CN110109108A - Moving target radar three-dimensional imaging method based on STFT and FRFT - Google Patents
Moving target radar three-dimensional imaging method based on STFT and FRFT Download PDFInfo
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- CN110109108A CN110109108A CN201910345967.6A CN201910345967A CN110109108A CN 110109108 A CN110109108 A CN 110109108A CN 201910345967 A CN201910345967 A CN 201910345967A CN 110109108 A CN110109108 A CN 110109108A
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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
- G01S13/904—SAR modes
- G01S13/9064—Inverse SAR [ISAR]
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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
- G01S13/9021—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
Abstract
The invention discloses a kind of moving target radar three-dimensional imaging method based on STFT and FRFT, mainly solve the problems, such as that prior art three-dimensional imaging precision is low.Its implementation is: 1) simulating ISAR echo-signal, carry out Short Time Fourier Transform to original echoed signals；2) by the straight line detected in time-frequency plane, the rough estimate evaluation of frequency and frequency modulation rate is obtained；3) original echoed signals are carried out fining Fourier Transform of Fractional Order in smart estimation interval by the analyst coverage that essence estimation is selected according to rough estimate evaluation, obtain signal frequency and the estimation of frequency modulation rate essence；4) CLEAN technology is used, estimates the frequency and frequency modulation rate essence estimated value of all signals；5) frequency and frequency modulation rate obtained using order phase parameter Estimation carries out the reconstruct of the three-dimensional coordinate of target, obtains the three-dimensional imaging of moving target.The present invention improves the precision of parameter Estimation, can be used for motion estimate while being effectively reduced computational complexity.
Description
Technical field
The invention belongs to digital signal processing technique field, in particular to a kind of moving target radar three-dimensional imaging Fang Fang
Method, when can be used for motion estimate, radar ISAR is to its three-dimensional imaging.
Background technique
Inverse Synthetic Aperture Radar ISAR is a kind of round-the-clock, round-the-clock remote probe means, have to moving target into
The ability of row imaging, is widely used in the occasions such as target following, target identification, airport monitoring.Compared to traditional system thunder
It reaches, the rise of ISAR is originated from the broadband signal of its transmitting from dimension resolution ratio, and high azimuth dimension resolution ratio then depends on radar and mesh
The Doppler effect that relative motion generates between mark.
Ozaktas et al. is in " Ozaktas H M, et al.Digital computation of the fractional
1996,44 (9): Fourier transform [J] .IEEE Trans on SP is proposed in fractional order Fu in 2141-2150. "
The decomposition-type algorithm of leaf transformation calculates Fourier Transform of Fractional Order, computation complexity O using Fourier transformation
(NlogN).After original signal has had rotated to suitable fractional order domain, need to carry out the two-dimensional search in fractional order domain,
Rotation angle is smaller, and the calculation amount of two-dimensional search is bigger；If increasing the angular dimension rotated every time, the calculating of algorithm can be reduced
Amount, but the precision of parameter Estimation can be also reduced simultaneously.
Bei Suzhang et al. is in " S C Pei, M H Yeh.Discrete fractional Fourier transform
basedon orthogonal projections[J].IEEE Transactions on SP,1999,47(5):1335-
It proposes to construct Discrete Fractional Fourier by the Hermite feature vector for solving Discrete Fourier transform in 1347. "
The nuclear matrix of transformation, computation complexity are O (N2).Traditional Fourier Transform of Fractional Order needs to revolve original signal from time-frequency domain
Fractional order domain is gone to, the angle rotated every time is smaller, and the section of division is finer, and the precision of estimation is higher, but also can simultaneously
Increase the complexity calculated.
Summary of the invention
It is an object of the invention to deficiencies present in view of the above technology, propose a kind of based on Short Time Fourier Transform
The ISAR three-D imaging method of STFT and fining Fourier Transform of Fractional Order FRFT, to be effectively reduced computational complexity
While, improve the precision of parameter Estimation.
To achieve the above object, technical solution of the present invention includes the following steps:
(1) ISAR echo-signal is simulated, original echoed signals s (t) is obtained；
(2) window function w (t) is selected, Short Time Fourier Transform is carried out to original echoed signals s (t), obtains Fourier in short-term
Transforming function transformation function STFT (t, f)；
(3) straight-line detection is carried out to Short Time Fourier Transform function STFT (t, f) in time-frequency plane, by time-frequency plane
The straight line detected carries out rough estimate to echo-signal, obtains the rough estimate evaluation f of frequency and frequency modulation rate1And k1；
(4) frequency and frequency modulation rate essence estimation interval are selected according to the rough estimate evaluation of frequency and frequency modulation rate；
(5) the essence estimation of parameter is carried out based on Fourier Transform of Fractional Order:
(5a) carries out fining Fourier Transform of Fractional Order FRFT to original echoed signals in smart estimation interval, obtains score
Rank Fourier transform function X (u, p), u are the coordinate of fractional number order Fourier, and p is transformation order；
(5b) finds optimal mapping order p according to X (u, p)0With the coordinate u of fractional number order Fourier0, poly- in energy height
The fractional order domain of collection carries out two-dimensional search and obtains the position [u of peak value0,p0]；
(5c) estimates frequency and frequency modulation rate essence according to peak position, obtains echo-signal frequency essence estimated value f2And frequency modulation
The smart estimated value k of rate2；
(6) CLEAN technology is used, polyteny FM signal is separated one by one, the frequency modulation rate estimated with essence is to multi-thread
Property FM signal is demodulated, and the high concentration peak value that signal occurs in frequency domain is obtained, by the position narrowband of the peak value
Filter filters out, and obtains the frequency f of all signals2And frequency modulation rate k2；
(7) three-dimensional imaging of moving target:
The posture of radar and target is arranged in (7a), establishes target initial coordinate system；
(7b) reconstructs the coordinate system of target under initial coordinate system, utilizes the frequency f of all signals2With frequency modulation rate k2In weight
The three-dimensional coordinate (x, y, z) that target is obtained in structure coordinate system, completes the three-dimensional imaging of moving target.
Compared with the prior art, the invention has the following advantages:
1. computational accuracy is high
The prior art needs to carry out the two dimension in fractional order domain when carrying out parameter Estimation using Fourier Transform of Fractional Order FRFT
Search, rotation angle is smaller, and the calculation amount of two-dimensional search is bigger；If increasing the angular dimension rotated every time, algorithm is reduced
Calculation amount, but the precision of parameter Estimation is also reduced simultaneously.
The method for parameter estimation of STFT and FRFT is used for the three-dimensional imaging of target by the present invention, is become by fractional order Fourier
FRFT is changed, efficiently solves the problems, such as that polyteny FM signal couples, so that the accuracy of three-dimension object is higher.
2. three-dimensional imaging is high-efficient
The present invention accelerates parameter due to combining Short Time Fourier Transform STFT with Fourier Transform of Fractional Order FRFT
The speed of estimation improves the efficiency of three-dimension object.
Detailed description of the invention
Fig. 1 is implementation flow chart of the present invention；
Fig. 2 is the illustraton of model of radar and aerial target in the present invention；
Fig. 3 is the ISAR three-dimensional imaging figure and plane figure in the present invention based on Fourier Transform of Fractional Order FRFT；
Fig. 4 be ISAR three-dimensional based on Short Time Fourier Transform STFT and Fourier Transform of Fractional Order FRFT in the present invention at
As figure and plane figure.
Specific embodiment
In the following with reference to the drawings and specific embodiments, present invention is further described in detail.
Step 1, simulated target echo-signal.
As shown in Fig. 2, radar is to objective emission linear FM signal, while receiving the echo-signal of target reflection, it is assumed that
The echo-signal is original echoed signals s (t), is expressed as follows:
S (t)=∫ a (x) ejφ(x,t)dx
Wherein a (x) is echo signal amplitude, and φ (x, t) is phase function, and j is imaginary unit.
Step 2, Short Time Fourier Transform is carried out to the received original echoed signals s (t) of radar.
According to following formula selecting range high resolution, the big Hanning window w (t) of side lobe attenuation:
W (t)=0.5 (1-cos (2 π t)), | t |≤Tw/2
Wherein t is time, TwIt is long for window；
Short Time Fourier Transform is carried out to the received original echoed signals s (t) of radar according to Hanning window w (t), formula is such as
Under:
Wherein f is frequency, and the coordinate of u fractional Fourier domain, w (u-t) is that Hanning window function w (t) translates u unit, j
For imaginary unit.
Step 3, according to the straight line detected in time-frequency plane, rough estimate is carried out to echo-signal.
(3a) time-frequency plane after Short Time Fourier Transform carries out straight-line detection, obtains straight slope k and straight line
Intercept b:
B=E (IF)-kE (t)
Wherein E (t) is the time average of time-frequency plane, and E (IF) is mean frequency value, and IF is frequency, and IF (t) is t moment
Instantaneous frequency,Wherein f is frequency, and t is the time；
The rough estimate of (3b) frequency modulation rate and frequency:
Using straight slope k as the rough estimate evaluation k of frequency modulation rate1, i.e. k1=k；
Using the intercept b of straight line as the rough estimate evaluation f of frequency1, i.e. f1=b.
Step 4, frequency and frequency modulation rate essence estimation interval are selected according to the rough estimate evaluation of frequency and frequency modulation rate.
If the main lobe width of window function w (t)=0.5 (1-cos (2 π t)) isA length of T when original echoed signals；
According to the rough estimate evaluation of frequency and frequency modulation rate, the estimation of frequency modulation rate essence is obtained
Abbreviation is carried out to above range, obtaining frequency modulation rate essence estimation interval isThe section of frequency essence estimation
For
Step 5, Fourier Transform of Fractional Order FRFT is carried out to original echoed signals in the smart estimation interval that step 4 determines,
Obtain the smart estimated value of frequency and frequency modulation rate.
(5a) is in frequency modulation rate essence estimation intervalWith frequency essence estimation intervalTo original echo
Fourier Transform of Fractional Order FRFT is carried out, formula is as follows:
Wherein j is imaginary unit, and p is the transformation order of Fourier Transform of Fractional Order, and u is fractional number order Fourier coordinate,
T is the time, and X (u, p) is the function after Fourier Transform of Fractional Order；
(5b) finds optimal mapping order p according to X (u, p)0With the coordinate u of fractional number order Fourier0, original echoed signals
When rotating by a certain angle, corresponding Fourier Transform of Fractional Order is an impulse functionIts energy
High concentration inPoint formed with the transformation order p and fractional number order Fourier u of Fourier Transform of Fractional Order
Number rank Fourier (u, p) carries out the two-dimensional search of peak point on this plane, obtains optimal mapping orderp0With fractional order Fu
In leaf domain coordinate u0；
The optimal mapping order p that (5c) is obtained by two-dimensional search0With the coordinate u of fractional number order Fourier0, obtain frequency
Smart estimated value k2And the smart estimated value f of frequency modulation rate2Are as follows:
k2=-cot (p0π/2)
f2=u0csc(p0π/2)。
Step 6, using CLEAN technology, the frequency essence estimated value f of all signals is obtained2And frequency modulation rate k2。
Estimated using the parameter that the estimation method by frequency and frequency modulation rate rough estimate evaluation to smart estimated value carries out first signal
Meter, with the frequency modulation rate k estimated2Polyteny FM signal is demodulated, signal then high concentration can occurring in frequency domain
Peak value；
The position of the peak value is filtered out with narrow band filter, obtains the frequency essence estimated value f of all signals2And frequency modulation
Rate k2。
Step 7, the three-dimensional imaging of moving target.
Radar posture is arranged in (7a1):
U, v, w axis rectangular coordinate system are initially set up, if thunder according to the geometrical relationship of radar and aerial target referring to Fig. 2
Up to rigidity rotation is carried out using u, v, w axis as shaft, it is respectively θ that corresponding instantaneous corner is shaken in radar rolling, pitching, headroll、
θpitch、θyaw, changing rule is with apparent periodical, form are as follows:
H in formularoll、Hpitch、HyawThe respectively amplitude of three-dimensional oscillating,Respectively three-dimensional oscillating
Initial phase, weTo meet with angular speed；
Then, the three-dimensional rotation matrix instantaneous corner of the posture of three-dimensional oscillating radar constituted indicates are as follows:
R (t)=Ryaw(t)Rpitch(t)Rroll(t)e
Wherein e is radar in the position of zero moment, Rroll、Rpitch、RyawFor radar three-dimensional spin matrix, respectively indicate are as follows:
The posture that target moves is arranged in (7a2), i.e. hypothesis target does the linear uniform motion with speed for v；
The posture for posture and the target movement that (7a3) is swung according to radar three-dimensional is built using target Doppler center as origin
Vertical x ', y ', the initial rectangular coordinate system of z ' axis；
(7b) reconstructs the coordinate system of target under initial coordinate system, utilizes the frequency f of all signals2With frequency modulation rate k2In weight
The three-dimensional coordinate (x, y, z) of target is obtained in structure coordinate system:
(7b1) under initial rectangular coordinate system, the phase of echo delay function by target in Doppler domain is indicated are as follows:
Wherein, P point is target Doppler center, and A point is any scattering point in target,Position for A point relative to P point
Set vector, rPFor radar to the distance of some scattering point of target, rAFor radar to the distance at target Doppler center, C is the light velocity,
fcFor carrier frequency,For rPUnit direction vector；
(7b2) establishes x-axis, y-axis, z-axis rectangular coordinate system, defines x-axis, y-axis, the corresponding direction vector of z-axis and is respectivelyAnd phase delay function is unfolded with direction vector:
WhereinForWithConvolution, o (t) be higher order term,For velocity vector,It is A point relative to P point
The position vector in the case where reconstructing coordinate system,It is led for the second order of t=0 moment radar instantaneous position r (t), t is the time；
(7b3) establishes direction vectorThe relationship between the coordinate (x, y, z) of scattering point A:
WhereinFor the position vector for A point relative to P point, x, y, z is the coordinate of target scattering point A, β be speed v with
X-axis angle, θ are radar instantaneous position r (t) and y-axis angle, and v is speed；
(7b4) is according to direction vectorWith the relationship between scattering point A coordinate (x, y, z), by phase delay function into one
Step expansion are as follows:
(7b5) is by phase of echo delay function frequency essence estimated value f2And frequency modulation rate essence estimated value k2It indicates are as follows:
Wherein, R is oblique distance；
(7b6) compares the coefficient of time t in two functions of (7b4) and (7b5), obtains:
X=R
(7b7) carries out abbreviation to the formula of (7b6), obtains the three-dimensionalreconstruction coordinate of target are as follows:
Wherein C is the light velocity, and v is target velocity, and n is the distance unit of scattering point.
Below by way of emulation experiment, technical effect of the invention is described further:
1, simulated conditions
The object module of 19 points is created, on computers, l-G simulation test is carried out using MATLAB R2017a, uses this
Invention and Fourier Transform of Fractional Order most practical in the prior art carry out the estimation of echo-signal higher order term, the ISAR system of acquisition
System simulation parameter, as shown in table 1:
1 ISAR system emulation parameter of table
2, emulation content
Emulation 1, in conjunction with above-mentioned ISAR system emulation parameter, using Fourier Transform of Fractional Order FRFT in the prior art to returning
Wave phase carries out parameter Estimation, carries out the ISAR three-dimensional imaging of aerial target, imaging results are as shown in Figure 3, in which:
Fig. 3 (a) is the ISAR three-dimensional imaging figure based on Fourier Transform of Fractional Order；
Fig. 3 (b) is the ISAR three-dimensional imaging yz plane figure based on Fourier Transform of Fractional Order；
Fig. 3 (c) is the ISAR three-dimensional imaging x/y plane perspective view based on Fourier Transform of Fractional Order；
Fig. 3 (d) is the ISAR three-dimensional imaging xz plane figure based on Fourier Transform of Fractional Order.
Emulation 2 carries out the ISAR three-dimensional imaging of aerial target using the present invention in conjunction with above-mentioned ISAR system emulation parameter,
As a result as shown in Figure 4.Wherein:
Fig. 4 (a) is the ISAR three-dimensional imaging figure based on STFT and FRFT；
Fig. 4 (b) is the ISAR three-dimensional imaging yz plane figure based on STFT and FRFT；
Fig. 4 (c) is the ISAR three-dimensional imaging x/y plane perspective view based on STFT and FRFT；
Fig. 4 (d) is the ISAR three-dimensional imaging xz plane figure based on STFT and FRFT.
3. analysis of simulation result
Comparison diagram 3 and Fig. 4 it can be found that the three-D imaging method based on STFT and FRFT than based on FRFT it is three-dimensional at
Faster, the traditional fractional order Fourier of effective solution changes computationally intensive problem to the speed of image space method.And the present invention and biography
The Fourier Transform of Fractional Order analysis of system is compared, and the parameter Estimation being more applicable in three-dimensional ISAR imaging not only reduces
Calculation amount also improves computational accuracy.
Claims (8)
1. a kind of moving target radar three-dimensional imaging method based on STFT and FRFT, which is characterized in that include the following:
(1) ISAR echo-signal is simulated, original echoed signals s (t) is obtained；
(2) window function w (t) is selected, Short Time Fourier Transform is carried out to original echoed signals s (t), obtains Short Time Fourier Transform
Function STFT (t, f)；
(3) straight-line detection is carried out to Short Time Fourier Transform function STFT (t, f) in time-frequency plane, by detecting in time-frequency plane
The straight line arrived carries out rough estimate to echo-signal, obtains the rough estimate evaluation f of frequency and frequency modulation rate1And k1；
(4) frequency and frequency modulation rate essence estimation interval are selected according to the rough estimate evaluation of frequency and frequency modulation rate；
(5) the essence estimation of parameter is carried out based on Fourier Transform of Fractional Order:
(5a) carries out fining Fourier Transform of Fractional Order FRFT to original echoed signals in smart estimation interval, obtains fractional order Fu
In leaf transformation function X (u, p), u be fractional number order Fourier coordinate, p be transformation order；
(5b) finds optimal mapping order p according to X (u, p)0With the coordinate u of fractional number order Fourier0, in energy height aggregation
Fractional order domain carries out two-dimensional search and obtains the position [u of peak value0,p0]；
(5c) estimates frequency and frequency modulation rate essence according to peak position, obtains echo-signal frequency essence estimated value f2With frequency modulation rate
Smart estimated value k2；
(6) CLEAN technology is used, polyteny FM signal is separated one by one, the frequency modulation rate estimated with essence is to polyteny tune
Frequency signal is demodulated, and the high concentration peak value that signal occurs in frequency domain is obtained, by the position narrow-band filtering of the peak value
Device filters out, and obtains the frequency f of all signals2And frequency modulation rate k2；
(7) three-dimensional imaging of moving target:
The posture of radar and target is arranged in (7a), establishes target initial coordinate system；
(7b) reconstructs the coordinate system of target under initial coordinate system, utilizes the frequency f of all signals2With frequency modulation rate k2It is sat in reconstruct
The three-dimensional coordinate (x, y, z) of target is obtained in mark system, completes the three-dimensional imaging of moving target.
2. according to the method described in claim 1, wherein original echoed signals s (t) in (1), is expressed as follows:
S (t)=∫ a (x) ejφ(x,t)dx
Wherein a (x) is echo signal amplitude, and φ (x, t) is phase function, and j is imaginary unit.
3. leading to according to the method described in claim 1, wherein (2) carry out Short Time Fourier Transform to original echoed signals s (t)
Following formula is crossed to carry out:
Wherein f is frequency, and the coordinate of u fractional Fourier domain, w (u-t) is that Hanning window function w (t) translates u unit, w's (t)
Expression formula are as follows:
W (t)=0.5 (1-cos (2 π t)), | t |≤Tw/2
Wherein t is time, TwIt is long for window.
4. according to the method described in claim 1, wherein according to the straight line detected in time-frequency plane in (3), to echo-signal
Rough estimate is carried out, is accomplished by
The time-frequency plane of (3a) after Short Time Fourier Transform carries out straight-line detection, obtains the intercept of straight slope k and straight line
B:
B=E (IF)-kE (t)
Wherein E (t) is the time average of time-frequency plane, and E (IF) is mean frequency value, and IF is frequency, and IF (t) is the instantaneous of t moment
Frequency,Wherein f is frequency, and t is the time；
The rough estimate of (3b) frequency modulation rate and frequency:
Using straight slope k as the rough estimate evaluation k of frequency modulation rate1, i.e. k1=k；
Using the intercept b of straight line as the rough estimate evaluation f of frequency1, i.e. f1=b.
5. according to the method described in claim 1, wherein selecting frequency and tune according to the rough estimate evaluation of frequency and frequency modulation rate in (4)
Frequency essence estimation interval, is accomplished by
If the main lobe width of window function w (t)=0.5 (1-cos (2 π t)) is▽, whens original echoed signals a length of T；
According to the rough estimate evaluation of frequency and frequency modulation rate, the estimation of frequency modulation rate essence is obtained
Abbreviation is carried out to above range, obtaining frequency modulation rate essence estimation interval isThe section of frequency essence estimation is
[f1-▽,f1+▽]。
6. according to the method described in claim 1, wherein (5a) smart estimation interval to original echoed signals carry out fining point
Number rank Fourier transformation FRFT, is in frequency modulation rate essence estimation intervalWith frequency essence estimation interval [f1-▽,f1+
▽], it is carried out by following formula:
Wherein j is imaginary unit, and p is the transformation order of Fourier Transform of Fractional Order, and u is fractional number order Fourier coordinate, when t is
Between, X (u, p) is the function after Fourier Transform of Fractional Order.
7. initial coordinate system is established according to the method described in claim 1, the posture of radar and target is wherein arranged in (7a),
It is accomplished by
Radar posture is arranged in (7a1):
U, v, w axis rectangular coordinate system are initially set up, if radar carries out rigidity rotation using u, v, w axis as shaft, radar rolling is indulged
It shakes, to shake corresponding instantaneous corner be respectively θ to headroll、θpitch、θyaw, changing rule is with apparent periodical, form are as follows:
H in formularoll、Hpitch、HyawThe respectively amplitude of three-dimensional oscillating,Respectively three-dimensional oscillating is initial
Phase, weTo meet with angular speed；
Then, the three-dimensional rotation matrix instantaneous corner of the posture of three-dimensional oscillating radar constituted indicates are as follows:
R (t)=Ryaw(t)Rpitch(t)Rroll(t)e
Wherein e is radar in the position of zero moment, Rroll、Rpitch、RyawFor radar three-dimensional spin matrix, respectively indicate are as follows:
The posture of (7a2) setting target: assuming that target does the linear uniform motion with speed for v；
The posture of posture and target movement that (7a3) is swung according to radar three-dimensional is established using target Doppler center as origin
X ', y ', the initial rectangular coordinate system of z ' axis.
8. according to the method described in claim 1, wherein (7b) reconstructs the coordinate system of target under initial coordinate system, using all
The frequency f of signal2With frequency modulation rate k2The three-dimensional coordinate (x, y, z) of target is obtained in reconstruct coordinate system, is accomplished by
(7b1) under initial rectangular coordinate system, the phase of echo delay function by target in Doppler domain is indicated are as follows:
Wherein, P point is target Doppler center, and A point is any scattering point in target,It swears position for A point relative to P point
Amount, rPFor radar to the distance of some scattering point of target, rAFor radar to the distance at target Doppler center, C is the light velocity, fcFor
Carrier frequency,For rPUnit direction vector；
(7b2) establishes x-axis, y-axis, z-axis rectangular coordinate system, defines x-axis, y-axis, the corresponding direction vector of z-axis and is respectivelyAnd phase delay function is unfolded with direction vector:
WhereinForWithConvolution, o (t) is negligible for higher order term,For velocity vector,It is A point relative to P
The position vector in the case where reconstructing coordinate system of point,Second order for t=0 moment radar instantaneous position is led, and t is the time；
(7b3) establishes direction vectorThe relationship between the coordinate (x, y, z) of scattering point A:
WhereinFor the position vector for A point relative to P point, x, y, z is the coordinate of target scattering point A, and β is speed v and x-axis is pressed from both sides
Angle, θ are radar instantaneous position and y-axis angle, and v is speed；
(7b4) is according to direction vectorRelationship between scattering point A coordinate (x, y, z), phase delay function is further spread out
Are as follows:
(7b5) is by phase of echo delay function frequency essence estimated value f2And frequency modulation rate essence estimated value k2It indicates are as follows:
Wherein R is oblique distance；
(7b6) compares the coefficient of time t in two functions of (7b4) and (7b5), obtains:
X=R
(7b7) carries out abbreviation to the formula of (7b6), obtains the three-dimensionalreconstruction coordinate of target are as follows:
Wherein C is the light velocity, and v is target velocity, and n is the distance unit of scattering point.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110456351A (en) * | 2019-08-29 | 2019-11-15 | 哈尔滨工业大学 | Based on when Variable Amplitude LFM Signal parameter estimation ISAR Imaging of Maneuvering Targets method |
| CN111190157A (en) * | 2020-01-10 | 2020-05-22 | 中国地质大学（武汉） | IPIX radar echo data time-frequency analysis method and system |
| CN116524051A (en) * | 2023-04-10 | 2023-08-01 | 哈尔滨工业大学 | High-resolution ISAR imaging method based on fractional Fourier transform domain modal decomposition |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101833035A (en) * | 2010-04-19 | 2010-09-15 | 天津大学 | Linear frequency-modulated parameter estimating method and implementing device thereof |
| CN101963662A (en) * | 2010-09-20 | 2011-02-02 | 北京理工大学 | Self-focusing preprocessing method based on short-time fractional order Fourier domain filter |
| CN102998672A (en) * | 2012-11-27 | 2013-03-27 | 西安电子科技大学 | Step frequency inverse synthetic aperture radar (ISAR) imaging method based on coherent processing |
| JP2013130472A (en) * | 2011-12-21 | 2013-07-04 | Mitsubishi Electric Corp | Image radar apparatus |
| CN103760558A (en) * | 2014-01-23 | 2014-04-30 | 电子科技大学 | Terahertz radar ISAR imaging method |
| WO2017198162A1 (en) * | 2016-04-29 | 2017-11-23 | 深圳市太赫兹科技创新研究院有限公司 | Three-dimensional image rebuilding method and device based on synthetic aperture radar imaging |
| US20180011182A1 (en) * | 2016-07-05 | 2018-01-11 | The Aerospace Corporation | Separating weak and strong moving targets using the fractional fourier transform |
| CN109444885A (en) * | 2018-12-17 | 2019-03-08 | 中国人民解放军空军工程大学 | Super-resolution imaging method, device and electronic equipment based on sparse matrix reconstruct |
-
2019
- 2019-04-26 CN CN201910345967.6A patent/CN110109108A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101833035A (en) * | 2010-04-19 | 2010-09-15 | 天津大学 | Linear frequency-modulated parameter estimating method and implementing device thereof |
| CN101963662A (en) * | 2010-09-20 | 2011-02-02 | 北京理工大学 | Self-focusing preprocessing method based on short-time fractional order Fourier domain filter |
| JP2013130472A (en) * | 2011-12-21 | 2013-07-04 | Mitsubishi Electric Corp | Image radar apparatus |
| CN102998672A (en) * | 2012-11-27 | 2013-03-27 | 西安电子科技大学 | Step frequency inverse synthetic aperture radar (ISAR) imaging method based on coherent processing |
| CN103760558A (en) * | 2014-01-23 | 2014-04-30 | 电子科技大学 | Terahertz radar ISAR imaging method |
| WO2017198162A1 (en) * | 2016-04-29 | 2017-11-23 | 深圳市太赫兹科技创新研究院有限公司 | Three-dimensional image rebuilding method and device based on synthetic aperture radar imaging |
| US20180011182A1 (en) * | 2016-07-05 | 2018-01-11 | The Aerospace Corporation | Separating weak and strong moving targets using the fractional fourier transform |
| CN109444885A (en) * | 2018-12-17 | 2019-03-08 | 中国人民解放军空军工程大学 | Super-resolution imaging method, device and electronic equipment based on sparse matrix reconstruct |
Non-Patent Citations (4)
| Title |
|---|
| YICHENG JIANG ET AL.: "Three-dimensional aircraft isar imaging based on shipborne radar", 《IEEE TRANSACTIONS ON AEROSPACE AND ELECTRONIC SYSTEMS》 * |
| 云涛等: "基于分数阶傅里叶变换的ISAＲ横向定标", 《数据采集与处理》 * |
| 刘宝华等: "多分量LFM信号在分数阶Fourier域的参数估计与分离", 《中国科技论文》 * |
| 孙乐等: "STFT和Zoom-FRFT联合的多分量LFM信号参数估计方法", 《四川大学学报(自然科学版)》 * |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110456351A (en) * | 2019-08-29 | 2019-11-15 | 哈尔滨工业大学 | Based on when Variable Amplitude LFM Signal parameter estimation ISAR Imaging of Maneuvering Targets method |
| CN111190157A (en) * | 2020-01-10 | 2020-05-22 | 中国地质大学（武汉） | IPIX radar echo data time-frequency analysis method and system |
| CN111190157B (en) * | 2020-01-10 | 2021-10-29 | 中国地质大学（武汉） | IPIX radar echo data time-frequency analysis method and system |
| CN116524051A (en) * | 2023-04-10 | 2023-08-01 | 哈尔滨工业大学 | High-resolution ISAR imaging method based on fractional Fourier transform domain modal decomposition |
| CN116524051B (en) * | 2023-04-10 | 2024-01-09 | 哈尔滨工业大学 | High-resolution ISAR imaging method based on fractional Fourier transform domain modal decomposition |
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