CN104931967B - A kind of improved High Resolution SAR Imaging self-focusing method - Google Patents
A kind of improved High Resolution SAR Imaging self-focusing method Download PDFInfo
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- 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
- G01S13/9019—Auto-focussing of the SAR signals
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- 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
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Abstract
The invention discloses a kind of improved High Resolution SAR Imaging self-focusing method, its thinking is：Range pulse compression is carried out successively to radar echo signal, preliminary motion is compensated, distance is to FFT, the reduced form of motion compensation radar echo signal and the motion compensation radar echo signal is obtained successively, the reduced form of motion compensation radar echo signal is multiplied by orientation Dechirp functions, two-dimensional interpolation is carried out respectively along distance to orientation again, obtain after two-dimensional interpolation radar echo signal, along distance to making inverse IFFT, obtain phase history numeric field data, the envelope error compensation of phase history numeric field data is completed using the SAR autofocus algorithms of image shift, the phase error for the phase history numeric field data for completing envelope error compensation is solved using conjugate gradient algorithms, after the phase history numeric field data for obtaining completion envelope error compensation and phase error compensation, IFFT is carried out along orientation, obtain focusing on good High Resolution SAR Imaging.
Description
Technical field
The invention belongs to radar imaging technology field, more particularly to a kind of improved High Resolution SAR Imaging self-focusing side
Method, it is adaptable to the kinematic error compensation of airborne SAR imaging.
Background technology
Self-focusing method is, from data, to estimate non-NULL changeable phases margin of error influential on imaging results
According to, and the non-NULL changeable phases error information is compensated, so as to obtain good imaging results.
Existing self-focusing method can generally be divided into three classes, and be specifically：Method based on image shift, phase gradient
The method of self-focusing (Phase Gradient Autofocus, PGA) and the method based on cost function.Based on image shift
Though method is easily achieved, in High Resolution SAR Imaging during the kinematic error of estimated form complexity, obtained kinematic error is estimated
Meter precision does not reach requirement；Phase gradient autofocus method be movement compensation process in SAR imagings it is commonly used it is a kind of from
Focus method, this method can accurately estimate its any form of kinematic error for the data containing isolated scattering point, but
The data without obvious strong scattering point, the data such as obtained under desert, sea condition, the party for signal to noise ratio is relatively low, in scene
The motion error extraction performance of method is also poor；Method amount of calculation based on cost function is general than larger, and this method is held very much
It is vulnerable to the influence of cost function self character, also cannot get good focusing effect using this method.
The content of the invention
The deficiency existed for existing method, it is an object of the invention to propose a kind of improved High Resolution SAR Imaging
Self-focusing method, this method is corrected under positive side-looking mode to the SAR envelope errors being imaged and phase error, can be obtained
To the good High Resolution SAR Imaging of focusing, and the type and complexity of phase error are not limited.
To reach above-mentioned technical purpose, the present invention, which is adopted the following technical scheme that, to be achieved.
A kind of improved High Resolution SAR imaging self-focusing method, comprises the following steps：
Step 1, the radar echo signal received to SAR radar antennas is carried out after range pulse compression, is obtained apart from arteries and veins
Press radar echo signalWherein,Represent orientation fast time, tmRepresent the orientation slow time.
Step 2, Pulse-compression Radar of adjusting the distance echo-signalMotion compensation is carried out, and does distance and becomes to fast Flourier
(FFT) is changed, motion compensation radar echo signal s (f are obtained successivelyr,tm) and the motion compensation radar echo signal reduced formWherein,Represent orientation fast time, tmRepresent orientation slow time, frRepresent pulse recurrence frequency.
Step 3, by the reduced form of motion compensation radar echo signalIt is multiplied by orientation Dechirp functions Ha(fr,
tm), obtain removing the motion compensation radar echo signal of orientation frequency modulation rate；Wherein, tmRepresent orientation slow time, frRepresent pulse
Repetition rate.
Step 4, to remove orientation frequency modulation rate motion compensation radar echo signal along distance to and orientation carry out respectively
After two-dimensional interpolation, two-dimensional interpolation radar echo signal S is obtainedr(kx；ky), then to two-dimensional interpolation radar echo signal Sr(kx；
ky) along distance to inverse fast fourier transform (IFFT) is made, obtain phase history numeric field data；Wherein, kxRepresent orientation interpolation letter
Number, kyRepresent distance to interpolating function.
Step 5, to phase history numeric field data along distance to (J-j) down-sampled operation again is carried out, then using image shift
SAR autofocus algorithms estimation (J-j) phase history numeric field data again after down-sampled operation (j+1) phase error, according to
(j+1) phase error obtains (j+1) envelope error of the phase history numeric field data of (J-j) again after down-sampled operation, and
Phase history numeric field data is carried out after envelope cancellation according to (j+1) the envelope error, obtains completing the phase of envelope error compensation
Position history numeric field data；Wherein, J represents the down-sampled multiple being manually set, j ∈ { 0,1,2 ..., J-1, J }, and J is positive integer.
Step 6, the phase error for the phase history numeric field data for completing envelope error compensation is solved using conjugate gradient algorithms
Estimate, and line phase is entered to the phase history numeric field data for completing envelope error compensation with the opposite number of the phase error estimation and phase error value
Compensation, obtains completing envelope error compensation and the phase history numeric field data of phase error compensation.
Step 7, orientation is carried out against quick Fu to the phase history numeric field data for completing envelope error and phase error compensation
In after leaf transformation (IFFT), obtain focusing on good High Resolution SAR Images.
Beneficial effects of the present invention are：The inventive method SAR is imaged in kinematic error estimation with very high sane
Property and accuracy, the type and complexity of kinematic error are not also limited in being imaged to SAR, are that a kind of high-precision self-focusing is calculated
Method；Also, without substantially isolating in scattering point, low signal-to-noise ratio, the SAR imagings of low contrast scene, use the inventive method
Result in good focusing effect.
Brief description of the drawings
The present invention is described in further detail with reference to the accompanying drawings and detailed description.
Fig. 1 is the High Resolution SAR imaging self-focusing method flow schematic diagram of a modification of the present invention；
Fig. 2 is geometrical model schematic diagram of the SAR platform in positive side view beam bunching mode；
Wherein, using scene center point O as the origin of coordinates, set up any point target P in plane right-angle coordinate, scene (x,
Y) flight path direction is that, along X-axis positive direction, the direction at scene center point O to synthetic aperture radar (SAR) center is square for Y-axis
To P (x, y) is any point target in scene, and the Desired Track of synthetic aperture radar (SAR) platform is square along X-axis with speed v
It is highly the straight line at H to and away from scene center point O, any point target P (x, y) is in the slow time t in orientation in scenemWhen
The ideal position at quarter is N, and N coordinate is (vtm,Rb), any point target P (x, y) is in the slow time t in orientation in scenemThe reality at moment
Border position is A, and A coordinate is (vtm+Δx,Rb+ Δ y), RbRepresent that any point target P (x, y) arrives scene center line in scene
Most short oblique distance；Wherein, Δ R (tm) represent the kinematic error that the non-ideal track of synthetic aperture radar (SAR) platform is introduced, Δ x
(tm) represent point target P (x, y) in the kinematic error of x-axis, Δ y (tm) represent kinematic errors of the point target P (x, y) in y-axis；
Fig. 3 (a) be using the inventive method obtain apart from Pulse-compression Radar echo signal envelope schematic diagram,
Fig. 3 (b) is the two-dimensional interpolation radar echo signal envelope schematic diagram obtained using the inventive method,
Fig. 3 (c) is that the signal envelope for the phase history numeric field data for obtaining completing envelope error compensation using the present invention is illustrated
Figure；
Fig. 4 (a) is, using in the phase history numeric field data of the invention for obtaining completion envelope error compensation, to be added along orientation
The result schematic diagram of conjugate gradient algorithms estimating phase error is utilized after phase error,
Fig. 4 (b) is the result schematic diagram using the self-focusing of conventional phase gradient (PGA) method estimating phase error,
Fig. 4 (c) is that the point target orientation arteries and veins after phase compensation is carried out using the self-focusing of conventional phase gradient (PGA) algorithm
Rush receptance function profile；
Fig. 5 (a) be obtain complete envelope error compensation phase history numeric field data in, along orientation add phase error after
Using the result schematic diagram of the SAR Imaging Autofocus Algorithm estimating phase errors of the image shift of the inventive method,
Fig. 5 (b) is that the point target after phase compensation is carried out using the SAR autofocus algorithms of the image shift of the inventive method
Orientation impulse response function profile.
Embodiment
Reference picture 1, is the High Resolution SAR Imaging self-focusing method flow schematic diagram of a modification of the present invention, this kind
Improved High Resolution SAR is imaged self-focusing method, comprises the following steps：
Step 1, the radar echo signal received to SAR radar antennas is carried out after range pulse compression, is obtained apart from arteries and veins
Press radar echo signalWherein,Represent orientation fast time, tmRepresent the orientation slow time.
The detailed process of step 1 is：
Reference picture 2, is geometrical model of the SAR radars in positive side view beam bunching mode, and it is that coordinate is former to choose scene center point O
Point, sets up plane right-angle coordinate, and SAR radar tracks direction is along X-axis positive direction, scene center to synthetic aperture radar
(SAR) direction at center is Y-axis positive direction, and P is any one point target in scene, and its coordinate is (x, y), and SAR radars are preferable
Flight path be with speed v along X-axis positive direction and away from scene center point O height be H straight line, SAR radars are in the orientation slow time
tmThe ideal position at moment is N, and N coordinate is (vtm,Rb), SAR radars are in the slow time t in orientationmThe physical location at moment is A, A
Coordinate be (vtm+Δx,Rb+ Δ y), RbRepresent SAR radars to scene center point O most short oblique distance, Δ R (tm) represent SAR thunders
Up to the kinematic error of non-ideal track, Δ x (tm) represent point target P in the kinematic error of x-axis, Δ y (tm) represent point target P in y
The kinematic error of axle.
In the slow time t in orientationmAt the moment, the ideal instant oblique distance of SAR radars to point target P is RP(tm), SAR radars are shown up
Scape central point O ideal instant oblique distance is RO(tm), its expression formula difference is as follows：
SAR radars to point target P actual instantaneous oblique distance is R (tm), and the actual instantaneous oblique distance R (tm) expression formula is：
Therefore, the radar echo signal that SAR radar antennas are receivedIt can be expressed as：
Wherein,Represent orientation fast time, tmThe orientation slow time is represented, c represents the light velocity, TpRepresent radar echo signal
Pulse width, γ represents the frequency modulation rate of radar echo signal, fcThe carrier frequency of radar echo signal is represented,RepresentIn the range of amplitude be 1 rectangular window function.
Then, the radar echo signal received to SAR radar antennasMake distance to Fast Fourier Transform (FFT)
(FFT) radar echo signal that, the SAR radar antennas are receivedWhen transforming to frequency of distance domain and orientation respectively
The radar echo signal in frequency of distance domain, is then multiplied by apart from matched filtering function H by domainRMF, eliminated with this apart from quadratic term,
The radar echo signal after matched filtering is obtained, then makees to the radar echo signal after matched filtering distance to inverse
FFT (IFFT), is obtained apart from Pulse-compression Radar echo-signal
Apart from matched filtering function HRMFExpression formula be：
Wherein, B represents the bandwidth of radar echo signal, and B=γ TP, γ represents the frequency modulation rate of radar echo signal, TPTable
Show the pulse width of radar echo signal,Represent orientation fast time, tmThe orientation slow time is represented, c represents the light velocity, fcRepresent thunder
Up to the carrier frequency of echo-signal, R (tm) represent SAR radars to point target P actual instantaneous oblique distance, frRepresent that pulse repeats frequency
Rate, sinc [x] represents non-normalized sinc functions, and exp () represents exponential function.
Step 2, Pulse-compression Radar of adjusting the distance echo-signalMotion compensation is carried out, and does distance and becomes to fast Flourier
(FFT) is changed, motion compensation radar echo signal s (f are obtained successivelyr,tm) and the motion compensation radar echo signal reduced formWherein,Represent orientation fast time, tmRepresent orientation slow time, frRepresent pulse recurrence frequency.
Specifically, motion compensation radar echo signal s (fr,tm) expression formula is：
The reduced form of the motion compensation radar echo signalFor：
Wherein,Represent orientation fast time, tmRepresent orientation slow time, frPulse recurrence frequency is represented, B represents that radar is returned
The bandwidth of ripple signal, c represents the light velocity, fcRepresent the carrier frequency of radar echo signal, R (tm) represent SAR platform to point target P
Actual instantaneous oblique distance, Δ R (tm) represent the non-ideal track of SAR platform in the slow time t in orientationmThe kinematic error at moment, x is represented
Point target P abscissa, y represents point target P ordinate, and v represents speed of the Desired Track of SAR platform along X-axis positive direction,
RP(tm) represent the slow time t in orientationmWhen SAR platform to point target P ideal instant oblique distance, RO(tm) represent SAR platform to scene
Central point O ideal instant oblique distance, RbSAR platform is represented to scene center point O most short oblique distance,Represent
In the range of amplitude be 1 rectangular window function, exp () represent exponential function.
Step 3, by the reduced form of motion compensation radar echo signalIt is multiplied by orientation Dechirp functions Ha(fr,
tm), obtain removing the motion compensation radar echo signal of orientation frequency modulation rate；Wherein, tmRepresent orientation slow time, frRepresent pulse
Repetition rate.
Specifically, orientation Dechirp functions Ha(fr,tm) expression formula be：
Wherein, tmRepresent orientation slow time, frPulse recurrence frequency is represented, c represents the light velocity, fcRepresent radar echo signal
Carrier frequency, v represents speed of the Desired Track of SAR platform along X-axis positive direction, RO(tm) represent SAR platform to scene center
Point O ideal instant oblique distance, RbRepresent SAR platform to scene center point O most short oblique distance, exp () expression exponential functions.
Step 4, to remove orientation frequency modulation rate motion compensation radar echo signal along distance to and orientation carry out respectively
After two-dimensional interpolation, two-dimensional interpolation radar echo signal S is obtainedr(kx；ky), then to two-dimensional interpolation radar echo signal Sr(kx；
ky) along distance to inverse fast fourier transform (IFFT) is made, obtain phase history numeric field data；Wherein, kxRepresent orientation interpolation letter
Number, kyRepresent distance to interpolating function.
Specifically, to remove orientation frequency modulation rate motion compensation radar echo signal along distance to and orientation carry out respectively
After two-dimensional interpolation, two-dimensional interpolation radar echo signal S is obtainedr(kx；ky), its expression formula is：
Wherein, kyDistance is represented to interpolating function, andkxRepresent orientation interpolation letter
Number, andγ represents the frequency modulation rate of radar echo signal, TPRepresent the arteries and veins of radar echo signal
Rush width, tmThe orientation slow time is represented, c represents the light velocity, fcRepresent the carrier frequency of radar echo signal, frRepresent that pulse is repeated
Frequency, sinc [x] represents non-normalized sinc functions, and exp () represents exponential function, and x represents point target P abscissa, y tables
Show point target P ordinate,Represent that the non-ideal track of SAR platform existsThe kinematic error at moment, RbRepresent
Most short oblique distance of the SAR platform to scene center point O.Then to two-dimensional interpolation radar echo signal Sr(kx；ky) enter row distance to
Inverse fast fourier transform (IFFT), obtains phase history numeric field data.
Step 5, to phase history numeric field data along distance to (J-j) down-sampled operation again is carried out, then using image shift
SAR autofocus algorithms estimation (J-j) phase history numeric field data again after down-sampled operation (j+1) phase error, according to
(j+1) phase error obtains (j+1) envelope error of the phase history numeric field data of (J-j) again after down-sampled operation, and
After being compensated according to (j+1) the envelope error to phase history numeric field data, the phase for obtaining completing envelope error compensation is gone through
History numeric field data；Wherein, J represents the down-sampled multiple being manually set, j ∈ { 0,1,2 ..., J-1, J }, and J is positive integer.
The specific sub-step of step 5 is：
5.1 pairs of phase history numeric field datas along distance to carry out J times of down-sampled operation, then using image shift SAR oneself
Focusing algorithm estimates the first phase error of the phase history numeric field data after J times of down-sampled operation, according to the first phase error
The first envelope error of the phase history numeric field data after J times of down-sampled operation is obtained, and according to the first envelope error to phase
History numeric field data is carried out after envelope cancellation, obtains the first compensation phase history numeric field data, wherein, J represents that the drop being manually set is adopted
Sample multiple, J is positive integer；
5.2 pairs of phase history numeric field data distances are to (J-1) down-sampled operation again is carried out, using the SAR autohemagglutinations of image shift
Burnt algorithm estimates the second phase error of phase history numeric field data, obtains J-1 times of (J-1) according to the second phase error down-sampled
Second envelope error of the phase history numeric field data after operation, is wrapped according to the second envelope error to phase history numeric field data
After network compensation, the second compensation phase history numeric field data is obtained.
5.3 similarly, to phase history numeric field data distance to (J-j) down-sampled operation again is carried out, using the SAR of image shift
Autofocus algorithm estimates (j+1) phase error of phase history numeric field data, is obtained (J-j) according to (j+1) phase error
(j+1) envelope error of phase history numeric field data after down-sampled operation, and by the envelope error of jth+1 to phase history again
Numeric field data is carried out after envelope cancellation, obtains (j+1) compensation phase history numeric field data；Wherein, j ∈ { 0,1,2 ..., J-1, J }, J
The down-sampled multiple being manually set is represented, J is positive integer.
This process is repeated, until (j+1) compensation phase of the phase history numeric field data after (J-j) again down-sampled operation is gone through
The signal envelope of history numeric field data is located in same range cell, iteration stopping, now according to (j+1) the envelope error to phase
Position history numeric field data is carried out after envelope cancellation, obtained (j+1) compensation phase history numeric field data, is as completed envelope error and is mended
The phase history numeric field data repaid.
Wherein, J represents the down-sampled multiple being manually set, and generally chooses J=8, and general iteration 3 to 5 times can be to cause
The signal envelope of phase history numeric field data after down-sampled is located in same range cell, you can obtain completing envelope error benefit
The phase history numeric field data repaid.
Step 6, the phase error for the phase history numeric field data for completing envelope error compensation is solved using conjugate gradient algorithms,
And phase compensation is carried out to the phase history numeric field data for completing envelope error compensation with the opposite number of the phase error estimation and phase error value, obtain
To the phase history numeric field data for completing envelope error compensation and phase error compensation.
Specifically, it is assumed that the phase history numeric field data for completing envelope error compensation is nrn row nan column matrix, that is, there are nrn
Range cell and nan localizer unit；The phase error that definition completes the phase history numeric field data of envelope error compensation is one
1*nan matrixes, respectively for nan localizer unit, one unknown number of each localizer unit correspondence.Due to carrying out fast Fourier
When converting (FFT) operation, the points typically taken are 2 integral number powers, therefore, and the integral number power that nan is 2 is set herein.Profit
During with completing the phase history numeric field data of envelope error compensation come estimating phase error, according to by the thick thought to essence, step 6 place
The sub-step of reason process is：
6.1 first stage：Assuming that the phase error for completing the phase history numeric field data of envelope error compensation is 1*nan squares
Battle array, the phase history numeric field data for completing envelope error compensation is nrn row nan column matrix, that is, has nrn range cell and nan
The phase error of localizer unit, then each localizer unit correspondence localizer unit, the corresponding nan phase of nan localizer unit
The initial value of position error is 0, and the phase error of nan localizer unit is solved with conjugate gradient algorithms, nan phase is obtained successively
Error estimate, is designated as Δ φ1；
6.2 second stage：By nan phase error estimation and phase error value Δ φ1It is quantified as four independent variables, first independent change
Measure asThe average value of individual phase error estimation and phase error value, second independent variable is theIndividual phase is missed
The average value of poor estimate, the 3rd independent variable is theThe average value of individual phase error estimation and phase error value, the 4th
Individual independent variable is theThe average value of individual phase error estimation and phase error value；
6.3 will quantify four obtained independent variables as initial value, and four independent variables are solved with conjugate gradient algorithms
Phase error estimation and phase error value, be designated as Δ φ2；
6.4 phase IIIs：Setting phase III independent variable number is 4 times of second stage independent variable number, i.e., 16
Individual independent variable, first independent variable is theThe average value of individual phase error estimation and phase error value, second independent variable be
TheThe average value of individual phase error estimation and phase error value, the 3rd independent variable is theIndividual phase
The average value of error estimate, the 4th independent variable is theThe average value of individual phase error estimation and phase error value, the
Five independent variables are theThe average value of individual phase error estimation and phase error value, the 6th independent variable is theThe average value of individual phase error estimation and phase error value, the 7th independent variable is theIndividual phase
The average value of error estimate, the 8th independent variable is theThe average value of individual phase error estimation and phase error value, the
Nine independent variables are theThe average value of individual phase error estimation and phase error value, the tenth independent variable is theThe average value of individual phase error estimation and phase error value, the 11st independent variable is theIt is individual
The average value of phase error estimation and phase error value, the 12nd independent variable is theIndividual phase error estimation and phase error value
Average value, the 13rd independent variable is theThe average value of individual phase error estimation and phase error value, the 14th solely
Vertical variable is theThe average value of individual phase error estimation and phase error value, the 15th independent variable is theThe average value of individual phase error estimation and phase error value, the 16th independent variable is theIt is individual
The average value of phase error estimation and phase error value, then it regard 16 independent variables after quantization as next stage phase error estimation and phase error
Initial value, the phase error estimation and phase error value of 16 independent variables after the quantization is solved with conjugate gradient algorithms, Δ φ is designated as3；
6.5 i-th stages：Using same quantization strategy, until the i-th stage, the number of independent variable increases to nan,
Iteration stopping, the phase error estimation and phase error value for the nan independent variable that the quantization is obtained is solved with conjugate gradient algorithms, Δ is designated as
φi；Now the phase error of each independent variable corresponds to the phase error of a localizer unit, i.e., each localizer unit pair
Answer a phase error；Wherein, i represents iterations.
Specifically, during iterative different phase phase error, iterations is not to be the bigger the better, because
In practice, the phase error for completing the phase history numeric field data of envelope error compensation is a continuous and slowly varying mistake
Journey, the iteration of too many number of times is likely to cause to complete localizer unit neighbouring in the phase history numeric field data of envelope error compensation
Between phase error variations it is larger so that the phase error curve of the whole phase history numeric field data for completing envelope error compensation
Unsmooth, this is not consistent with actual conditions.Generally, the iteration of 5 times or so is designed with regard to preferable effect can be obtained.
The phase error estimation and phase error value Δ φ of the 6.6 nan independent variables obtained with quantizationiOpposite number, to complete envelope
The phase history numeric field data of error compensation is carried out after phase compensation along orientation, obtains completing envelope error compensation and phase error
The phase history numeric field data of compensation.
Step 7, orientation is carried out against quick Fu to the phase history numeric field data for completing envelope error and phase error compensation
In after leaf transformation (IFFT), obtain focusing on good High Resolution SAR Images.
The correctness and validity of the present invention is further illustrated below by emulation experiment.
(1) simulation parameter
SAR radar simulation parameters are as shown in table 1
Table 1
| Carrier frequency | 10GHz |
| Signal bandwidth | 600MHz |
| Frequency modulation rate | 800MHz |
| Pulse width | 12μs |
| Pulse recurrence frequency | 1.25KHz |
| Carrier aircraft speed | 105m/s |
| Scene center distance | 12km |
| Angle of squint | 0° |
(2) emulation content
Emulation 1：In the SAR radar echo signal gatherer processes of X-band pack, it is plus size along orientationError amount, wherein tmRepresent the orientation slow time.Believed using the motion compensation radar return to removing orientation frequency modulation rate
Number carry out two-dimensional interpolation respectively along distance to orientation, verify the image shift autofocus algorithm of successive ignition to envelope error
The validity of compensation.
Emulation 2：Kinematic error is not added with the radar echo signal gatherer process of X-band Spotlight SAR Imaging, using to removal side
The motion compensation radar echo signal of position frequency modulation rate is carried out after two-dimensional interpolation respectively along distance to orientation, remakes distance to inverse
Fast Fourier Transform (FFT) (IFFT), obtains first phase history numeric field data；Now, edge is added to the first phase history numeric field data
The phase error of orientation, is handled using Phase gradient autofocus (PGA) method and the inventive method, verifies this hair respectively
Validity of the bright method to phase error compensation.
(3) analysis of simulation result
Emulation 1 in, using the inventive method obtain apart from Pulse-compression Radar echo signal envelope schematic diagram, such as Fig. 3 (a)
It is shown；The two-dimensional interpolation radar echo signal envelope schematic diagram obtained using the inventive method, shown in such as Fig. 3 (b), phase history
The envelope of data can change, such as shown in Fig. 3 (b)；Obtain completing the phase history domain of envelope error compensation using the present invention
The signal envelope schematic diagram of data, shown in such as Fig. 3 (c).
Now remaining envelope error very little is can be seen that from Fig. 3 (c), the phase history of envelope error compensation is completed
The signal envelope of numeric field data illustrates that this method is capable of the envelope error of preferably thermal compensation signal in a range cell.
In emulation 2, in the phase history numeric field data for obtaining completing envelope error compensation using the present invention, along orientation plus
The result schematic diagram of conjugate gradient algorithms estimating phase error is utilized after applying aspect error, shown in such as Fig. 4 (a).Using traditional phase
The result schematic diagram of potential gradient self-focusing (PGA) method estimating phase error, shown in such as Fig. 4 (b).
Correspondingly, in the phase history numeric field data for obtaining completing envelope error compensation, phase error is added along orientation
The result schematic diagram of the SAR Imaging Autofocus Algorithm estimating phase errors of the image shift of the inventive method, such as Fig. 5 are used afterwards
(a) shown in；The point target orientation arteries and veins after phase compensation is carried out using the SAR autofocus algorithms of the image shift of the inventive method
Receptance function profile is rushed, shown in such as Fig. 5 (b).
From Fig. 4 (b) as can be seen that substantially being included in the phase error estimated with Phase gradient autofocus (PGA) algorithm
One linear component, though the linear component does not interfere with the focusing performance of final SAR image, can make the position of final SAR image
Put generation overall offset.Fig. 5 (a) shows the phase error estimated using the SAR Imaging Autofocus Algorithms of image shift, with reality
Phase error added by border almost only differs a constant phase, in SAR imaging processes, and constant phase is schemed to final SAR
The focusing results of picture do not influence.Fig. 4 (c) represents to carry out the point mesh after phase compensation with Phase gradient autofocus (PGA) algorithm
The impulse response function center marked in orientation impulse response function profile, the figure is offset, corresponding peak value
Secondary lobe ratio and integration secondary lobe ratio are respectively -12.06dB and -9.34dB, and the SAR for the image shift that Fig. 5 (b) uses for the present invention is certainly
Focusing algorithm carries out the point target orientation impulse response function profile after phase compensation, wherein, integration secondary lobe ratio and peak value
Secondary lobe is than being respectively -13.39dB and -9.88dB.
Simulation result shows that traditional Phase gradient autofocus (PGA) method is missed to the estimate of phase error with phase
There is a linear component between poor actual value so that the estimation obtained using traditional Phase gradient autofocus (PGA) method
Error amount gradually increases, and the inventive method is to the difference between the estimate and actual value of phase error close to zero, and the degree of accuracy is bright
Aobvious to be better than traditional Phase gradient autofocus (PGA) method, azimuth focus effect is close to theoretical value.
In summary, emulation experiment demonstrates the correctness of the present invention, validity and reliability.
Obviously, those skilled in the art can carry out the essence of various changes and modification without departing from the present invention to the present invention
God and scope；So, if these modifications and modification of the present invention belong to the scope of the claims in the present invention and its equivalent technologies
Within, then the present invention is also intended to comprising including these changes and modification.
Claims (8)
1. a kind of improved High Resolution SAR Imaging self-focusing method, it is characterised in that comprise the following steps：
Step 1, the radar echo signal received to SAR radar antennas is carried out after range pulse compression, is obtained apart from pulse pressure thunder
Up to echo-signalWherein,Represent orientation fast time, tmRepresent the orientation slow time；
Step 2, Pulse-compression Radar of adjusting the distance echo-signalMotion compensation is carried out, and does distance to Fast Fourier Transform (FFT), according to
It is secondary to obtain motion compensation radar echo signal s (fr, tm) and the motion compensation radar echo signal reduced formIts
In,Represent orientation fast time, tmRepresent orientation slow time, frRepresent pulse recurrence frequency；
Step 3, by the reduced form of motion compensation radar echo signalIt is multiplied by orientation Dechirp functions Ha(fr, tm), obtain
To the motion compensation radar echo signal for removing orientation frequency modulation rate；Wherein, tmRepresent orientation slow time, frRepresent that pulse repeats frequency
Rate；
Step 4, to remove orientation frequency modulation rate motion compensation radar echo signal along distance to and orientation carry out two dimension respectively
After interpolation, two-dimensional interpolation radar echo signal S is obtainedr(kx；ky), then to two-dimensional interpolation radar echo signal Sr(kx；ky)
Along distance to inverse fast fourier transform is made, phase history numeric field data is obtained；Wherein, kxRepresent orientation interpolating function, kyRepresent
Distance is to interpolating function；
Step 5, to phase history numeric field data along distance to (J-j) down-sampled operation again is carried out, then using the SAR of image shift
(j+1) phase error of the phase history numeric field data of autofocus algorithm estimation (J-j) again after down-sampled operation the, according to (j
+ 1) phase error obtains (j+1) envelope error of the phase history numeric field data of (J-j) again after down-sampled operation, and according to this
(j+1) envelope error is carried out after envelope cancellation to phase history numeric field data, obtains completing the phase history of envelope error compensation
Numeric field data；Wherein, J represents the down-sampled multiple being manually set, j ∈ { 0,1,2 ..., J-1, J }, and J is positive integer；
Step 6, the phase error for the phase history numeric field data for completing envelope error compensation is solved using conjugate gradient algorithms, is used in combination
The opposite number of the phase error estimation and phase error value carries out phase compensation to the phase history numeric field data for completing envelope error compensation, has obtained
Into envelope error compensation and the phase history numeric field data of phase error compensation；
Step 7, orientation is carried out against fast Fourier to the phase history numeric field data for completing envelope error and phase error compensation
After conversion, obtain focusing on good High Resolution SAR Images.
2. improved High Resolution SAR Imaging self-focusing method as claimed in claim 1, it is characterised in that in step 1,
It is described apart from Pulse-compression Radar echo-signalIts expression formula is：
Wherein, B represents the bandwidth of radar echo signal, and B=γ TP, γ represents the frequency modulation rate of radar echo signal, TPRepresent thunder
Up to the pulse width of echo-signal,Represent orientation fast time, tmThe orientation slow time is represented, c represents the light velocity, fcRepresent radar return
The carrier frequency of signal, R (tm) represent SAR platform to point target P actual instantaneous oblique distance, frRepresent pulse recurrence frequency, sin
C [x] represents non-normalized sin c functions, and exp () represents exponential function.
3. improved High Resolution SAR Imaging self-focusing method as claimed in claim 1, it is characterised in that in step 2,
The motion compensation radar echo signal s (fr, tm), its expression formula is：
Wherein, tmRepresent orientation slow time, frPulse recurrence frequency is represented, B represents the bandwidth of radar echo signal, and c represents light
Speed, fcRepresent the carrier frequency of radar echo signal, R (tm) represent SAR platform to point target P actual instantaneous oblique distance, Δ R
(tm) represent the non-ideal track of SAR platform in the slow time t in orientationmThe kinematic error at moment, RP(tm) represent the slow time t in orientationmWhen
SAR platform is to point target P ideal instant oblique distance, RO(tm) SAR platform is represented to scene center point O ideal instant oblique distance,RepresentIn the range of amplitude be 1 rectangular window function, exp () represent exponential function.
4. improved High Resolution SAR Imaging self-focusing method as claimed in claim 1, it is characterised in that in step 2,
The reduced form of the motion compensation radar echo signalIts expression formula is：
Wherein, tmRepresent orientation slow time, frPulse recurrence frequency is represented, B represents the bandwidth of radar echo signal, and c represents light
Speed, fcRepresent the carrier frequency of radar echo signal, Δ R (tm) represent the non-ideal track of SAR platform in the slow time t in orientationmMoment
Kinematic error, x represents point target P abscissa, and y represents point target P ordinate, and v represents the Desired Track edge of SAR platform
The speed of X-axis positive direction, RbSAR platform is represented to scene center point O most short oblique distance,RepresentIn the range of
Amplitude is 1 rectangular window function, and exp () represents exponential function.
5. improved High Resolution SAR Imaging self-focusing method as claimed in claim 1, it is characterised in that in step 3,
The orientation Dechirp functions Ha(fr, tm), its expression formula is：
Wherein, tmRepresent orientation slow time, frPulse recurrence frequency is represented, c represents the light velocity, fcRepresent the load of radar echo signal
Wave frequency rate, v represents speed of the Desired Track of SAR platform along X-axis positive direction, RO(tm) represent SAR platform to scene center point O
Ideal instant oblique distance, RbRepresent SAR platform to scene center point O most short oblique distance, exp () expression exponential functions.
6. improved High Resolution SAR Imaging self-focusing method as claimed in claim 1, it is characterised in that in step 4,
The two-dimensional interpolation radar echo signal Sr(kx；ky), its expression formula is：
Wherein, kyDistance is represented to interpolating function, andkxOrientation interpolating function is represented, andγ represents the frequency modulation rate of radar echo signal, TPRepresent that the pulse of radar echo signal is wide
Degree, tmThe orientation slow time is represented, c represents the light velocity, fcRepresent the carrier frequency of radar echo signal, frRepresent pulse recurrence frequency,
Sin c [x] represent non-normalized sin c functions, and exp () represents exponential function, and x represents point target P abscissa, and y is represented
Point target P ordinate,Represent that the non-ideal track of SAR platform existsThe kinematic error at moment, RbRepresent SAR
Most short oblique distance of the platform to scene center point O.
7. improved High Resolution SAR Imaging self-focusing method as claimed in claim 1, it is characterised in that in steps of 5,
The phase history numeric field data for obtaining completing envelope error compensation, its specific sub-step is：
7.1 pairs of phase history numeric field datas are along distance to J times of down-sampled operation is carried out, then using the SAR self-focusings of image shift
Algorithm estimates the first phase error of the phase history numeric field data after J times of down-sampled operation, and J is obtained according to the first phase error
First envelope error of the phase history numeric field data after down-sampled operation, and according to the first envelope error to phase history domain again
Data are carried out after envelope cancellation, obtain the first compensation phase history numeric field data, wherein, J represents the down-sampled multiple being manually set,
J is positive integer；
7.2 pairs of phase history numeric field data distances are calculated to (J-1) down-sampled operation again is carried out using the SAR self-focusings of image shift
Method estimates the second phase error of phase history numeric field data, and (J-1) is obtained again after down-sampled operation according to the second phase error
Phase history numeric field data the second envelope error, according to the second envelope error to phase history numeric field data carry out envelope cancellation
Afterwards, the second compensation phase history numeric field data is obtained；
7.3 pairs of phase history numeric field data distances are calculated to (J-j) down-sampled operation again is carried out using the SAR self-focusings of image shift
Method estimates (j+1) phase error of phase history numeric field data, obtains (J-j) according to (j+1) phase error down-sampled again
(j+1) envelope error of phase history numeric field data after operation, and by (j+1) the envelope error to phase history numeric field data
Carry out after envelope cancellation, obtain (j+1) compensation phase history numeric field data；Wherein, j ∈ { 0,1,2 ..., J-1, J }, J represents people
For the down-sampled multiple of setting, J is positive integer；
This process is repeated, until (j+1) compensation phase history domain of the phase history numeric field data after (J-j) again down-sampled operation
The signal envelope of data is located in same range cell, and iteration stopping is now gone through according to (j+1) the envelope error to phase
After history numeric field data is compensated, obtained (j+1) compensation phase history numeric field data as completes the phase of envelope error compensation
History numeric field data.
8. improved High Resolution SAR Imaging self-focusing method as claimed in claim 1, it is characterised in that in step 6,
The utilization conjugate gradient algorithms solve the phase error for the phase history numeric field data for completing envelope error compensation, its specific sub-step
Suddenly it is：
8.1 first stage：Assuming that the phase error for completing the phase history numeric field data of envelope error compensation is 1*nan matrixes, it is complete
Phase history numeric field data into envelope error compensation is nrn row nan column matrix, that is, has nrn range cell and nan orientation list
The phase error of member, then each localizer unit correspondence localizer unit, the corresponding nan phase error of nan localizer unit
Initial value be 0, with conjugate gradient algorithms solve nan localizer unit phase error, nan phase error is obtained successively and is estimated
Evaluation, is designated as Δ φ1；
8.2 second stage：By nan phase error estimation and phase error value Δ φ1Four independent variables are quantified as, first independent variable is
TheThe average value of individual phase error estimation and phase error value, second independent variable is theIndividual phase error estimation and phase error
The average value of value, the 3rd independent variable is theThe average value of individual phase error estimation and phase error value, the 4th independence
Variable isThe average value of individual phase error estimation and phase error value；
8.3 will quantify four obtained independent variables as initial value, and the phase of four independent variables is solved with conjugate gradient algorithms
Position error estimate, is designated as Δ φ2；
8.4 phase IIIs：Setting phase III independent variable number is 4 times of second stage independent variable number, i.e., 16 solely
Vertical variable, first independent variable is theThe average value of individual phase error estimation and phase error value, second independent variable is theThe average value of individual phase error estimation and phase error value, the 3rd independent variable is theIndividual phase is missed
The average value of poor estimate, the 4th independent variable is theThe average value of individual phase error estimation and phase error value, the 5th
Individual independent variable is theThe average value of individual phase error estimation and phase error value, the 6th independent variable is theThe average value of individual phase error estimation and phase error value, the 7th independent variable is theIndividual phase
The average value of error estimate, the 8th independent variable is theThe average value of individual phase error estimation and phase error value, the
Nine independent variables are theThe average value of individual phase error estimation and phase error value, the tenth independent variable is theThe average value of individual phase error estimation and phase error value, the 11st independent variable is theIndividual phase
The average value of position error estimate, the 12nd independent variable is theIndividual phase error estimation and phase error value is averaged
Value, the 13rd independent variable is theThe average value of individual phase error estimation and phase error value, the 14th independent change
Measure asThe average value of individual phase error estimation and phase error value, the 15th independent variable is theThe average value of individual phase error estimation and phase error value, the 16th independent variable is theIndividual phase
The average value of position error estimate, then it regard 16 independent variables after quantization as the first of next stage phase error estimation and phase error
Value, the phase error estimation and phase error value of 16 independent variables after the quantization is solved with conjugate gradient algorithms, Δ φ is designated as3；
8.5 i-th stages：Using same quantization strategy, until the i-th stage, the number of independent variable increases to nan, iteration
Stop, the phase error estimation and phase error value for the nan independent variable that the quantization is obtained is solved with conjugate gradient algorithms, Δ φ is designated asi, the
The Δ φ that the i stages obtainiThe phase error of the phase history numeric field data of the completion envelope error compensation of as required solution；Its
In, i represents iterations, and which stage i also illustrates that.
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Families Citing this family (25)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105974414B (en) * | 2016-06-24 | 2019-01-11 | 西安电子科技大学 | High-resolution Spotlight SAR Imaging autohemagglutination focusing imaging method based on two-dimentional self-focusing |
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| CN113670301B (en) * | 2021-07-29 | 2024-02-13 | 西安电子科技大学 | Airborne SAR motion compensation method based on inertial navigation system parameters |
| CN116148856B (en) * | 2023-04-17 | 2023-07-04 | 南京邮电大学 | SAR moving target two-dimensional self-focusing imaging processing method |
| CN116755092B (en) * | 2023-08-17 | 2023-11-07 | 中国人民解放军战略支援部队航天工程大学 | Radar imaging translational compensation method based on complex domain long-short-term memory network |
| CN116973877B (en) * | 2023-09-22 | 2023-12-12 | 南京楚航科技有限公司 | Millimeter wave radar deformation measurement method, system and measurement truth value calibration method |
| CN118112566A (en) * | 2024-04-25 | 2024-05-31 | 中国石油大学(华东) | SAR imaging method of unmanned aerial vehicle |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6037892A (en) * | 1998-05-28 | 2000-03-14 | Multispec Corporation | Method for automatic focusing of radar or sonar imaging systems using high-order measurements |
| US6255981B1 (en) * | 1999-08-04 | 2001-07-03 | Raytheon Company | Method for range alignment and rotation correction of a high resolution image in an inverse synthetic aperture radar system |
| CN101710174B (en) * | 2009-12-10 | 2012-05-23 | 南京航空航天大学 | Self-focusing method for strip synthetic aperture radar images |
| CN104199031B (en) * | 2014-08-12 | 2017-01-25 | 北京理工大学 | Self-focusing method for compensating geosynchronous synthetic aperture radar (GEO SAR) ionized layer scintillation amplitude-phase errors |
| CN104316924B (en) * | 2014-10-15 | 2016-07-13 | 南京邮电大学 | The self-focusing motion compensation process of airborne ultrahigh resolution SAR back projection image |
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