An inversion positioning system for micro-movement targets based on multi-channel detection

Abstract

The present invention discloses an inversion positioning system for micro-moving targets based on multi-channel detection, belonging to the field of radar target detection technology, and solving the technical problem of the inability to detect and locate micro-moving targets in the prior art. The inversion positioning system includes an electrically connected imaging unit and a target positioning unit; the imaging unit includes a sub-aperture carrier frequency removal and fast time matched filtering processing module, a module that compensates for additional Doppler centroid deviation caused by azimuth deviation of dual-channel antennas, and a convolution processing module; the target positioning unit includes a compensation module and a micro-moving target positioning module. The present invention can extract moving targets from SAR images and obtain motion parameter information of the moving targets.

Description

Technical Field

[0001] The present invention belongs to the technical field of radar target detection, and in particular relates to an inversion positioning system for micro-motion targets based on multi-channel detection. Background Art

[0002] Traditional SAR is only suitable for detecting and imaging targets in static scenes. However, in actual reconnaissance areas, high-value targets often exhibit unusual motion, such as the rotation of the radar antenna or the pitch and roll of a ship. These micro-movements also produce the Doppler effect, modulating the phase of the radar echo. This causes a time-varying Doppler modulation frequency and broadens the signal spectrum, manifesting as ghosting or defocusing at the locations of these targets in the SAR image. This motion distorts the phase history of the target echo, appearing as an out-of-focus signal in the SAR image. Consequently, existing detection methods are unable to detect and locate micro-moving targets. Summary of the Invention

[0003] In view of the above analysis, the present invention aims to provide an inversion positioning system for micro-motion targets based on multi-channel detection, so as to solve the problem that existing detection methods are unable to detect and locate micro-motion targets.

[0004] The purpose of the present invention is mainly achieved through the following technical solutions:

[0005] The present invention provides an inversion positioning system for a micro-motion target based on multi-channel detection, comprising an imaging unit and a target positioning unit that are electrically connected;

[0006] The imaging unit includes a sub-aperture carrier removal and fast time matched filtering processing module, a module for compensating for additional Doppler centroid deviation caused by the azimuth deviation of the dual-channel antenna, and a convolution processing module;

[0007] The target positioning unit includes a compensation module and a micro-motion target positioning module.

[0008] Furthermore, the data output end of the sub-aperture de-carrier and fast-time matched filtering processing module is connected to a module for compensating for an additional Doppler centroid deviation caused by the azimuth deviation of the dual-channel antenna, the data output end of the module for compensating for an additional Doppler centroid deviation caused by the azimuth deviation of the dual-channel antenna is connected to a convolution processing module, the data output end of the convolution processing module is connected to a compensation module, and the data output end of the compensation module is connected to a micro-motion target positioning module.

[0009] Furthermore, in the sub-aperture carrier removal and fast time matched filtering processing module, the sub-aperture carrier removal and fast time matched filtering processing are performed, and the echo signal obtained is:

[0010]

[0011]

[0012] in, They represent the Doppler center frequency and modulation rate of the uniform rotation passive micro-interference echo received by the middle aperture respectively; λ is the wavelength of the radar transmission signal; j is an imaginary number; k is the signal modulation rate; R0 is the distance from the radar to the target; r is the target rotation radius; r<<R o ;ω is the rotation speed; is the initial phase; is the corresponding position history; D a is the phase center distance between the two antennas of the dual-channel SAR system; V a is the flight speed of the SAR carrier along the positive direction of the X axis; B is the signal bandwidth; Tp is the signal pulse width; c is the speed of light; t r Fast time; t a For slow time, J m (2kr) is the first kind of m-order Bessel function, where m is the order; θ(t a ) is the transformation angle.

[0013] Furthermore, in the module for compensating for the additional Doppler centroid deviation caused by the azimuth deviation of the dual-channel antenna, the additional Doppler centroid deviation caused by the azimuth deviation of the dual-channel antenna is compensated, and the compensation function is:

[0014]

[0015] Where j is an imaginary number; k is the signal modulation frequency; R0 is the distance from the radar to the target; t a is the flight time; D a is the phase center distance between the two antennas of the dual-channel SAR system; V a is the flight speed of the SAR carrier along the positive direction of the X-axis.

[0016] Furthermore, in the module for compensating the additional Doppler centroid deviation caused by the azimuth deviation of the dual-channel antenna, the compensation function C1(t a ) directly multiplied by J p1 To compensate, J p2 The echo signal after compensation is unchanged:

[0017]

[0018]

[0019] in, They represent the Doppler center frequency and modulation rate of the uniform rotation passive micro-interference echo received by the middle aperture respectively; λ is the wavelength of the radar transmission signal; j is an imaginary number; k is the signal modulation rate; R0 is the distance from the radar to the target; r is the target rotation radius; r<<R o ;ω is the rotation speed; is the initial phase; D a is the phase center distance between the two antennas of the dual-channel SAR system; V a is the flight speed of the SAR carrier along the positive direction of the X axis; B is the signal bandwidth; T p is the signal pulse width; c is the speed of light; t r Fast time; t a For slow time, J m (2kr) is the first kind of m-order Bessel function, where m is the order; θ(t a ) is the transformation angle.

[0020] Furthermore, in the convolution processing module, the azimuth reference function is used Respectively with J p1 and J p2 Perform convolution processing and obtain the imaging result after convolution processing:

[0021]

[0022]

[0023] Among them, A3(t r ,t a ) is an additional modulation term; θ(t a ) is the transformation angle; λ is the wavelength of the radar transmission signal; j is an imaginary number; k is the signal modulation frequency; R0 is the distance from the radar to the target; r is the target rotation radius; r<<R o ;ω is the rotation speed; is the initial phase; t a is the flight time; D a is the phase center distance between the two antennas of the dual-channel SAR system; V a is the flight speed of the SAR carrier along the positive direction of the X axis; B is the signal bandwidth; Tp is the signal pulse width; c is the speed of light; tr is the fast time; J m (2kr) is the first kind of m-order Bessel function, where m is the order; B d is the Doppler bandwidth of the echo signal, θ(t a ) is the transformation angle.

[0024] Furthermore, in the compensation module, the compensation function C is used 12 (t a ) interpolates and registers the two complex images to compensate for the phase error caused by the position deviation of the receiving aperture. The compensation function C12 (t a )for:

[0025]

[0026] Where j is the imaginary unit, k is the signal modulation frequency; R0 is the distance from the radar to the target; t a is the flight time; D a is the phase center distance between the two antennas of the dual-channel SAR system; V a is the flight speed of the SAR carrier along the positive direction of the X-axis.

[0027] Furthermore, in the micro-motion target positioning module, the phases of the two images are extracted, and the interference phase is detected by setting a certain threshold phase, the stationary target is canceled, and then the cancellation result is modulo-ed to obtain the micro-motion target energy.

[0028] Furthermore, in the micro-movement target positioning module, the stationary target is canceled, and the result after cancellation is:

[0029]

[0030] Where j is the imaginary unit; k is the signal modulation frequency; R0 is the distance from the radar to the target; t a is the flight time; D a is the phase center distance between the two antennas of the dual-channel SAR system; V a is the flight speed of the SAR carrier along the positive direction of the X-axis.

[0031] Furthermore, in the micro-motion target positioning module, the cancellation result is modulo-valued to obtain the micro-motion target energy:

[0032]

[0033] Among them, A3(t r ,t a ) is the additional modulation term; λ is the wavelength of the radar transmission signal; k is the signal modulation frequency; R0 is the distance from the radar to the target; r is the target rotation radius; r<<R o ;ω is the rotation speed; D a is the phase center distance between the two antennas of the dual-channel SAR system; V a is the flight speed of the SAR carrier along the positive direction of the X axis; B is the signal bandwidth; c is the speed of light; t r Fast time; t a For slow time, J m (2kr) is the first kind of m-order Bessel function, where m is the order; B d is the Doppler bandwidth of the echo signal, θ(t a ) is the transformation angle.

[0034] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0035] The present invention utilizes the variations in Doppler frequencies of echoes from different antennas to offset stationary targets and extract moving targets. The system utilizes the relationship between the phase difference between two SAR images, interferometric SAR system parameters, and target motion parameters to derive target motion parameter information. The system has a simple structure and strong operability, combining SAR high-resolution imaging of ground targets with micro-motion target detection. In subsequent engineering applications and practical applications, it can detect and locate high-value targets, providing valuable information for battlefield situation assessment, command, and control, and possessing significant significance for reconnaissance and battlefield perception.

[0036] In the present invention, the above-mentioned technical solutions can be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages will become apparent from the description or be understood through practice of the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the embodiments of the description and the contents particularly pointed out in the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like parts throughout the drawings.

[0038] Figure 1 Schematic diagram of the composition of the inversion positioning system of the present invention;

[0039] Figure 2 A schematic diagram of a dual-channel SAR system according to the present invention;

[0040] Figure 3 This is a schematic diagram of the imaging results of a ship and a micro-moving target according to the present invention;

[0041] Figure 4 Schematic diagram of the micro-motion target interference detection result of the present invention;

[0042] Figure 5 Schematic diagram of the repositioning result of the micro-movement target of the present invention. DETAILED DESCRIPTION

[0043] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0044] The present invention provides an inversion positioning system for micro-movement targets based on multi-channel detection, such as Figure 1As shown, the inversion positioning system includes an electrically connected imaging unit and a target positioning unit; the imaging unit includes a slant range acquisition module from two antennas to the target in a dual-channel SAR system, a sub-aperture carrier removal and fast time matched filtering processing module, a module for compensating for additional Doppler centroid deviation caused by the azimuth deviation of the dual-channel antenna, and a convolution processing module; the target positioning unit includes a compensation module and a micro-motion target positioning module; the data output end of the slant range acquisition module from two antennas to the target in the dual-channel SAR system is connected to the sub-aperture carrier removal and fast time matched filtering processing module, the data output end of the sub-aperture carrier removal and fast time matched filtering processing module is connected to the module for compensating for additional Doppler centroid deviation caused by the azimuth deviation of the dual-channel antenna, the data output end of the module for compensating for additional Doppler centroid deviation caused by the azimuth deviation of the dual-channel antenna is connected to the convolution processing module, the data output end of the convolution processing module is connected to the compensation module, and the data output end of the compensation module is connected to the micro-motion target positioning module.

[0045] When the inversion positioning system is working, it first performs SAR imaging on the two echo signals respectively; then the two complex images are interpolated and aligned; then the two complex image data are conjugate multiplied to extract the phase; by setting a certain threshold phase, the interference phase is detected. If the interference phase exceeds the threshold phase, the target is determined to be present; finally, the target motion parameter information is obtained by using the relationship between the phase difference between the two SAR images and the interferometric SAR system parameters and the target motion parameters.

[0046] Compared to existing technologies, this invention uses the variation in Doppler frequency of echoes from different antennas to offset stationary targets and extract moving targets. It also uses the relationship between the phase difference between two SAR images, the interferometric SAR system parameters, and the target motion parameters to derive target motion parameter information. By combining SAR's high-resolution imaging of ground targets with micro-motion target detection, this invention addresses the effects of micro-motion effects on targets and maps them onto clear SAR images. This allows for the detection and location of high-value targets, providing valuable information for on-site situation assessment, command and control, and is of great significance for reconnaissance and on-site awareness.

[0047] like Figure 2 As shown, R0 is the distance from the radar to the target, the target rotation radius is r, r<<R o , the speed is ω, the initial phase is t a is the flight time, is the corresponding position history; D ais the phase center distance between the two antennas of the dual-channel SAR system. Antenna No. 2 transmits, and the echo signal is received by antenna No. 1 and antenna No. 2 at the same time. The radar coordinate system (X, Y, Z) is established with antenna No. 2 as the origin. The origin is always fixed on the phase center of antenna No. 2. The SAR carrier moves along the positive direction of the X axis at a speed of V a Flight; Assume that the position of the target P in the radar coordinate system is (x0, y0, -h), and the flight speed of the SAR platform is (V a ,0,0), the phase center position of antenna No. 1 is (0,0,D a ).

[0048] It should be noted that Figure 2 In the figure, the dotted line represents a plane parallel to the XOY plane.

[0049] In the sub-aperture carrier removal and fast time matched filtering processing module, the two sub-apertures are orthogonally demodulated to remove the carrier frequency, and matched filtering is performed by a matched filter in the fast time domain. The obtained echo signal is:

[0050]

[0051]

[0052] in, They represent the Doppler center frequency and modulation rate of the uniform rotation passive micro-interference echo received by the middle aperture respectively; λ is the wavelength of the radar transmission signal; j is an imaginary number; k is the signal modulation rate; R0 is the distance from the radar to the target; r is the target rotation radius; r<<R o ;ω is the rotation speed; is the initial phase; t a is the flight time; D a is the phase center distance between the two antennas of the dual-channel SAR system; V a is the flight speed of the SAR carrier along the positive direction of the X axis; B is the signal bandwidth; T p is the signal pulse width; c is the speed of light; t r Fast time; t a For slow time.

[0053] In the module for compensating for the additional Doppler centroid deviation caused by the azimuth deviation between the dual-channel antennas, additional Doppler centroid deviation is caused by the azimuth deviation between the dual-channel antennas, so compensation is required. The compensation function is as follows:

[0054]

[0055] Where j is an imaginary number; k is the signal modulation frequency; R0 is the distance from the radar to the target; t a is the flight time; D ais the phase center distance between the two antennas of the dual-channel SAR system; V a is the flight speed of the SAR carrier along the positive direction of the X-axis.

[0056] Using the compensation function C1(t a ) is directly multiplied by Jp1 in the previous step for compensation, and Jp2 remains unchanged. The specific compensation process is:

[0057]

[0058] That is, the echo signal of antenna 1 after compensation is:

[0059]

[0060]

[0061] in, They represent the Doppler center frequency and modulation rate of the uniform rotation passive micro-interference echo received by the middle aperture respectively; λ is the wavelength of the radar transmission signal; j is an imaginary number; k is the signal modulation rate; R0 is the distance from the radar to the target; r is the target rotation radius; r<<R o ;ω is the rotation speed; is the initial phase; D a is the phase center distance between the two antennas of the dual-channel SAR system; V a is the flight speed of the SAR carrier along the positive direction of the X axis; B is the signal bandwidth; Tp is the signal pulse width; c is the speed of light; t r For fast time, t a For slow time, J m (2kr) is the first kind of m-order Bessel function, m is the order, θ(t a ) is the transformation angle.

[0062] In the convolution processing module, the azimuth reference function is:

[0063]

[0064] Using the above azimuth phase reference function and J p1 and J p2 Perform convolution processing to obtain imaging results;

[0065]

[0066]

[0067] Among them, A3(t r ,t a ) is an additional modulation term, which reflects the effect of the additional phase term on the expansion and blurring of the image, but does not affect the peak position of the interference; θ(t a) is the transformation angle; λ is the wavelength of the radar transmission signal; j is an imaginary number; k is the signal modulation frequency; R0 is the distance from the radar to the target; r is the target rotation radius; r<<R o ;ω is the rotation speed; is the initial phase; D a is the phase center distance between the two antennas of the dual-channel SAR system; V a is the flight speed of the SAR carrier along the positive direction of the X axis; B is the signal bandwidth; c is the speed of light; t r Fast time; t a For slow time, J m (2kr) is the first kind of m-order Bessel function, where m is the order; B d is the Doppler bandwidth of the echo signal, θ(t a ) is the transformation angle.

[0068] In the compensation module, the two complex images are interpolated and registered using the following compensation function to compensate for the phase error caused by the azimuth position deviation of the receiving aperture.

[0069] Specifically, after imaging processing, since the receiving aperture has an azimuth position deviation, it is necessary to compensate for the phase error caused by this position deviation before performing ground clutter cancellation.

[0070] The compensation function is shown below:

[0071]

[0072] Using the compensation function C 12 (t a ) multiplied by I P1 , the result is approximately equal to I P2 The specific calculation process is as follows:

[0073]

[0074]

[0075] I p1 (t r ,t a )*C 12 (t a )≈I p2 (t r ,t a )

[0076] It should be noted that in the above calculation process, x0=V a *t a .

[0077] Where, The term actually corresponds to the compensation function Compensation function C1(t a ) is because the time domain linear term corresponds to the frequency domain shift, so compensation is performed to align the center. However, the image obtained after imaging is a dual time domain image. Therefore, the phase before compensation corresponds to the phase error caused by the antenna aperture, which can be seen to be independent of the starting position x0 of the target point; where j is the imaginary unit, k is the signal modulation frequency; R0 is the distance from the radar to the target; t a is the flight time; D a is the phase center distance between the two antennas of the dual-channel SAR system; V a is the flight speed of the SAR carrier along the positive direction of the X-axis.

[0078] In the micro-motion target positioning module, the phases of the two images are extracted. By setting a certain threshold phase, the interference phase is detected and the stationary target is canceled. That is, the two images are subtracted and canceled. Then the cancellation result is modulo (see the following formula) to obtain the micro-motion target energy.

[0079]

[0080] Take the modulus value of the cancellation result to obtain the micro-motion target energy:

[0081]

[0082] Among them, A3(t r ,t a ) is the additional modulation term; λ is the wavelength of the radar transmission signal; k is the signal modulation frequency; R0 is the distance from the radar to the target; r is the target rotation radius; r<<R o ;ω is the rotation speed; D a is the phase center distance between the two antennas of the dual-channel SAR system; V a is the flight speed of the SAR carrier along the positive direction of the X axis; B is the signal bandwidth; c is the speed of light; t r Fast time; t a For slow time, J m (2kr) is the first kind of m-order Bessel function, where m is the order; B d is the Doppler bandwidth of the echo signal, θ(t a ) is the transformation angle.

[0083] After obtaining the energy of the micro-motion target, the maximum value of the micro-motion target energy is calculated, and the position of the maximum value is the position of the micro-motion target in the SAR image.

[0084] In one embodiment, through digital simulation, a ship is selected as an imaging target, wherein the ship warning radar has micro-motion target characteristics, and the simulation parameters used are shown in Table 1.

[0085] Table 1 Simulation parameters of micro-motion target

[0086]

[0087] According to the above simulation parameters, the ship target imaging results are as follows: Figure 3 As shown in Figure 2, we can see that the ship target can be well imaged and the outline of the ship is clear. At the same time, during the accumulation time, the radar rotation causes obvious Doppler stripes, such as Figure 3 As shown in the white circle.

[0088] The method provided by the present invention is used to perform dual-channel image interference cancellation, and to detect micro-movement targets based on the detection threshold, and to extract micro-movement target results such as Figure 4 According to the relationship between the dual-channel interferometric phase and the rotation parameters, the relocation of the rotating radar target is realized, and the results are shown in Figure 5 As shown in the figure, when the SNR is better than 15dB, the corresponding target positioning accuracy can reach 1 / 15 of the beam width, and is better than 0.5° when the beam width is less than 7°.

[0089] In summary, the method presented here is able to exploit variations in the Doppler frequency of echoes from different antennas to offset stationary targets and extract moving ones. This method is simple and highly operational, combining SAR's high-resolution imaging of ground targets with the detection of micro-moving targets. In subsequent engineering applications and practical applications, it will be able to detect, locate, and track high-value targets, providing valuable information for on-site situation assessment, command and control, and possessing significant significance for reconnaissance and on-site awareness.

[0090] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. An inversion positioning system for micro-motion targets based on multi-channel detection, characterized in that: including an imaging unit and a target positioning unit electrically connected; The imaging unit includes a sub-aperture carrier removal and fast time matched filtering processing module, a module for compensating for additional Doppler centroid deviation caused by the azimuth deviation of the dual-channel antenna, and a convolution processing module; In the sub-aperture carrier removal and fast time matched filtering processing module, the sub-aperture carrier removal and fast time matched filtering processing are performed, and the echo signal obtained is: in, They represent the Doppler center frequency and modulation rate of the uniform rotation passive micro-interference echo received by the middle aperture respectively; λ is the wavelength of the radar transmission signal; j is an imaginary number; k is the signal modulation rate; R0 is the distance from the radar to the target; r is the target rotation radius; r<<R o ;ω is the rotation speed; is the initial phase; D a is the phase center distance between the two antennas of the dual-channel SAR system; V a is the flight speed of the SAR carrier along the positive direction of the X axis; B is the signal bandwidth; Tp is the signal pulse width; c is the speed of light; t r Fast time; t a For slow time, J m (2kr) is the first kind of m-order Bessel function, where m is the order; θ(t a ) is the transformation angle; The target positioning unit includes a compensation module and a micro-motion target positioning module.

2. The inversion positioning system for micro-motion targets based on multi-channel detection according to claim 1 is characterized in that: The data output end of the sub-aperture de-carrier and fast-time matched filtering processing module is connected to the module for compensating for the additional Doppler centroid deviation caused by the azimuth deviation of the dual-channel antenna, the data output end of the module for compensating for the additional Doppler centroid deviation caused by the azimuth deviation of the dual-channel antenna is connected to the convolution processing module, the data output end of the convolution processing module is connected to the compensation module, and the data output end of the compensation module is connected to the micro-motion target positioning module.

3. The inversion positioning system for micro-motion targets based on multi-channel detection according to claim 2 is characterized in that: In the module for compensating for the additional Doppler centroid deviation caused by the azimuth deviation of the dual-channel antenna, the additional Doppler centroid deviation caused by the azimuth deviation of the dual-channel antenna is compensated, and the compensation function is: Where, j is an imaginary number; k is the signal modulation frequency; R0 is the distance from the radar to the target; t a is the flight time; D a is the phase center distance between the two antennas of the dual-channel SAR system; V a is the flight speed of the SAR carrier along the positive direction of the X-axis.

4. The inversion positioning system for micro-motion targets based on multi-channel detection according to claim 3 is characterized in that: In the module for compensating the additional Doppler centroid deviation caused by the azimuth deviation of the dual-channel antenna, the compensation function C1(t a ) directly multiplied by the J p1 To compensate, J p2 The echo signal after compensation is unchanged: in, They represent the Doppler center frequency and modulation rate of the uniform rotation passive micro-interference echo received by the middle aperture respectively; λ is the wavelength of the radar transmission signal; j is an imaginary number; k is the signal modulation rate; R0 is the distance from the radar to the target; r is the target rotation radius; r<<R o ;ω is the rotation speed; is the initial phase; D a is the phase center distance between the two antennas of the dual-channel SAR system; V a is the flight speed of the SAR carrier along the positive direction of the X axis; B is the signal bandwidth; Tp is the signal pulse width; c is the speed of light; t r Fast time; t a For slow time, J m (2kr) is the first kind of m-order Bessel function, where m is the order; θ(t a ) is the transformation angle.

5. The inversion positioning system for micro-motion targets based on multi-channel detection according to claim 4 is characterized in that: In the convolution processing module, the azimuth reference function is used Respectively with J p1 and J p2 Perform convolution processing and obtain the imaging result after convolution processing: Among them, A3(t r ,t a ) is an additional modulation term; θ(t a ) is the transformation angle; λ is the wavelength of the radar transmission signal; j is an imaginary number; k is the signal modulation frequency; R0 is the distance from the radar to the target; r is the target rotation radius; r<<R o ;ω is the rotation speed; is the initial phase; t a is the flight time; D a is the phase center distance between the two antennas of the dual-channel SAR system; V a is the flight speed of the SAR carrier along the positive direction of the X axis; B is the signal bandwidth; Tp is the signal pulse width; c is the speed of light; tr is the fast time; ta is the slow time, and J m (2kr) is the first kind of m-order Bessel function, where m is the order; B d is the Doppler bandwidth of the echo signal, θ(t a ) is the transformation angle.

6. The inversion positioning system for micro-motion targets based on multi-channel detection according to claim 5, characterized in that: In the compensation module, the compensation function C is used 12 (t a ) interpolates and registers the two complex images to compensate for the phase error caused by the position deviation of the receiving aperture. The compensation function C 12 (t a )for: Where j is the imaginary unit, k is the signal modulation frequency; R0 is the distance from the radar to the target; t a is the flight time; D a is the phase center distance between the two antennas of the dual-channel SAR system; V a is the flight speed of the SAR carrier along the positive direction of the X-axis.

7. The inversion positioning system for micro-motion targets based on multi-channel detection according to any one of claims 1 to 6, characterized in that: In the micro-motion target positioning module, the phases of the two images are extracted, and the interference phase is detected by setting a certain threshold phase, the stationary target is canceled, and then the cancellation result is modulo-ed to obtain the micro-motion target energy.

8. The inversion positioning system for micro-motion targets based on multi-channel detection according to claim 7, characterized in that: In the micro-movement target positioning module, the stationary target is canceled, and the result after cancellation is: Where j is the imaginary unit; k is the signal modulation frequency; R0 is the distance from the radar to the target; t a is the flight time; D a is the phase center distance between the two antennas of the dual-channel SAR system; V a is the flight speed of the SAR carrier along the positive direction of the X-axis.

9. The inversion positioning system for micro-motion targets based on multi-channel detection according to claim 8, characterized in that: In the micro-motion target positioning module, the cancellation result is modulo value to obtain the micro-motion target energy: Among them, A3(t r ,t a ) is the additional modulation term; λ is the wavelength of the radar transmission signal; k is the signal modulation frequency; R0 is the distance from the radar to the target; r is the target rotation radius; r<<R o ;ω is the rotation speed; D a is the phase center distance between the two antennas of the dual-channel SAR system; V a is the flight speed of the SAR carrier along the positive direction of the X axis; B is the signal bandwidth; c is the speed of light; t r Fast time; t a For slow time, J m (2kr) is the first kind of m-order Bessel function, where m is the order; B d is the Doppler bandwidth of the echo signal, θ(t a ) is the transformation angle.

Images