CN108776342B - High-speed platform SAR slow moving target detection and speed estimation method - Google Patents

High-speed platform SAR slow moving target detection and speed estimation method Download PDF

Info

Publication number
CN108776342B
CN108776342B CN201810767255.9A CN201810767255A CN108776342B CN 108776342 B CN108776342 B CN 108776342B CN 201810767255 A CN201810767255 A CN 201810767255A CN 108776342 B CN108776342 B CN 108776342B
Authority
CN
China
Prior art keywords
imaging
radar
moving target
azimuth
antenna
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
Application number
CN201810767255.9A
Other languages
Chinese (zh)
Other versions
CN108776342A (en
Inventor
张晓玲
唐欣欣
马德娇
贾淑培
张星月
师君
韦顺军
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
University of Electronic Science and Technology of China
Original Assignee
University of Electronic Science and Technology of China
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by University of Electronic Science and Technology of China filed Critical University of Electronic Science and Technology of China
Priority to CN201810767255.9A priority Critical patent/CN108776342B/en
Publication of CN108776342A publication Critical patent/CN108776342A/en
Application granted granted Critical
Publication of CN108776342B publication Critical patent/CN108776342B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

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
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/88—Radar or analogous systems specially adapted for specific applications
    • G01S13/89—Radar or analogous systems specially adapted for specific applications for mapping or imaging
    • G01S13/90—Radar or analogous systems specially adapted for specific applications for mapping or imaging using synthetic aperture techniques, e.g. synthetic aperture radar [SAR] techniques
    • G01S13/9021—SAR image post-processing techniques
    • G01S13/9029—SAR image post-processing techniques specially adapted for moving target detection within a single SAR image or within multiple SAR images taken at the same time
    • 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
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/88—Radar or analogous systems specially adapted for specific applications
    • G01S13/89—Radar or analogous systems specially adapted for specific applications for mapping or imaging
    • G01S13/90—Radar or analogous systems specially adapted for specific applications for mapping or imaging using synthetic aperture techniques, e.g. synthetic aperture radar [SAR] techniques
    • G01S13/9004—SAR image acquisition techniques
    • G01S13/9017—SAR image acquisition techniques with time domain processing of the SAR signals in azimuth
    • 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
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/88—Radar or analogous systems specially adapted for specific applications
    • G01S13/89—Radar or analogous systems specially adapted for specific applications for mapping or imaging
    • G01S13/90—Radar or analogous systems specially adapted for specific applications for mapping or imaging using synthetic aperture techniques, e.g. synthetic aperture radar [SAR] techniques
    • G01S13/904—SAR modes
    • G01S13/9058—Bistatic or multistatic SAR

Abstract

The invention discloses a method for detecting and estimating a slow moving target of a high-speed platform SAR, which comprises the steps of firstly, simultaneously obtaining front and back view two SAR images by adopting a bidirectional SAR imaging mode, then detecting the slow moving target by the azimuth offset of the front and back view two SAR images of the moving target caused by the time delay of front and back beams and imaging mismatch, roughly estimating the azimuth speed of the moving target by the azimuth pixel offset of the moving target, and finally, further improving the accuracy of azimuth speed estimation by adopting an iterative refocusing method. The invention can realize the detection and speed estimation of the high-speed platform SAR on the slow moving target, and can refocus the moving target, thereby providing a good data base for the subsequent moving target identification. Compared with the traditional single-channel moving target detection method, the method can detect the slow moving target with the frequency spectrum submerged in the clutter spectrum. The detection probability of the slow moving target is improved.

Description

High-speed platform SAR slow moving target detection and speed estimation method
Technical Field
The invention belongs to the technical field of Radar signal processing, and particularly relates to a method for indicating a Moving Target (SAR-GMTI) of a high-speed platform Synthetic Aperture Radar.
Background
Synthetic aperture radar ground moving target indication (SAR-GMTI) techniques may detect and parameter estimate and locate ground moving targets. The high-speed platform SAR has the advantages of being not easily interfered and rapidly reaching the region of interest due to the high moving speed of the platform, and is a research hotspot in recent years. However, the existing SAR imaging method for high-speed platform has not been studied, and the detailed study is shown in the documents "Wang Y, Cao Y, Peng Z, et al. Cluter providing and moving target imaging for multichannel super sonic bone radar, digital Signal Processing,2017,68: 81-92", but the research on the SAR-GMTI method for high-speed platform is not many, so the research on the SAR-GMTI method for high-speed platform is needed.
The traditional single-channel SAR-GMTI mainly adopts a filtering method to detect moving targets, but only can detect moving targets of which the frequency spectrum is totally or partially outside a clutter spectrum, and detect slow moving targets of which the frequency spectrum is totally submerged in the clutter spectrum, the traditional single-channel method is generally difficult to detect, and the traditional single-channel method is described in documents of Tianbin, Daiguyin, Wudy, and the like.
The two-channel SAR-GMTI method mainly includes a Displacement Phase Center Antenna (DPCA) technique and an Along-Track interference processing (ATI) technique. The DPCA-based moving target detection method mainly comprises the steps of adding space domain information, utilizing an antenna phase center compensation principle, enabling a system to obtain the same clutter information in different time domains and different space domains, compensating clutter spectrum broadening caused by platform motion, reserving moving target information, and realizing moving target detection, and is particularly shown in a document 'Muhuili, research of a multi-channel SAR moving target detection method, a university of Harbin industry, a Master thesis, 2016'. However, the DPCA technique needs to satisfy certain conditions, which are difficult to be satisfied in a high-speed platform, and thus the performance of clutter cancellation is affected, so that a slow moving target is difficult to be detected. Moreover, in the aspect of velocity Estimation, the Dual-Channel DPCA method estimates the Motion parameters of the Moving Target by using a method of estimating the doppler chirp rate and the doppler center frequency of the Moving Target, which is described in the literature "Li Y, Wang T, Liu B, et al, group Moving Target Imaging and Motion Parameter Estimation With air Dual-Channel cssar. ieee Transactions on geometry & Motion Sensing,2017, PP (99):1-12.
The ATI measuring device and the DPCA device have almost the same system structure, and only the back-end information processing flow is different, which is described in the literature, "noble, etc., and the detection and speed estimation of the moving target of interferometric synthetic aperture radar, scientific publishing agency, 2017". ATI, although not needing to satisfy the harsh DPCA conditions as DPCA, needs to keep the baseline along the track direction all the time, otherwise, will introduce the elevation phase, drastically reduce the detection performance of moving targets, as detailed in the literature, "yan base, multichannel SAR-GMTI method research, doctor thesis of the university of west ampere electronics, 2009". However, the high-speed platform SAR has difficulty in ensuring that the baseline always follows the track direction, so that applying ATI to the high-speed platform SAR moving target detection also brings certain difficulty. And ATI can only estimate the radial velocity of the moving target generally, and can not estimate the azimuth velocity of the moving target.
In addition to the above reasons, the size limitation of the high-speed stage also becomes a factor affecting the detection and speed estimation of the DPCA and ATI slow moving targets, as detailed in "Wang Y, Cao Y, Peng Z, et al. Cleater application and GMTI for a super dynamic boiler SAR system with MIMO anti-noise. Iet Signal Processing,2017,11(8): 909-. Therefore, the detection and speed estimation of the slow moving target of the high-speed platform are currently a difficult point, and research on the detection method of the slow moving target of the high-speed platform is urgently needed.
Disclosure of Invention
The invention provides a method for detecting and estimating a slow moving target of a high-speed platform SAR, which adopts a Bi-Directional SAR imaging mode (BiDi) to simultaneously obtain a front view SAR image and a back view SAR image. The slow moving target is detected by the azimuth offset of the moving target caused by the time delay of the front beam and the back beam and imaging mismatch and the azimuth offset of the front SAR image and the back SAR image, the azimuth speed of the moving target is roughly estimated by the azimuth pixel offset of the moving target, and then the accuracy of azimuth speed estimation is further improved by adopting an iterative refocusing method. By the method, the detection and speed estimation of the high-speed platform SAR on the slow moving target can be realized, the moving target can be refocused, and a good data basis is provided for subsequent moving target identification.
For the convenience of describing the present invention, the following terms are first defined:
definitions 1, Bi-Directional synthetic Aperture Radar (BiDi SAR) imaging mode
The BiDi SAR Imaging mode refers to that a single antenna simultaneously transmits two beams pointing to different directions from an azimuth direction and simultaneously receives echo data of the two beams to respectively obtain a front view SAR image and a rear view SAR image, which are disclosed in the documents "Mittermayer J, Wollstadt S, Prats-Iraola P, et al.
Definition 2, BiDi SAR along track time interval
The temporal interval of the BiDi SAR along the flight path refers to the time interval required by the front beam and the rear beam to irradiate the same observation area, and is described in the literature "mistermayer, Josef, and s.wollstadt." Simultaneous Bi-directional SARAcquisition with terrras-x. "Synthetic Aperture Radar (EUSAR), 20108 th European Conference on VDE,2010:1-4.
Definition 3, standard fourier transform method and inverse fourier transform method
Fourier transformation is a classical method of analyzing a signal, and can represent a certain signal satisfying a certain condition as a trigonometric function (sine and/or cosine function) or a linear combination of their integrals. The inverse fourier transform is an inverse process of the fourier transform, and is described in the literature "digital signal processing theory, algorithm and implementation", written by huguang, published by the university of qinghua.
Definition 4, standard synthetic aperture radar back projection imaging algorithm
The standard synthetic aperture radar back projection imaging algorithm is a synthetic aperture radar imaging algorithm based on a matched filtering principle, and mainly realizes the focusing imaging of the original echo data of the synthetic aperture radar through SAR scene resolution unit slant range calculation, distance unit search, original echo Doppler phase compensation, echo data coherent accumulation and the like. For details, reference may be made to: the research on bistatic SAR and linear array SAR principles and imaging technology is a doctor jun, doctor thesis of electronic science and technology university.
Definition 5, standard synthetic aperture radar distance compression method
The standard synthetic aperture radar distance compression method is a process of generating a distance compression reference signal by using a transmission signal parameter of a synthetic aperture radar system and filtering a distance direction signal of the synthetic aperture radar by adopting a matched filtering technology. See the literature "radar imaging technology", written texts such as shines, published by electronic industry publishers.
Definition 6, frequency resolution
Frequency resolution refers to the ability of the algorithm used to keep two closely spaced spectral peaks in the signal apart. For details, see the literature "digital signal processing theory, algorithm and implementation", written by the Huguang book, published by Qinghua university Press.
Definition 7, synthetic aperture radar slow and fast time
Synthetic aperture radar slow time refers to the time required for a radar platform to fly through a synthetic aperture. The radar system transmits the receiving pulse with a certain repetition period, so the slow time can be expressed as a discretization time variable taking the repetition period as a step, wherein each discretization time variable value is a slow moment.
Synthetic aperture radar fast time refers to the time of one cycle of the radar transmitting a received pulse. Since the radar received echo is sampled at a sampling rate, the fast time can be represented as a discretized time variable, each discretized variable value being a fast time. For details, see the literature, "synthetic aperture radar imaging principle", edited by buzz, electronic technology university press.
Definition 8, synthetic aperture radar slow time frequency
The synthetic aperture radar slow time frequency refers to a discretization frequency variable corresponding to the radar slow time Fourier transform to a frequency domain, wherein each discretization frequency variable value is a slow time frequency. For details, see the literature, "synthetic aperture radar imaging principle", edited by buzz, electronic technology university press.
Definition 9, synthetic aperture radar imaging scene reference point
The synthetic aperture radar imaging scene reference point refers to a certain scattering point in a synthetic aperture radar projection imaging space and is used as a reference for synthetic aperture radar data processing and other resolution units in a scene. Generally, a middle point of the imaging scene is selected as a synthetic aperture radar imaging scene reference point.
Definition 10, synthetic aperture radar projection imaging space
The synthetic aperture radar projection imaging space refers to an imaging space selected during synthetic aperture radar data imaging, and the synthetic aperture radar imaging needs to project echo data to the imaging space for focusing processing. Generally, the synthetic aperture radar imaging projection imaging space is selected as an inclined distance plane coordinate system or a horizontal ground coordinate system.
Defining 11, high-speed platform SAR radar system reference slope distance
The reference slant range of the SAR radar system of the high-speed platform refers to the distance from the middle position of the synthetic aperture length of an antenna in the SAR radar system to an imaging space reference point, and the reference slant range of the SAR radar system is recorded as R in the invention0。
Definition 12, standard synthetic aperture radar original echo simulation method
The standard synthetic aperture radar original echo simulation method is a method for obtaining an original echo signal with SAR echo signal characteristics through simulation based on a synthetic aperture radar imaging principle under the condition of giving parameters required by radar system parameters, platform track parameters, observation scene parameters and the like, and the detailed contents can refer to documents: "research on interference SAR echo signal and system simulation", Zhang Qin, Master thesis of Harbin university of Industrial science.
Definition 13 and large value selection constant false alarm rate detection method
The constant false alarm rate detection of radar signals requires that the false alarm probability is kept constant, and the probability of correct detection can reach the maximum value under the condition of keeping the constant false alarm probability by adopting the Neyman-Pearson criterion. The method for selecting the large-value constant false alarm is provided by reducing the influence of clutter edges in a constant false alarm processing method of a plurality of Rayleigh envelope clutter environments, and is disclosed in the literature, "multichannel SAR ground moving target detection and parameter estimation research", Ph-Darby university of Harbin, Shandong, Sun.
Define 14, 2 norm of vector
2 norm | | | | luminance of vector2The square sum and then the square root of each element of the vector are shown in detail in the literature "matrix theory", edited by huangting congratulatory et al, advanced education press.
The invention provides a method for detecting and estimating a slow moving target of a high-speed platform SAR, which comprises the following steps:
step 1: initializing system parameters of a bidirectional synthetic aperture imaging radar BiDi SAR:
initializing system parameters of a bidirectional synthetic aperture imaging radar BiDi SAR, comprising the following steps: the wavelength of the radar carrier wave is recorded as lambda, the bandwidth of the signal transmitted by the radar antenna is recorded as B, and the time width of the pulse transmitted by the radar is recorded as TrRadar sampling frequency, denoted FsRadar incident angle, recorded as phi, radar pulse repetition frequency, recorded as PRF, number of sampling points in radar system distance direction, recorded as NrThe number of sampling points of the radar system in the azimuth direction is recorded as NaAzimuth frequency resolution of the radar system, denoted as Δ fa＝PRF/NaThe initial position of the radar system antenna is marked as P (0), and the azimuth squint angle of the forward-looking wave beam emitted by the radar antenna is marked as theta1The azimuth squint angle of the radar antenna transmitting the rear view beam is marked as theta2Velocity vector of radar platform motion, denoted Vp＝[Vpx,0,0]Wherein V ispxRepresenting the moving speed of the radar platform in the azimuth direction, and the sampling time of the radar system in the azimuth direction, and is recorded as
Figure GDA0003342884320000051
j is a natural number, j is 0,1,2, …, (N)a-1); among the above parameters, the wavelength λ of radar carrier, the bandwidth B of signal transmitted by radar antenna, and the time width T of pulse transmitted by radarrRadar sampling frequency FsRadar incident angle phi, radar pulse repetition frequency PRF, radarTo the azimuth squint angle theta of the antenna transmitting forward looking wave beam1Azimuth squint angle theta of radar antenna transmitting back view beam2It has been determined during the radar system design process; radar platform motion velocity vector VpDistance sampling point number N of radar systemrAnd the number N of sampling points in the azimuth direction of the radar systemaSampling time t of radar system azimuthmAzimuth frequency resolution Δ f of radar systemaInitial position P (0) of radar system antenna and motion velocity vector V of radar platformpIt has been determined in radar imaging observation scheme design.
Step 2, initializing parameters of the moving target
Initializing parameters of the moving object includes: velocity vector of moving object, denoted Vm＝[vx,vy,0]Initial position of moving object, noted as Pm(0) Wherein v isxVelocity, v, representing the azimuth of a moving targetyRepresenting the velocity of the moving target distance direction.
Step 3, obtaining original echo data of the bidirectional synthetic aperture imaging radar BiDi SAR system:
the method includes the steps that raw echo data of a bidirectional synthetic aperture imaging radar BiDi SAR system antenna in the kth slow time from the tth fast time to the kth slow time is recorded as E (t, k), and t is 1,2, … and Nr，k＝1,2,…,NaWhere t and k are natural numbers, t represents the fast time from the distance to the tth, k represents the slow time from the azimuth to the kth, and NrNumber of sampling points in radar system distance direction, N, obtained for initialization in step 1aInitializing the number of the obtained sampling points of the radar system in the azimuth direction in the step 1; in the actual imaging of the high-speed platform BiDi SAR, the bidirectional synthetic aperture imaging radar BiDi SAR system antenna is used for obtaining original echo data E (t, k) from the distance to the tth fast time and the direction to the kth slow time, wherein t is 1,2, …, Nr，k＝1,2,…,NaAnd the data is provided by a bidirectional synthetic aperture imaging radar BiDi SAR system data receiver.
Step 4, performing distance compression on the original echo data of the antenna of the bidirectional synthetic aperture imaging radar BiDi SAR system:
synthesized by using conventional standardThe aperture radar distance compression method is used for the original echo data E (t, k) of the bidirectional synthetic aperture imaging radar BiDi SAR system antenna obtained in the step 3 in the kth fast time azimuth direction to the kth slow time, wherein t is 1,2, … and Nr，k＝1,2,…,NaAnd performing range compression to obtain echo data of the bi-directional synthetic aperture imaging radar BiDi SAR system antenna after range compression from the tth fast time azimuth to the kth slow time, and recording the echo data as S (t, k), wherein t is 1,2, …, Nr，k＝1,2,…,Na。
And 5, performing azimuth Fourier transform on the original echo data of the bidirectional synthetic aperture imaging radar BiDi SAR system antenna:
performing Fourier transform on echo data S (t, k) obtained by compressing the distance of the bidirectional synthetic aperture imaging radar BiDi SAR system antenna obtained in the step 4 from the tth fast time to the kth slow time in the azimuth direction by adopting a traditional standard Fourier transform method, obtaining echo data of the radar system from the distance to the tth fast time and the frequency of the radar system from the azimuth direction to the fth slow time, and recording the echo data as SFFT(t,f)，t＝1,2,…,Nr，f＝1,2,…,NaAnd f is a natural number and represents the frequency of the f-th slow time in the azimuth direction.
Step 6, separating original echo data of the antenna of the bidirectional synthetic aperture imaging radar BiDi SAR system:
using a formula
Figure GDA0003342884320000061
Calculating the frequency echo data S of the bi-directional synthetic aperture imaging radar BiDi SAR system in the distance direction to the tth fast time and the azimuth direction to the fth slow timeFFTThe azimuthal frequency of (t, F), denoted as Fa(ii) a f is a natural number obtained in the step 5 and represents the f-th slow time frequency of the azimuth direction, delta faThe radar system azimuth frequency resolution, N, obtained by initialization in step 1aThe number of sampling points in the azimuth direction of the radar system, S, obtained by initialization in step 1FFT(t, f) is echo data of the radar system obtained in the step 5 in the distance direction to the tth fast moment and the frequency direction to the fth slow moment;
the distance is moved to the t-th timeEcho data S of f-th slow moment frequency in azimuth directionFFT(t,f)，t＝1,2,…,Nr，f＝1,2,…,NaEcho data S from the tth fast time azimuth to the f slow time frequency pointFFT(t,f)，t＝1,2,…,Nr，f＝1,2,…,NaAzimuthal frequency F ofaCentered at 0, divided into Fa> 0 and Fa< 0 two moieties;
the distance is changed to the tth fast time azimuth to the fth slow time frequency echo data SFFT(t,f)，t＝1,2,…,Nr，f＝1,2,…,NaFrequency F of the middle azimuthaThe echo with the part less than 0 is set to zero to obtain the forward looking distance time domain-azimuth frequency domain echo data which is recorded as SFFFT(t,f)，t＝1,2,…,Nr，f＝1,2,…,Na；
The distance is changed to the tth fast time azimuth to the fth slow time frequency echo data SFFT(t,f)，t＝1,2,…,Nr，f＝1,2,…,NaFrequency F of the middle azimuthaThe echo with the part larger than 0 is set to zero to obtain the echo data of the rear-view distance time domain-azimuth frequency domain, which is recorded as SBFFT(t,f)，t＝1,2,…,Nr，f＝1,2,…,Na；
Adopting a standard Fourier inverse transformation method to carry out forward-looking distance time domain-azimuth frequency domain echo data SFFFT(t,f)，t＝1,2,…,Nr，f＝1,2,…,NaPerforming inverse Fourier transform in the azimuth direction to obtain echo data after distance compression of the radar system antenna in the forward looking direction from the t-th fast time azimuth to the k-th slow time, and recording the echo data as SF (t, k), wherein t is 1,2, …, Nr，k＝1,2,…,Na；
Adopting a standard Fourier inverse transformation method to carry out backward vision distance time domain-azimuth frequency domain echo data SBFFT(t,f)，t＝1,2,…,Nr，f＝1,2,…,NaPerforming inverse Fourier transform in the azimuth direction to obtain echo data compressed by the high-speed platform BiDi SAR system antenna from the azimuth direction to the kth fast time to the kth slow time, and recording the echo data as SB (t, k), wherein t is 1,2, …, Nr，k＝1,2,…,Na。
Step 7, initializing parameters of a bidirectional synthetic aperture imaging radar BiDi SAR projection imaging space:
initializing a BiDi SAR projection imaging space of the bidirectional synthetic aperture imaging radar as a ground plane coordinate system, wherein the horizontal axis of the coordinate system is marked as an X axis, the horizontal longitudinal axis of the coordinate system is marked as a Y axis, and the central coordinate of the radar projection imaging space is positioned in [2040,110000 ]]The number of X axial resolution units in the radar projection imaging space is recorded as NxThe number of Y-axis resolution units in the radar projection imaging space is recorded as NyX-axis imaging range of radar projection imaging space, denoted as WxY-axis imaging range of radar projection imaging space, denoted as WyX-axial Unit resolution of the Radar projection imaging space, denoted as ρxThe Y-axis unit resolution of the radar projection imaging space is recorded as rhoyReference slant distance, denoted R, of the radar system to the projection imaging space0(ii) a Uniformly dividing the radar projection imaging space to obtain a two-dimensional resolution unit of the projection imaging space, and recording the two-dimensional resolution unit as PT(a,r)＝[x(a,r),y(a,r)]，a＝1,…,Nx，r＝1,…,NyWherein a and r are natural numbers, a represents the a-th resolution unit in the X-axis direction in the projection imaging space, r represents the r-th resolution unit in the Y-axis direction in the projection imaging space, and X (a, r) and Y (a, r) respectively represent the X-axis position and the Y-axis position of the two-dimensional resolution unit in the projection imaging space.
Step 8, performing projection imaging processing on the resolution unit by adopting a standard synthetic aperture radar back projection imaging algorithm
Enabling all resolution units P in the projection imaging space of the bidirectional synthetic aperture imaging radar BiDi SAR system obtained in the step 7T(a,r)，a＝1,…,Nx，r＝1,…,NyAnd the coordinate of the altitude direction is 0, and the standard synthetic aperture radar back projection imaging algorithm is adopted to perform foresight distance compression on echo data SF (t, k) of the radar system antenna from the tth fast time azimuth to the kth slow time, wherein t is 1,2, … and Nr，k＝1,2,…,NaImaging processing is carried out to obtain a forward-looking imaging result of the radar system antenna, which is marked as If(a,r)，a＝1,…,Nx，r＝1,…,NyWherein SF (t, k), t ═ 1,2, …, Nr，k＝1,2,…,NaAnd 6, compressing the distance of the radar system antenna obtained in the step 6 before the distance is towards the kth slow time from the tth fast time.
Enabling all resolution units P in the projection imaging space of the bidirectional synthetic aperture imaging radar BiDi SAR system obtained in the step 7T(a,r)，a＝1,…,Nx，r＝1,…,NyAnd the height-direction coordinate is 0, echo data SB (t, k) compressed by the radar system antenna from the distance to the tth fast time azimuth to the kth slow time rearview distance is acquired by adopting a standard synthetic aperture radar back projection imaging algorithm, and t is 1,2, … and Nr，k＝1,2,…,NaImaging processing is carried out to obtain a radar system antenna rearview imaging result which is marked as Ib(a,r)，a＝1,…,Nx，r＝1,…,NyWherein SB (t, k), t ═ 1,2, …, Nr，k＝1,2,…,NaAnd 6, the compressed echo data of the radar system antenna at the distance from the tth fast time azimuth to the kth slow time backward sight distance is obtained.
Step 9, adopting an amplitude subtraction method to suppress stationary clutter
The forward-looking imaging result I of the radar system antenna obtained in the step 8f(a, r) and radar system antenna rearview imaging result Ib(a, r) using formula Iresult(a,r)＝|If(a,r)|-|Ib(a, r) |, calculating to obtain a signal after static clutter suppression, and marking as Iresult(a,r)，a＝1,…,Nx，r＝1,…,NyWhere | represents the absolute operator.
Step 10, detecting a moving target and determining the position range of the moving target
Adopting a large value selection method constant false alarm detection method for defining 13 traditional standards to carry out detection on the signal I after the static clutter suppression obtained in the step 9result(a,r)，a＝1,…,Nx，r＝1,…,NyAnd carrying out constant false alarm detection, and respectively detecting:
(1) detecting radar system antenna forward-looking imaging result IfMoving targets in (a, r) are described as
Figure GDA0003342884320000081
a＝1,…,Nx，r＝1,…,Ny；
(2) Detecting radar system antenna back vision imaging result IbMoving targets in (a, r) are described as
Figure GDA0003342884320000082
a＝1,…,Nx，r＝1,…,Ny；
(3) Detecting the forward-looking imaging result I of the moving target on the antenna of the radar systemfThe range of positions in (a, r) is described as
Figure GDA0003342884320000083
Figure GDA0003342884320000084
Wherein the content of the first and second substances,
Figure GDA0003342884320000085
representing the forward view imaging result I of the moving target on the antenna of the radar systemf(a, r) position coordinates of azimuth direction,
Figure GDA0003342884320000086
representing the forward view imaging result I of the moving target on the antenna of the radar systemf(a, r) position coordinates in the radial direction,
Figure GDA0003342884320000087
representing the forward view imaging result I of the moving target on the antenna of the radar systemf(a, r) coordinates of the azimuth center point,
Figure GDA0003342884320000088
representing the forward view imaging result I of the moving target on the antenna of the radar systemf(a, r) coordinates of the distance to the center point,
Figure GDA0003342884320000089
representing the forward view imaging result I of the moving target on the antenna of the radar systemfThe length of the position in the azimuth direction in (a, r),
Figure GDA00033428843200000810
representing the forward view imaging result I of the moving target on the antenna of the radar systemf(a,r)，a＝1,…,Nx，r＝1,…,Ny；
(4) Detecting the back vision imaging result I of the moving target in the radar system antennafThe range of positions in (a, r) is described as
Figure GDA00033428843200000811
Figure GDA0003342884320000091
Wherein the content of the first and second substances,
Figure GDA0003342884320000092
representing the back-view imaging result I of the moving target on the radar system antennab(a, r) position coordinates of azimuth direction,
Figure GDA0003342884320000093
representing the back-view imaging result I of the moving target on the radar system antennab(a, r) position coordinates in the radial direction,
Figure GDA0003342884320000094
representing the back-view imaging result I of the moving target on the radar system antennaf(a, r) coordinates of the azimuth center point,
Figure GDA0003342884320000095
representing the back-view imaging result I of the moving target on the radar system antennaf(a,r)，a＝1,…,Nx，r＝1,…,NyThe middle distance is towards the coordinate of the central point,
Figure GDA0003342884320000096
representing the back-view imaging result I of the moving target on the radar system antennafThe length of the position in the azimuth direction in (a, r),
Figure GDA0003342884320000097
indicating a moving object inRadar system antenna rearview imaging result Ib(a, r) wherein a is 1, …, Nx，r＝1,…,Ny；
Step 11, obtaining the azimuth speed of the moving target with low precision
Forward-looking imaging result I of the moving target obtained in the step 10 on the radar system antennafCoordinates of azimuth center point in (a, r)
Figure GDA0003342884320000098
Position coordinates of the moving target in the forward-looking imaging result of the radar system antenna are recorded
Figure GDA0003342884320000099
a＝1,…,Nx，r＝1,…,Ny(ii) a The moving target obtained in the step 10 is subjected to back vision imaging result I of the radar system antennabCoordinates of azimuth center point in (a, r)
Figure GDA00033428843200000910
As a result of the back-view imaging of moving targets on the radar system antenna IbPosition coordinates in (a, r) are noted
Figure GDA00033428843200000911
a＝1,…,Nx，r＝1,…,Ny；
Using a formula
Figure GDA00033428843200000912
Calculating to obtain the speed of the initial azimuth direction of the moving target,
Figure GDA00033428843200000913
speed representing initial azimuth direction of moving target, Δ t ═ R0tanθ1-R0tanθ2)/VpxRepresenting the time interval, V, of the bidirectional synthetic aperture imaging radar BiDi SAR along the trackpxFor the azimuthal speed of movement, R, of the radar platform initialized in step 10Reference slope distance theta of the radar system to the projection imaging space in step 71And theta2The azimuth squint angle of the radar antenna for transmitting the forward-looking wave beam and the azimuth squint angle of the radar antenna for transmitting the backward-looking wave beam initialized in the step 1 are respectively.
Step 12, initializing parameters required by moving target iterative imaging
Initializing parameters required by moving target iterative imaging, comprising: the maximum number of times of algorithm iteration is marked as MI, and the threshold value of algorithm iteration is marked as epsilon; the estimated speed of the moving target in the ith iteration process is recorded as
Figure GDA00033428843200000914
The azimuth velocity of the moving target estimated by the ith iteration is recorded as
Figure GDA00033428843200000915
I is 1, …, MI in the process of the ith iteration, wherein i is a natural number and represents the ith iteration of the imaging algorithm,
Figure GDA00033428843200000916
is the speed of the initial azimuth direction of the moving target.
Step 13, initializing parameters of a moving target iterative imaging projection space:
recording the moving target iterative imaging projection space as omega; x-axis imaging range, marked as W ', of moving target iterative imaging projection space omega'x(ii) a Y-axis imaging range, noted as W ', of moving target iterative imaging projection space omega'y(ii) a X-axis center coordinate of moving target iterative imaging projection space omega is marked as W'xc(ii) a Y-axis center coordinate of moving target iterative imaging projection space omega is marked as W'yc(ii) a Wherein, the X-axis imaging range of the moving target iterative imaging projection space omega
Figure GDA0003342884320000101
Y-axis imaging range W 'of moving target iterative imaging projection space omega'y＝W′x(ii) a X-axis center coordinate of moving target iterative imaging projection space omega
Figure GDA0003342884320000102
Y-axis center coordinate of moving target iterative imaging projection space omega
Figure GDA0003342884320000103
Wherein the content of the first and second substances,
Figure GDA0003342884320000104
for the moving target obtained in step 10, an imaging result I is obtained before the radar system antennaf(a,r)，a＝1,…,Nx，r＝1,…,NyThe length of the position in the middle azimuth direction,
Figure GDA0003342884320000105
the moving target obtained in the step 10 is viewed from the rear of the radar system antenna to form an imaging result Ib(a,r)，a＝1,…,Nx，r＝1,…,NyThe length of the position in the middle azimuth direction,
Figure GDA0003342884320000106
for the moving target obtained in step 10, an imaging result I is obtained before the radar system antennaf(a,r)，a＝1,…,Nx，r＝1,…,NyThe coordinates of the middle position towards the center point,
Figure GDA0003342884320000107
the moving target obtained in the step 10 is viewed from the rear of the radar system antenna to form an imaging result Ib(a,r)，a＝1,…,Nx，r＝1,…,NyThe middle position is towards the coordinates of the center point. The X axial unit resolution of the moving target iterative imaging projection space omega is set as rholx(ii) a The Y-axis unit resolution of the moving target iterative imaging projection space omega is set as rholy(ii) a The number of X-axis resolution units of the moving target iterative imaging projection space omega is recorded as N'x(ii) a The number of Y-axis resolution units of the moving target iterative imaging projection space omega is recorded as N'y(ii) a And the reference slant distance of the projection space omega of the iterative imaging of the moving target is marked as R0；
Uniformly dividing the moving target iterative imaging projection space omega to obtain a two-dimensional resolution unit of the moving target iterative imaging projection space omega, and marking as PΩ(m,n)＝[x(m,n),y(m,n)]，m＝1,…,N′x，n＝1,…,N′yWherein m and n are natural numbers, m represents the mth resolution unit in the X axis direction in the moving target iterative imaging projection space Ω, n represents the nth resolution unit in the Y axis direction in the moving target iterative imaging projection space Ω, and X (m, n) and Y (m, n) respectively represent the X axis direction position and the Y axis direction position of the two-dimensional resolution unit in the moving target iterative imaging projection space Ω.
Step 14, projection imaging processing is carried out on the moving target
The speed of the moving target in the ith iteration imaging is recorded as
Figure GDA0003342884320000108
i-1, …, MI, representing the ith iteration of the imaging algorithm, MI being the maximum number of iterations of the algorithm; all resolution units P of the moving target iterative imaging projection space omega obtained in the step 13Ω(m, N) coordinates of the height direction are 0, m is 1, …, N'x，n＝1,…,N′yBy the formula
Figure GDA0003342884320000109
Calculating azimuth time t of radar platformmAll resolution units P of the projection space omega from time to moment to moving target iterative imagingΩ(m, N), m ═ 1, …, N'x，n＝1,…,N′yIs denoted as R (P)Ω,tm). Wherein, tmFor the time of the azimuth direction initialized in step 1, P (0) is the initial position of the antenna of the radar system mentioned in step 1, VpVelocity vector of platform motion, V, mentioned for step 1mFor the moving target speed vector mentioned in step 1, | | | | non-calculation2Representing a 2-norm operation of the vector.
Constructing a compensation function
Figure GDA0003342884320000111
Where lambda is the radar carrier wavelength mentioned in step 1,
Figure GDA0003342884320000112
denotes an imaginary unit, e-2.71828183 is constantAnd (4) counting.
Compressing the distance of the radar system antenna to the kth slow time in the direction from the tth fast time, wherein t is 1,2, …, Nr，k＝1,2,…,NaAnd a compensation function
Figure GDA0003342884320000113
Iterative imaging processing is carried out by adopting a standard back projection imaging algorithm to obtain an iterative projection imaging result of the forward-looking echo data, and the result is recorded as
Figure GDA0003342884320000114
m＝1,…,N′x，n＝1,…,N′y(ii) a i is 1, …, MI represents the ith iteration of the imaging algorithm, SF (t, k) is echo data obtained by distance compression of the radar system antenna obtained in step 6 when the distance is observed to the kth slow time from the tth fast time, and t is 1,2, …, Nr，k＝1,2,…,Na；
Compressing echo data SB (t, k) of radar system antenna after the distance from the tth fast time azimuth to the kth slow time, wherein t is 1,2, …, Nr，k＝1,2,…,NaAnd a compensation function
Figure GDA0003342884320000115
Performing iterative imaging processing by adopting a standard back projection imaging algorithm to obtain an iterative projection imaging result of the back vision echo data, and recording the result as a
Figure GDA00033428843200001111
m＝1,…,N′x，n＝1,…,N′y(ii) a i is 1, …, MI represents the ith iteration of the imaging algorithm, SB (t, k) is the echo data of the radar system antenna obtained in step 6 after the distance compression from the tth fast time azimuth to the kth slow time, t is 1,2, …, Nr，k＝1,2,…,Na。
Step 15, calculating the speed of the moving target in the azimuth direction in an iterative manner
Taking the peak value of the moving target as the imaging position of the moving target, the moving target sees the superposition of echo data in frontGeneration of projection imaging results
Figure GDA0003342884320000116
m＝1,…,N′x，n＝1,…,N′yPosition in (1) is noted
Figure GDA0003342884320000117
i is 1, …, MI represents the ith iteration of the imaging algorithm, and the iterative projection imaging result of the moving target rearview echo data
Figure GDA0003342884320000118
m＝1,…,N′x，n＝1,…,N′yPosition in (1) is noted
Figure GDA0003342884320000119
i-1, …, MI representing the ith iteration of the imaging algorithm;
using a formula
Figure GDA00033428843200001110
Calculating the speed of the residual azimuth direction of the moving target, wherein i is 1, …, and MI represents the ith iteration of the imaging algorithm; wherein MI is the maximum number of times of algorithm iteration obtained by initialization in the step 12, delta t is the time interval of the high-speed platform BiDi SAR along the flight path in the step 11,
Figure GDA0003342884320000121
indicating the remaining azimuthal velocity.
Using a formula
Figure GDA0003342884320000122
Calculating the residual azimuth velocity of the moving target in the ith iteration process
Figure GDA0003342884320000123
Compensating the azimuth velocity of the moving target estimated by the i-1 th iteration
Figure GDA0003342884320000124
Obtaining the moving target calculated in the ith iteration processAzimuth and velocity of
Figure GDA0003342884320000125
Where i is 1, …, MI represents the ith iteration of the imaging algorithm, MI is the maximum number of iterations of the algorithm initialized in step 12, and the iteration initial value of the moving target azimuth velocity is the azimuth velocity of the moving target calculated in step 11
Figure GDA0003342884320000126
Step 16, determining the iterative condition of the algorithm and obtaining the final azimuth velocity estimation result
If it is not
Figure GDA0003342884320000127
And i is less than or equal to MI, adding 1 to the iteration times i of the imaging algorithm to obtain i ← i + 1; repeating the steps 13, 14 and 15;
if it is not
Figure GDA0003342884320000128
Or i is more than or equal to MI, the iteration step is terminated, and the obtained product
Figure GDA0003342884320000129
The final estimated speed of the moving target azimuth direction is obtained; where i is 1, …, MI represents the ith iteration of the imaging algorithm, MI is the maximum number of iterations of the algorithm initialized in step 12, epsilon is the threshold value of the algorithm iteration initialized in step 12,
Figure GDA00033428843200001210
for the estimated azimuth velocity of the moving target in the ith iteration process of the algorithm,
Figure GDA00033428843200001211
the estimated azimuth velocity of the moving target in the i-1 iteration process of the algorithm.
Innovation point of the invention
A method for detecting and estimating the slow moving target of a high-speed platform SAR in a BiDi mode is provided. The method detects a slow moving target by using azimuth offset of a moving target in front and back view of two SAR images caused by time delay of front and back beams and imaging mismatch, roughly estimates the speed of the moving target in the azimuth direction by using the azimuth position offset of the moving target in front and back view of the two SAR images, and further improves the accuracy of azimuth speed estimation by adopting a moving target iterative imaging method. The detection and the azimuth velocity estimation of the slow moving target are completed under the condition of a single channel.
THE ADVANTAGES OF THE PRESENT INVENTION
Compared with the traditional single-channel moving target detection method, the method can detect the slow moving target with the frequency spectrum submerged in the clutter spectrum. Secondly, due to the adoption of a moving target iterative imaging method, if a static target is imaged by adopting a matching function of the moving target, an imaging mismatch phenomenon occurs, so that the focusing energy of the static target is reduced, and on the contrary, the focusing energy of the moving target is enhanced due to imaging matching.
Drawings
FIG. 1 is a schematic block diagram of a process for providing the method of the present invention
FIG. 2 is a diagram of values of system simulation parameters
Detailed Description
The invention mainly adopts a simulation experiment method for verification, and all steps and conclusions are verified to be correct on MATLABR2017b software. The specific implementation steps are as follows:
step 1: initializing system parameters of a bidirectional synthetic aperture imaging radar BiDi SAR:
initializing system parameters of a high-speed platform BiDi SAR imaging radar, comprising the following steps: the wavelength λ of radar carrier wave is 0.03m, and the bandwidth B of signal transmitted by radar antenna is 1.5 × 108Hz, radar pulse time width Tr＝1×10-6s, radar sampling frequency Fs＝2.1×108Hz, radar incidence angle phi is 79.7 degrees, radar pulse repetition frequency PRF is 8000Hz, and the distance sampling point number N of the radar system isr2048, the number of sampling points in the azimuth direction of the radar system is N a16384, radar system azimuth frequency resolution, denoted Δ fa8000/16384, the radar system antenna initial position P (0) [ [0,0,20000 [ ]]m, azimuth squint angle theta of forward-looking wave beam emitted by radar antenna11 DEG, the azimuth squint angle theta of the radar antenna for transmitting the rearview beam21 deg. radar platform motion velocity vector Vp＝[2040,0,0]m/s, wherein Vpx2040m/s represents the movement speed of the radar platform in the azimuth direction, and the sampling time t of the radar system in the azimuth directionm＝-1.024，-1.0239，-1.0238，…1.0238,1.0239。
Step 2, initializing parameters of the moving target
Initializing parameters of the moving object includes: velocity vector of moving object, denoted Vm＝[-9.22,0,0]Initial position P of moving objectm(0)＝[2342,109859,0]m。
Step 3, obtaining original echo data of the bidirectional synthetic aperture imaging radar BiDi SAR system:
the method includes the steps that raw echo data of a BiDi SAR radar system antenna of a high-speed platform in the kth slow time from the tth fast time to the kth slow time are recorded as E (t, k), and t is 1,2, … and Nr，k＝1,2,…,NaWhere t and k are natural numbers, t represents the fast time from the distance to the tth, k represents the slow time from the azimuth to the kth, and NrSampling point number N of radar system distance direction obtained for initialization of step 1r＝2048，NaThe number N of sampling points of the radar system in the azimuth direction obtained by initialization in the step 1a16384; in the actual imaging of the high-speed platform BiDi SAR, the high-speed platform BiDi SAR radar system antenna is used for obtaining raw echo data E (t, k) from the distance to the tth fast time azimuth to the kth slow time, wherein t is 1,2, …, Nr，k＝1,2,…,Na，Nr＝2048，N a16384, provided by the high-speed platform BiDi SAR radar system data receiver.
Step 4, performing distance compression on the original echo data of the antenna of the bidirectional synthetic aperture imaging radar BiDi SAR system:
and (3) adopting a standard synthetic aperture radar distance compression method to obtain the original echo data E (t, k) of the high-speed platform BiDi SAR radar system antenna obtained in the step (3) in the kth fast time azimuth direction at the kth slow time, wherein t is 1,2, … and Nr，k＝1,2,…,Na，Nr＝2048，N a16384, performing range compression to obtain echo data S (t, k) of the high-speed platform BiDi SAR system antenna after range compression from the tth fast time azimuth to the kth slow time, wherein t is 1,2, …, Nr，k＝1,2,…,Na，Nr＝2048，Na＝16384。
And 5, performing azimuth Fourier transform on the original echo data of the bidirectional synthetic aperture imaging radar BiDi SAR system antenna:
and (3) performing azimuth direction pair on the echo data S (t, k) t obtained in the step (4) of the high-speed platform BiDi SAR radar system antenna by adopting a standard Fourier transform method, after the distance compression from the azimuth direction to the kth fast time to the kth slow time, is 1,2, …, Nr，k＝1,2,…,Na，Nr＝2048，N a16384, Fourier transform is carried out to obtain echo data S of the radar system in the distance direction to the fth fast moment and the fth slow momentFFT(t,f)，t＝1,2,…,Nr，f＝1,2,…,Na，Nr＝2048，N a16384, f is a natural number, indicating the frequency of the f-th slow time instant in the azimuth direction.
Step 6, separating original echo data of the antenna of the bidirectional synthetic aperture imaging radar BiDi SAR system:
using a formula
Figure GDA0003342884320000141
Calculating the frequency echo data S of the radar system from the distance to the tth fast time azimuth to the fth slow timeFFTAzimuthal frequency F of (t, F)a(ii) a f is a natural number obtained in step 5, f is 1,2, …, Na，N a16384, the f-th slow time frequency of the azimuth direction, Δ faRadar obtained by initialization for step 1System azimuth frequency resolution, Δ fa＝8000/16384，NaThe number N of sampling points of the radar system in the azimuth direction obtained by initialization in the step 1a＝16384，SFFT(t,f)t＝1,2,…,Nr，f＝1,2,…,Na，Nr＝2048，N a16384, obtaining echo data of the radar system with the frequency from the tth fast time azimuth to the fth slow time azimuth in the step 5;
the echo data S of the distance to the tth fast time azimuth and the fth slow time frequencyFFT(t,f)，t＝1,2,…,Nr，f＝1,2,…,Na，Nr＝2048，N a16384, the echo data S from the tth fast time azimuth to the fth slow time frequency pointFFT(t,f)t＝1,2,…,Nr，f＝1,2,…,Na，Nr＝2048，N a16384, of a directional frequency FaCentered at 0, divided into Fa> 0 and Fa< 0.
The distance is changed to the tth fast time azimuth to the fth slow time frequency echo data SFFT(t,f)t＝1,2,…,Nr，f＝1,2,…,Na，Nr＝2048，N a16384, medium azimuth frequency FaThe echo of the part less than 0 is set to zero to obtain the forward looking distance time domain-azimuth frequency domain echo data SFFFT(t,f)，t＝1,2,…,Nr，f＝1,2,…,Na，Nr＝2048，N a16384; the distance is changed to the tth fast time azimuth to the fth slow time frequency echo data SFFT(t,f)，t＝1,2,…,Nr，f＝1,2,…,Na，Nr＝2048，N a16384, medium azimuth frequency FaThe echo with the part larger than 0 is set to zero to obtain the echo data SB of the time domain-azimuth frequency domain of the rearview distanceFFT(t,f)，t＝1,2,…,Nr，f＝1,2,…,Na，Nr＝2048，Na＝16384；
Adopting a standard Fourier inverse transformation method to carry out forward-looking distance time domain-azimuth frequency domain echo data SFFFT(t,f)，t＝1,2,…,Nr，f＝1,2,…,Na，Nr＝2048，Na16384, performing inverse fourier transform in the azimuth direction to obtain echo data SF (t, k) of the radar system antenna after distance compression looking ahead from the t-th fast time to the k-th slow time, wherein t is 1,2, …, Nr，k＝1,2,…,Na，Nr＝2048，Na16384; adopting a standard Fourier inverse transformation method to carry out backward vision distance time domain-azimuth frequency domain echo data SBFFT(t,f)，t＝1,2,…,Nr，k＝1,2,…,Na，Nr＝2048，Na16384, performing inverse Fourier transform in the azimuth direction to obtain echo data SB (t, k) of the high-speed platform BiDi SAR system antenna after the distance compression from the azimuth direction to the kth slow time at the tth fast time, wherein t is 1,2, …, and N isr，k＝1,2,…,Na，Nr＝2048，Na＝16384。
Step 7, initializing parameters of a bidirectional synthetic aperture imaging radar BiDi SAR projection imaging space:
initializing a high-speed platform BiDi SAR projection imaging space as a ground plane coordinate system, wherein the horizontal axis of the coordinate system is marked as an X axis, the horizontal vertical axis of the coordinate system is marked as a Y axis, and the central coordinate of the radar projection imaging space is positioned in [2040,110000 ]]Number N of X-axis resolution units in radar projection imaging spacex200, the number of Y-axis resolution units N of the radar projection imaging spacey200, X-axis imaging range W of radar projection imaging spacex200m, Y-axis imaging range W of radar projection imaging spacey200m, X-axis unit resolution ρ of radar projection imaging spacex1m, Y-axis unit resolution ρ of radar projection imaging spacey1m, reference slant distance R of radar system to projection imaging space0111820 m; uniformly dividing the radar projection imaging space to obtain a two-dimensional resolution unit P of the projection imaging spaceT(a,r)＝[x(a,r),y(a,r)]，a＝1,…,Nx，r＝1,…,Ny，Nx＝200，NyWhere a and r are natural numbers, a denotes an a-th resolving unit in the X-axis direction in the projection imaging space, r denotes an r-th resolving unit in the Y-axis direction in the projection imaging space, and X (a, r) and Y (a, r) denote X (a, r), respectivelyAnd projecting the X axial position and the Y axial position of the two-dimensional resolution unit in the imaging space.
Step 8, performing projection imaging processing on the resolution unit by adopting a standard synthetic aperture radar back projection imaging algorithm
Enabling all resolution units P in the projection imaging space of the high-speed platform BiDi SAR system obtained in the step 7T(a,r)，a＝1,…,Nx，r＝1,…,Ny，Nx＝200，N y200, the coordinate of the altitude direction is 0, and the standard synthetic aperture radar back projection imaging algorithm is adopted to look ahead distance compressed echo data SF (t, k) of the radar system antenna from the distance to the tth fast time azimuth to the kth slow time, wherein t is 1,2, …, Nr，k＝1,2,…,Na，Nr＝2048，N a16384, imaging processing is carried out to obtain an antenna foresight imaging result I of the radar systemf(a,r)，a＝1,…,Nx，r＝1,…,Ny，Nx＝200，N y200, where SF (t, k), t 1,2, …, Nr，k＝1,2,…,Na，Nr＝2048，N a16384, looking ahead the distance compressed echo data of the radar system antenna from the tth fast time to the kth slow time in the distance direction of the antenna from the step 6.
Enabling all resolution units P in the projection imaging space of the high-speed platform BiDi SAR system obtained in the step 7T(a,r)，a＝1,…,Nx，r＝1,…,Ny，Nx＝200，N y200, the coordinate of the altitude direction is 0, echo data SB (t, k) compressed by the radar system antenna from the distance direction to the tth fast time azimuth to the kth slow time rearview distance is processed by adopting a standard synthetic aperture radar back projection imaging algorithm, and t is 1,2, …, Nr，k＝1,2,…,Na，Nr＝2048，N a16384, imaging processing is carried out to obtain a radar system antenna rearview imaging result Ib(a,r)，a＝1,…,Nx，r＝1,…,Ny，Nx＝200，N y200, where SB (t, k), t 1,2, …, Nr，k＝1,2,…,Na，Nr＝2048，N a16384, the radar system obtained in step 6And the echo data compressed by the system antenna is viewed from the distance to the kth fast time azimuth to the kth slow time.
Step 9, adopting an amplitude subtraction method to suppress stationary clutter
The forward-looking imaging result I of the radar system antenna obtained in the step 8f(a,r)，a＝1,…,Nx，r＝1,…,Ny，Nx＝200，N y200, and a radar system antenna rearview imaging result Ib(a,r)，a＝1,…,Nx，r＝1,…,Ny，，Nx＝200，N y200, using formula Iresult(a,r)＝|If(a,r)|-|Ib(a, r) | suppresses the stationary clutter to obtain a signal I after stationary clutter suppressionresult(a,r)，a＝1,…,Nx，r＝1,…,Ny，Nx＝200，N y200 where | represents the absolute arithmetic sign.
Step 10, detecting a moving target and determining the position range of the moving target
Adopting a large value selection method constant false alarm detection method for defining 13 traditional standards to carry out detection on the signal I after the static clutter suppression obtained in the step 9result(a,r)，a＝1,…,Nx，r＝1,…,Ny，Nx＝200，NyAnd (5) performing constant false alarm detection, and respectively detecting:
(1) detecting radar system antenna forward-looking imaging result If(a,r)，a＝1,…,Nx，r＝1,…,Ny，Nx＝200，NyMoving target of 200
Figure GDA0003342884320000161
(2) Detecting radar system antenna back vision imaging result Ib(a,r)，a＝1,…,Nx，r＝1,…,Ny，Nx＝200，NyMoving target of 200
Figure GDA0003342884320000171
(3) Forward-looking imaging junction of detected moving target on radar system antennaFruit If(a,r)，a＝1,…,Nx，r＝1,…,Ny，Nx＝200，NyPosition range of 200
Figure GDA0003342884320000172
Figure GDA0003342884320000173
Figure GDA0003342884320000174
Wherein the content of the first and second substances,
Figure GDA0003342884320000175
representing the forward view imaging result I of the moving target on the antenna of the radar systemf(a,r)，a＝1,…,Nx，r＝1,…,Ny，Nx＝200，Ny200, the position coordinates of the middle azimuth direction,
Figure GDA0003342884320000176
representing the forward view imaging result I of the moving target on the antenna of the radar systemf(a,r)，a＝1,…,Nx，r＝1,…,Ny，Nx＝200，Ny200, the position coordinates of the middle distance direction,
Figure GDA0003342884320000177
representing the forward view imaging result I of the moving target on the antenna of the radar systemf(a,r)，a＝1,…,Nx，r＝1,…,Ny，Nx＝200，Ny200, the coordinates of the middle position towards the center point,
Figure GDA0003342884320000178
Figure GDA0003342884320000179
representing the forward view imaging result I of the moving target on the antenna of the radar systemf(a,r)，a＝1,…,Nx，r＝1,…,Ny，Nx＝200，Ny200, the coordinates of the middle distance to the center point,
Figure GDA00033428843200001710
Figure GDA00033428843200001711
representing the forward view imaging result I of the moving target on the antenna of the radar systemf(a,r)，a＝1,…,Nx，r＝1,…,Ny，Nx＝200，Ny200, the length of the position in the middle azimuth direction,
Figure GDA00033428843200001712
Figure GDA00033428843200001713
representing the forward view imaging result I of the moving target on the antenna of the radar systemf(a,r)，a＝1,…,Nx，r＝1,…,Ny，Nx＝200，Ny200, the position length of the middle distance direction,
Figure GDA00033428843200001714
(4) detecting the back vision imaging result I of the moving target in the radar system antennaf(a,r)，a＝1,…,Nx，r＝1,…,Ny，Nx＝200，NyPosition range of 200
Figure GDA00033428843200001715
Figure GDA00033428843200001716
Figure GDA00033428843200001717
Wherein the content of the first and second substances,
Figure GDA00033428843200001718
representing the back-view imaging result I of the moving target on the radar system antennab(a,r)，a＝1,…,Nx，r＝1,…,Ny，Nx＝200，Ny200, the position coordinates of the middle azimuth direction,
Figure GDA00033428843200001719
representing the back-view imaging result I of the moving target on the radar system antennab(a,r)，a＝1,…,Nx，r＝1,…,Ny，Nx＝200，Ny200, the position coordinates of the middle distance direction,
Figure GDA00033428843200001720
representing the back-view imaging result I of the moving target on the radar system antennaf(a,r)，a＝1,…,Nx，r＝1,…,Ny，Nx＝200，Ny200, the coordinates of the middle position towards the center point,
Figure GDA00033428843200001721
Figure GDA00033428843200001722
representing the back-view imaging result I of the moving target on the radar system antennaf(a,r)，a＝1,…,Nx，r＝1,…,Ny，Nx＝200，Ny200, the coordinates of the middle distance to the center point,
Figure GDA00033428843200001723
Figure GDA00033428843200001724
representing the back-view imaging result I of the moving target on the radar system antennaf(a,r)，a＝1,…,Nx，r＝1,…,Ny，Nx＝200，Ny200, the length of the position in the middle azimuth direction,
Figure GDA00033428843200001725
Figure GDA00033428843200001726
representing the back-view imaging result I of the moving target on the radar system antennab(a,r)，a＝1,…,Nx，r＝1,…,Ny，Nx＝200，Ny200, the position length of the middle distance direction,
Figure GDA0003342884320000181
step 11, obtaining the azimuth speed of the moving target with low precision
Forward-looking imaging result I of the moving target obtained in the step 10 on the radar system antennaf(a,r)，a＝1,…,Nx，r＝1,…,Ny，Nx＝200，N y200, coordinates of the middle position to the center point
Figure GDA0003342884320000182
Imaging result I as moving target forward looking at radar system antennaf(a,r)，a＝1,…,Nx，r＝1,…,Ny，Nx＝200，NyPosition coordinates of 200 ═ m
Figure GDA0003342884320000183
Figure GDA0003342884320000184
The moving target obtained in the step 10 is subjected to back vision imaging result I of the radar system antennab(a,r)，a＝1,…,Nx，r＝1,…,Ny，Nx＝200，N y200, coordinates of the middle position to the center point
Figure GDA0003342884320000185
As a result of the back-view imaging of moving targets on the radar system antenna Ib(a,r)，a＝1,…,Nx，r＝1,…,Ny，Nx＝200，NyPosition coordinates of 200 ═ m
Figure GDA0003342884320000186
Figure GDA0003342884320000187
Using a formula
Figure GDA0003342884320000188
Calculating initial azimuth of moving objectThe speed of the motor is controlled by the speed of the motor,
Figure GDA0003342884320000189
the speed of the initial azimuth direction of the moving target is represented,
Figure GDA00033428843200001810
Δ t represents the time interval of the BiDi SAR along the track, and Δ t is 2 s; vpxFor the azimuthal speed of movement, V, of the radar platform initialized in step 1px＝2040m/s；R0Reference slope distance, R, of the radar system to the projection imaging space in step 70＝111820m；θ1And theta2The azimuth squint angle of the radar antenna for transmitting the forward-looking wave beam and the azimuth squint angle of the radar antenna for transmitting the backward-looking wave beam, theta, initialized in step 1 are respectively1＝1°，θ2＝-1°。
Step 12, initializing parameters required by moving target iterative imaging
Initializing parameters required by moving target iterative imaging, comprising: the maximum number MI of algorithm iteration is 10, the threshold epsilon of algorithm iteration is 0.025, and the estimated speed of the residual azimuth direction of the moving target in the ith iteration process is recorded as
Figure GDA00033428843200001811
The azimuth velocity of the moving target calculated by the ith iteration is recorded as
Figure GDA00033428843200001812
I is 1, …, MI in the process of the ith iteration, wherein i is a natural number and represents the ith iteration of the imaging algorithm,
Figure GDA00033428843200001813
the velocity of the moving object in the initial azimuth direction,
Figure GDA00033428843200001814
step 13, initializing parameters of a moving target iterative imaging projection space:
and (5) iteratively imaging the moving target into a projection space, and recording as omega. Eye movementX-axis imaging range W 'of target iteration imaging projection space omega'x75m, the Y-axis imaging range W 'of the moving target iterative imaging projection space omega'y75 m. X-axis center coordinate W 'of moving target iterative imaging projection space omega'xc2047.5, moving target iterative imaging projection space Ω Y-axis center coordinate W'yc109864. Wherein, the X-axis imaging range W 'of the moving target iterative imaging projection space omega'x75m, the Y-axis imaging range W 'of the moving target iterative imaging projection space omega'y75 m; x-axis center coordinate W 'of moving target iterative imaging projection space omega'xc2047.5, moving target iterative imaging projection space Ω Y-axis center coordinate W'yc109864. Wherein the content of the first and second substances,
Figure GDA0003342884320000191
for the moving target obtained in step 10, an imaging result I is obtained before the radar system antennaf(a,r)，a＝1,…,Nx，r＝1,…,Ny，Nx＝200，Ny200, the length of the position in the middle azimuth direction,
Figure GDA0003342884320000192
the moving target obtained in the step 10 is viewed from the rear of the radar system antenna to form an imaging result Ib(a,r)，a＝1,…,Nx，r＝1,…,Ny，Nx＝200，Ny200, the length of the position in the middle azimuth direction,
Figure GDA0003342884320000193
for the moving target obtained in step 10, an imaging result I is obtained before the radar system antennaf(a,r)，a＝1,…,Nx，r＝1,…,Ny，Nx＝200，Ny200, the coordinates of the middle position towards the center point,
Figure GDA0003342884320000194
the moving target obtained in the step 10 is viewed from the rear of the radar system antenna to form an imaging result Ib(a,r)，a＝1,…,Nx，r＝1,…,Ny，Nx＝200，Ny＝200，Coordinates of the center point of the middle position
X-axis unit resolution rho of moving target iterative imaging projection space omegalxThe unit resolution rho of the Y axis of the moving target iterative imaging projection space omega is 0.04mly0.04m, and N 'is an X-axis resolution unit number of a moving target iterative imaging projection space omega'x1875Y-axial resolution unit number N 'of moving target iterative imaging projection space Ω'y1875. Reference slope distance R of moving target iterative imaging projection space omega0111820m, uniformly dividing the moving target iterative imaging projection space omega to obtain a two-dimensional resolution unit P of the moving target iterative imaging projection space omegaΩ(m,n)＝[x(m,n),y(m,n)]，m＝1,…,N′x，n＝1,…,N′y，N′x＝1875，N′y1875, where m and n are natural numbers, m denotes the mth resolution unit in the X-axis direction in the moving target iterative imaging projection space Ω, n denotes the nth resolution unit in the Y-axis direction in the moving target iterative imaging projection space Ω, and X (m, n) and Y (m, n) denote the X-axis position and the Y-axis position of the two-dimensional resolution unit in the moving target iterative imaging projection space Ω, respectively.
Step 14, projection imaging processing is carried out on the moving target
The speed of the moving target in the ith iteration imaging is recorded as
Figure GDA0003342884320000195
i-1, …, where MI denotes the ith iteration of the imaging algorithm, and MI-10 is the maximum number of iterations of the algorithm; all resolution units P of the moving target iterative imaging projection space omega obtained in the step 13Ω(m, N) coordinates of the height direction are 0, m is 1, …, N'x，n＝1,…,N′y，N′x＝1875，N′y1875, using the formula
Figure GDA0003342884320000196
Calculating azimuth time t of radar platformmAll resolution units P of the projection space omega from time to moment to moving target iterative imagingΩ(m, N), m ═ 1, …, N'x，n＝1,…,N′yIs denoted as R (P)Ω,tm). Wherein, tmFor the time of the azimuth direction initialized in step 1, P (0) ═ 0,20000]m is the initial position of the antenna of the radar system, V, mentioned in step 1p＝[2040,0,0]m/s is the platform motion velocity vector, V, mentioned in step 1m＝[-9.22,0,0]m/s is the moving target velocity vector mentioned in step 1, | | | | | purple2Representing a 2-norm operation of the vector.
Constructing a compensation function
Figure GDA0003342884320000201
Where lambda is the radar carrier wavelength mentioned in step 1,
Figure GDA0003342884320000202
denotes an imaginary unit, and e-2.71828183 is a constant.
Compressing the distance of the radar system antenna to the kth slow time in the direction from the tth fast time, wherein t is 1,2, …, Nr，k＝1,2,…,Na，Nr＝2048，N a16384, and a compensation function
Figure GDA0003342884320000203
Iterative imaging processing is carried out by adopting a standard back projection imaging algorithm to obtain an iterative projection imaging result of the forward-looking echo data, and the result is recorded as
Figure GDA0003342884320000204
m＝1,…,N′x，n＝1,…,N′y，N′x＝1875，N′y1875; i is 1, …, MI is 10, which represents the ith iteration of the imaging algorithm, SF (t, k) is the echo data of the radar system antenna obtained in step 6 after the distance compression in the forward looking direction from the tth fast time to the kth slow time, t is 1,2, …, Nr，k＝1,2,…,Na，Nr＝2048，Na＝16384；
Compressing echo data SB (t, k) of radar system antenna after the distance from the tth fast time azimuth to the kth slow time, wherein t is 1,2, …, Nr，k＝1,2,…,Na，Nr＝2048，N a16384 and the compensation function
Figure GDA0003342884320000205
Performing iterative imaging processing by adopting a standard back projection imaging algorithm to obtain an iterative projection imaging result of the back vision echo data, and recording the result as a
Figure GDA0003342884320000206
m＝1,…,N′x，n＝1,…,N′y，N′x＝1875，N′y1875, i is 1, …, MI is 10, which represents the ith iteration of the imaging algorithm, SB (t, k) is the echo data of the radar system antenna obtained in step 6 after the distance compression from the tth fast time azimuth to the kth slow time, t is 1,2, …, Nr，k＝1,2,…,Na，Nr＝2048，Na＝16384。
Step 15, calculating the speed of the moving target in the azimuth direction in an iterative manner
The peak value of the moving target is taken as the imaging position of the moving target, and the moving target is subjected to iterative projection imaging result of the front-view echo data
Figure GDA0003342884320000207
m＝1,…,N′x，n＝1,…,N′yPosition in (1) is noted
Figure GDA0003342884320000208
i is 1, …, MI represents the ith iteration of the imaging algorithm, and the iterative projection imaging result of the moving target rearview echo data
Figure GDA0003342884320000209
m＝1,…,N′x，n＝1,…,N′y，N′x＝1875，N′y1875, position therein
Figure GDA00033428843200002010
i-1, …, where MI denotes the ith iteration of the imaging algorithm, and MI-10 is the maximum number of iterations of the algorithm;
using a formula
Figure GDA0003342884320000211
Calculating the speed of the remaining azimuth direction of the moving target, wherein i is 1, …, MI represents the ith iteration of the imaging algorithm, and MI is 10, which is the maximum iteration number of the algorithm; wherein, Δ t ═ 2s is the time interval of the high-speed platform BiDi SAR along the flight path in step 11,
Figure GDA0003342884320000212
indicating the remaining azimuthal velocity.
Using a formula
Figure GDA0003342884320000213
Calculating the residual azimuth velocity of the moving target in the ith iteration process
Figure GDA0003342884320000214
Compensating the azimuth velocity of the moving target estimated by the i-1 th iteration
Figure GDA0003342884320000215
Obtaining the azimuth velocity of the moving target calculated in the ith iteration process, and recording the azimuth velocity as
Figure GDA0003342884320000216
Where MI is 1 and …, MI represents the ith iteration of the imaging algorithm, MI is 10, which is the maximum number of iterations of the algorithm, and the initial value of the moving target azimuth velocity is the azimuth velocity of the moving target calculated in step 11
Figure GDA0003342884320000217
Step 16, determining the iterative condition of the algorithm and obtaining the final azimuth velocity estimation result
If it is not
Figure GDA0003342884320000218
And i is less than or equal to MI, adding 1 to the iteration times i of the imaging algorithm to obtain i ← i + 1; repeating the steps 13, 14 and 15; if it is not
Figure GDA0003342884320000219
Or i is more than or equal to MI, the iteration step is terminated, and the obtained product
Figure GDA00033428843200002110
Namely the final estimated speed of the azimuth direction of the moving target,
Figure GDA00033428843200002111
where i is 1, …, MI represents the ith iteration of the imaging algorithm, MI is the maximum number of iterations of the algorithm initialized in step 12, MI is 10, epsilon is the threshold value of the algorithm iteration initialized in step 12, epsilon is 0.025,
Figure GDA00033428843200002112
for the estimated azimuth velocity of the moving target in the ith iteration process of the algorithm,
Figure GDA00033428843200002113
the estimated azimuth velocity of the moving target in the i-1 iteration process of the algorithm.

Claims (1)

1. A method for detecting and estimating a slow moving target of a high-speed platform SAR is characterized by comprising the following steps:
step 1: initializing system parameters of a bidirectional synthetic aperture imaging radar BiDi SAR:
initializing system parameters of a bidirectional synthetic aperture imaging radar BiDi SAR, comprising the following steps: the wavelength of the radar carrier wave is recorded as lambda, the bandwidth of the signal transmitted by the radar antenna is recorded as B, and the time width of the pulse transmitted by the radar is recorded as TrRadar sampling frequency, denoted FsRadar incident angle, recorded as phi, radar pulse repetition frequency, recorded as PRF, number of sampling points in radar system distance direction, recorded as NrThe number of sampling points of the radar system in the azimuth direction is recorded as NaAzimuth frequency resolution of the radar system, denoted as Δ fa＝PRF/NaThe initial position of the radar system antenna is marked as P (0), and the azimuth squint angle of the forward-looking wave beam emitted by the radar antenna is marked as theta1After radar antenna transmissionThe azimuthal squint angle of the apparent beam, denoted as θ2Velocity vector of radar platform motion, denoted Vp＝[Vpx,0,0]Wherein V ispxRepresenting the moving speed of the radar platform in the azimuth direction, and the sampling time of the radar system in the azimuth direction, and is recorded as
Figure FDA0003409463310000011
j is a natural number, j is 0,1,2, …, (N)a-1); among the above parameters, the wavelength λ of radar carrier, the bandwidth B of signal transmitted by radar antenna, and the time width T of pulse transmitted by radarrRadar sampling frequency FsRadar incident angle phi, radar pulse repetition frequency PRF, azimuth squint angle theta of forward looking wave beam emitted by radar antenna1Azimuth squint angle theta of radar antenna transmitting back view beam2It has been determined during the radar system design process; radar platform motion velocity vector VpDistance sampling point number N of radar systemrAnd the number N of sampling points in the azimuth direction of the radar systemaSampling time t of radar system azimuthmAzimuth frequency resolution Δ f of radar systemaInitial position P (0) of radar system antenna and motion velocity vector V of radar platformpIt has been determined in radar imaging observation scheme design;
step 2, initializing parameters of the moving target
Initializing parameters of the moving object includes: velocity vector of moving object, denoted Vm＝[vx,vy,0]Initial position of moving object, noted as Pm(0) Wherein v isxVelocity, v, representing the azimuth of a moving targetyRepresenting the speed of the moving target distance direction;
step 3, obtaining original echo data of the bidirectional synthetic aperture imaging radar BiDi SAR system:
the method includes the steps that raw echo data of a bidirectional synthetic aperture imaging radar BiDi SAR system antenna in the kth slow time from the tth fast time to the kth slow time is recorded as E (t, k), and t is 1,2, … and Nr，k＝1,2,…,NaWhere t and k are natural numbers, t represents the fast time from the distance to the tth, k represents the slow time from the azimuth to the kth, and NrIs the first step of step 1Sampling point number, N, of radar system distance obtained by initializationaInitializing the number of the obtained sampling points of the radar system in the azimuth direction in the step 1; in the actual imaging of the high-speed platform BiDi SAR, the bidirectional synthetic aperture imaging radar BiDi SAR system antenna is used for obtaining original echo data E (t, k) from the distance to the tth fast time and the direction to the kth slow time, wherein t is 1,2, …, Nr，k＝1,2,…,NaThe data is provided by a bidirectional synthetic aperture imaging radar BiDi SAR system data receiver;
step 4, performing distance compression on the original echo data of the antenna of the bidirectional synthetic aperture imaging radar BiDi SAR system:
and (3) adopting a traditional standard synthetic aperture radar distance compression method to obtain original echo data E (t, k) of the bidirectional synthetic aperture imaging radar BiDi SAR system antenna obtained in the step (3) in the kth fast time azimuth direction at the kth slow time, wherein t is 1,2, … and Nr，k＝1,2,…,NaAnd performing range compression to obtain echo data of the bi-directional synthetic aperture imaging radar BiDi SAR system antenna after range compression from the tth fast time azimuth to the kth slow time, and recording the echo data as S (t, k), wherein t is 1,2, …, Nr，k＝1,2,…,Na；
And 5, performing azimuth Fourier transform on the original echo data of the bidirectional synthetic aperture imaging radar BiDi SAR system antenna:
performing Fourier transform on echo data S (t, k) obtained by compressing the distance of the bidirectional synthetic aperture imaging radar BiDi SAR system antenna obtained in the step 4 from the tth fast time to the kth slow time in the azimuth direction by adopting a traditional standard Fourier transform method, obtaining echo data of the radar system from the distance to the tth fast time and the frequency of the radar system from the azimuth direction to the fth slow time, and recording the echo data as SFFT(t,f)，t＝1,2,…,Nr，f＝1,2,…,NaF is a natural number and represents the frequency of the f-th slow moment in the azimuth direction;
step 6, separating original echo data of the antenna of the bidirectional synthetic aperture imaging radar BiDi SAR system:
using a formula
Figure FDA0003409463310000021
Calculating the frequency echo data S of the bi-directional synthetic aperture imaging radar BiDi SAR system in the distance direction to the tth fast time and the azimuth direction to the fth slow timeFFTThe azimuthal frequency of (t, F), denoted as Fa(ii) a f is a natural number obtained in the step 5 and represents the f-th slow time frequency of the azimuth direction, delta faThe radar system azimuth frequency resolution, N, obtained by initialization in step 1aThe number of sampling points in the azimuth direction of the radar system, S, obtained by initialization in step 1FFT(t, f) is echo data of the radar system obtained in the step 5 in the distance direction to the tth fast moment and the frequency direction to the fth slow moment;
the echo data S of the distance to the tth fast time azimuth and the fth slow time frequencyFFT(t,f)，t＝1,2,…,Nr，f＝1,2,…,NaEcho data S from the tth fast time azimuth to the f slow time frequency pointFFT(t,f)，t＝1,2,…,Nr，f＝1,2,…,NaAzimuthal frequency F ofaCentered at 0, divided into Fa> 0 and Fa< 0 two moieties;
the distance is changed to the tth fast time azimuth to the fth slow time frequency echo data SFFT(t,f)，t＝1,2,…,Nr，f＝1，2，…，NaFrequency F of the middle azimuthaThe echo with the part less than 0 is set to zero to obtain the forward looking distance time domain-azimuth frequency domain echo data which is recorded as SFFFT(t，f)，t＝1，2，…，Nr，f＝1，2，…，Na；
The distance is changed to the tth fast time azimuth to the fth slow time frequency echo data SFFT(t，f)，t＝1，2，…，Nr，f＝1，2，…，NaFrequency F of the middle azimuthaThe echo with the part larger than 0 is set to zero to obtain the echo data of the rear-view distance time domain-azimuth frequency domain, which is recorded as SBFFT(t，f)，t＝1，2，…，Nr，f＝1，2，…，Na；
Adopting a standard Fourier inverse transformation method to carry out forward-looking distance time domain-azimuth frequency domain echo data SFFFT(t，f)，t＝1，2，…，Nr，f＝1，2，…，NaPerforming inverse Fourier transform in the azimuth direction to obtain echo data after distance compression of the radar system antenna in the forward looking direction from the t-th fast time azimuth to the k-th slow time, and recording the echo data as SF (t, k), wherein t is 1,2, …, Nr，k＝1，2，…，Na；
Adopting a standard Fourier inverse transformation method to carry out backward vision distance time domain-azimuth frequency domain echo data SBFFT(t，f)，t＝1，2，…，Nr，f＝1，2，…，NaPerforming inverse Fourier transform in the azimuth direction to obtain echo data compressed by the high-speed platform BiDi SAR system antenna from the azimuth direction to the kth fast time to the kth slow time, and recording the echo data as SB (t, k), wherein t is 1,2, …, Nr，k＝1，2，…，Na；
Step 7, initializing parameters of a bidirectional synthetic aperture imaging radar BiDiSAR projection imaging space:
initializing a BiDiSAR projection imaging space of the bidirectional synthetic aperture imaging radar as a ground plane coordinate system, marking the horizontal axis of the coordinate system as an X axis, marking the horizontal vertical axis of the coordinate system as a Y axis, and positioning the central coordinate of the radar projection imaging space at [2040,110000 ]]The number of X axial resolution units in the radar projection imaging space is recorded as NxThe number of Y-axis resolution units in the radar projection imaging space is recorded as NyX-axis imaging range of radar projection imaging space, denoted as WxY-axis imaging range of radar projection imaging space, denoted as WyX-axial Unit resolution of the Radar projection imaging space, denoted as ρxThe Y-axis unit resolution of the radar projection imaging space is recorded as rhoyReference slant distance, denoted R, of the radar system to the projection imaging space0(ii) a Uniformly dividing the radar projection imaging space to obtain a two-dimensional resolution unit of the projection imaging space, and recording the two-dimensional resolution unit as PT(a，r)＝[x(a，r)，y(a，r)]，a＝1，…，Nx，r＝1，…，NyWherein a and r are natural numbers, a represents the a-th resolution unit in the X-axis direction in the projection imaging space, r represents the r-th resolution unit in the Y-axis direction in the projection imaging space, and X (a, r) and Y (a, r) represent the X-axis position, X (a, r) and Y (a, r) of the two-dimensional resolution unit in the projection imaging space, respectively,A Y axial position;
step 8, performing projection imaging processing on the resolution unit by adopting standard synthetic aperture radar rear homography projection imaging algorithm
Enabling all resolution units P in the projection imaging space of the bidirectional synthetic aperture imaging radar BiDi SAR system obtained in the step 7T(a，r)，a＝1，…，Nx，r＝1，…，NyAnd the coordinate of the altitude direction is 0, and the standard synthetic aperture radar back projection imaging algorithm is adopted to perform foresight distance compression on echo data SF (t, k) of the radar system antenna from the tth fast time azimuth to the kth slow time, wherein t is 1,2, … and Nr，k＝1，2，…，NaImaging processing is carried out to obtain a forward-looking imaging result of the radar system antenna, which is marked as If(a，r)，a＝1，…，Nx，r＝1，…，NyWherein SF (t, k), t ═ 1,2, …, Nr，k＝1，2，…，NaStep 6, compressing the distance of the radar system antenna forward looking at the kth fast time and the kth slow time from the distance to the tth fast time;
enabling all resolution units P in the projection imaging space of the bidirectional synthetic aperture imaging radar BiDi SAR system obtained in the step 7T(a，r)，a＝1，…，Nx，r＝1，…，NyAnd the height-direction coordinate is 0, echo data SB (t, k) compressed by the radar system antenna from the distance to the tth fast time azimuth to the kth slow time rearview distance is acquired by adopting a standard synthetic aperture radar back projection imaging algorithm, and t is 1,2, … and Nr，k＝1，2，…，NaImaging processing is carried out to obtain a radar system antenna rearview imaging result which is marked as Ib(a，r)，a＝1，…，Nx，r＝1，…，NyWherein SB (t, k), t ═ 1,2, …, Nr，k＝1，2，…，NaStep 6, echo data obtained by compressing the distance of the radar system antenna from the distance to the tth fast time azimuth to the kth slow time backsight;
step 9, adopting an amplitude subtraction method to suppress stationary clutter
The forward-looking imaging result I of the radar system antenna obtained in the step 8f(a, r) and radar system antenna rearview imaging result Ib(a, r) using formula Iresult(a，r)＝|If(a，r)|-|Ib(a, r) |, calculating to obtain a signal after static clutter suppression, and marking as Iresult(a，r)，a＝1，…，Nx，r＝1，…，NyWhere | represents an absolute operator;
step 10, detecting a moving target and determining the position range of the moving target
Adopting a maximum value selection method constant false alarm detection method of the traditional standard to carry out the signal I after the static clutter suppression obtained in the step 9result(a，r)，a＝1，…，Nx，r＝1，…，NyAnd carrying out constant false alarm detection, and respectively detecting:
(1) detecting radar system antenna forward-looking imaging result IfMoving targets in (a, r) are described as
Figure FDA0003409463310000041
Figure FDA0003409463310000042
(2) Detecting radar system antenna back vision imaging result IbMoving targets in (a, r) are described as
Figure FDA0003409463310000043
Figure FDA0003409463310000044
(3) Detecting the forward-looking imaging result I of the moving target on the antenna of the radar systemfThe range of positions in (a, r) is described as
Figure FDA0003409463310000051
Figure FDA0003409463310000052
Wherein the content of the first and second substances,
Figure FDA0003409463310000053
representing the forward view imaging result I of the moving target on the antenna of the radar systemf(a, r) position coordinates of azimuth direction,
Figure FDA0003409463310000054
representing the forward view imaging result I of the moving target on the antenna of the radar systemf(a, r) position coordinates in the radial direction,
Figure FDA0003409463310000055
representing the forward view imaging result I of the moving target on the antenna of the radar systemf(a, r) coordinates of the azimuth center point,
Figure FDA0003409463310000056
representing the forward view imaging result I of the moving target on the antenna of the radar systemf(a, r) coordinates of the distance to the center point,
Figure FDA0003409463310000057
representing the forward view imaging result I of the moving target on the antenna of the radar systemfThe length of the position in the azimuth direction in (a, r),
Figure FDA0003409463310000058
representing the forward view imaging result I of the moving target on the antenna of the radar systemf(a，r)，a＝1，…，Nx，r＝1，…，Ny；
(4) Detecting the back vision imaging result I of the moving target in the radar system antennafThe range of positions in (a, r) is described as
Figure FDA0003409463310000059
Figure FDA00034094633100000510
Wherein the content of the first and second substances,
Figure FDA00034094633100000511
representing the back-view imaging result I of the moving target on the radar system antennab(a, r) position coordinates of azimuth direction,
Figure FDA00034094633100000512
representing the back-view imaging result I of the moving target on the radar system antennab(a, r) position coordinates in the radial direction,
Figure FDA00034094633100000513
representing the back-view imaging result I of the moving target on the radar system antennaf(a, r) coordinates of the azimuth center point,
Figure FDA00034094633100000514
representing the back-view imaging result I of the moving target on the radar system antennaf(a，r)，a＝1，…，Nx，r＝1，…，NyThe middle distance is towards the coordinate of the central point,
Figure FDA00034094633100000515
representing the back-view imaging result I of the moving target on the radar system antennafThe length of the position in the azimuth direction in (a, r),
Figure FDA00034094633100000516
representing the back-view imaging result I of the moving target on the radar system antennab(a, r) wherein a is 1, …, Nx，r＝1，…，Ny；
Step 11, obtaining the azimuth speed of the moving target with low precision
Forward-looking imaging result I of the moving target obtained in the step 10 on the radar system antennafCoordinates of azimuth center point in (a, r)
Figure FDA00034094633100000517
Position coordinates of the moving target in the forward-looking imaging result of the radar system antenna are recorded
Figure FDA00034094633100000518
Figure FDA00034094633100000524
The moving target obtained in the step 10 is subjected to back vision imaging result I of the radar system antennabCoordinates of azimuth center point in (a, r)
Figure FDA00034094633100000519
As a result of the back-view imaging of moving targets on the radar system antenna IbPosition coordinates in (a, r) are noted
Figure FDA00034094633100000520
Figure FDA00034094633100000521
Using a formula
Figure FDA00034094633100000522
Calculating to obtain the speed of the initial azimuth direction of the moving target,
Figure FDA00034094633100000523
speed representing initial azimuth direction of moving target, Δ t ═ R0tanθ1-R0tanθ2)/VpxRepresenting the time interval, V, of the bidirectional synthetic aperture imaging radar BiDi SAR along the trackpxFor the azimuthal speed of movement, R, of the radar platform initialized in step 10Reference slope distance theta of the radar system to the projection imaging space in step 71And theta2Respectively transmitting an azimuth squint angle of a front-view wave beam by the radar antenna initialized in the step 1 and transmitting an azimuth squint angle of a rear-view wave beam by the radar antenna;
step 12, initializing parameters required by moving target iterative imaging
Initializing parameters required by moving target iterative imaging, comprising: the maximum number of times of algorithm iteration is marked as MI, and the threshold value of algorithm iteration is marked as epsilon; estimated motion during the ith iterationThe velocity of the remaining azimuth of the target is recorded as
Figure FDA0003409463310000061
The azimuth velocity of the moving target estimated by the ith iteration is recorded as
Figure FDA0003409463310000062
I is 1, …, MI in the process of the ith iteration, wherein i is a natural number and represents the ith iteration of the imaging algorithm,
Figure FDA0003409463310000063
the speed of the moving target in the initial azimuth direction;
step 13, initializing parameters of a moving target iterative imaging projection space:
recording the moving target iterative imaging projection space as omega; x-axis imaging range, marked as W ', of moving target iterative imaging projection space omega'x(ii) a Y-axis imaging range, noted as W ', of moving target iterative imaging projection space omega'y(ii) a X-axis center coordinate of moving target iterative imaging projection space omega is marked as W'xc(ii) a Y-axis center coordinate of moving target iterative imaging projection space omega is marked as W'yc(ii) a Wherein, the X-axis imaging range of the moving target iterative imaging projection space omega
Figure FDA0003409463310000064
Y-axis imaging range W 'of moving target iterative imaging projection space omega'y＝W′x(ii) a X-axis center coordinate of moving target iterative imaging projection space omega
Figure FDA0003409463310000065
Y-axis center coordinate of moving target iterative imaging projection space omega
Figure FDA0003409463310000066
Wherein the content of the first and second substances,
Figure FDA0003409463310000067
for the moving target obtained in step 10, an imaging result I is obtained before the radar system antennaf(a，r)，a＝1，…，Nx，r＝1，…，NyThe length of the position in the middle azimuth direction,
Figure FDA0003409463310000068
the moving target obtained in the step 10 is viewed from the rear of the radar system antenna to form an imaging result Ib(a，r)，a＝1，…，Nx，r＝1，…，NyThe length of the position in the middle azimuth direction,
Figure FDA0003409463310000069
for the moving target obtained in step 10, an imaging result I is obtained before the radar system antennaf(a，r)，a＝1，…，Nx，r＝1，…，NyThe coordinates of the middle position towards the center point,
Figure FDA00034094633100000610
the moving target obtained in the step 10 is viewed from the rear of the radar system antenna to form an imaging result Ib(a，r)，a＝1，…，Nx，r＝1，…，NyThe coordinates of the central point in the middle direction; the X axial unit resolution of the moving target iterative imaging projection space omega is set as rholx(ii) a The Y-axis unit resolution of the moving target iterative imaging projection space omega is set as rholy(ii) a The number of X-axis resolution units of the moving target iterative imaging projection space omega is recorded as N'x(ii) a The number of Y-axis resolution units of the moving target iterative imaging projection space omega is recorded as N'y(ii) a And the reference slant distance of the projection space omega of the iterative imaging of the moving target is marked as R0；
Uniformly dividing the moving target iterative imaging projection space omega to obtain a two-dimensional resolution unit of the moving target iterative imaging projection space omega, and marking as PΩ(m，n)＝[x(m，n)，y(m，n)]，m＝1，…，N′x，n＝1，…，N′yWherein m and n are natural numbers, m represents the m-th resolution unit in the X axial direction in the moving target iterative imaging projection space omega, and n represents the Y-th resolution unit in the Y axial direction in the moving target iterative imaging projection space omegaThe system comprises n resolution units, wherein X (m, n) and Y (m, n) respectively represent the X axial position and the Y axial position of an omega two-dimensional resolution unit in a moving target iterative imaging projection imaging space;
step 14, projection imaging processing is carried out on the moving target
The speed of the moving target in the ith iteration imaging is recorded as
Figure FDA0003409463310000071
Representing the ith iteration of the imaging algorithm, and MI is the maximum iteration number of the algorithm; all resolution units P of the moving target iterative imaging projection space omega obtained in the step 13Ω(m, N) coordinates of the height direction are 0, m is 1, …, N'x，n＝1，…，N′yBy the formula
Figure FDA0003409463310000072
Calculating azimuth time t of radar platformmAll resolution units P of the projection space omega from time to moment to moving target iterative imagingΩ(m, N), m ═ 1, …, N'x，n＝1，…，N′yIs denoted as R (P)Ω，tm) (ii) a Wherein, tmFor the time of the azimuth direction initialized in step 1, P (0) is the initial position of the antenna of the radar system mentioned in step 1, VpVelocity vector of platform motion, V, mentioned for step 1mFor the moving target speed vector mentioned in step 1, | | | | non-calculation22 norm operation representing a vector;
constructing a compensation function
Figure FDA0003409463310000073
Where lambda is the radar carrier wavelength mentioned in step 1,
Figure FDA0003409463310000074
denotes an imaginary unit, and c is 2.71828183 constant;
compressing the distance of the radar system antenna to the kth slow time in the direction from the tth fast time, wherein t is 1,2, …, Nr，k＝1，2，…，NaAnd a compensation function
Figure FDA0003409463310000075
Iterative imaging processing is carried out by adopting a standard back projection imaging algorithm to obtain an iterative projection imaging result of the forward-looking echo data, and the result is recorded as
Figure FDA0003409463310000076
Figure FDA0003409463310000077
And representing the ith iteration of the imaging algorithm, wherein SF (t, k) is echo data obtained by the radar system antenna obtained in the step 6 after the distance compression is carried out before the distance is oriented to the kth fast time and the kth slow time, and t is 1,2, …, Nr，k＝1，2，…，Na；
Compressing echo data SB (t, k) of radar system antenna after the distance from the tth fast time azimuth to the kth slow time, wherein t is 1,2, …, Nr，k＝1，2，…，NaAnd a compensation function
Figure FDA0003409463310000078
Performing iterative imaging processing by adopting a standard back projection imaging algorithm to obtain an iterative projection imaging result of the back vision echo data, and recording the result as a
Figure FDA0003409463310000079
Figure FDA00034094633100000710
Representing the ith iteration of the imaging algorithm, SB (t, k) is echo data of the radar system antenna obtained in the step 6 after the radar system antenna is compressed from the distance direction to the tth fast time to the kth slow time, wherein t is 1,2, …, Nr，k＝1，2，…，Na；
Step 15, calculating the speed of the moving target in the azimuth direction in an iterative manner
Using the peak value of the moving target as the imaging bit of the moving targetIterative projection imaging result of moving target in front-view echo data
Figure FDA0003409463310000081
Position in
Figure FDA0003409463310000082
Representing the ith iteration of the imaging algorithm, the iterative projection imaging result of the moving target rearview echo data
Figure FDA0003409463310000083
Position in
Figure FDA0003409463310000084
Represents the ith iteration of the imaging algorithm;
using a formula
Figure FDA0003409463310000085
Calculating the speed of the residual azimuth direction of the moving target, wherein i is 1, …, and MI represents the ith iteration of the imaging algorithm; wherein MI is the maximum number of times of algorithm iteration obtained by initialization in step 12, Δ t is the time interval of the BiDiSAR along the track in step 11,
Figure FDA0003409463310000086
representing the remaining azimuth velocity;
using a formula
Figure FDA0003409463310000087
Calculating the residual azimuth velocity of the moving target in the ith iteration process
Figure FDA0003409463310000088
Compensating the azimuth velocity of the moving target estimated by the i-1 th iteration
Figure FDA0003409463310000089
In the ith iteration processThe calculated azimuth velocity of the moving target is recorded as
Figure FDA00034094633100000810
Where i is 1, …, MI represents the ith iteration of the imaging algorithm, MI is the maximum number of iterations of the algorithm initialized in step 12, and the iteration initial value of the moving target azimuth velocity is the azimuth velocity of the moving target calculated in step 11
Figure FDA00034094633100000811
Step 16, determining the iterative condition of the algorithm and obtaining the final azimuth velocity estimation result
If it is not
Figure FDA00034094633100000812
And i is less than or equal to MI, adding 1 to the iteration times i of the imaging algorithm to obtain i ← i + 1; repeating the steps 13, 14 and 15;
if it is not
Figure FDA00034094633100000813
Or i is more than or equal to MI, the iteration step is terminated, and the obtained product
Figure FDA00034094633100000814
The final estimated speed of the moving target azimuth direction is obtained; where i is 1, …, MI represents the ith iteration of the imaging algorithm, MI is the maximum number of iterations of the algorithm initialized in step 12, epsilon is the threshold value of the algorithm iteration initialized in step 12,
Figure FDA00034094633100000815
for the estimated azimuth velocity of the moving target in the ith iteration process of the algorithm,
Figure FDA00034094633100000816
the estimated azimuth velocity of the moving target in the i-1 iteration process of the algorithm.
CN201810767255.9A 2018-07-13 2018-07-13 High-speed platform SAR slow moving target detection and speed estimation method Active CN108776342B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201810767255.9A CN108776342B (en) 2018-07-13 2018-07-13 High-speed platform SAR slow moving target detection and speed estimation method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201810767255.9A CN108776342B (en) 2018-07-13 2018-07-13 High-speed platform SAR slow moving target detection and speed estimation method

Publications (2)

Publication Number Publication Date
CN108776342A CN108776342A (en) 2018-11-09
CN108776342B true CN108776342B (en) 2022-03-15

Family

ID=64031248

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201810767255.9A Active CN108776342B (en) 2018-07-13 2018-07-13 High-speed platform SAR slow moving target detection and speed estimation method

Country Status (1)

Country Link
CN (1) CN108776342B (en)

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109581377B (en) * 2018-12-28 2021-02-26 中科院计算技术研究所南京移动通信与计算创新研究院 Resolution evaluation method and device for point echo imaging quality and storage medium
CN110146882B (en) * 2019-04-03 2021-04-23 北京空间飞行器总体设计部 Moving target detection and parameter estimation method based on spaceborne video SAR
CN110109102B (en) * 2019-04-04 2022-05-03 电子科技大学 SAR moving target detection and speed estimation method
CN110412568B (en) * 2019-07-05 2022-12-23 西安电子科技大学 Distance fuzzy clutter suppression method based on extended azimuth phase coding
CN110568434B (en) * 2019-07-15 2022-06-03 电子科技大学 Multi-channel uniform acceleration SAR moving target two-dimensional speed estimation method
CN113447926B (en) * 2021-06-25 2023-02-28 北京航空航天大学 Method and system for detecting foreign matters on airfield runway based on vehicle-mounted sliding rail SAR imaging
CN114002674A (en) * 2021-10-08 2022-02-01 电子科技大学 Multiple-overlapping-movement target position and speed estimation method based on SBRIM
CN115291213B (en) * 2022-09-28 2022-12-20 中国电子科技集团公司第十四研究所 Moving target azimuth velocity estimation method based on dual-beam SAR
CN115657031B (en) * 2022-12-12 2023-03-07 中国科学院空天信息创新研究院 Image domain moving target detection method based on long-time sliding bunching

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6911933B1 (en) * 2004-05-14 2005-06-28 The United States Of America As Represented By The Secretary Of The Air Force Dynamic logic algorithm used for detecting slow-moving or concealed targets in synthetic aperture radar (SAR) images
JP2008185375A (en) * 2007-01-29 2008-08-14 Mitsubishi Electric Corp 3d shape calculation device of sar image, and distortion correction device of sar image
JP2014160027A (en) * 2013-02-20 2014-09-04 Mitsubishi Electric Corp Synthetic opening radar device
CN104297759A (en) * 2014-10-23 2015-01-21 中国科学院上海光学精密机械研究所 Hyperbolic wave forward difference self-scanning direct-view synthetic aperture laser imaging radar
CN107748362A (en) * 2017-10-10 2018-03-02 电子科技大学 A kind of quick autohemagglutination focusing imaging methods of linear array SAR based on maximum sharpness

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7109911B1 (en) * 2002-04-01 2006-09-19 Cataldo Thomas J Dual synthetic aperture radar system
DE102006006962A1 (en) * 2006-02-14 2007-08-16 Smiths Heimann Gmbh Method and device for the high-resolution imaging of test objects by means of electromagnetic waves, in particular for checking persons for suspicious objects
WO2012061945A1 (en) * 2010-11-10 2012-05-18 Ambercore Software Inc. System and method for object searching using spatial data
JP6016529B2 (en) * 2012-08-27 2016-10-26 三菱電機株式会社 Synthetic aperture radar equipment
CN103278820B (en) * 2013-05-27 2015-04-15 电子科技大学 Moving target detection method and imaging method for near space slow platform SAR (Synthetic Aperture Radar)
CN104808204A (en) * 2015-04-13 2015-07-29 电子科技大学 Moving-target detecting method and imaging method of stationary transmitter bistatic forward-looking synthetic aperture radar (SAR)
CN106443671A (en) * 2016-08-30 2017-02-22 西安电子科技大学 SAR radar moving target detecting and imaging method based on FM continuous wave
CN106772378B (en) * 2017-03-06 2019-04-09 中国人民解放军国防科学技术大学 A kind of synthetic aperture radar movement overseas Ship Target speed estimation method
CN107728144B (en) * 2017-10-10 2020-06-16 电子科技大学 Interference SAR imaging method based on forward-looking double-basis mode

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6911933B1 (en) * 2004-05-14 2005-06-28 The United States Of America As Represented By The Secretary Of The Air Force Dynamic logic algorithm used for detecting slow-moving or concealed targets in synthetic aperture radar (SAR) images
JP2008185375A (en) * 2007-01-29 2008-08-14 Mitsubishi Electric Corp 3d shape calculation device of sar image, and distortion correction device of sar image
JP2014160027A (en) * 2013-02-20 2014-09-04 Mitsubishi Electric Corp Synthetic opening radar device
CN104297759A (en) * 2014-10-23 2015-01-21 中国科学院上海光学精密机械研究所 Hyperbolic wave forward difference self-scanning direct-view synthetic aperture laser imaging radar
CN107748362A (en) * 2017-10-10 2018-03-02 电子科技大学 A kind of quick autohemagglutination focusing imaging methods of linear array SAR based on maximum sharpness

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
《多波段/多波形新体制SAR运动目标检测与成像》;王金伟;《中国博士学位论文全文数据库 信息科技辑》;20170215;I136-240 *

Also Published As

Publication number Publication date
CN108776342A (en) 2018-11-09

Similar Documents

Publication Publication Date Title
CN108776342B (en) High-speed platform SAR slow moving target detection and speed estimation method
CN108051809B (en) Moving target imaging method and device based on Radon transformation and electronic equipment
Marques et al. Velocity estimation of fast moving targets using a single SAR sensor
CN110109102B (en) SAR moving target detection and speed estimation method
JP6660857B2 (en) Method of generating image of region of interest using radar system
US8797206B2 (en) Method and apparatus for simultaneous multi-mode processing performing target detection and tracking using along track interferometry (ATI) and space-time adaptive processing (STAP)
EP1505408B1 (en) A method for SAR processing without INS data
CN109856635B (en) CSAR ground moving target refocusing imaging method
USH1720H (en) Time frequency processor for radar imaging of moving targets
CN110568434B (en) Multi-channel uniform acceleration SAR moving target two-dimensional speed estimation method
US20050179579A1 (en) Radar receiver motion compensation system and method
Sjogren et al. Moving target relative speed estimation and refocusing in synthetic aperture radar images
CN104898119B (en) A kind of moving target parameter estimation method based on correlation function
CN109407070B (en) High-orbit platform ground moving target detection method
Martorella Introduction to inverse synthetic aperture radar
Duman et al. Moving target artifacts in bistatic synthetic aperture radar images
Rahman Focusing moving targets using range migration algorithm in ultra wideband low frequency synthetic aperture radar
JP2017003494A (en) Radar system, and radar signal processing method
Zhang et al. An airborne/missile-borne array radar forward-looking imaging algorithm based on super-resolution method
US20230314588A1 (en) Method, radar system and vehicle for signal processing of radar signals
CN114325700A (en) Satellite-borne multi-channel SAR moving target imaging method
US11753126B2 (en) Underwater vehicle inspection
CN114814761A (en) Radar data processing for vehicle ego-motion estimation
Farhadi et al. Synthetic aperture radar imaging of moving targets for automotive applications
CN103543452A (en) Bistatic synthetic aperture radar imaging method on basis of Doppler frequency expansion

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