipe 5. In this way, on the one hand, since the first arc-shaped rod 3 and the second arc-shaped rod 4 are both arc-shaped, when the memory 2 is impacted, the first arc-shaped rod 3 and the second arc-shaped rod 4 can be elastically deformed to a certain extent, thereby playing a buffering role; on the other hand, one end of the first arc-shaped rod 3 is slidably connected with one end of the second arc-shaped rod 4 through the connecting pipe 5, and in the elastic deformation process of the first arc-shaped rod 3 and the second arc-shaped rod 4, the end portions of the two are close to each other, thereby increasing the elastic deformation amount of the two, and further buffering the impact.

[0156] Considering that any material has a deformation limit, in order to avoid excessive deformation of the first arc-shaped rod 3 and the second arc-shaped rod 4, it is necessary to appropriately limit the relative sliding displacement between the first arc-shaped rod 3 and the second arc-shaped rod 4, one end of the connecting pipe 5 is sleeved on the outer wall of the first arc-shaped rod 3, the other end of the connecting pipe 5 is sleeved on the outer wall of the second arc-shaped pipe, and a limiting piece is arranged between the connecting pipe 5 and the first arc-shaped rod 3 and between the connecting pipe 5 and the second arc-shaped rod 4, and the limiting piece is shown in Figure 2 .

[0157] Exemplarily, the limiting piece comprises an outer ring 6 arranged on the outer wall of the first arc-shaped rod 3 and the second arc-shaped rod 4 and an inner ring arranged on the inner wall of the connecting pipe 5, the outer ring 6 is a rigid ring, the inner ring is an elastic ring, the inner diameter of the inner ring is smaller than the outer diameter of the outer ring 6, and the inner diameters of the multiple inner rings gradually decrease in the direction gradually close to the midpoint of the connecting pipe 5.

[0158] Taking the inner ring and the outer ring 6 between the connecting pipe 5 and the first arc-shaped rod 3 as an example, the number of the outer ring 6 is 1, the number of the inner ring is 2, which are the first inner ring 7 and the second inner ring 8 respectively, the side of the second inner ring 8 away from the first inner ring 7 is provided with the baffle 9, when not impacted, the outer ring 6 is located on the side of the first inner ring 7 away from the second inner ring 8 and does not contact the first inner ring 7; when the elastic deformation of the first arc-shaped rod 3 is too large, the outer ring 6 extrudes the first inner ring 7 and enters between the first inner ring 7 and the second inner ring 8, and collides with the second inner ring 8, absorbing part of the impact force, and the second inner ring 8 can limit the sliding displacement between the first arc-shaped rod and the connecting pipe 5, preventing the further sliding displacement of the outer ring 6; when the first arc-shaped rod 3 approaches the maximum elastic deformation, the outer ring 6 extrudes the second inner ring 8 and abuts against the baffle 9, thereby preventing the further sliding displacement of the outer ring 6, and further avoiding the damage of the outer ring 6.

[0159] The above merely describes the preferred embodiments of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A method for obtaining a two-dimensional analysis map of radar detection capability, characterized in that, The method comprises the following steps: determining a ground beam coverage range, obtaining a grid point coordinate matrix in the beam coverage range, calculating a ground reflection coefficient matrix corresponding to the grid points at different distance resolutions, a distance resolution matrix and an azimuth resolution matrix; screening the distance resolution in the distance resolution matrix, the azimuth resolution in the azimuth resolution matrix and the ground reflection coefficient in the ground reflection coefficient matrix of the grid points according to a threshold range of the distance resolution, a threshold range of the azimuth resolution and a threshold range of the ground reflection coefficient; if the distance resolution is within the threshold range of the distance resolution, the azimuth resolution is within the threshold range of the azimuth resolution and the ground reflection coefficient is within the threshold range of the ground reflection coefficient, then the distance resolution, the azimuth resolution and the ground reflection coefficient of the corresponding multiple grid points simultaneously satisfy the conditions, the multiple grid points simultaneously satisfying the distance resolution, the azimuth resolution and the ground reflection coefficient are graphically displayed to obtain a two-dimensional analysis graph; the ground reflection coefficient matrix adopts the following formula: where σ is the ground reflection coefficient matrix, R is the slant range matrix, K = 1.38 x 10 -23 is the Boltzmann constant, T0 is the noise temperature, F n is the noise factor, L is the system loss, v is the and velocity of the carrier in the north-east plane in the navigation coordinate system, θ is the angle of sight matrix, P av is the average power, G tT is the actual transmitting gain matrix of the antenna to the grid point, G rT is the actual receiving gain matrix of the antenna to the grid point, SNR is the image signal-to-noise ratio, λ is the wavelength, D r is the distance resolution, in the formula, D r is a specified value, k = 1.4 is the azimuth broadening factor; Distance resolution matrix D r The following equation is used: where D r is the distance resolution matrix, R is the slant range matrix, B r is the bandwidth of the radar, (P x ,P y ,P z ) is the coordinate of the carrier in the navigation coordinate system, k is the azimuth spread factor, c is the speed of light, and β is the ground contact angle. Azimuth resolution matrix D a Using the following equation: where D a is the azimuth resolution matrix, k = is the azimuth broadening factor, λ is the wavelength, R is the slant range matrix, v is the and velocity of the carrier in the North-East-Plane in the navigation coordinate system, Θ is the squint angle matrix, T a is the synthetic aperture time.

2. The method of claim 1, wherein, the flight parameters of the carrier, the antenna installation angle and the scanning range of the radar are used to determine the ground beam coverage range, and the grid points in the beam coverage range are obtained to draw the grid and obtain the grid point coordinate matrix in the beam coverage range.

3. The method of claim 2, wherein, The carrier is an airplane, a satellite or a spacecraft.

4. The method of claim 2, wherein, The flight parameters of the carrier include the coordinates, the pitch attitude, the yaw attitude, the roll attitude and the three-dimensional velocity of the carrier in the navigation coordinate system.

5. The method according to any one of claims 1 to 4, characterized in that, The screening of the distance resolution in the distance resolution matrix, the azimuth resolution in the azimuth resolution matrix and the ground reflection coefficient in the ground reflection coefficient matrix of the grid points according to the threshold range of the distance resolution, the threshold range of the azimuth resolution and the threshold range of the ground reflection coefficient comprises the following steps: Step a: judging whether the distance resolution in the distance resolution matrix is within the threshold range of the distance resolution, if yes, judging that the grid point corresponding to the distance resolution satisfies the condition to obtain multiple grid points satisfying the distance resolution; Step b: judging whether the azimuth resolution in the multiple grid points satisfying the distance resolution is within the threshold range of the azimuth resolution, if yes, judging that the grid point corresponding to the azimuth resolution satisfies the condition to obtain multiple grid points simultaneously satisfying the distance resolution and the azimuth resolution; Step c: judging whether the ground reflection coefficient in the multiple grid points simultaneously satisfying the distance resolution and the azimuth resolution is within the threshold range of the ground reflection coefficient, if yes, judging that the grid point corresponding to the ground reflection coefficient satisfies the condition to obtain multiple grid points simultaneously satisfying the distance resolution, the azimuth resolution and the ground reflection coefficient.

6. The method according to any one of claims 1 to 4, characterized in that, The screening of the distance resolution in the distance resolution matrix, the azimuth resolution in the azimuth resolution matrix and the ground reflection coefficient in the ground reflection coefficient matrix of the grid points according to the threshold range of the distance resolution, the threshold range of the azimuth resolution and the threshold range of the ground reflection coefficient comprises the following steps: Step a': judging whether the azimuth resolution in the azimuth resolution matrix is within the threshold range of the azimuth resolution, if yes, judging that the grid point corresponding to the azimuth resolution meets the condition, and obtaining a plurality of grid points meeting the azimuth resolution; Step b': judging whether the range resolution in the plurality of grid points meeting the azimuth resolution is within the threshold range of the range resolution, if yes, judging that the grid point corresponding to the range resolution meets the condition, and obtaining a plurality of grid points meeting the azimuth resolution and the range resolution at the same time; Step c': judging whether the ground reflection coefficient in the plurality of grid points meeting the azimuth resolution and the range resolution at the same time is within the threshold range of the ground reflection coefficient, if yes, judging that the grid point corresponding to the ground reflection coefficient meets the condition, and obtaining a plurality of grid points meeting the range resolution, the azimuth resolution and the ground reflection coefficient at the same time.

7. The method according to any one of claims 1 to 4, characterized in that, The screening of the range resolution in the range resolution matrix, the azimuth resolution in the azimuth resolution matrix and the ground reflection coefficient in the ground reflection coefficient matrix of the grid point according to the threshold range of the range resolution, the threshold range of the azimuth resolution and the threshold range of the ground reflection coefficient includes the following steps: Step a": judging whether the ground reflection coefficient in the ground reflection coefficient matrix is within the threshold range of the ground reflection coefficient, if yes, judging that the grid point corresponding to the ground reflection coefficient meets the condition, and obtaining a plurality of grid points meeting the ground reflection coefficient; Step b": judging whether the azimuth resolution in the plurality of grid points meeting the ground reflection coefficient is within the threshold range of the azimuth resolution, if yes, judging that the grid point corresponding to the azimuth resolution meets the condition, and obtaining a plurality of grid points meeting the ground reflection coefficient and the azimuth resolution at the same time; Step c": judging whether the range resolution in the plurality of grid points meeting the ground reflection coefficient and the azimuth resolution at the same time is within the threshold range of the range resolution, if yes, judging that the grid point corresponding to the range resolution meets the condition, and obtaining a plurality of grid points meeting the range resolution, the azimuth resolution and the ground reflection coefficient at the same time.

8. The method according to any one of claims 1 to 4, characterized in that, The screening of the range resolution in the range resolution matrix, the azimuth resolution in the azimuth resolution matrix and the ground reflection coefficient in the ground reflection coefficient matrix of the grid point according to the threshold range of the range resolution, the threshold range of the azimuth resolution and the threshold range of the ground reflection coefficient includes the following steps: Step A: judging whether the ground reflection coefficient in the ground reflection coefficient matrix is within the threshold range of the ground reflection coefficient, if yes, judging that the grid point corresponding to the ground reflection coefficient meets the condition, and obtaining a plurality of grid points meeting the ground reflection coefficient; Step B: judging whether the range resolution in the plurality of grid points meeting the ground reflection coefficient is within the threshold range of the range resolution, if yes, judging that the grid point corresponding to the range resolution meets the condition, and obtaining a plurality of grid points meeting the ground reflection coefficient and the range resolution at the same time; Step C: judging whether the azimuth resolution of the multiple grid points satisfying the ground reflection coefficient and the distance resolution simultaneously is within the threshold range of the azimuth resolution, if yes, judging that the grid point corresponding to the azimuth resolution satisfies the condition, and obtaining the multiple grid points satisfying the distance resolution, the azimuth resolution and the ground reflection coefficient simultaneously.

9. The method according to any one of claims 1 to 4, characterized in that, The filtering of the distance resolution in the distance resolution matrix, the azimuth resolution in the azimuth resolution matrix and the ground reflection coefficient in the ground reflection coefficient matrix of the grid points according to the threshold range of the distance resolution, the threshold range of the azimuth resolution and the threshold range of the ground reflection coefficient comprises the following steps: Step A': judging whether the azimuth resolution in the azimuth resolution matrix is within the threshold range of the azimuth resolution, if yes, judging that the grid point corresponding to the azimuth resolution satisfies the condition, and obtaining the multiple grid points satisfying the azimuth resolution; Step B': judging whether the ground reflection coefficient in the multiple grid points satisfying the azimuth resolution is within the threshold range of the ground reflection coefficient, if yes, judging that the grid point corresponding to the ground reflection coefficient satisfies the condition, and obtaining the multiple grid points satisfying the azimuth resolution and the ground reflection coefficient simultaneously; Step C': judging whether the distance resolution in the multiple grid points satisfying the azimuth resolution and the ground reflection coefficient simultaneously is within the threshold range of the distance resolution, if yes, judging that the grid point corresponding to the distance resolution satisfies the condition, and obtaining the multiple grid points satisfying the distance resolution, the azimuth resolution and the ground reflection coefficient simultaneously.

10. The method according to any one of claims 1 to 4, characterized in that, The filtering of the distance resolution in the distance resolution matrix, the azimuth resolution in the azimuth resolution matrix and the ground reflection coefficient in the ground reflection coefficient matrix of the grid points according to the threshold range of the distance resolution, the threshold range of the azimuth resolution and the threshold range of the ground reflection coefficient comprises the following steps: Step A": judging whether the distance resolution in the distance resolution matrix is within the threshold range of the distance resolution, if yes, judging that the grid point corresponding to the distance resolution satisfies the condition, and obtaining the multiple grid points satisfying the distance resolution; Step B": judging whether the ground reflection coefficient in the multiple grid points satisfying the distance resolution is within the threshold range of the ground reflection coefficient, if yes, judging that the grid point corresponding to the ground reflection coefficient satisfies the condition, and obtaining the multiple grid points satisfying the distance resolution and the ground reflection coefficient simultaneously; Step C": judging whether the azimuth resolution in the multiple grid points satisfying the distance resolution and the ground reflection coefficient simultaneously is within the threshold range of the azimuth resolution, if yes, judging that the grid point corresponding to the azimuth resolution satisfies the condition, and obtaining the multiple grid points satisfying the distance resolution, the azimuth resolution and the ground reflection coefficient simultaneously.

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