CN111781603A - Airborne weather radar ground clutter suppression method - Google Patents
Airborne weather radar ground clutter suppression method Download PDFInfo
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- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
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Abstract
The invention discloses a ground clutter suppression method for airborne weather radar, which comprises the following steps: 1) determining the prior knowledge of radar system parameters, ground clutter and meteorological target distribution geometrical relations by adopting an area array antenna; 2) obtaining a ground clutter pitch angle, a ground clutter azimuth angle, a meteorological target pitch angle and a meteorological target azimuth angle through distance circulation and azimuth circulation, and thus respectively obtaining respective time domain guide vectors and airspace two-dimensional guide vectors of the ground clutter pitch angle, the ground clutter azimuth angle, the meteorological target pitch angle and the meteorological target azimuth angle; 3) obtaining a ground clutter target three-dimensional space-time guide vector by the time domain dimension guide vector, the azimuth dimension guide vector and the pitching dimension guide vector; 4) obtaining a snapshot signal and a covariance matrix of ground clutter and a meteorological target by the three-dimensional guide vector; 5) and after the covariance matrix is obtained, carrying out full-dimensional optimal processing to obtain a weight vector, and then filtering the snapshot signal by using the weight vector. The method can improve the estimation precision and the convergence speed, can effectively improve the detection performance of the system in the non-uniform environment, and has good clutter suppression effect.
Description
Technical Field
The invention belongs to the technical field of ground clutter suppression of airborne weather radar and the technical field of array signal processing, and particularly relates to a ground clutter suppression method of airborne weather radar
Background
The airborne weather radar is important electronic equipment of an airplane, and can detect and early warn thunderstorm rain, turbulence, wind shear and other disaster weather existing in front of a flight path in real time, so that a pilot is guided to avoid a dangerous area. At present, manufacturers of airborne weather radars mainly have two companies, Collins and Honeywell. The airborne weather radar usually works in a down-looking mode, at the moment, the echo of the airborne weather radar not only contains a weather target, but also noise and ground clutter, and the main lobe and the side lobe ground clutter must be effectively inhibited to identify the weather target and reduce the false alarm probability. As shown in fig. 1, when the radar transmits and receives signals downwards at a certain pitch angle, weather clutter and ground clutter signals exist simultaneously in the same range gate in echoes, but the downward pitch angle of a weather target is different from that of the ground clutter, so that the ground clutter can be better suppressed by expanding the traditional two-dimensional space-time adaptive processing (2D-STAP) to the three-dimensional space-time adaptive processing (3D-STAP) on the basis of increasing the pitch dimension information. In a conventional 2D-STAP, a two-dimensional area array is generally synthesized into a one-dimensional horizontal line array by adopting a column weighting synthesis method, that is, clutter suppression is performed only by using azimuth domain information and doppler domain information, and pitch domain information is ignored. The 3D-STAP fully utilizes the pitching dimension information and performs combined adaptive processing in two dimensions of an airspace and a time domain, so that the ground clutter suppression performance can be improved, and the stability is good. However, the application of the 3D-STAP technology to ground clutter suppression and weather detection of an airborne weather radar has not been proposed in the prior art.
Currently, the main ground clutter suppression technologies can be classified into the following categories: 1) a ground clutter suppression technique based on beam multi-scanning. Determining the scanning range of the main beam to the ground by using a geometric relation according to the flight path of the airplane, continuously adjusting the pitch angle of an antenna to generate echoes at different spatial positions, and then superposing data which are not interfered by clutter and exist on certain range gates together to achieve the purpose of suppressing the clutter; 2) a ground clutter suppression technique based on frequency domain. According to the model of the meteorological echo and the ground clutter, after Doppler compensation is carried out on the echo, the meteorological target is not zero point on the frequency domain and occupies a large range, and the ground clutter is distributed near the zero point on the frequency domain and has a small range. According to the characteristics, a proper null filter is designed, so that the ground clutter component can be effectively suppressed; 3) clutter suppression technology based on spatial adaptive filtering. Because the meteorological target and the ground object target have height difference information, the airspace cancellation weighting coefficient is accurately estimated according to the echo data generated in the dual-channel mode, the two-channel cancellation is carried out by using the obtained cancellation weighting coefficient, and the meteorological target component after the cancellation is reserved, so that the ground clutter suppression purpose is achieved. 4) Ground clutter suppression in multi-polarization mode. The polarization scattering characteristic of the target can be utilized to identify non-meteorological signals caused by meteorological and ground-sea clutter, flying bird insects and the like, and the interference of the non-meteorological signals on radar display is reduced, so that the clutter suppression capability is further enhanced. In view of the above, many researchers have conducted intensive research at home and abroad.
In the technical scheme disclosed above, the scheme 1) is easily limited by flight conditions, and the medium-distance clutter suppression effect is not obvious; in the scheme 2), the frequency shift and the broadening of an echo frequency spectrum can be caused by the motion of a carrier, so that the difference between a meteorological target frequency spectrum and a ground clutter frequency spectrum is not very large, and the suppression effect is not obvious relative to a ground radar; in the scheme 3), due to the existence of uncertain factors such as channel amplitude-phase errors, antenna direction pointing errors and the like, the estimated airspace cancellation weighting coefficient is often deviated from an actual value, and the clutter suppression effect is influenced; scheme 4) the acquisition of original data is more difficult, and polarization information processing generally requires that clutter polarization degree is higher, and the motion of airborne machine makes clutter spectrum extension, and polarization information has increased very big degree of difficulty in applying to airborne weather radar in independent application. In view of the above problems, how to effectively suppress ground clutter under various complex conditions is still a key problem to be solved in practical processing.
Disclosure of Invention
The invention aims to solve the technical problem of providing a ground clutter suppression method of an airborne weather radar, which can overcome the difficulty under the influence of various factors to effectively suppress ground clutter and overcome the influence of non-uniform clutter environment and the limitation of independent and identically distributed samples in practice.
In order to solve the technical problems, the invention adopts the following technical scheme:
a method for suppressing ground clutter of airborne weather radar comprises the following steps:
1) determining the prior knowledge of radar system parameters, ground clutter and meteorological target distribution geometrical relations by adopting an area array antenna;
2) obtaining a ground clutter pitch angle, a ground clutter azimuth angle, a meteorological target pitch angle and a meteorological target azimuth angle through distance circulation and azimuth circulation, and thus respectively obtaining respective time domain guide vectors and airspace two-dimensional guide vectors of the ground clutter pitch angle, the ground clutter azimuth angle, the meteorological target pitch angle and the meteorological target azimuth angle;
3) obtaining a ground clutter target three-dimensional space-time guide vector by the time domain dimension guide vector, the azimuth dimension guide vector and the pitching dimension guide vector;
4) obtaining a snapshot signal and a covariance matrix of ground clutter and a meteorological target by the three-dimensional guide vector;
5) and after the covariance matrix is obtained, carrying out full-dimensional optimal processing to obtain a weight vector, and then filtering the snapshot signal by using the weight vector.
Further, the area array antenna is adopted in the step 1), and the prior knowledge process for determining the radar system parameters, the ground clutter and the meteorological target distribution geometrical relationship is as follows: arranging each array element in the array antenna system into an area array at a certain interval in the vertical height and the horizontal direction, then determining the prior knowledge of the distribution geometric relationship of radar system parameters, ground clutter and meteorological targets, and laying a cushion by adopting a structured STAP technology.
Further, the step 2) obtains a ground clutter pitch angle, a ground clutter azimuth angle, a meteorological target pitch angle and a meteorological target azimuth angle through distance circulation and azimuth circulation, and accordingly obtains respective time domain guidance vectors and space domain two-dimensional guidance vectors of the ground clutter pitch angle, the ground clutter azimuth angle, the meteorological target pitch angle and the meteorological target azimuth angle respectively: obtaining the pitch angle and the azimuth angle of the ground clutter and the meteorological target by distance and azimuth, and respectively constructing a time domain guide vector, a pitch dimension guide vector and an azimuth dimension guide vector of the ground clutter and the meteorological target; the time domain steering vector consists of M pulses; the pitching dimensional guiding vector consists of P pitching arrays; the azimuth dimension steering vector is composed of N azimuth arrays.
Further, the process of obtaining the ground clutter and the meteorological target three-dimensional space-time guidance vector from the time domain guidance vector, the azimuth guidance vector and the pitch guidance vector in the step 3) is as follows: after the time domain guide vector, the direction guide vector and the pitching dimension guide vector are obtained by distance-direction one by one, Kronecker direct product is carried out on the time domain guide vector, the direction guide vector and the pitching dimension guide vector to obtain the three-dimensional space-time guide vector.
Further, the process of obtaining the snapshot signal of the ground clutter and the meteorological target and the covariance matrix from the three-dimensional guide vector in the step 4) is as follows: and obtaining a snapshot signal after obtaining the three-dimensional guide vector of the ground clutter and the meteorological target, performing conjugate transposition on the time domain guide vector, the azimuth guide vector and the pitch guide vector, and performing Kronecker direct product to obtain a covariance matrix of the time domain guide vector, the azimuth guide vector and the pitch guide vector.
Further, after the covariance matrix is obtained in step 5), performing full-dimensional optimal processing to obtain a weight vector, and then performing a filtering process on the snapshot signal by using the weight vector: according to the step 4), a weight is obtained through the covariance matrix of ground clutter and noise and a meteorological target guide vector according to full-dimensional self-adaptive processing, and then the weight is multiplied by a snapshot signal to obtain a filtered signal
The invention discloses a method for suppressing ground clutter of airborne weather radar, which is based on a three-dimensional space-time adaptive processing algorithm, can overcome the influence of non-uniform clutter environment and the limitation of independent and identically distributed samples in practice, and can make full use of prior information, namely, a vector matrix model of the ground clutter and the meteorological target is directly constructed according to the known clutter structure, the meteorological target characteristics, system parameters and the space geometric relationship. According to the principle of the ground clutter suppression method of the airborne weather radar based on the three-dimensional space-time adaptive processing algorithm, the three-dimensional space-time adaptive processing is utilized, and the weather target is optimally separated from the ground clutter and the noise environment through the combined processing of the pitching domain, the Doppler domain and the azimuth domain. The problems that ground clutter suppression performance is reduced and the like caused by factors such as inaccurate estimation of a weight coefficient by a radar scanning limitation, Doppler spectrum broadening, influence of an airspace on the weight coefficient, limitation of independent and uniformly distributed samples and the like in the actual process are solved, and simulation results show that the airborne weather radar ground clutter suppression method based on the three-dimensional space-time adaptive processing algorithm is a feasible ground clutter suppression method.
Drawings
FIG. 1 is a schematic diagram of a spatial geometry of meteorological radar received data;
FIG. 2 is a schematic diagram of three-dimensional space-time adaptive data processing;
FIG. 3 is a flow chart of ground clutter suppression processing of three-dimensional space-time adaptive processing;
FIG. 4 is a slice of a three-dimensional power spectrum at a meteorological target;
FIG. 5(a) is a two-dimensional planar meteorological and earth clutter power spectrum of azimuth sine value-Doppler frequency;
FIG. 5(b) is a two-dimensional planar meteorological and ground clutter power spectrum of pitch angle sine value-Doppler frequency;
FIG. 5(c) is a two-dimensional planar meteorological and earth clutter power spectrum of azimuth sine-pitch sine;
FIG. 6 is a slice view of a three-dimensional adaptive antenna pattern at a meteorological target;
figure 7(a) is a pitch angle sine value-doppler frequency two-dimensional planar adaptive antenna pattern;
figure 7(b) is a two-dimensional planar adaptive antenna pattern of azimuth sine-pitch sine;
figure 7(c) is a 2D-STAP azimuth sine value-doppler frequency two-dimensional planar antenna pattern;
figure 7(D) is a 3D-STAP azimuth sine value-doppler frequency two-dimensional planar antenna pattern;
FIG. 8(a) is a meteorological target azimuth profile;
FIG. 8(b) is a Doppler frequency profile at a meteorological target;
FIG. 9 is a three-dimensional improvement factor slice;
FIG. 10(a) is an azimuthal dimension improvement factor map;
fig. 10(b) is a doppler domain improvement factor graph.
FIG. 11(a) is a graph of filtered residual power for a meteorological target in the vicinity of a dominant clutter;
FIG. 11(b) is a graph of filtered residual power of a meteorological target in the vicinity of a side lobe clutter.
Detailed Description
The following describes a control algorithm for servo system profile error according to the present invention in detail with reference to the accompanying drawings.
The invention discloses a method for suppressing ground clutter of an airborne weather radar, which adopts an area array antenna to determine the prior knowledge of radar system parameters, ground clutter and a distribution geometric relation of a weather target, and then obtains a ground clutter pitch angle, a ground clutter azimuth angle, a weather target pitch angle and a weather target azimuth angle through distance circulation and azimuth circulation, thereby respectively obtaining respective time domain guide vectors and airspace two-dimensional guide vectors of the ground clutter pitch angle, the ground clutter azimuth angle, the weather target pitch angle and the weather target azimuth angle. And obtaining a ground clutter and a meteorological target three-dimensional space-time guide vector by the time domain dimension guide vector, the azimuth dimension guide vector and the pitching dimension guide vector, and obtaining a snapshot signal and a covariance matrix of the ground clutter and the meteorological target by the three-dimensional guide vector. And after the covariance matrix is obtained, carrying out full-dimensional optimal processing to obtain a weight vector, and then filtering the snapshot signal by using the weight vector.
In view of the principle, the invention provides an airborne weather radar ground clutter suppression method based on a three-dimensional space-time adaptive processing algorithm, which can fully utilize the height range difference between ground clutter and a weather target to suppress the ground clutter in actual processing, and applies the spatial filtering principle in array signal processing and the moving target detection and clutter suppression characteristics of the STAP technology, and simulation results show that the 3D-STAP technology has greater superiority compared with the 2D-STAP technology.
As shown in figure 1, the working wavelength is lambda, the radar antenna is positioned on a yoz plane, P × N units are adopted to form a two-dimensional plane array, and the distances between array elements are d respectivelyzAnd dyThe height of the carrier from the ground is H and at a speed vaFlying parallel to the direction of the antenna planar array (front side view). In this schematic, the meteorological target and ground clutter appear within the same range gate, θcThe pitch angle of the ground clutter and the downward depression angle of the meteorological target are represented by thetawPhi is the azimuth angle (theta appears below)c_iI-th pitch angle, theta, representing ground clutterw_ιIota pitch angle, phi, representing meteorological targetc_jRepresents the jth azimuth angle of the ground clutter,
indicating a meteorological target
Azimuth angle). The processing flow is shown in fig. 3, and the main steps are as follows:
1) determining the prior knowledge of radar system parameters, ground clutter and meteorological target distribution geometrical relations by adopting an area array antenna;
in order to overcome the problems of influence of non-uniform clutter environment and limitation of independent same-distribution samples in practice, priori knowledge can be fully utilized, and therefore a three-dimensional structured space-time self-adaptive method is adopted to lay a cushion for the following steps.
2) Obtaining a ground clutter pitch angle, a ground clutter azimuth angle, a meteorological target pitch angle and a meteorological target azimuth angle through distance circulation and azimuth circulation, and thus respectively obtaining respective time domain guide vectors and airspace two-dimensional guide vectors of the ground clutter pitch angle, the ground clutter azimuth angle, the meteorological target pitch angle and the meteorological target azimuth angle;
for a given range gate, NPM echoes can be obtained from M pulses, N azimuth-dimension antenna elements, and P elevation-dimension antenna elements. The following defines the pitch dimension guide vector of the ground clutter
Time dimension guide vector
And an orientation dimension guide vector a (ξ)ij) Their expressions are as follows:
in the above formula, the symbol "e" represents an exponential function with e as the base, the superscript T represents the matrix transpose,
representing the spatial frequency of the pitch dimension at the ith pitch angle of the ground clutter, ξijRepresenting the azimuth dimension space frequency of the ground clutter at the ith pitch angle and the jth azimuth angle,
the normalized Doppler frequency generated by the ground clutter at the ith pitch angle and the jth azimuth angle is expressed as follows:
in the above formula, fc_ij＝2vacosθc_isinφc_jλ is the ground clutter Doppler shift, frIs the pulse repetition frequency and λ is the wavelength. Similarly, the meteorological target pitch dimension guide vector (ρ)ι) The direction dimension of the guide vector
And a time dimension steering vector
They are respectively represented as follows:
in the above formula, ριRepresenting the spatial frequency of the pitch dimension at the iota pitch angle of the meteorological target,
iota pitch angle and t pitch angle representing meteorological target
The azimuth dimension spatial frequency at each azimuth angle,
iota pitch angle and t pitch angle representing meteorological target
Normalized doppler frequency at each azimuth, expressed as follows:
in the above formula, the first and second carbon atoms are,
is the iota th pitch angle
Doppler shift of meteorological targets at each azimuth.
3) Obtaining a ground clutter target three-dimensional space-time guide vector by the time domain dimension guide vector, the azimuth dimension guide vector and the pitching dimension guide vector;
three-dimensional space-time steering vector S of ground clutter at ith pitch angle and jth azimuth anglec_ijCan be expressed as:
similarly, the meteorological target is at the third elevation angle and the fourth elevation angle
Three-dimensional space-time steering vector of individual azimuth angle
Can be expressed as:
in the above formula, the first and second carbon atoms are,
represents the direct product of Kronecker, wherein
Representing the amplitude, σ, of the meteorological target time-domain disturbancevThe motion variance of the meteorological target is shown, the size of the motion variance reflects the motion intensity of the meteorological target, G is the number of range gates distributed by the meteorological target, and ⊙ is a Hadamard product.
4) Obtaining a snapshot signal and a covariance matrix of ground clutter and a meteorological target by the three-dimensional guide vector;
ground clutter snapshot signal XcThe sum of the echoes of all clutter scatter points within the equidistant ring for all range gates is expressed as:
in the above formula, Nr is the number of range gates generated by the ground clutter (the number of the range gates of the ground clutter is consistent with the number of the pitch angles), J is the number of the clutter azimuth directions, ηijThe magnitude of the ground clutter amplitude for the ith range gate, the jth azimuth.
Ground clutter covariance matrix RcCan be expressed as:
in the above formula, the symbol "E" represents mathematical expectation.
Similarly, meteorological target snapshot signal XwExpressed as:
in the above formula, G is the number of range gates of meteorological distribution (the number of range gates of meteorological targets is consistent with the number of pitch angles), J is the number of azimuth directions of meteorological distribution,
is the iota distance gate
Magnitude of meteorological target at each azimuth.
The covariance matrix of the meteorological target is expressed as:
5) and after the covariance matrix is obtained, carrying out full-dimensional optimal processing to obtain a weight vector, and then filtering the snapshot signal by using the weight vector.
In order to minimize the power of the residual spur plus noise in the output and to obtain the maximum output signal-to-noise-ratio (SCNR), according to the linearly constrained minimum output energy criterion (LCMV), the constraint equation is as follows:
in the above formula, R ═ Rc+RwRepresenting the sum of the ground clutter covariance matrix and the meteorological target covariance matrix. SwIs shown at any third pitch angle
And obtaining a three-dimensional space-time guidance vector of the meteorological target at each azimuth angle. w represents a weight vector, and the optimal weight vector is obtained by a Lagrange multiplier method:
wopt＝ηR-1(12)
where η is the high resolution spectral estimate (Capon spectrum) that constitutes the beamformer, expressed as:
in the above formula, R-1Is the inverse matrix of R.
Array output for full-dimensional optimization:
in the above formula, X ═ Xc+XwRepresenting the sum of the ground clutter snapshot signal and the meteorological target snapshot signal.
The airborne weather radar ground clutter suppression method based on the three-dimensional space-time adaptive processing algorithm is used for simulation verification, and the experimental result fully proves the effectiveness of the method.
The experiment adopts a rectangular plane array 8 × 8, the pitch wave beam is directed to be 8 degrees deviated from the normal direction of the array surface, the horizontal wave beam is directed to be 0 degree deviated from the normal direction of the array surfacevAt an angular pitch of 5 ° and a pitch of 30km, 2 °w8 deg., doppler frequency 200 Hz. The range of clutter generation distance is 25 km-35 km, the interval is 100m, the range of azimuth generation is-13 degrees, and each range gate is divided into 200 clutter scattering units at equal intervals in each azimuth range.
TABLE 1 Radar simulation parameters
Fig. 4 is a slice view of a three-dimensional power spectrum at a meteorological target in side-looking motion of an airborne radar, and fig. 5 is a cross-sectional view of the three-dimensional power spectrum. Ground clutter and meteorological targets can be well distinguished by utilizing the pitching dimension information. Fig. 6 gives a slice of the three-dimensional adaptive antenna pattern at a meteorological object. Fig. 7(a), (b) and (D) are cross-sectional views of a three-dimensional space-time adaptive antenna pattern, fig. 7(c) and (D) are two-dimensional planar adaptive antenna patterns of azimuth sine value-doppler frequency obtained by a 2D-STAP and a 3D-STAP, respectively, fig. 8 is a cross-sectional view of both fig. 7(c) and (D), the 3D-STAP adaptive antenna pattern can obtain the highest gain at the target, while the 2D-STAP ignores the elevation dimension information, cannot form the highest gain at the target, causes the meteorological signals to be filtered out, and has higher gain in the clutter region, which will cause clutter to remain. Fig. 9 gives a three-dimensional improvement factor slice. FIG. 10 is a comparison of the improvement factors of the 3D-STAP and the 2D-STAP, and it can be seen that the maximum improvement factor obtained for the 3D-STAP is about 18dB greater than that obtained for the 2D-STAP, while the minimum improvement factor obtained is about 19dB greater than that obtained for the 2D-STAP. FIG. 11(a) is a comparison of the filtered residual power outputs of the 3D-STAP method and the 2D-STAP method when the meteorological target is near the main clutter, and FIG. 11(b) is a comparison of the filtered residual power outputs of the 3D-STAP method and the 2D-STAP method when the meteorological target is near the side lobe clutter, wherein the solid line is the 3D-STAP processing and the dotted line is the 2D-STAP processing. It can be seen that when the meteorological signals are in the main clutter region, the meteorological signals processed by the 2D method are submerged in the clutter, and the meteorological signals processed by the 3D method are 13dB higher than the clutter and can be completely detected. When the meteorological signals are near the side lobe clutter, the meteorological signals processed by the 2D method are higher than the clutter by 6dB and can be detected, and the meteorological signals processed by the 3D method are higher than the clutter by 19dB and can be completely detected.
Claims (6)
1. A method for suppressing ground clutter of airborne weather radar is characterized in that: the method comprises the following steps:
1) determining the prior knowledge of radar system parameters, ground clutter and meteorological target distribution geometrical relations by adopting an area array antenna;
2) obtaining a ground clutter pitch angle, a ground clutter azimuth angle, a meteorological target pitch angle and a meteorological target azimuth angle through distance circulation and azimuth circulation, and thus respectively obtaining respective time domain guide vectors and airspace two-dimensional guide vectors of the ground clutter pitch angle, the ground clutter azimuth angle, the meteorological target pitch angle and the meteorological target azimuth angle;
3) obtaining a ground clutter target three-dimensional space-time guide vector by the time domain dimension guide vector, the azimuth dimension guide vector and the pitching dimension guide vector;
4) obtaining a snapshot signal and a covariance matrix of ground clutter and a meteorological target by the three-dimensional guide vector;
5) and after the covariance matrix is obtained, carrying out full-dimensional optimal processing to obtain a weight vector, and then filtering the snapshot signal by using the weight vector.
2. The airborne weather radar ground clutter suppression method of claim 1, wherein: the area array antenna is adopted in the step 2), and the prior knowledge processes of determining the radar system parameters, the ground clutter and the meteorological target distribution geometrical relationship are as follows: arranging each array element in the array antenna system into an area array at a certain interval in the vertical height and the horizontal direction, then determining the prior knowledge of the distribution geometric relationship of radar system parameters, ground clutter and meteorological targets, and laying a cushion by adopting a structured STAP technology.
3. The airborne weather radar ground clutter suppression method of claim 1, wherein: the step 2) obtains a ground clutter pitch angle, a ground clutter azimuth angle, a meteorological target pitch angle and a meteorological target azimuth angle through distance circulation and azimuth circulation, and accordingly obtains respective time domain guide vectors and space domain two-dimensional guide vectors of the ground clutter pitch angle, the ground clutter azimuth angle, the meteorological target pitch angle and the meteorological target azimuth angle respectively: obtaining the pitch angle and the azimuth angle of the ground clutter and the meteorological target by distance and azimuth, and respectively constructing a time domain guide vector, a pitch dimension guide vector and an azimuth dimension guide vector of the ground clutter and the meteorological target; the time domain pilot vector is composed ofMEach pulse is formed; the pitch dimension guide vector is composed ofPA plurality of pitch arrays; the orientation dimension guide vector is composed ofNAnd an azimuth array.
4. The method for suppressing ground clutter of airborne weather radar based on three-dimensional space-time adaptive processing algorithm according to claim 1, wherein: the three-dimensional space-time guidance vector process of the ground clutter and the meteorological target obtained by the time domain dimension guidance vector, the azimuth dimension guidance vector and the pitching dimension guidance vector in the step 3) is as follows: after the time domain guide vector, the direction guide vector and the pitching dimension guide vector are obtained by distance-direction one by one, Kronecker direct product is carried out on the time domain guide vector, the direction guide vector and the pitching dimension guide vector to obtain the three-dimensional space-time guide vector.
5. The method for suppressing ground clutter of airborne weather radar based on three-dimensional space-time adaptive processing algorithm according to claim 1, wherein: the process of obtaining the snapshot signal of the ground clutter and the meteorological target and the covariance matrix by the three-dimensional guide vector in the step 4) is as follows: and obtaining a snapshot signal after obtaining the three-dimensional guide vector of the ground clutter and the meteorological target, performing conjugate transposition on the time domain guide vector, the azimuth guide vector and the pitch guide vector, and performing Kronecker direct product to obtain a covariance matrix of the time domain guide vector, the azimuth guide vector and the pitch guide vector.
6. The method for suppressing ground clutter of airborne weather radar based on three-dimensional space-time adaptive processing algorithm according to claim 1, wherein: after the covariance matrix is obtained in the step 5), performing full-dimensional optimal processing to obtain a weight vector, and then performing a filtering process on the snapshot signal by using the weight vector: and 4) obtaining a weight value according to the full-dimensional self-adaptive processing by the covariance matrix of the ground clutter and the noise and the meteorological target guide vector in the step 4), and multiplying the weight value by the snapshot signal to obtain a filtered signal.
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