Clutter Doppler sharpening method for space-based double-station detection in presence of range ambiguity

Abstract

The invention discloses a clutter Doppler sharpening method under range ambiguity of space-based double-station detection. The clutter Doppler sharpening method comprises the following steps: determining a squint angle change range in a beam detection area according to system parameters of a space-based double-station radar; dividing a beam detection area into a strong space-variant area and a weak space-variant area based on the squint angle variation range; constructing a partition compensation function for the strong space-variant region and the weak space-variant region to compensate the distance linear walking of the clutter signal to obtain a compensated clutter signal; fitting based on the compensated clutter signal to obtain a clutter equivalent energy center; and constructing a secondary phase compensation function by using the clutter equivalent energy center, and performing secondary phase compensation on the compensated clutter signal through the secondary phase compensation function. According to the clutter Doppler sharpening method, the compensation precision is high, compensation failure is avoided, and clutter energy diffusion caused by distance ambiguity component secondary phase compensation deviation can be avoided.

Description

Technical Field

[0001] The present invention belongs to the field of radar technology, and in particular relates to a clutter Doppler sharpening method in the presence of range ambiguity in space-based dual-station detection. Background Art

[0002] Space-based bistatic detection systems achieve collaborative detection through spatially separated onboard transmitters and receivers. Compared to traditional monostatic radar systems, they can observe targets from multiple perspectives, acquiring multi-dimensional scattering information. They also offer significant advantages such as strong stealth and excellent anti-interference capabilities. However, due to the high altitude of the satellites, the antenna beam illuminates a large area of ​​the ground. When radars detect targets on land or in the air, clutter in these areas can severely impact the effectiveness of Ground Moving Target Indication (GMTI) and Air Moving Target Indication (AMTI) processing. Therefore, clutter suppression is crucial. In space-based bistatic systems, the platform's displacement during pulse transmission and reception is significant. The clutter received by the radar exhibits range migration, resulting in clutter energy dispersion and spectrum broadening, significantly degrading clutter suppression performance. Clutter range migration compensation can reduce clutter energy dispersion, thereby improving clutter suppression performance. Therefore, high-precision clutter range migration compensation is a key step in achieving high-performance clutter suppression. In practical detection, space-based radars often employ medium-to-high pulse repetition frequency (PRF) designs to balance wide-area coverage with high resolution. However, their maximum ambiguity range is smaller than the satellite's observation range of the target, resulting in range ambiguity. Therefore, range migration and range ambiguity often coexist, making clutter range migration compensation more difficult. Clutter range migration compensation schemes can be categorized as linear and curved. For linear migration, existing envelope migration compensation methods based on linear fitting utilize curve fitting to achieve envelope migration compensation. However, due to the complex dynamic distribution of bistatic radar clutter, existing methods lack accuracy in compensating for linear range migration of some clutter. This is particularly true for detection geometries that rapidly vary with range and beam azimuth. For compensating for quadratic phase modulation caused by range curvature, existing methods use the center range or the range gate with the strongest spatial variability as the reference slant range. However, these methods cannot eliminate the clutter energy spread caused by quadratic phase compensation deviations in the range ambiguity component, significantly degrading subsequent clutter suppression performance.

[0003] Therefore, how to provide a clutter Doppler sharpening method with high compensation accuracy, no compensation failure, and the ability to avoid clutter energy diffusion caused by the secondary phase compensation deviation of the range ambiguity component has become an important issue. SUMMARY

[0004] In order to solve the above problems existing in the prior art, the present application provides a clutter Doppler sharpening method under the existence of range ambiguity in space-based bistatic detection.

[0005] The technical problem to be solved by the present application is solved by the following technical scheme: In a first aspect, the present application provides a clutter Doppler sharpening method under the existence of range ambiguity in space-based bistatic detection, the clutter Doppler sharpening method comprising: determining a squint angle variation range in a beam detection region according to space-based bistatic radar system parameters; dividing the beam detection region into a strong space variation region and a weak space variation region based on the squint angle variation range; constructing a partition compensation function for compensating distance linear migration of a clutter signal for the strong space variation region and the weak space variation region, to obtain a compensated clutter signal; fitting to obtain a clutter equivalent energy center based on the compensated clutter signal; constructing a quadratic phase compensation function using the clutter equivalent energy center, and performing quadratic phase compensation on the compensated clutter signal through the quadratic phase compensation function, to obtain a clutter Doppler sharpening result.

[0006] Optionally, dividing the beam detection region into a strong space variation region and a weak space variation region based on the squint angle variation range comprises: calculating a first-order linear migration amount of squint angle variation in the beam detection region, and determining a region with a first-order linear migration amount greater than or equal to one distance unit as a strong space variation region, and a region with a first-order linear migration amount less than one distance unit as a weak space variation region.

[0007] Optionally, constructing a partition compensation function for compensating distance linear migration of a clutter signal for the strong space variation region and the weak space variation region comprises: constructing a first compensation function with the beam center as a reference for the weak space variation region; constructing a second compensation function with a two-dimensional frequency domain per-distance Doppler unit as a reference for the strong space variation region; compensating distance linear migration in the distance-frequency domain-pulse domain of the clutter signal according to the first compensation function, and compensating distance linear migration in the frequency-Doppler domain per-distance Doppler unit of the clutter signal according to the second compensation function, to obtain a compensated clutter signal.

[0008] Optionally, fitting to obtain a clutter equivalent energy center based on the compensated clutter signal comprises: performing pulse compression processing on the compensated clutter signal to obtain a clutter pulse compression result; Calculating the theoretical CNR of the clutter pulse pressure result; An energy distribution curve of the compensated clutter signal along the distance dimension is fitted based on the theoretical CNR, and a clutter equivalent energy center is calculated through the energy distribution curve.

[0009] Optionally, performing quadratic phase compensation on the compensated clutter signal using the quadratic phase compensation function to obtain a clutter Doppler sharpening result includes: The quadratic phase compensation function is used to compensate the compensated clutter signal for the quadratic phase in the range time domain-pulse domain by each range gate to obtain a quadratic phase compensated result; Performing pulse Fourier transform on the result after the secondary phase compensation to obtain a clutter Doppler sharpening result.

[0010] Optionally, constructing a quadratic phase compensation function using the clutter equivalent energy center includes: The slant distance of the clutter equivalent energy center is used as a reference slant distance of the quadratic phase compensation function to construct the quadratic phase compensation function.

[0011] In a second aspect, the present invention provides a clutter Doppler sharpening device for space-based dual-station detection with range ambiguity, the clutter Doppler sharpening device comprising: A determination module, configured to determine a slant angle variation range within a beam detection area according to parameters of a space-based dual-station radar system; A division module, configured to divide the beam detection area into a strong space-variation area and a weak space-variation area based on the slant angle variation range; A first compensation module is configured to construct a partition compensation function for the strong space-variation region and the weak space-variation region to compensate for the linear movement of the clutter signal to obtain a compensated clutter signal; A fitting module, configured to obtain a clutter equivalent energy center based on the compensated clutter signal fitting; The second compensation module is used to construct a quadratic phase compensation function using the clutter equivalent energy center, and perform quadratic phase compensation on the compensated clutter signal through the quadratic phase compensation function to obtain a clutter Doppler sharpening result.

[0012] In a third aspect, the present invention provides an electronic device comprising a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other via the communication bus; Memory for storing computer programs; The processor is configured to implement the method steps described in any one of the above-mentioned methods for clutter Doppler sharpening in the presence of range ambiguity in space-based dual-station detection when executing the computer program stored in the memory.

[0013] In a fourth aspect, the present invention provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, the method steps described in any of the above-mentioned methods for clutter Doppler sharpening in the presence of range ambiguity in space-based dual-station detection are implemented.

[0014] The present invention provides a clutter Doppler sharpening method in space-based dual-station detection with range ambiguity. The method divides a beam detection area into a strong space-variant area and a weak space-variant area, constructs a partition compensation function for the strong space-variant area and the weak space-variant area to compensate for the linear range movement of the clutter signal, thereby improving the linear compensation accuracy of the clutter range movement and overcoming the problem of compensation failure in some detection geometric areas that change rapidly with the detection range and beam azimuth. The method also obtains a clutter equivalent energy center based on fitting of the compensated clutter signal, constructs a quadratic phase compensation function using the clutter equivalent energy center, and performs quadratic phase compensation on the compensated clutter signal using the quadratic phase compensation function. This method solves the problem of clutter energy diffusion caused by the quadratic phase compensation deviation of the range ambiguity component in existing compensation methods and further improves the compensation accuracy.

[0015] The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 1 is a flow chart of a clutter Doppler sharpening method for space-based dual-station detection with range ambiguity provided by an embodiment of the present invention; Figure 2 This is a flow chart of another method for clutter Doppler sharpening in space-based dual-station detection with range ambiguity, improved by an embodiment of the present invention; Figure 3 This is a graph showing the variation of normalized clutter energy diffusion with detection slant range due to quadratic phase compensation deviation using different distances as reference slant ranges provided by an embodiment of the present invention; Figure 4 The quadratic phase compensation loss provided by the embodiment of the present invention is The eigenvalue distribution of the covariance matrix and the output signal-to-noise ratio loss result after STAP processing; Figure 5 The quadratic phase compensation loss provided by the embodiment of the present invention is The eigenvalue distribution of the covariance matrix and the output signal-to-noise ratio loss result after STAP processing; Figure 6This is a distribution diagram of clutter secondary phase compensation deviation after secondary phase compensation is performed using the clutter equivalent energy center distance as the reference slant distance, provided by an embodiment of the present invention; Figure 7 1 is a schematic structural diagram of a clutter Doppler sharpening device for space-based dual-station detection with range ambiguity provided by an embodiment of the present invention; Figure 8 It is a structural diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0017] The present invention will be further described in detail below with reference to specific examples, but the embodiments of the present invention are not limited thereto.

[0018] In order to solve the problem that the existing clutter Doppler sharpening method has insufficient accuracy in compensating for linear movement of some clutter ranges, especially for the detection geometric area that changes rapidly with the detection range and beam azimuth, the compensation fails, and the clutter energy diffusion caused by the quadratic phase compensation deviation of the range ambiguity component cannot be eliminated, the embodiment of the present invention provides a clutter Doppler sharpening method for space-based dual-station detection with range ambiguity. Figure 1 , Figure 1 The present invention provides a flow chart of a method for clutter Doppler sharpening in space-based dual-station detection with range ambiguity, which specifically includes the following steps: Step S101: determining a slant angle variation range within a beam detection area according to space-based bistatic radar system parameters.

[0019] In an embodiment of the present invention, relevant space-based bistatic radar system parameters may include orbit altitude, geometric configuration, platform speed, integration time, antenna size, transmission power and other parameters.

[0020] In the embodiment of the present invention, the oblique viewing angle is calculated as follows: ; in, Indicates oblique viewing angle; Indicates the azimuth of the receiving beam center; Indicates the downward viewing angle of the receive beam center.

[0021] Step S102: dividing the beam detection area into a strong space-variation area and a weak space-variation area based on the slant angle variation range.

[0022] In the embodiment of the present invention, the beam detection area can be divided into a strong space-variation area and a weak space-variation area according to the variation range of the oblique angle, which can be specifically determined according to the first-order linear movement amount.

[0023] See also Figure 2 , Figure 2This is a flow chart of another method for clutter Doppler sharpening in space-based dual-station detection with range ambiguity, according to an embodiment of the present invention. The calculation of the slant angle variation range is described in step S101 above and will not be repeated here. The calculation divides the beam detection area into a strong space-variance area and a weak space-variance area based on the slant angle variation range, including: The first-order linear movement of the oblique angle change in the beam detection area is calculated, and the area where the first-order linear movement is greater than or equal to one distance unit is determined as a strong space-variation area, and the area where the first-order linear movement is less than one distance unit is determined as a weak space-variation area.

[0024] Among them, the first-order linear movement The calculation formula is: ; in, Indicates the speed of the receiving star, that is, the speed of the satellite receiving the signal; Indicates slow time.

[0025] Step S103 : constructing a partition compensation function for the strong space-variation region and the weak space-variation region to compensate for the linear movement of the clutter signal to obtain a compensated clutter signal.

[0026] In the embodiment of the present invention, after the strong and weak air-variable regions are classified, a distance linear movement compensation function is constructed for different regions.

[0027] In one implementation, see Figure 2 , for the strong space-variant area and the weak space-variant area, a partition compensation function is constructed to compensate for the linear movement of the clutter signal, and the compensated clutter signal is obtained, including: For the weak spatial variation area, the first compensation function is constructed with the beam center as the reference; For the strong spatial variation area, the second compensation function is constructed with the two-dimensional frequency domain range-by-range Doppler unit as a reference; See also Figure 2 According to the first compensation function, the linear movement of the distance is compensated in the frequency domain-pulse domain of the clutter signal, and according to the second compensation function, the linear movement of the distance is compensated in the frequency domain-Doppler domain of the clutter signal by Doppler unit to obtain the compensated clutter signal.

[0028] In the embodiment of the present invention, for the weak space-variable region, the first compensation function is constructed with the beam center, that is, the main lobe illumination direction of the antenna beam, as a reference. ,include: ; in, represents the distance frequency; represents an imaginary unit; represents the unambiguous Doppler center, which is calculated as follows: ; in, Indicates wavelength.

[0029] In the embodiment of the present invention, for the strong space-variable area, the second compensation function is constructed with the two-dimensional frequency domain range-by-range Doppler unit as a reference. ,include: ; in, Indicates the reference slant range, that is, the receiving slant range corresponding to the current range Doppler unit; represents the Doppler frequency; It represents the Doppler-dependent walk factor, which is calculated as: ; Next, distance linear movement compensation may be performed according to the first compensation function and the second compensation function.

[0030] Specifically, the linear movement of the distance is compensated in the range frequency domain-pulse domain of the clutter signal according to the first compensation function, and the linear movement of the distance is compensated for by each Doppler unit in the frequency domain-Doppler domain of the clutter signal according to the second compensation function, so as to obtain the compensated clutter signal.

[0031] Step S104: obtaining a clutter equivalent energy center based on the compensated clutter signal fitting.

[0032] In the embodiment of the present invention, the fuzzy clutter equivalent energy center may be fitted according to the PRF.

[0033] In one implementation, obtaining a clutter equivalent energy center based on the compensated clutter signal fitting includes: Perform pulse compression processing on the compensated clutter signal to obtain the clutter pulse compression result; Calculate the theoretical CNR (Clutter-to-Noise Ratio) of the clutter pulse pressure result; The energy distribution curve of the compensated clutter signal along the distance dimension is fitted based on the theoretical CNR, and the clutter equivalent energy center is calculated through the energy distribution curve.

[0034] In the embodiment of the present invention, the theoretical CNR of the clutter pulse compression result can be calculated based on the clutter pulse compression result and the parameters of the space-based dual-station radar system. The calculation formula is: ; in, Indicates the transmit power; represents the transmit antenna gain; Indicates receiving antenna gain; Indicates wavelength; Indicates accumulation time; represents the scattering coefficient; Indicates the azimuth resolution; Indicates the distance resolution; represents the Boltzmann constant; Indicates room temperature; represents the noise figure; Indicates system loss; Indicates the launch distance; Indicates the receiving distance.

[0035] The energy distribution curve of the clutter along the distance dimension after compensation is fitted based on the system priori parameters , the calculation formula is: ; in, represents the normalized antenna pattern; Indicates the elevation angle of the clutter scattering point relative to the antenna surface, which varies with the receiving slant range as follows: ; in, represents the radius of the Earth; Indicates the track height; Indicates the receiving slant distance, that is, the aforementioned receiving distance.

[0036] In the embodiment of the present invention, the clutter equivalent energy center is calculated by the energy distribution curve. The calculation formula is: ; in, It represents the function of the change of the azimuth modulation frequency along the distance dimension; Represents the variation function of the clutter energy distribution curve along the distance dimension; same ; The calculation formula is as follows: ; in, Indicates the receiving satellite speed; Indicates oblique viewing angle; Indicates the initial receiving slant distance when walking.

[0037] Step S105 : constructing a quadratic phase compensation function using the clutter equivalent energy center, and performing quadratic phase compensation on the compensated clutter signal using the quadratic phase compensation function to obtain a clutter Doppler sharpening result.

[0038] In practical applications, the distance distribution range of clutter signals is limited, and echo signals are discrete, so the aforementioned clutter equivalent energy center The integral of the calculation formula is approximated by summation: ; in, , Indicates the number of distance blurs; Indicates the The Doppler modulation rate of the secondary range ambiguity component.

[0039] According to the clutter equivalent energy center Get the corresponding slope distance ; In an embodiment of the present invention, a quadratic phase compensation function is constructed using the clutter equivalent energy center, including: The slant distance of the clutter equivalent energy center is used as the reference slant distance of the quadratic phase compensation function to construct the quadratic phase compensation function.

[0040] Constructing a quadratic phase compensation function using the clutter equivalent energy center , the calculation formula is: ; in, Indicates the reference slope distance The Doppler modulation frequency is calculated as: ; The clutter Doppler sharpening result is obtained by performing quadratic phase compensation on the compensated clutter signal through the quadratic phase compensation function, including: The quadratic phase compensation function is used to compensate the compensated clutter signal for the quadratic phase in the range time domain and pulse domain, and the quadratic phase compensation result is obtained. The pulse Fourier transform (FFT) of the result after quadratic phase compensation is performed to obtain the clutter Doppler sharpening result.

[0041] In an embodiment of the present invention, the beam detection area is divided into a strong space-variant area and a weak space-variant area. A partitioned compensation function is constructed for the strong space-variant area and the weak space-variant area to compensate for the linear range movement of the clutter signal. This improves the accuracy of the linear compensation for the clutter range movement and overcomes the problem of compensation failure in some detection geometric areas that change rapidly with the detection range and beam azimuth. Based on the fitted clutter signal after compensation, the clutter equivalent energy center is obtained, and the quadratic phase compensation function is constructed using the clutter equivalent energy center. The quadratic phase compensation function is used to perform quadratic phase compensation on the compensated clutter signal. This solves the problem of clutter energy diffusion caused by the quadratic phase compensation deviation of the range ambiguity component under existing compensation methods and further improves the compensation accuracy.

[0042] A simulation experiment using a clutter Doppler sharpening method for space-based dual-station detection with range ambiguity provided by an embodiment of the present invention is as follows: This simulation experiment takes the space-based dual-station radar system as an example. The simulation parameters are configured as follows: pulse accumulation time 0.4s, pulse repetition rate 1200Hz, radar operating wavelength 0.25m, orbital altitude of the receiving satellite is 500km, and inter-satellite baselines are 0, 3.75, 7.5, 11.25, 15, 18.75, 22.5, and 26.25 meters. The detailed parameters of the space-based dual-station radar system are shown in Table 1: Table 1 Space-based dual-station radar system parameters

[0043] This simulation experiment uses the clutter Doppler sharpening method provided in the first embodiment of the present invention for space-based dual-station detection with range ambiguity. In the space-based dual-station detection system, after linear clutter range movement compensation and range bending after pulse compression, a quadratic phase compensation function is designed to perform quadratic phase compensation for clutter range bending based on the closest distance, the farthest distance, the beam center distance, and the clutter equivalent energy center as reference slant ranges. After considering clutter energy modulation, the normalized clutter energy spread caused by the quadratic phase compensation deviation in each scheme is compared with the detection slant range. The effect of the quadratic phase compensation deviation on the clutter suppression performance is then evaluated and verified using the eigenvalue distribution of the covariance matrix and the output signal-to-noise ratio loss after STAP (Space-Time Adaptive Processing) processing under different quadratic phase compensation deviations. This verifies the effectiveness of the clutter Doppler sharpening method for space-based dual-station detection with range ambiguity.

[0044] See also Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 , Figure 3 This is a graph showing the variation of normalized clutter energy diffusion with detection slant range when different distances are used as reference slant ranges, as provided by an embodiment of the present invention. Figure 4 The quadratic phase compensation loss provided by the embodiment of the present invention is The eigenvalue distribution of the covariance matrix and the output signal-to-noise ratio loss result after STAP processing are shown in the figure. Figure 5 The quadratic phase compensation loss provided by the embodiment of the present invention is The eigenvalue distribution of the covariance matrix and the output signal-to-noise ratio loss result after STAP processing are shown in the figure. Figure 6 This is a distribution diagram of clutter secondary phase compensation deviation after secondary phase compensation is performed with the clutter equivalent energy center distance as the reference slant distance, provided by an embodiment of the present invention.

[0045] Figure 3 This is a graph showing the change in normalized clutter energy diffusion caused by the secondary phase compensation deviation with the detection slant range after clutter energy modulation based on different detection distances as the reference slant range. The horizontal axis is the receiving distance, and the vertical axis is the average accumulated loss of the main lobe energy, that is, the main lobe energy loss. The greater the average loss, the more serious the diffusion of the clutter energy main lobe energy to the side lobes. Figure 3 (a) shows the variation of clutter energy diffusion with the minimum detection distance as the reference slant range. The average clutter mainlobe energy diffusion value to the sidelobe is 10.5dB. Figure 3 (b) shows the variation of clutter energy diffusion with the longest detection distance as the reference slant range. The average clutter mainlobe energy diffusion value to the sidelobe is 5.4dB. Figure 3 (c) shows the variation of clutter energy spread with the beam center distance as the reference slant distance. The average clutter mainlobe energy spread to the sidelobes is 3.9 dB. Figure 3 Figure (d) shows the variation in clutter energy spread using the clutter equivalent energy center distance as the reference slant distance, as proposed by the present invention. The measured average clutter mainlobe energy spread to the sidelobes is 2.4 dB. This data demonstrates that constructing a quadratic phase compensation function using the clutter equivalent energy center distance as the reference slant distance minimizes the average clutter mainlobe energy spread to the sidelobes.

[0046] Figure 4 The quadratic phase compensation loss is The eigenvalue distribution of the covariance matrix and the output signal-to-noise ratio loss result after STAP processing are shown in the figure. Figure 4 (a) in the equation represents eigenvalue diffusion. Figure 4 (b) in the figure shows the target oSCNR loss. The integrated sidelobe is -18.61 dB. Due to the presence of quadratic phase compensation deviation, the mainlobe energy loss leaks into the sidelobes. This energy causes clutter to spread into the noise subspace, which is equivalent to a noise energy boost after STAP processing. Figure 4 It shows that the quadratic phase compensation deviation is When , the eigenvalue diffusion of the clutter covariance matrix is ​​consistent with the change in the integrated sidelobe. That is, the clutter subspace will be widened to a certain extent, resulting in a widening of the clutter suppression filter null, but the noise floor does not change significantly, and the output signal-to-noise ratio loss is small.

[0047] Figure 5 The quadratic phase compensation loss is The eigenvalue distribution of the covariance matrix and the output signal-to-noise ratio loss result after STAP processing are shown in the figure. Figure 5 (a) in the equation represents eigenvalue diffusion. Figure 5 (b) in the figure represents the target oSCNR loss, where the integrated sidelobe is -6.62dB. Figure 5It can be seen that the quadratic phase compensation deviation is When the clutter leakage component diffuses seriously into the orthogonal subspace of the clutter main component, the output signal-to-noise ratio loss of STAP processing is seriously deteriorated.

[0048] Figure 6 This is a clutter Doppler sharpening method proposed by the present invention for space-based dual-station detection with range ambiguity, that is, the distribution diagram of the clutter secondary phase compensation deviation after secondary phase compensation using the clutter equivalent energy center distance as the reference slant range. The horizontal axis is the velocity system azimuth, and the vertical axis is the sum of the dual-station distances. Figure 6 It can be seen that only when the velocity system azimuth is less than 60 degrees and the sum of the two-base distance is greater than The quadratic phase compensation error is slightly greater than that of the smaller area of ​​kilometers. The quadratic phase compensation deviations in the remaining regions are all less than In general, the clutter equivalent energy center distance is used as the reference slant distance to make the secondary phase compensation, which can satisfy the clutter secondary phase compensation deviation less than .

[0049] From the simulation results, it can be concluded that the method of the present invention can minimize the diffusion of clutter energy caused by the secondary phase compensation deviation of the range ambiguity component under range migration bending compensation. ,The output signal-to-noise ratio loss of STAP processing is small, and it can achieve Doppler sharpening of clutter with range ambiguity under robust space-based dual-station detection.

[0050] The present invention adopts a clutter Doppler sharpening method based on a space-based dual-station detection system with range ambiguity. For the linear compensation of clutter range migration, a partitioned compensation scheme based on prior information of dual-station geometric configuration parameters is adopted. This significantly improves the accuracy of linear compensation of clutter range migration, overcoming the problem of reduced compensation accuracy or even compensation failure due to the spatial variation of clutter range migration in the prior art. The present invention also provides a quadratic phase compensation method for fitting the clutter equivalent energy center. The system prior parameters are used to fit the energy distribution curve of the clutter along the range dimension, and then the slant range corresponding to the clutter equivalent energy center is calculated. This is used as the reference slant range of the current ambiguity range unit compensation function, solving the problem of clutter energy diffusion caused by the quadratic phase compensation deviation of the range ambiguity component in the prior compensation method.

[0051] Based on the same inventive concept, the embodiment of the present invention also provides a clutter Doppler sharpening device for space-based dual-station detection with range ambiguity, see Figure 7 , Figure 7 1 is a schematic structural diagram of a clutter Doppler sharpening device for space-based dual-station detection with range ambiguity provided by an embodiment of the present invention. The clutter Doppler sharpening device includes: The determining module 701 is configured to determine a variation range of the squint angle in the beam detection region according to a space-based bistatic radar system parameter. The dividing module 702 is configured to divide the beam detection region into a strong space variation region and a weak space variation region based on the variation range of the squint angle. The first compensation module 703 is configured to compensate the distance linear migration of the clutter signal by constructing a partition compensation function for the strong space variation region and the weak space variation region, to obtain a compensated clutter signal. The fitting module 704 is configured to fit to obtain a clutter equivalent energy center based on the compensated clutter signal. The second compensation module 705 is configured to construct a quadratic phase compensation function by using the clutter equivalent energy center, and perform quadratic phase compensation on the compensated clutter signal by using the quadratic phase compensation function, to obtain a clutter Doppler sharpening result.

[0052] In the embodiment of the application, the beam detection region is divided into a strong space variation region and a weak space variation region, and the distance linear migration of the clutter signal is compensated by constructing a partition compensation function for the strong space variation region and the weak space variation region, thereby improving the clutter distance migration linear compensation precision and overcoming the problem of compensation failure for some detection geometry regions with rapid variation of the detection distance and the beam azimuth angle. The clutter equivalent energy center is fitted based on the compensated clutter signal, the quadratic phase compensation function is constructed by using the clutter equivalent energy center, and the quadratic phase compensation is performed on the compensated clutter signal by using the quadratic phase compensation function, thereby solving the problem of clutter energy diffusion caused by the quadratic phase compensation deviation of the distance ambiguity component under the existing compensation method, and further improving the compensation precision.

[0053] Optionally, the dividing module is specifically configured to: calculate a first-order linear migration amount of the squint angle in the beam detection region, and determine a region with a first-order linear migration amount greater than or equal to a distance unit as the strong space variation region, and determine a region with a first-order linear migration amount less than a distance unit as the weak space variation region.

[0054] Optionally, the first compensation module is specifically configured to: construct a first compensation function with the beam center as a reference for the weak space variation region, construct a second compensation function with a two-dimensional frequency domain per-distance Doppler unit as a reference for the strong space variation region, compensate the distance linear migration of the clutter signal in the distance-frequency domain-pulse domain according to the first compensation function, and compensate the distance linear migration of the clutter signal in the frequency-Doppler domain per-distance Doppler unit according to the second compensation function, to obtain a compensated clutter signal.

[0055] Optionally, the fitting module is specifically configured to: The compensated clutter signal is subjected to pulse compression processing to obtain a clutter pulse compression result; a theoretical CNR of the clutter pulse compression result is calculated; an energy distribution curve of the compensated clutter signal along the distance dimension is fitted based on the theoretical CNR, and a clutter equivalent energy center is calculated through the energy distribution curve.

[0056] Optionally, the second compensation module performs secondary phase compensation on the compensated clutter signal using the secondary phase compensation function to obtain a clutter Doppler sharpening result, including: The compensated clutter signal is compensated for the quadratic phase in the range time domain-pulse domain by the quadratic phase compensation function, thereby obtaining a quadratic phase compensated result; and the quadratic phase compensated result is subjected to pulse Fourier transform to obtain a clutter Doppler sharpening result.

[0057] Optionally, the second compensation module constructs a quadratic phase compensation function using the clutter equivalent energy center, including: The slant distance of the clutter equivalent energy center is used as a reference slant distance of the quadratic phase compensation function to construct the quadratic phase compensation function.

[0058] The embodiment of the present invention further provides an electronic device, such as Figure 8 As shown, it includes a processor 801, a communication interface 802, a memory 803 and a communication bus 804, wherein the processor 801, the communication interface 802, and the memory 803 communicate with each other through the communication bus 804. Memory 803, used for storing computer programs; The processor 801 is configured to implement the steps of any of the above-mentioned clutter Doppler sharpening methods in the presence of range ambiguity in space-based dual-station detection when executing the program stored in the memory 803.

[0059] The communication bus mentioned in the electronic device mentioned above may be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus. This communication bus can be divided into an address bus, a data bus, a control bus, etc. For ease of illustration, only one thick line is used in the figure, but this does not mean that there is only one bus or only one type of bus.

[0060] The communication interface is used for communication between the above electronic device and other devices.

[0061] The memory may include random access memory (RAM) or non-volatile memory (NVM), such as at least one disk storage. Alternatively, the memory may be at least one storage device located away from the processor.

[0062] The above-mentioned processor can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, and discrete hardware components.

[0063] The present invention also provides a computer-readable storage medium having a computer program stored therein, which, when executed by a processor, implements the steps of any of the above-mentioned methods for clutter Doppler sharpening in space-based dual-station detection with range ambiguity.

[0064] Optionally, the computer-readable storage medium may be a non-volatile memory (NVM), such as at least one disk memory.

[0065] Optionally, the computer-readable storage medium may also be at least one storage device located away from the processor.

[0066] In another embodiment of the present invention, a computer program product comprising instructions is provided, which, when executed on a computer, causes the computer to execute the method steps described in any of the above-mentioned methods for clutter Doppler sharpening in the presence of range ambiguity in space-based dual-station detection.

[0067] It should be noted that the terms "first," "second," and the like are used to distinguish similar objects and are not necessarily used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of the present invention described herein can be implemented in sequences other than those illustrated or described herein. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Instead, they are merely examples of devices and methods consistent with some aspects of the present invention.

[0068] In the description of this specification, the reference terms "one embodiment," "some embodiments," "example," "specific example," or "some examples" mean that the specific features or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features or characteristics described can be combined in any suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification.

[0069] Although the present invention is described herein in conjunction with various embodiments, in the process of implementing the claimed invention, those skilled in the art can understand and implement other variations of the disclosed embodiments by viewing the drawings and the disclosed content. In the description of the present invention, the word "comprising" does not exclude other components or steps, "one" or "a" does not exclude multiple situations, and "multiple" means two or more, unless otherwise clearly and specifically defined. In addition, certain measures are recorded in different embodiments, but this does not mean that these measures cannot be combined to produce good results.

[0070] The method provided in the embodiments of the present invention can be applied to electronic devices. Specifically, the electronic devices can be desktop computers, portable computers, smart mobile terminals, servers, etc. This is not limited here; any electronic device that can implement the present invention falls within the scope of protection of the present invention.

[0071] As for the device / electronic device / storage medium embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0072] It should be noted that the device, electronic device and storage medium of the embodiments of the present invention are respectively a device, electronic device and storage medium that apply the above-mentioned method for clutter Doppler sharpening in the presence of range ambiguity in space-based dual-station detection. All embodiments of the above-mentioned method for clutter Doppler sharpening in the presence of range ambiguity in space-based dual-station detection are applicable to the device, electronic device and storage medium, and can achieve the same or similar beneficial effects.

[0073] The above is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention should not be considered to be limited to these descriptions. For those skilled in the art of the present invention, without departing from the concept of the present invention, several simple deductions or substitutions can be made, which should be considered to fall within the scope of protection of the present invention.

Claims

1. A clutter Doppler sharpening method for space-based dual-station detection with range ambiguity, characterized in that: The clutter Doppler sharpening method comprises: Determine the range of slant angle variation within the beam detection area based on the space-based bistatic radar system parameters; Dividing the beam detection area into a strong space-variable area and a weak space-variable area based on the range of the squint angle change; Constructing a partition compensation function for the strong space-variant region and the weak space-variant region to compensate for the linear movement of the clutter signal to obtain a compensated clutter signal; Obtaining a clutter equivalent energy center based on the compensated clutter signal fitting; A quadratic phase compensation function is constructed using the clutter equivalent energy center, and quadratic phase compensation is performed on the compensated clutter signal using the quadratic phase compensation function to obtain a clutter Doppler sharpening result.

2. The clutter Doppler sharpening method according to claim 1, characterized in that: Dividing the beam detection area into a strong space-variable area and a weak space-variable area based on the slant angle variation range includes: The first-order linear movement of the oblique angle change in the beam detection area is calculated, and the area where the first-order linear movement is greater than or equal to one distance unit is determined as a strong space-variation area, and the area where the first-order linear movement is less than one distance unit is determined as a weak space-variation area.

3. The clutter Doppler sharpening method according to claim 1, characterized in that: Constructing a partition compensation function for the strong space-variant region and the weak space-variant region to compensate for the linear movement of the clutter signal to obtain a compensated clutter signal, including: For the weak space-variant region, constructing a first compensation function with the beam center as a reference; For the strong spatial variation region, a second compensation function is constructed with reference to the two-dimensional frequency domain range-by-range Doppler unit; The linear movement of the distance is compensated in the range frequency domain-pulse domain of the clutter signal according to the first compensation function, and the linear movement of the distance is compensated for each Doppler unit in the frequency domain-Doppler domain of the clutter signal according to the second compensation function to obtain a compensated clutter signal.

4. The clutter Doppler sharpening method according to claim 1, characterized in that: Obtaining a clutter equivalent energy center based on the compensated clutter signal fitting includes: performing pulse compression processing on the compensated clutter signal to obtain a clutter pulse compression result; Calculating the theoretical CNR of the clutter pulse pressure result; An energy distribution curve of the compensated clutter signal along the distance dimension is fitted based on the theoretical CNR, and a clutter equivalent energy center is calculated through the energy distribution curve.

5. The clutter Doppler sharpening method according to claim 1, characterized in that: Performing quadratic phase compensation on the compensated clutter signal by using the quadratic phase compensation function to obtain a clutter Doppler sharpening result, including: The quadratic phase compensation function is used to compensate the compensated clutter signal for the quadratic phase in the range time domain-pulse domain by each range gate to obtain a quadratic phase compensated result; Performing pulse Fourier transform on the result after the secondary phase compensation to obtain a clutter Doppler sharpening result.

6. The clutter Doppler sharpening method according to claim 1, characterized in that: The quadratic phase compensation function is constructed using the clutter equivalent energy center, including: The slant distance of the clutter equivalent energy center is used as a reference slant distance of the quadratic phase compensation function to construct the quadratic phase compensation function.

7. A clutter Doppler sharpening device for space-based dual-station detection with range ambiguity, characterized in that: The clutter Doppler sharpening device comprises: A determination module, configured to determine a slant angle variation range within a beam detection area according to parameters of a space-based dual-station radar system; A division module, configured to divide the beam detection area into a strong space-variation area and a weak space-variation area based on the slant angle variation range; A first compensation module is configured to construct a partition compensation function for the strong space-variation region and the weak space-variation region to compensate for the linear movement of the clutter signal to obtain a compensated clutter signal; A fitting module, configured to obtain a clutter equivalent energy center based on the compensated clutter signal fitting; The second compensation module is used to construct a quadratic phase compensation function using the clutter equivalent energy center, and perform quadratic phase compensation on the compensated clutter signal through the quadratic phase compensation function to obtain a clutter Doppler sharpening result.

8. The clutter Doppler sharpening device according to claim 7, characterized in that: The partitioning module is specifically used to: The first-order linear movement of the oblique angle change in the beam detection area is calculated, and the area where the first-order linear movement is greater than or equal to one distance unit is determined as a strong space-variation area, and the area where the first-order linear movement is less than one distance unit is determined as a weak space-variation area.

9. An electronic device, characterized in that: It includes a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other via the communication bus; Memory for storing computer programs; The processor is configured to implement the clutter Doppler sharpening method according to any one of claims 1 to 6 when executing the computer program stored in the memory.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the clutter Doppler sharpening method according to any one of claims 1 to 6 is implemented.

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