CN109471083B - Airborne external radiation source radar clutter suppression method based on space-time cascade - Google Patents
Airborne external radiation source radar clutter suppression method based on space-time cascade Download PDFInfo
- Publication number
- CN109471083B CN109471083B CN201811328082.7A CN201811328082A CN109471083B CN 109471083 B CN109471083 B CN 109471083B CN 201811328082 A CN201811328082 A CN 201811328082A CN 109471083 B CN109471083 B CN 109471083B
- Authority
- CN
- China
- Prior art keywords
- signal
- clutter
- scattering point
- multipath
- direct wave
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000000034 method Methods 0.000 title claims abstract description 45
- 230000005855 radiation Effects 0.000 title claims abstract description 34
- 230000001629 suppression Effects 0.000 title claims abstract description 19
- 239000011159 matrix material Substances 0.000 claims abstract description 56
- 238000001514 detection method Methods 0.000 claims abstract description 33
- 238000001914 filtration Methods 0.000 claims abstract description 25
- 238000004422 calculation algorithm Methods 0.000 claims abstract description 21
- 230000003044 adaptive effect Effects 0.000 claims abstract description 18
- 239000013598 vector Substances 0.000 claims description 28
- 230000004044 response Effects 0.000 claims description 13
- 238000005070 sampling Methods 0.000 claims description 5
- 230000017105 transposition Effects 0.000 claims description 5
- 230000001427 coherent effect Effects 0.000 claims description 4
- 238000005457 optimization Methods 0.000 claims description 3
- 230000011218 segmentation Effects 0.000 claims description 3
- 101000802640 Homo sapiens Lactosylceramide 4-alpha-galactosyltransferase Proteins 0.000 claims description 2
- 102100035838 Lactosylceramide 4-alpha-galactosyltransferase Human genes 0.000 claims description 2
- 230000010354 integration Effects 0.000 claims 1
- 238000004088 simulation Methods 0.000 description 6
- 238000001228 spectrum Methods 0.000 description 6
- 238000005516 engineering process Methods 0.000 description 5
- 238000013499 data model Methods 0.000 description 2
- 230000018109 developmental process Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000002592 echocardiography Methods 0.000 description 1
- 238000013139 quantization Methods 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
- G01S7/41—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00 using analysis of echo signal for target characterisation; Target signature; Target cross-section
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A90/00—Technologies having an indirect contribution to adaptation to climate change
- Y02A90/10—Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Radar Systems Or Details Thereof (AREA)
Abstract
The invention discloses a clutter suppression method for an airborne external radiation source radar based on space-time cascading, which mainly solves the problem that moving targets are cancelled when the existing problem is directly processed by a space-time cascading two-dimensional adaptive algorithm STAP. The implementation scheme is as follows: 1) Acquiring a reference signal and an echo signal received by an airborne external radiation source radar; 2) Segmenting the reference signal and the echo signal respectively; 3) Performing matched filtering on the segmented reference signal and the echo signal; 4) Constructing a dictionary matrix from the matched and filtered signals; 5) According to the dictionary matrix, a joint iteration algorithm is adopted to suppress multipath clutter components; 6) And performing direct wave suppression on the matched signal for eliminating the multipath clutter by adopting a space-time cascade two-dimensional adaptive algorithm to obtain a target echo signal. The method can update the regularization parameters in real time, filter the multipath clutter in the reference signal, improve the clutter suppression capability of the airborne external radiation source radar, and can be used for target detection.
Description
Technical Field
The invention relates to the technical field of radars, in particular to a clutter suppression method for an airborne external radiation source radar, which can realize suppression of multipath clutter and detection of a moving target under the condition that the airborne external radiation source radar contains the multipath clutter in a reference channel.
Background
The external radiation source radar is a radar system which uses non-cooperative radiation signals such as broadcast FM, television, satellite and the like as a radiation source and does not emit signals, and has the advantages of low cost, small volume and strong survivability. The development of detection technologies for detecting, positioning and tracking the target of the traditional external radiation source radar is relatively mature. The airborne external radiation source radar applies the external radiation source radar technology to an airborne platform, and has the advantages of wide detection visual field, wide application prospect, high detection power and the like due to the fact that the receiver platform is lifted. The external radiation source radar technology based on the airborne platform becomes an important development direction of the external radiation source radar technology.
Different from the traditional external radiation source radar, the airborne external radiation source radar has the advantages that static clutter is not distributed near zero Doppler any more due to the movement of an aircraft, and clutter and a detection target cannot be filtered by adopting a general time domain adaptive filtering algorithm, so that moving target detection is a key technology for researching an airborne external radiation source radar system. The clutter suppression and the detection of the moving target are realized by usually adopting an offset phase center antenna DPCA and a space-time cascade two-dimensional adaptive algorithm STAP, the existing methods detect the target under the condition that a reference channel does not contain multipath clutter signals, and when a station address error exists in an irradiation source base station or an antenna main lobe is wider, the multipath clutter signals possibly exist in the reference channel. At this time, after the reference signal containing the multipath clutter and the received echo signal are matched and filtered, the clutter component matched with the corresponding direct wave and the clutter component matched with the corresponding multipath signal jointly influence the distance unit to be detected. At this time, all the sample data are likely to contain information of the moving target, which results in estimation error of the clutter covariance matrix. When the space-time cascade two-dimensional adaptive algorithm STAP is directly used for suppressing clutter, targets falling into a multipath clutter component area are suppressed, namely, a moving target signal cancellation phenomenon occurs, clutter suppression of the airborne external radiation source radar when multipath clutter signals are contained in a reference channel cannot be effectively realized, and moving target detection is not facilitated.
Disclosure of Invention
The invention aims to provide a clutter suppression method of an airborne external radiation source radar based on space-time cascade aiming at the problems in the prior art, which can effectively suppress clutter and realize the detection of a moving target under the condition that a reference channel contains multipath clutter.
The technical idea for realizing the purpose of the invention is as follows: constructing a dictionary matrix and a sparsely constrained cost function by processing clutter space-time snapshot data of a multipath echo signal received by a radar reference antenna, and utilizing L based on joint iteration 1 Norm constrained recursive least square algorithm L 1 And (4) iteratively deriving a weight vector by JI-RLS to realize the suppression of clutter components of multipath echoes, and realizing moving target detection by suppressing the clutter components of direct waves by utilizing a space-time cascade two-dimensional adaptive algorithm STAP.
According to the above thought, the implementation scheme of the invention comprises the following steps:
(1) Acquiring signals received by an airborne external radiation source radar, wherein the signals comprise reference signals and echo signals received by an observation antenna;
(2) Respectively segmenting the reference signal and the echo signal to obtain a segmented reference signal s r (t) and a segmented echo signal s n,i (t)；
(3) Will segment the reference signal s r (t) and the segmented echo signal s n,i (t) intoLine matching filtering, and outputting response x from matched and filtered clutter scattering point n,i (t) is divided into two parts, one part is the matching result x of clutter scattering point echo signal and direct wave signal d The other part is the matching result x of the clutter scattering point echo signal and the multipath clutter signal p ；
(4) Matching result x of echo signal and direct wave signal from clutter scattering point d Matching result x of echo signal of sum clutter scattering point and multipath clutter signal p Constructing a dictionary matrix S l ；
(5) According to a dictionary matrix S l Using L based on joint iteration optimization 1 Norm constrained recursive least squares method L 1 -JI-RLS solving the iterative weight vector w (k) and the regularization parameter μ and for the multipath clutter component x p Suppression is carried out to obtain a matched signal y for eliminating multipath clutter l ；
(6) Adopting space-time cascade two-dimensional adaptive algorithm STAP to match signal y for eliminating multipath clutter l Carrying out direct wave suppression to obtain a target echo signal z l 。
Compared with the prior art, the invention has the advantages that:
the method constructs a sparse matrix for multipath clutter signals contained in a reference signal received by an airborne external radiation source radar, and adopts the optimal L based on joint iteration 1 Norm constrained recursive least squares method L 1 The method adopts a JI-RLS algorithm to update regularization parameters in real time and filter multi-path clutter, overcomes the problem that moving target cancellation may occur when a space-time cascade two-dimensional adaptive algorithm STAP is directly adopted to process received signals in the prior art, improves the clutter suppression capability in the signal processing process of the airborne external radiation source radar, and is beneficial to target detection.
Drawings
FIG. 1 is a schematic view of a bistatic configuration of an airborne external radiation source radar used in the present invention;
FIG. 2 is a flow chart of an implementation of the present invention;
FIG. 3 is a graph of the regularization parameter μ versus snapshot variation results obtained by processing the received signals using the method of the present invention;
fig. 4 is a diagram of a signal clutter power spectrum obtained by processing a received signal by using a conventional space-time cascade two-dimensional adaptive algorithm STAP;
FIG. 5 is a graph of a received signal processed by the method of the present invention to obtain a signal clutter power spectrum;
fig. 6 is a comparison graph of the results of the change of the improvement factor with the doppler frequency obtained by respectively processing the received signals by using the existing space-time cascade two-dimensional adaptive algorithm STAP and the method of the present invention.
Detailed Description
The following describes the implementation steps and effects of the present invention in further detail with reference to the accompanying drawings.
The implementation of the invention is based on the scene of the double-base working mode of the existing airborne external radiation source radar, as shown in figure 1. The scene setting includes: the radiation source of the airborne external radiation source radar is a ground non-cooperative source and is used for transmitting signals; a reference antenna and an observation receiving antenna are erected on the airborne platform, the observation antenna comprises N array elements, the center distance d between the array elements is half wavelength, the cone angle of the distance ring inner clutter scattering unit relative to the airborne machine is phi, and the airborne machine flies in a straight line at a constant speed parallel to the ground at a speed v.
Referring to fig. 2, the implementation steps of the invention are as follows:
Acquiring signals received by an airborne external radiation source radar, wherein the signals comprise reference signals and echo signals received by an observation antenna; the method comprises the steps that the signals are received through two pairs of antennas, one pair of antennas receives a reference signal through a reference antenna, and the reference signal comprises a direct wave signal and a multipath clutter signal; the other is to receive the echo signal with the observation antenna.
Step 2, segmenting the reference signal and the echo signal respectively to obtain a segmented reference signal s r (t) and a segmented echo signal s n,i (t)。
Existing methods for segmenting signals are: the present embodiment adopts, but is not limited to, a uniform segmentation method for segmenting the received reference signal and echo signal, and the method is implemented as follows:
(2a) The reference signal is segmented by equally dividing the reference signal into M segments in a coherent processing time, and then each segment of signal data is equivalent to pulse data, wherein the equivalent pulse repetition period of the pulse data is T r Each segment of the signal satisfies
Obtaining a segmented reference signal s containing multipath clutter and direct waves after segmentation r (t) is:
wherein v is R Is the speed of the aircraft flying parallel to the ground, d is the array element spacing, alpha d Is the complex amplitude of the direct wave signal, u m (t) is the base station signal of the emission source, t is the signal time, τ d For time delay of direct wave signals, T r Is equivalent pulse repetition period, j is an imaginary unit, f d Doppler frequency, N, of the direct wave signal T Is the number of multipath clutter, alpha p For the complex amplitude of the p-th multipath clutter signal, tau p For the time delay of the p-th multipath clutter signal, f p The Doppler frequency of the p-th multipath clutter signal;
(2b) The method for segmenting the echo signal comprises the steps of equally dividing the echo signal into M segments in one coherent processing time, and then equivalently converting each segment of signal data into pulse data, wherein the equivalent pulse repetition period of the pulse data is T r Each segment of the signal satisfies
Obtaining the segmented echo signal s of the ith clutter scattering point received by the nth array element n,i (t) is:
wherein alpha is i Is the complex amplitude of the ith scattering point, M is the number of segments, u m (t) is the base station signal of the emission source, t is the signal time, τ i The time delay of the ith scattering point; j is an imaginary unit, f i ＝(v R /λ)cosφ i Is the Doppler frequency of the scattering point, phi i Is the spatial cone angle of the ith scattering point relative to the aircraft, λ is the signal wavelength,
is the spatial frequency of the scattering point, and n is the nth array element.
Step 3, segmenting the reference signal s r (t) and the segmented echo signal s n,i (t) performing matched filtering, and outputting a response x from the clutter scattering point after matched filtering n,i (t) is divided into two parts, one part is the matching result x of clutter scattering point echo signal and direct wave signal d The other part is the matching result x of the clutter scattering point echo signal and the multipath clutter signal p 。
The specific implementation of this step is as follows:
(3a) Reference signal s r (t) and the echo signal s of the ith scattering point of the nth array element n,i (t) performing matched filtering to obtain clutter scattering point output response x after matched filtering n,i (t) the following:
wherein x is n,i (t) is output response of ith clutter scattering point of nth array element after matched filtering, t is signal time, x is integral variable, s n,i (x) For the echo signal of the ith scattering point of the nth array element, s r (x-t) is a delay reference signal (·) * Is a conjugate operation;
the above formula is further simplified, namely, let beta = x-tau i -mT r ，ε i ＝α i α d * Then x = β + τ i +mT r D beta/d tau =1, and obtaining the output response x of the simplified ith clutter scattering point of the nth array element n,i (t) is:
wherein epsilon i ＝α i α d * ，α i Is the complex amplitude of the ith scattering point, α d Is the complex amplitude of the direct wave signal (·) * Is a conjugate operation, j is an imaginary unit, n is the nth array element,
is the spatial frequency of the scattering point and,
f i doppler frequency of scattering point, f d Is the doppler frequency of the direct wave signal,
is the angular frequency of the scattering point and,
is the angular frequency of the direct wave,
u m (t) is the base station signal of the emission source, t is the signal time, τ i Time delay of the ith scattering point, T r Is an equivalent pulse repetition period of alpha' p ＝α p * /α d * ，p＝1,2,...,N T ，α p The complex amplitude of the pth multipath clutter signal,
f p the doppler frequency of the pth multipath clutter signal,
angular frequency, N, of multipath clutter T Is the number of multipath clutter, τ p Is a p-th polyTime delay of the path clutter signal;
(3b) Taking the ith clutter scattering point of the nth array element after matched filtering to output a response x n,i Time t = τ of (t) i -τ d And bring it into x n,i In (t), is obtained in i -l d The ith scattering point echo signal s of the nth array element of each range unit n,i (t) and the direct wave signal s d (t) matched filtering result x d Comprises the following steps:
wherein, tau i Time delay of ith scattering point, τ d For time delay of direct wave signals,/ i -l d ＝(τ i -τ d )f s ，f s For the sampling frequency, ∈ i ＝α i α d * ，α i Is the complex amplitude of the ith scattering point, α d Complex amplitude of the direct wave signal, (. Cndot.) * Is a conjugate operation, j is an imaginary number unit,
is the spatial frequency of the scattering point, m is the number of segments,
T r for the pulse repetition period, f i Doppler frequency of scattering point, f d Is the doppler frequency of the direct wave signal,
in order to be the angular frequency of the scattering point,
is the direct wave angular frequency;
(3c) Taking the ith clutter scattering point of the nth array element after matched filtering to output a response x n,i Time t = τ of (t) i -τ p And t = τ i -τ p Carry-in x n,i In (t), the first i -l p Nth clutter scattering point echo signal s of array element of each distance unit n,i (t) and a multipath clutter signal s r The matched filtering result of (t) is:
wherein, tau i Time delay of ith scattering point, τ p Is the time delay of the p-th multipath clutter signal,/ i -l p ＝(τ i -τ p )f s ，f s Is the sampling frequency, α' p ＝α p * /α d * ，α p Is the complex amplitude, alpha, of the p-th multipath clutter signal d Complex amplitude of the direct wave signal, (. Cndot.) * For conjugate operation,. Epsilon i ＝α i α d * ，α i Is the complex amplitude of the ith scattering point, α d Is the complex amplitude of the direct wave signal,
is the spatial frequency of the scattering point and,
T r for the pulse repetition period, f i Doppler frequency of scattering point, f p The doppler frequency of the pth multipath clutter signal,
is the angular frequency of the scattering point and,
the angular frequency of the p-th multipath clutter signal.
Step 4, matching result x of clutter scattering point echo signal and direct wave signal d Matching result x of echo signal of sum clutter scattering point and multipath clutter signal p Constructing a dictionary matrix S l 。
The existing method for constructing the dictionary matrix comprises the following steps: constructing a dictionary matrix based on the data model; the example adopts but is not limited to the existing dictionary matrix construction method based on a data model, and the specific implementation is as follows:
(4a) Firstly, the first step i -l d Matched filtering result x of mth pulse of nth array element on each distance unit d As the nth column, mth row element, of the matrix P, then i -l d The matched filtering results of M pulses of N array elements on each distance unit form an M multiplied by N dimensional matrix P; then all elements of the matrix P are arranged in a row to obtain a result x of matched filtering of the direct wave and the clutter scattering point echo signal on the detection unit l d,l Comprises the following steps:
wherein N is C Is shown in the distance unit l + l d The total number of clutter scattering units; epsilon i ＝α i α d * ，α i Is the complex amplitude of the ith scattering point, α d Is the complex amplitude of the direct wave signal (·) * In order to perform the conjugate operation,
is a space-time snapshot guide vector of MN x 1,
is the difference between the angular frequency of the scattering point and the angular frequency of the direct wave,
is the spatial frequency of the ith scattering point,
which represents the product of the Kronecker,
is a spatial steering vector of Nx 1 dimension, N is an array elementNumber, (.) T Which represents the operation of transposition by means of a transposition operation,
is a time-oriented vector of dimension M x 1, M being the number of segments,
is the spatial frequency of the scattering point and,
is the angular frequency;
(4b) The l < th > pulse of the m < th > pulse of the n < th > array element i -l p Matching result x of clutter scattering point echo signal and reference signal on each range unit p Substituting the matched filtering result x of the echo signal of the direct wave and the clutter scattering point d,l In the method, a matching result of the multipath clutter and the clutter scattering point echo signal on the detection distance unit l is obtained
Comprises the following steps:
wherein N is T Is the number of multipath clutter, N p Is shown in the distance unit l + l p Total number of clutter scattering units of alpha' p ＝α p * /α d * ，α p Is the complex amplitude, alpha, of the p-th multipath clutter signal d Is the complex amplitude of the direct wave signal (·) * For conjugate operation,. Epsilon j ＝α j α d * ，α j Is the complex amplitude of the jth scattering point,
in order to be the angular frequency of the frequency,
is the spatial frequency of the scattering point;
(4c) Matching result x of direct wave and clutter scattering point echo signal d,l Substituting the matching result of the multipath signal and the clutter scattering point echo signal
In the method, a matching result of the multipath clutter on the detection distance unit l and the echo signal of the clutter scattering point is obtained
Comprises the following steps:
wherein, N T Is the number of multipath clutter, alpha p '＝α p * /α d * ，(·) * For conjugate operation, α p Is the complex amplitude, alpha, of the p-th multipath clutter signal d Is the complex amplitude of the direct wave signal, epsilon j ＝α j α d * ，α j Is the complex amplitude of the jth scattering point,
is the angular frequency of the jth scattering point,
the angular frequency of the pth multipath clutter signal,
a spatial frequency of the jth scattering point, <' > indicating a Hadamard product,
is shown in distance cell l + (l) p -l d ) The component of the upper direct wave is,
wherein 1 F×G Representing an F x G dimensional matrix with elements all 1,
denotes the Kronecker product, v t In the form of a time-oriented vector,
the angular frequency of the pth multipath clutter signal,
is the angular frequency of the direct wave signal;
(4d) Matching the multipath clutter on the detection distance unit l with the echo signal of the clutter scattering point
Matching result x of direct wave and echo signal d,l And noise x n The three are added to obtain a total signal x received by a detection distance unit l l Comprises the following steps:
multipath clutter component due to single range unit
And noise x n Is far lower than the energy x of direct wave clutter component dc,l Neglecting the matching result of the direct wave and the echo signal
And noise x n Obtaining the total signal x received at the detecting distance unit l l Comprises the following steps:
x l ≈x d,l ；
(4e) The total signal x received by the distance detection unit l is detected l Substituting to obtain the multi-path clutter and clutter scattering point echo signal on the detection distance unitNumber matching results
In the method, the matrix form of the obtained total multipath clutter component data in the detection distance unit l is as follows:
wherein N is T Is the number of multipath clutter, alpha' p ＝α p * /α d * ，α p Is the complex amplitude, alpha, of the p-th multipath clutter signal d Is the complex amplitude of the direct wave signal (·) * In order to perform the conjugate operation,
is shown in distance cell l + (l) p -l d ) The total signal of indicates a Hadamard product,
1 F×G denotes an F × G dimensional matrix whose elements are all 1,
denotes the Kronecker product, v t In the form of a time-oriented vector,
the angular frequency of the pth multipath clutter signal,
is the angular frequency of the direct wave signal,
an equivalent space-time steering vector, S, representing the pth multipath clutter component for the corresponding range bin l Is MN multiplied by M t Dictionary matrix of D dimension, M t To quantize the Doppler frequency resolution cell, w (k) = [ w 1 ,w 2 ,...,w MtD ] T As a weight vector, D is the cancellation distance order, S D,l ＝[χ l+1 ,χ l+2 ,...,χ l+D ]The space-time snapshot data from distance unit l +1 to distance unit l + D,
the angular frequency of the qth multipath clutter signal.
The steps are specifically realized as follows:
(5a) According to a dictionary matrix S l Using the mean minimization to obtain the cost function J of the iteration weight coefficient w (k) 1 Comprises the following steps:
wherein E is the mean value, k is the iteration number,
is a two norm square, x l To detect the total signal received at distance unit/, μ is a regularization parameter, | · | |. Luminance | 1 Is a norm;
(5b) Solving the cost function J of (5 a) 1 And obtaining an iteration weight coefficient w (k) as:
w(k)＝w(k-1)+g(k)e(k)+μ(ρ-1)P(k)sign(w(k))，
wherein k is the number of iterations,
(·) -1 for inversion operation, (.) H For conjugate transposition, w (k-1)) For the (k-1) th iteration weight coefficient, P (k) = ρ -1 [P(k-1)-g(k)S k P(k-1)]ρ is the forgetting factor, S (k) is the dictionary matrix for the kth iteration, I MN Is a unit matrix, e (k) = x k -S k w(k-1)，x k For the total signal of the kth iteration, μ is the regularization parameter and sign () is a sign function defined as
| · | is a modulo operation;
(5c) According to a dictionary matrix S l Obtaining a cost function J of the regularization parameter mu by minimizing the difference 2 Comprises the following steps:
wherein,
is a two norm square, k is the number of iterations, x l For the total signal received at detection range unit l, w (k) is the k-th iteration weight coefficient, g (k) = P (k-1) S (k) (ρ I) MN +S(k)P(k-1)S(k) H ) -1 ，(·) -1 For inversion operation, (.) H For conjugate transpose, S (k) is the dictionary matrix for the kth iteration, P (k) = ρ -1 [P(k-1)-g(k)S(k)P(k-1)]ρ is a forgetting factor, I MN An identity matrix with dimension of M multiplied by N, sign (·) is a symbolic function, x (k) a total signal at the k-th iteration, e (k) = x (k) -S (k) w (k-1), and w (k-1) is a weight vector of the k-1-th iteration;
(5d) Solving the cost function J of (5 c) 2 And obtaining a regularization parameter mu of the kth iteration as follows:
wherein R is e {. Is the operation of the entity part, (.) H For conjugate transpose operations, x l For the total message received at the detecting distance unit lThe number w (k-1) is the weight vector of the (k-1) th iteration, P (k) = rho- 1 [P(k-1)-g(k)S(k)P(k-1)]S (k) is a dictionary matrix of the kth iteration, rho is a forgetting factor, and g (k) = P (k-1) S (k) (rho I) MN +S(k)P(k-1)S(k) H ) -1 ，(·) -1 For the inversion operation, I MN An identity matrix of dimension M multiplied by N, e (k) = x (k) -S (k) w (k-1), the total signal of x (k) at the k-th iteration, sign (·) is a sign function;
(5e) Using w (k) in (5 b) and mu in (5 d), obtaining matched signal y for eliminating multipath clutter l Comprises the following steps:
wherein x is l For the total signal received at the detection range unit l, S l For a dictionary matrix, w (k-1) is the weight coefficient of the k-1 iteration, g (k) = P (k-1) S k (ρI MN +S k P(k-1)S k H ) -1 ，(·) -1 For the inversion operation, ρ is a forgetting factor, S (k) is a dictionary matrix of the kth iteration, P (k) = ρ -1 [P(k-1)-g(k)S k P(k-1)]，(·) H For conjugate transpose operation, e (k) = x k -S k w(k-1)，x k Sign () is a sign function, defined as
And | is a modulo operation.
Step 6, canceling the matched signal y for eliminating the multipath clutter l Carrying out direct wave suppression to obtain a target echo signal z l 。
The existing methods for performing direct wave suppression on the matching signal include: the embodiment adopts the space-time cascade two-dimensional adaptive algorithm STAP to carry out direct wave suppression, namely weight vectors in the space-time cascade two-dimensional adaptive algorithm STAP
Matched signal y with multipath clutter removed l Outputting a target echo signal z l Comprises the following steps:
wherein R is x As a clutter covariance matrix, R x ＝R d +R n ，R d Covariance matrix, R, being the component of direct-wave clutter n Is a noise covariance matrix, (.) H For conjugate transpose operation, (. Cndot.) -1 For the inversion operation, v t Is a time-oriented vector.
The effect of the present invention will be further described with reference to simulation experiments.
1. Simulation conditions of the embodiment of the invention are as follows:
the airborne external radiation source radar system in the experiment of the invention takes DVB-T signals as radiation sources and uses random signals to approximately emit signals. In the experiment, the frequency of a signal source is 600MHz, the bandwidth is 8MHz, the sampling frequency is 10MHz, the flight speed of a carrier is 100M/s, the coherent processing time is 25ms, the equivalent pulse number M is 10, and the number N of receiving array elements is 10.
Assuming that the normalized Doppler frequency of a direct wave in a reference signal is 1Hz, and the energy ratio of the direct wave to noise is 70dB; the reference signal contains three multipath clutter, normalized Doppler frequency is 0.2Hz,0.4Hz and 0.6Hz, corresponding distance units are 3,5 and 9 respectively, energy ratio of the three multipath clutter and direct wave is-30 dB, doppler frequency quantization M t The order of the cancellation distance is 21, and the initial value of the weight vector for suppressing the multipath clutter component is set to be 0 vector for 101 resolution units.
2. The experimental contents are as follows:
simulation 1: under the above conditions, the radar received signal is processed by the method of the present invention, and the result of the regularization parameter μ changing with the snapshot data is obtained, and as shown in fig. 3, the result is that the regularization parameter is a discrete variable, as can be seen from fig. 3.
Simulation 2: the clutter space-time two-dimensional power spectrum of the signal is calculated by using the existing space-time cascade two-dimensional adaptive algorithm STAP, the result is shown in figure 4, and as can be seen from figure 4, the clutter space-time two-dimensional power spectrum has obvious output at the multipath clutter component position near the main clutter ridge line.
Simulation 3: the signal clutter power spectrum is calculated by the method of the invention to obtain a signal clutter space-time two-dimensional power spectrogram, the result is shown in figure 5, and as can be seen from figure 5, the clutter space-time two-dimensional power spectrum is mainly concentrated on the main clutter ridge line, and no output is generated at the position corresponding to the multipath clutter component, thus indicating the effectiveness of the method.
And (4) simulation: the received signals are respectively processed by the existing space-time cascade two-dimensional adaptive algorithm STAP and the method, the calculation improvement factor changes along with the Doppler frequency, the result is shown in figure 6, as can be seen from figure 6, notches appear at the position where the normalized Doppler frequency is 0.2-0.6 in the existing space-time cascade two-dimensional adaptive algorithm STAP, and the method has no notches at the corresponding positions.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and the present invention shall be covered thereby. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (9)
1. A clutter suppression method for an airborne external radiation source radar based on space-time cascade is characterized by comprising the following steps:
(1) Acquiring signals received by an airborne external radiation source radar, wherein the signals comprise reference signals and echo signals received by an observation antenna;
(2) Respectively segmenting the reference signal and the echo signal to obtain a segmented reference signal s r (t) and segmented echo signal s n,i (t)；
(3) Will segment the reference signal s r (t) and the segmented echo signal s n,i (t) performing matched filtering, and outputting a response x from the clutter scattering point after matched filtering n,i (t) is divided into two partsPart of the result x is the matching result of the clutter scattering point echo signal and the direct wave signal d The other part is the matching result x of the clutter scattering point echo signal and the multipath clutter signal p ；
(4) Matching result x of echo signal and direct wave signal from clutter scattering point d Matching result x of echo signal of sum clutter scattering point and multipath clutter signal p Constructing a dictionary matrix S l ；
(5) According to a dictionary matrix S l Using L based on joint iteration optimization 1 Norm constrained recursive least squares method L 1 -JI-RLS solving the iterative weight vector w (k) and the regularization parameter μ and for the multipath clutter component x p Suppressing to obtain matched signal y for eliminating multipath clutter l ；
(6) Adopting space-time cascade two-dimensional adaptive algorithm STAP to match signal y for eliminating multipath clutter l Carrying out direct wave suppression to obtain a target echo signal z l 。
2. The method according to claim 1, characterized in that the signals received by the radar of the airborne external radiation source are acquired in (1) by means of two antennas, one antenna receiving the reference signal by means of the reference antenna and the other antenna receiving the echo signal by means of the observation antenna.
3. The method of claim 1, wherein the reference signal is segmented in (2) and implemented as follows:
in a coherent processing time, a reference signal is equally divided into M sections, each section of signal data is equivalent to pulse data, and the equivalent pulse repetition period of the pulse data is T r Each segment of the signal satisfies
Obtaining a segmented reference signal s containing multipath clutter and direct waves after segmentation r (t) is:
wherein v is R Is the speed of the aircraft flying parallel to the ground, d is the array element spacing, alpha d Is the complex amplitude of the direct wave signal, u m (t) is the base station signal of the emission source, t is the signal time, τ d For time delay of direct wave signals, T r Is an equivalent pulse repetition period, j is an imaginary unit, f d Doppler frequency, N, of the direct wave signal T Is the number of multipath clutter, alpha p For the complex amplitude, tau, of the p-th multipath clutter signal p For the time delay of the p-th multipath clutter signal, f p The doppler frequency of the p-th multipath clutter signal.
4. The method of claim 1, wherein the step (2) of segmenting the echo signal comprises dividing the echo signal into M segments, and then equating each segment of signal data to a pulse data with an equivalent pulse repetition period T r Each segment of the signal satisfies
Obtaining the segmented echo signal s of the ith clutter scattering point received by the nth array element n,i (t) is:
wherein alpha is i Is the complex amplitude of the ith scattering point, M is the number of segments, u m (t) is the base station signal of the emission source, t is the signal time, τ i Time delay of the ith scattering point; j is an imaginary unit, f i ＝(v R /λ)cosφ i Is the Doppler frequency of the scattering point, phi i Is the space cone angle of the ith scattering point relative to the aircraft, λ is the signal wavelength, n is the nth array element, θ i ＝(d/λ)cosφ i Is the spatial frequency of the scattering point.
5. The method of claim 1, wherein the matched filtered clutter scattering point output response x in (3) is obtained n,i (t), expressed as follows:
where t is the signal time, x is the integration variable, s n,i (x) Is the echo signal of the ith scattering point, s r (x-t) is the reference signal time delay, (. Cndot.) * Is a conjugate operation;
the above formula is further simplified, namely, the formula is led to be beta = x-tau i -mT r ，ε i ＝α i α d * Then x = β + τ i +mT r D beta/d tau =1, obtaining simplified clutter scattering point output response x n,i (t) is:
wherein epsilon i ＝α i α d * ，α i Is the complex amplitude of the ith scattering point, α d Is the complex amplitude of the direct wave signal (·) * For conjugate operation, j is an imaginary unit, n is the nth array element, theta i Is the spatial frequency of the scattering point and,
f i doppler frequency of scattering point, f d Is the doppler frequency of the direct wave signal,
is the angular frequency of the scattering point and,
is the angular frequency of the direct wave,
u m (t) is the base station signal of the emission source, t is the signal time, τ i Time delay of the ith scattering point, T r Is an equivalent pulse repetition period of alpha' p ＝α p * /α d * ，p＝1,2,...,N T ，α p The complex amplitude of the pth multipath clutter signal,
f p the doppler frequency of the pth multipath clutter signal,
angular frequency, N, of multipath clutter T Is the number of multipath clutter, τ p The time delay of the p-th multipath clutter signal.
6. The method of claim 1, wherein the matched filtered clutter scattering point output response x in (3) n,i (t) is divided into two parts, which are implemented as follows:
(3a) Obtaining clutter scattering point output response x after matched filtering n,i Time t = τ of (t) i -τ d And bring it into x n,i (t) obtaining the l-th pulse of the m-th pulse in the n-th array element i -l d The ith scattering point echo signal s on each range unit n,i (t) and the direct wave signal s d (t) matched filtering result x d Comprises the following steps:
wherein, tau i Time delay of ith scattering point, τ d For time delay of direct wave signals,/ i -l d ＝(τ i -τ d )f s ，f s For the sampling frequency, ∈ i ＝α i α d * ，α i Is the complex amplitude of the ith scattering point, α d Is the complex amplitude of the direct wave signal (·) * For conjugate operation, j is an imaginary unit, θ i Is the spatial frequency of the scattering point, m is the number of segments,
T r for the pulse repetition period, f i Doppler frequency of scattering point, f d Is the doppler frequency of the direct wave signal,
in order to be the angular frequency of the scattering point,
is the direct wave angular frequency;
(3b) Obtaining clutter scattering point output response x after matched filtering n,i Time t = τ of (t) i -τ p And t = τ i -τ p Brought into x n,i (t) obtaining the l-th pulse of the m-th pulse in the n-th array element i -l p Echo signal s of ith clutter scattering point on each range unit n,i (t) and a multipath clutter signal s r The matched filtering result of (t) is:
wherein, tau i Time delay of ith scattering point, τ p Is the time delay of the p-th multipath clutter signal,/ i -l p ＝(τ i -τ p )f s ，f s Is the sampling frequency, α' p ＝α p * /α d * ，α p Is the complex amplitude, alpha, of the p-th multipath clutter signal d Is the complex amplitude of the direct wave signal (·) * For conjugate operation,. Epsilon i ＝α i α d * ，α i Is the complex amplitude of the ith scattering point, α d Is the complex amplitude of the direct wave signal, theta i Is the spatial frequency of the scattering point and,
T r for the pulse repetition period, f i Doppler frequency of scattering point, f p The doppler frequency of the pth multipath clutter signal,
in order to be the angular frequency of the scattering point,
the angular frequency of the p-th multipath clutter signal.
7. The method of claim 1, wherein the matching result x of the echo signal from the clutter scattering point and the direct wave signal in (4) d Matching result x of echo signal of sum clutter scattering point and multipath clutter signal p Constructing a dictionary matrix S l It is implemented as follows:
(4a) Firstly, the mth pulse of the nth array element is subjected to the ith pulse i -l d Matched filter result x over a range unit d As the nth column and mth row of the matrix P, the pulse ith of M pulses of N array elements i -l d The matched filtering results on the distance units form an M multiplied by N dimensional matrix P; then all elements of the matrix P are arranged in a row to obtain a result x of matched filtering of the direct wave and the clutter scattering point echo signal on the detection unit l d,l Comprises the following steps:
wherein, N C Is shown in the distance unit l + l d Total number of clutter scattering units; epsilon i ＝α i α d * ，α i Is the complex amplitude of the ith scattering point, α d Is the complex amplitude of the direct wave signal (·) * In order to perform the conjugate operation,
is a space-time snapshot guide vector of MN x 1,
is the difference between the angular frequency of the scattering point and the angular frequency of the direct wave, θ i Is the spatial frequency of the ith scattering point,
which represents the product of the Kronecker,
is a space steering vector of Nx 1 dimension, N is an array element number (.) T Which represents the operation of transposition by means of a transposition operation,
is a time-oriented vector of dimension M x 1, M being the number of segments, θ i Is the spatial frequency of the scattering point and,
is the angular frequency;
(4b) The l < th > pulse of the m < th > pulse of the n < th > array element i -l p Matching result x of clutter scattering point echo signal and reference signal on each range unit p Substituting the matched filtering result x of the echo signal of the direct wave and the clutter scattering point d,l In the method, a matching result of the multipath clutter and the clutter scattering point echo signal on the detection distance unit l is obtained
Comprises the following steps:
wherein N is T As the number of multipath clutter，N p Is shown in the distance unit l + l p Total number of clutter scattering units of alpha' p ＝α p * /α d * ，α p Is the complex amplitude, alpha, of the p-th multipath clutter signal d Is the complex amplitude of the direct wave signal (·) * For conjugate operation,. Epsilon j ＝α j α d * ，α j Is the complex amplitude of the jth scattering point,
is the angular frequency, theta j Is the spatial frequency of the scattering point;
(4c) Matching result x of direct wave and clutter scattering point echo signal d,l Substituting the matching result of the multipath signal and the clutter scattering point echo signal
In the method, a matching result of the multipath clutter on the detection distance unit l and the echo signal of the clutter scattering point is obtained
Comprises the following steps:
wherein N is T Is the number of multipath clutter, alpha' p ＝α p * /α d * ，α p Is the complex amplitude, alpha, of the p-th multipath clutter signal d Is the complex amplitude of the direct wave signal, epsilon j ＝α j α d * ，α j Is the complex amplitude of the jth scattering point,
is the angular frequency, theta j Spatial frequency of the scattering point, which indicates a Hadamard product,
is shown in distance cell l + (l) p -l d ) The component of the direct wave clutter of (1),
wherein 1 is F×G Representing an F x G dimensional matrix with elements all 1,
denotes the Kronecker product, v t In the form of a time-oriented vector,
the angular frequency of the pth multipath clutter signal,
is the angular frequency of the direct wave signal;
(4d) Matching the multipath clutter on the detection distance unit l with the echo signal of the clutter scattering point
Matching result x of direct wave and echo signal d,l Sum noise x n Adding to obtain the total signal x received by the detection distance unit l l Comprises the following steps:
multipath clutter component due to single range unit
And noise x n The energy of which is far lower than the energy x of direct wave clutter component d,l Neglecting to
And x n Obtaining the distance between the detectorsTotal signal x received from unit l l Comprises the following steps:
x l ≈x d,l ，
(4e) The total signal x received by the distance detection unit l is detected l Substituting to obtain the matching result of the multipath clutter and the clutter scattering point echo signal on the detection distance unit
In the method, the matrix form of the data matrix of the total multipath clutter components in the detection distance unit l is obtained as follows:
wherein, N T Is the number of multipath clutter, alpha' p ＝α p * /α d * ，α p Is the complex amplitude, alpha, of the p-th multipath clutter signal d Is the complex amplitude of the direct wave signal (·) * In order to perform the conjugate operation,
is shown in distance cell l + (l) p -l d ) The total signal of indicates a Hadamard product,
1 F×G representing an F x G dimensional matrix with elements all 1,
denotes the Kronecker product, v t In the form of a time-oriented vector,
the angular frequency of the pth multipath clutter signal,
is the angular frequency of the direct wave signal,
representing the equivalent space-time steering vector, S, corresponding to the pth multipath clutter component l Is MN multiplied by M t Dictionary matrix of D dimension, M t In order to quantify the doppler frequency resolution element,
as a weight vector, D is the cancellation distance order, S D , l ＝[χ l+1 ,χ l+2 ,...,χ l+D ]The space-time snapshot data from distance unit l +1 to distance unit l + D,
for the angular frequency of the qth multipath clutter signal, q =1 t 。
8. The method according to claim 1, characterized in that said (5), it is implemented as follows:
(5a) According to a dictionary matrix S l Using the mean minimization to obtain the cost function J of the iteration weight coefficient w (k) 1 Comprises the following steps:
wherein E is the mean value, k is the iteration number,
is a two norm square, x l To detect the total signal received at distance unit/, μ is a regularization parameter, | · | |. Luminance | 1 Is a norm;
(5b) Solving the cost function J of (5 a) 1 And obtaining an iteration weight coefficient w (k) as:
w(k)＝w(k-1)+g(k)e(k)+μ(ρ-1)P(k)sign(w(k))，
wherein k is the number of iterations,
(·) -1 for inversion operation, (.) H For the conjugate transpose operation, w (k-1) is the (k-1) th iteration weight coefficient, P (k) = rho -1 [P(k-1)-g(k)S k P(k-1)]ρ is the forgetting factor, S (k) is the dictionary matrix for the kth iteration, I MN Is an identity matrix of dimension M × N, e (k) = x k -S k w(k-1)，x k For the total signal of the kth iteration, μ is the regularization parameter and sign () is a sign function defined as
| · | is a modulo operation;
(5c) According to a dictionary matrix S l Obtaining a cost function J of the regularization parameter mu by minimizing the difference 2 Comprises the following steps:
wherein,
is a two norm square, k is the number of iterations, x l For the total signal received at detection range unit l, w (k) is the k-th iteration weight coefficient, g (k) = P (k-1) S (k) (ρ I) MN +S(k)P(k-1)S(k) H ) -1 S (k) is a dictionary matrix of the kth iteration, P (k) = rho -1 [P(k-1)-g(k)S(k)P(k-1)]Rho is a forgetting factor, (.) -1 For the inversion operation, I MN An identity matrix with dimension M multiplied by N, sign (·) is a symbolic function, e (k) = x (k) -S (k) w (k-1), x (k) is a total signal at the k iteration, and w (k-1) is a weight vector of the k-1 iteration;
(5d) Solving the cost function J of (5 c) 2 And obtaining a regularization parameter mu of the kth iteration as follows:
wherein R is e {. Is the operation of the entity part, (.) H For conjugate transpose operation, (.) -1 For the inversion operation, x l For the total signal received at detection range unit l, w (k-1) is the weight vector of the k-1 th iteration, P (k) = ρ -1 [P(k-1)-g(k)S(k)P(k-1)]，g(k)＝P(k-1)S(k)(ρI MN +S(k)P(k-1)S(k) H ) -1 S (k) is a dictionary matrix of the kth iteration, rho is a forgetting factor, I MN An identity matrix of dimension M × N, e (k) = x (k) -S (k) w (k-1), total signal at k-th iteration of x (k), sign (·) is a sign function;
(5e) Using w (k) in (5 b) and mu in (5 d), obtaining a matching signal y for eliminating multipath clutter l Comprises the following steps:
wherein x is l For the total signal received at the detection range unit l, S l Is a dictionary matrix, w (k-1) is the (k-1) th iteration weight coefficient,
ρ is the forgetting factor, S (k) is the dictionary matrix of the kth iteration, P (k) = ρ -1 [P(k-1)-g(k)S k P(k-1)]，(·) H For conjugate transpose operations, x k For the total signal of the kth iteration, e (k) = x k -S k w (k-1), sign (·) is a sign function defined as
And | is a modulo operation.
9. The method of claim 1, wherein (6) employs a space-time cascade two-dimensional adaptive algorithm STAP pair inhibits direct wave to obtain target echo signal z l Is a weight vector in a space-time cascade two-dimensional adaptive algorithm STAP
Matched signal y with multipath clutter removed l Outputting a target echo signal z l Comprises the following steps:
wherein R is x As a clutter covariance matrix, R x ＝R d +R n ，R d Covariance matrix, R, being the component of the clutter of the direct waves n Is a noise covariance matrix, (.) H For conjugate transpose operation, (.) -1 For the inversion operation, v t Is a time-oriented vector.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811328082.7A CN109471083B (en) | 2018-11-09 | 2018-11-09 | Airborne external radiation source radar clutter suppression method based on space-time cascade |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811328082.7A CN109471083B (en) | 2018-11-09 | 2018-11-09 | Airborne external radiation source radar clutter suppression method based on space-time cascade |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109471083A CN109471083A (en) | 2019-03-15 |
| CN109471083B true CN109471083B (en) | 2022-12-02 |
Family
ID=65672741
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811328082.7A Active CN109471083B (en) | 2018-11-09 | 2018-11-09 | Airborne external radiation source radar clutter suppression method based on space-time cascade |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109471083B (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110824432B (en) * | 2019-08-28 | 2023-02-28 | 深圳大学 | Radar clutter suppression method, device and computer readable storage medium |
| CN113449263A (en) * | 2020-03-26 | 2021-09-28 | 太原理工大学 | Multi-path error correction method, system and equipment based on sparsity-promoted regularization |
| CN112014818B (en) * | 2020-08-25 | 2022-09-16 | 北京理工大学 | Clutter suppression method based on batch processing CLEAN |
| CN113156381A (en) * | 2021-04-01 | 2021-07-23 | 湖南城市学院 | Multipath clutter suppression method for airborne external radiation source radar |
| CN113435299B (en) * | 2021-06-23 | 2022-05-13 | 电子科技大学 | Bistatic forward-looking SAR clutter suppression method based on space-time matching |
| CN113820679B (en) * | 2021-08-10 | 2023-12-26 | 西安电子科技大学 | Filtering method, device, equipment and storage medium for radar echo data |
| CN115453477B (en) * | 2022-08-03 | 2024-06-25 | 西安电子科技大学 | Method for canceling multipath clutter in external radiation source radar monitoring channel signal |
| CN115327505B (en) * | 2022-10-12 | 2023-01-24 | 深圳大学 | Low-altitude target angle estimation method in multipath environment and related equipment |
| CN116449398B (en) * | 2023-04-10 | 2023-11-03 | 中国矿业大学 | Self-adaptive anti-interference method for satellite navigation receiver in antenna array element mutual coupling environment |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4727311B2 (en) * | 2005-06-15 | 2011-07-20 | 三菱電機株式会社 | Radar equipment |
| CN104345301A (en) * | 2014-11-05 | 2015-02-11 | 西安电子科技大学 | Non-adaptive clutter pre-filtering space-time two-dimensional cancellation method for airborne MIMO (Multiple-Input-Multiple-Output) radar |
| CN105527610B (en) * | 2015-12-05 | 2017-10-20 | 中国人民解放军信息工程大学 | The multiple antennas combined optimization clutter suppression method estimated based on fractional order time delay |
-
2018
- 2018-11-09 CN CN201811328082.7A patent/CN109471083B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN109471083A (en) | 2019-03-15 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109471083B (en) | Airborne external radiation source radar clutter suppression method based on space-time cascade | |
| CN110412559B (en) | Non-coherent fusion target detection method for MIMO radar of distributed unmanned aerial vehicle | |
| CN107121670B (en) | Anti-unmanned aerial vehicle defense method based on synthetic aperture radar | |
| US11525910B2 (en) | Synthetic aperture radar apparatus and methods | |
| CN105182300B (en) | The land clutter interference real-time suppression method of space-based external illuminators-based radar | |
| US20060181451A1 (en) | System and method for combining displaced phase center antenna and space-time adaptive processing techniques to enhance clutter suppression in radar on moving platforms | |
| CN109765529B (en) | Millimeter wave radar anti-interference method and system based on digital beam forming | |
| Sui et al. | Cascaded least square algorithm for strong clutter removal in airborne passive radar | |
| Malanowski et al. | Passive radar based on LOFAR radio telescope for air and space target detection | |
| CN106291547B (en) | Doppler ambiguity component Adaptive Suppression method based on antenna radiation pattern auxiliary | |
| del-Rey-Maestre et al. | Optimum beamforming to improve UAV’s detection using DVB-T passive radars | |
| CN109143235A (en) | A kind of biradical forward sight synthetic aperture radar Ground moving target detection method | |
| Carlo et al. | A least squares multiple constraint direct data domain approach for STAP | |
| CN110471040B (en) | Inverse synthetic aperture radar interference method based on FDA antenna | |
| Lim et al. | Time-and frequency-domain MIMO FLGPR imaging | |
| Xiaode et al. | Range-Doppler NLMS (RDNLMS) algorithm for cancellation of strong moving targets in passive coherent location (PCL) radar | |
| Quirini et al. | Non-uniform linear arrays for target detection and DoA estimation in passive radar STAP | |
| Fabrizio | High frequency over-the-horizon radar | |
| Gao et al. | Arc array radar IAA-STAP algorithm based on sparse constraint | |
| Tang et al. | A novel 3D imaging method of FMCW MIMO-SAR | |
| Venkatesh et al. | A frequency diversity pulse-pair algorithm for extending Doppler radar velocity Nyquist range | |
| Lin et al. | Novel data acquisition method for interference suppression in dual-channel SAR | |
| Wu et al. | A mini radar system for low altitude targets detection | |
| Deng et al. | Calibrating the amplitude and phase imbalances in AgileDARN HF radar | |
| Sui et al. | A Novel Strong Clutter Suppression Algorithm for Airborne Passive Radar |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |