CN108132465A - Terahertz radar foresight imaging method based on reflecting antenna - Google Patents
Terahertz radar foresight imaging method based on reflecting antenna 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
- G01S13/904—SAR modes
- G01S13/9043—Forward-looking SAR
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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
- G01S13/9005—SAR image acquisition techniques with optical processing 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
- G01S13/904—SAR modes
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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
- G01S13/9094—Theoretical aspects
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Abstract
The invention discloses a kind of Terahertz radar foresight imaging method based on reflecting antenna, main thought is：Determine Terahertz radar, and the Terahertz radar includes a phase shift reflecting antenna, the state when phase center of phase shift reflecting antenna is in different location is denoted as wave position respectively, and the direction that wave displacement is moved is orientation；Wave position total number is set as Na, and then obtains the echo-signal two dimension wave-number spectrum of Na wave position；The echo-signal two dimension wave-number spectrum for calculating Na wave position after three rank Taylor expansions simplifies result；After the echo-signal two dimension wave-number spectrum of Na wave position after quadravalence Taylor expansion；It carries out phase compensation, oblique, orientation Fast Fourier Transform (FFT) and the removal of scallop effect is gone against Fast Fourier Transform, orientation, tiltedly two-dimentional wave-number spectrum is removed in the echo-signal orientation for obtaining Na wave position after scallop effect removes, and it is the Terahertz radar foresight imaging results based on reflecting antenna that oblique two dimension wave-number spectrum is removed in the echo-signal orientation of Na wave position after the scallop effect removal.
Description
Technical field
The present invention relates to radar foresight technical field of imaging, before more particularly to a kind of Terahertz radar based on reflecting antenna
Depending on imaging method, suitable for carrying out imaging to the Terahertz radar return data based on phase shift reflecting antenna.
Background technology
Radar for high-resolution imaging is often synthetic aperture radar (SAR) and Inverse Synthetic Aperture Radar (ISAR), SAR
Image-forming principle and ISAR image-forming principles are realized using the Doppler frequency otherness that relative motion between radar and target generates
To the resolution of target in orientation；And in the case where relative motion is unknowable, the resolution of target cannot be completed or thunder
Up to target there is only radial direction relative motion when, i.e., be imaged under the conditions of forward sight, the Doppler frequency of different target echo will
High-precision discriminating in orientation to target can not be equally completed without or there are minimum otherness.
Invention content
In view of the above-mentioned problems of the prior art, the purpose of the present invention, which is taken notice of, proposes a kind of terahertz based on reflecting antenna
Hereby radar foresight imaging method, Terahertz radar foresight imaging method of this kind based on reflecting antenna are real using pulse compression technique
Now distance is to the resolution to target, antenna phase center when realizing radar emission and return pulse signal using phase shift reflecting antenna
Movement, and emitted using out of phase center and receive the otherness of signal and realized to the azimuth discrimination of target.
To reach above-mentioned technical purpose, the present invention is realised by adopting the following technical scheme.
A kind of Terahertz radar foresight imaging method based on reflecting antenna, includes the following steps：
Step 1, Terahertz radar is determined, the Terahertz radar includes a phase shift reflecting antenna, phase shift is reflected day
The state when phase center of line is in different location is denoted as wave position respectively, and the direction that wave displacement is moved is orientation；Set wave position
Total number is Na, and then obtains the echo-signal two dimension wave-number spectrum of Na wave position；Wherein, Na is the positive integer more than 0；
Step 2, phase compensation is carried out according to the echo-signal two dimension wave-number spectrum of Na wave position, three rank Taylor's exhibitions is calculated
The echo-signal two dimension wave-number spectrum for opening rear Na wave position simplifies result；
Step 3, according to the echo-signal two dimension wave-number spectrum simplification of Na wave position after three rank Taylor expansions as a result, obtaining quadravalence
The echo-signal two dimension wave-number spectrum of Na wave position after Taylor expansion；
Step 4, phase compensation is carried out to the echo-signal two dimension wave-number spectrum of Na wave position after quadravalence Taylor expansion, obtains phase
The echo-signal two dimension wave-number spectrum of Na wave position after the compensation of position；
Step 5, inverse quick Fu is carried out along orientation to the echo-signal two dimension wave-number spectrum of Na wave position after phase compensation
Vertical leaf transformation, obtains orientation against the echo-signal two dimension wave-number spectrum of Na wave position after Fast Fourier Transform；
Step 6, orientation is carried out to the echo-signal two dimension wave-number spectrum of orientation against Na wave position after Fast Fourier Transform
It goes tiltedly, to obtain to orientation the echo-signal two dimension wave-number spectrum for going to tiltedly rear Na wave position；
Step 7, the echo-signal two dimension wave-number spectrum of Na wave position is carried out along orientation in quick Fu after being gone to orientation tiltedly
Tiltedly two-dimentional wave-number spectrum is removed in leaf transformation, the echo-signal orientation for obtaining Na wave position after Fast Fourier Transform (FFT) FFT；
Step 8, oblique two-dimentional wave-number spectrum is gone to fan to the echo-signal orientation of Na wave position after Fast Fourier Transform (FFT) FFT
Shellfish effect removes, and then tiltedly two-dimentional wave-number spectrum, the fan are removed in the echo-signal orientation for obtaining Na wave position after scallop effect removes
Oblique two-dimentional wave-number spectrum is removed as before the Terahertz radar based on reflecting antenna in the echo-signal orientation of Na wave position after the removal of shellfish effect
Depending on imaging results.
Beneficial effects of the present invention：The present invention realizes that distance to the resolution to target, utilizes shifting using pulse compression technique
The movement of antenna phase center when phase reflecting antenna realizes radar emission and return pulse signal, and sent out using out of phase center
The otherness realization penetrated and receive signal can be realized and be imaged under the conditions of forward sight, different target returns to the azimuth discrimination of target
The Doppler frequency of wave will can not equally complete high-precision discriminating in orientation to target without or there are minimum otherness.
Description of the drawings
The present invention is described in further detail with reference to the accompanying drawings and detailed description.
Fig. 1 is a kind of Terahertz radar foresight imaging method flow chart based on reflecting antenna of the present invention.
Specific embodiment
With reference to Fig. 1, a kind of Terahertz radar foresight imaging method flow chart based on reflecting antenna for the present invention；Wherein
The Terahertz radar foresight imaging method based on reflecting antenna, includes the following steps：
Step 1, Terahertz radar is determined, Terahertz radar, which refers to, to be emitted the electromagnetic wave of Terahertz frequency range by antenna and pass through
Antenna receives echo to detect the electronic equipment of environment；The Terahertz radar includes a phase shift reflecting antenna, the phase shift
Reflecting antenna has under conditions of radiation pattern is not changed that antenna phase center is uniform in antenna aperature length
Mobile function, wherein radiation pattern refer to that antenna produces Terahertz radar transmitter on relative antenna assigned direction
Raw radiofrequency signal amplification factor, antenna phase center are the ideals in calculating signal from Terahertz radar emission to receive process
Point source；There are targets in the detection range of the Terahertz radar.
The state when phase center of phase shift reflecting antenna is in different location is denoted as wave position, the side that wave displacement is moved respectively
To for orientation；Wave position total number is set as Na, Na is the positive integer more than 0；Terahertz radar emits respectively in each wave position
Then one pulse signal receives corresponding transmitting signal respectively in each wave position.The pulse signal difference of each wave position transmitting
For linear FM signal, and each wave position is respectively adopted the mode that oblique dechirp is received and corresponds to returning for return pulse signal
Wave signal, and then obtain the echo-signal of Na wave position.
It is the echo-signal and the arteries and veins of wave position transmitting for receiving Terahertz radar in arbitrary wave position to go oblique dechirp receptions
It is identical but with time delay to rush signalPulse signal mixing；Wherein, C represents the light velocity, RsRepresent phase shift reflecting antenna aperture
To the vertical range of Terahertz radar imagery scene center.
Terahertz radar imagery scene is the one piece rectangular area in the same plane with phase shift reflecting antenna, the block square
Apart from the ranging length that upward length is Terahertz radar, which is in shape regionThe block rectangular area center is to distance, that is, phase shift reflecting antenna aperture of phase shift reflecting antenna to Terahertz radar imagery
The vertical range of scene center；Image scene coordinate system, image scene are established by origin of Terahertz radar imagery scene center
The longitudinal axis of coordinate system is Terahertz radar range finding direction, and the horizontal axis of image scene coordinate system is orientation, Terahertz radar imagery
Scene center is located at apart from phase shift reflecting antenna RsAt distance, and set in Terahertz radar imagery scene and be dispersed with M scattering
Point, the backscatter intensity of M scattering point differ respectively；Wherein, θ represents the phase shift reflecting antenna directional diagram of Terahertz radar
Main lobe width, M are the positive integer more than 0.
Fast Fourier Transform (FFT) is done along orientation to the echo-signal of the Na wave position after past oblique dechirp receptions
FFT obtains the echo-signal two dimension wave-number spectrum S (K of Na wave positionR,KX), expression formula is：
Wherein, n=1,2 ..., M, AnIt represents the reflection echo signal intensity value of n-th of scattering point, is to be evaluated；Exp tables
Show exponential function, j represents imaginary unit, KRRepresent the echo-signal distance dimension wave-number spectrum of Na wave position,B represents the pulse signal bandwidth of each wave position transmitting；KXRepresent the echo of Na wave position
Aspect ties up wave-number spectrum,fcRepresent the pulse letter of each wave position transmitting
Number carrier frequency, R represent target to the vertical range in phase shift reflecting antenna aperture, XnRepresent n-th of scattering point in orientation to too
The distance of hertz radar, RsRepresent phase shift reflecting antenna aperture to the vertical range of Terahertz radar imagery scene center, ∈ tables
Show and belong to, sin represents SIN function.
Setting phase shift reflecting antenna makes the admission data time shift of Terahertz radar mutually reflect antenna phase center in its antenna hole
DiameterInterior even variation, L are phase shift reflecting antenna aperture length.
Step 2, to the echo-signal two dimension wave-number spectrum S (K of Na wave positionR,KX) in two-dimensional frequency compensation phaseThe echo-signal two dimension of Na wave position after two-dimensional frequency phase compensation is calculated
Wave-number spectrumIts expression formula is：
Wherein, RB=R-Rs, RBRepresent target to the vertical range of Terahertz radar scene center, RsRepresent phase shift reflection
For antenna aperature to the vertical range of Terahertz radar imagery scene center, R represents target to the vertical of phase shift reflecting antenna aperture
Distance, n=1,2 ..., M, AnIt represents the reflection echo signal intensity value of n-th of scattering point, is to be evaluated；XnIt represents to dissipate for n-th
Exit point arrives the distance of Terahertz radar, K in orientationRRepresent the echo-signal distance dimension wave-number spectrum of Na wave position, KXRepresent Na
The echo-signal azimuth dimension wave-number spectrum of a wave position, exp represent exponential function, and j represents imaginary unit.
To the echo-signal two dimension wave-number spectrum of Na wave position after two-dimensional frequency phase compensationCarry out three rank Taylors
Expansion, obtains the echo-signal two dimension wave-number spectrum of Na wave position after three rank Taylor expansionsIts expression formula is：
Wherein,fcRepresent the pulse signal carrier frequency of each wave position transmitting, △
KR=a+KR, the C expression lighies velocity, RBRepresent target to the vertical range of Terahertz radar scene center；A is sets constant, this implementation
A values are 0 in example.
Under conditions of small scene imaging and resolution ratio are not less than 0.3 meter, i.e. Terahertz radar imagery scene breadth is small
In 100 meters, formula (3)WithIt is much smaller thanTherefore it is considered pair
Terahertz radar imagery does not influence, and space-variant itemThe influence brought is less than a range cell, then formula (3) carries out near
Like abbreviation, the echo-signal two dimension wave-number spectrum simplification result of Na wave position after three rank Taylor expansions is obtainedIts table
It is up to formula：
Wherein, n=1,2 ..., M, AnIt represents the reflection echo signal intensity value of n-th of scattering point, is to be evaluated；XnIt represents
N-th of scattering point arrives the distance of Terahertz radar in orientation.
Step 3, result is simplified to the echo-signal two dimension wave-number spectrum of Na wave position after three rank Taylor expansions
Along distance to Fast Fourier Transform (FFT) FFT is carried out, the echo-signal of distance Na wave position after Fast Fourier Transform (FFT) FFT is obtained
Two-dimentional wave-number spectrum S (y, KX), expression formula is：
Wherein, y is represented to △ KRCarry out the result output that Fast Fourier Transform (FFT) obtains, △ KR=a+KR, a is sets often
Number, KRRepresent the echo-signal distance dimension wave-number spectrum of Na wave position, sinc represents sinc function, A (y, KX) represent distance to quick
The echo-signal voltage of Na wave position after Fourier transformation FFT；It is ideally the pulse signal bandwidth of each wave position transmitting
When interior each frequency component electromagnetic wave decays identical in propagation in atmosphere, A (y, KX) it is constant.
By-jA in formula (5)XKcRBIn KXQuadravalence Taylor expansion is carried out at=0, obtains Na wave position after quadravalence Taylor expansion
Echo-signal two dimension wave-number spectrumIts expression formula is：
Wherein, A (KX) represent quadravalence Taylor expansion after Na wave position echo-signal voltage.
Step 4, to the echo-signal two dimension wave-number spectrum of Na wave position after quadravalence Taylor expansionCarry out phase benefit
It repays, obtains the echo-signal two dimension wave-number spectrum of Na wave position after phase compensation
Specifically, formula (6) is multiplied byAfter can obtain
Wherein,R represent target to phase shift reflecting antenna aperture vertical range,fcTable
Show the pulse signal carrier frequency of each wave position transmitting, △ KR=a+KR, the C expression lighies velocity, RB=R-Rs, RBRepresent target to Terahertz thunder
Up to the vertical range of scene center, RsRepresent phase shift reflecting antenna aperture to Terahertz radar imagery scene center it is vertical away from
From n=1,2 ..., M, XnRepresent that n-th of scattering point arrives the distance of Terahertz radar, K in orientationXNa wave position of expression
Echo-signal azimuth dimension wave-number spectrum, exp represent exponential function, and j represents imaginary unit, and y is represented to △ KRCarry out fast Fourier
Convert obtained result output, △ KR=a+KR, a is sets constant, KRRepresent the echo-signal distance dimension wave number of Na wave position
Spectrum.
Step 5, to the echo-signal two dimension wave-number spectrum of Na wave position after phase compensationIt is carried out along orientation inverse
Fast Fourier Transform IFFT obtains orientation against the echo-signal two dimension wave number of Na wave position after Fast Fourier Transform IFFT
S (y, x) is composed, expression formula is：
Wherein, x represents the echo-signal two dimension wave-number spectrum to Na wave position after phase compensationAlong KXIt carries out quick
The result output obtained after Fourier transformation FFT, KXRepresent the echo-signal azimuth dimension wave-number spectrum of Na wave position,fcRepresent the pulse signal carrier frequency of each wave position transmitting, R represents that target reflects day to phase shift
The vertical range of string holes diameter.
Step 6, to orientation against Na wave position after Fast Fourier Transform IFFT echo-signal two dimension wave-number spectrum S (y,
X) it is multiplied by orientation and removes oblique function H=exp [- jKax2], it obtains to orientation and removes the echo-signal two dimension wave-number spectrum of tiltedly rear Na wave position
Specifically, it is determined that remove oblique function H=exp [- jKax2], and oblique function will be gone to ignore constant term after being multiplied with formula (8),
The echo-signal two dimension wave-number spectrum of Na wave position after orientation is gone tiltedly can be obtainedIts expression formula is：
Wherein, R represent target to phase shift reflecting antenna aperture vertical range,fc
Represent the pulse signal carrier frequency of each wave position transmitting, n=1,2 ..., M, XnRepresent that n-th of scattering point arrives terahertz in orientation
The hereby distance of radar, x represent the echo-signal two dimension wave-number spectrum to Na wave position after phase compensationAlong KXIt carries out quick
The result output obtained after Fourier transformation FFT, KXRepresent the echo-signal azimuth dimension wave-number spectrum of Na wave position.
Step 7, the echo-signal two dimension wave-number spectrum of Na wave position after being gone to orientation tiltedlyIt is carried out along orientation quick
Tiltedly two-dimentional wave-number spectrum is removed in Fourier transformation FFT, the echo-signal orientation for obtaining Na wave position after Fast Fourier Transform (FFT) FFTIts expression formula is：
Wherein, L represents phase shift reflecting antenna aperture length, n=1,2 ..., M, XnRepresent n-th of scattering point in orientation
The upper distance to Terahertz radar, y are represented to △ KRCarry out the result output that Fast Fourier Transform (FFT) obtains, △ KR=a+KR, a
To set constant, KRRepresent the echo-signal distance dimension wave-number spectrum of Na wave position, fcIt represents
The pulse signal carrier frequency of each wave position transmitting, R represent target to the vertical range in phase shift reflecting antenna aperture, KXRepresent Na wave
The echo-signal azimuth dimension wave-number spectrum of position.
Envelope function sinc [△ K in formula (10)R(y-R)] reflect target distance to position, envelope functionTarget is reflected in the position of orientation, wherein there are space-variants in the position of orientation for target, empty
VariableLinear function of the target to the vertical range R in phase shift reflecting antenna aperture, can cause the azimuth width of image with
It the variation of distance and is stretched, this phenomenon is referred to as scallop distortion.
Scallop distortion may be considered that only have been done script Terahertz radar image known to one simply in orientation
It stretches, the information of geometrical relationship makes not lose between target in Terahertz radar imagery, and scallop effect can also lead to
Cross the method removal of existing image procossing or signal processing.
Step 8, using existing image procossing or signal processing method to Na wave position after Fast Fourier Transform (FFT) FFT
Tiltedly two-dimentional wave-number spectrum is removed in echo-signal orientationScallop effect removal is carried out, and then obtains after the removal of scallop effect Na
Tiltedly two-dimentional wave-number spectrum is removed in the echo-signal orientation of wave position, and the echo-signal orientation of Na wave position is gone tiltedly after the scallop effect removal
Two-dimentional wave-number spectrum is the Terahertz radar foresight imaging results based on reflecting antenna, includes the reflection echo letter of the 1st scattering point
Number intensity value to m-th scattering point reflection echo signal intensity value.
Claims (8)
1. a kind of Terahertz radar foresight imaging method based on reflecting antenna, which is characterized in that include the following steps：
Step 1, Terahertz radar is determined, and the Terahertz radar includes a phase shift reflecting antenna, by phase shift reflecting antenna
State of phase center when being in different location be denoted as wave position respectively, the direction that wave displacement is moved is orientation；It is total to set wave position
Number is Na, and then obtains the echo-signal two dimension wave-number spectrum of Na wave position；Wherein, Na is the positive integer more than 0；
Step 2, phase compensation is carried out according to the echo-signal two dimension wave-number spectrum of Na wave position, after three rank Taylor expansions are calculated
The echo-signal two dimension wave-number spectrum of Na wave position simplifies result；
Step 3, according to the echo-signal two dimension wave-number spectrum simplification of Na wave position after three rank Taylor expansions as a result, obtaining quadravalence Taylor
The echo-signal two dimension wave-number spectrum of Na wave position after expansion；
Step 4, phase compensation is carried out to the echo-signal two dimension wave-number spectrum of Na wave position after quadravalence Taylor expansion, obtains phase benefit
Repay the echo-signal two dimension wave-number spectrum of rear Na wave position；
Step 5, inverse fast Flourier is carried out along orientation to the echo-signal two dimension wave-number spectrum of Na wave position after phase compensation
Transformation, obtains orientation against the echo-signal two dimension wave-number spectrum of Na wave position after Fast Fourier Transform；
Step 6, orientation is carried out to the echo-signal two dimension wave-number spectrum of orientation against Na wave position after Fast Fourier Transform to go tiltedly,
The echo-signal two dimension wave-number spectrum of Na wave position after going tiltedly is obtained to orientation；
Step 7, the echo-signal two dimension wave-number spectrum of Na wave position carries out fast Fourier change along orientation after being gone to orientation tiltedly
It changes, tiltedly two-dimentional wave-number spectrum is removed in the echo-signal orientation for obtaining Na wave position after Fast Fourier Transform (FFT) FFT；
Step 8, tiltedly two-dimentional wave-number spectrum progress scallop effect is gone to the echo-signal orientation of Na wave position after Fast Fourier Transform (FFT) FFT
It should remove, and then tiltedly two-dimentional wave-number spectrum, the scallop effect are gone in the echo-signal orientation for obtaining Na wave position after scallop effect removes
After should removing the echo-signal orientation of Na wave position go tiltedly two-dimentional wave-number spectrum for the Terahertz radar foresight based on reflecting antenna into
As result.
2. a kind of Terahertz radar foresight imaging method based on reflecting antenna as described in claim 1, which is characterized in that
In step 1, the echo-signal two dimension wave-number spectrum of the Na wave position is S (KR,KX), expression formula is：
Wherein, n=1,2 ..., M, M represent the scattering point total number in Terahertz radar imagery scene, and M is just whole more than 0
Number；AnRepresent the reflection echo signal intensity value of n-th of scattering point, exp represents exponential function, and j represents imaginary unit, KRIt represents
The echo-signal distance dimension wave-number spectrum of Na wave position,B represents the arteries and veins of each wave position transmitting
Rush signal bandwidth；KXRepresent the echo-signal azimuth dimension wave-number spectrum of Na wave position,
fcRepresent the pulse signal carrier frequency of each wave position transmitting, R represents mesh
Mark the vertical range in phase shift reflecting antenna aperture, XnRepresent that n-th of scattering point arrives the distance of Terahertz radar in orientation,
RsRepresent phase shift reflecting antenna aperture arrive Terahertz radar imagery scene center vertical range, ∈ expression belong to, sin expression just
String function；
Terahertz radar imagery scene is the one piece rectangular area in the same plane with phase shift reflecting antenna, the block rectangle region
Apart from the ranging length that upward length is Terahertz radar, which is in domain
The distance of block rectangular area center to the phase shift reflecting antenna is in phase shift reflecting antenna aperture to Terahertz radar imagery scene
The vertical range of the heart；Wherein, θ represents the phase shift reflecting antenna major lobe of directional diagram width of Terahertz radar；The Terahertz radar
Detection range in there are targets.
3. a kind of Terahertz radar foresight imaging method based on reflecting antenna as claimed in claim 2, which is characterized in that
In step 2, the echo-signal two dimension wave-number spectrum of Na wave position is simplified as a result, it obtains process is after the three ranks Taylor expansion：
First, to the echo-signal two dimension wave-number spectrum S (K of Na wave positionR,KX) in two-dimensional frequency compensation phase
The echo-signal of Na wave position after two-dimensional frequency phase compensation is calculated
Two-dimentional wave-number spectrumIts expression formula is：
Wherein, RB=R-Rs, RBRepresent target to the vertical range of Terahertz radar scene center, RsRepresent phase shift reflecting antenna hole
For diameter to the vertical range of Terahertz radar imagery scene center, R represents target to the vertical range in phase shift reflecting antenna aperture, n
=1,2 ..., M, AnRepresent the reflection echo signal intensity value of n-th of scattering point, XnRepresent that n-th of scattering point arrives in orientation
The distance of Terahertz radar, KRRepresent the echo-signal distance dimension wave-number spectrum of Na wave position, KXRepresent the echo-signal of Na wave position
Azimuth dimension wave-number spectrum, exp represent exponential function, and j represents imaginary unit；
Then, to the echo-signal two dimension wave-number spectrum of Na wave position after two-dimensional frequency phase compensationCarry out three rank Taylors
Expansion, obtains the echo-signal two dimension wave-number spectrum of Na wave position after three rank Taylor expansionsIts expression formula is：
Wherein,fcRepresent the pulse signal carrier frequency of each wave position transmitting, △ KR=
a+KR, the C expression lighies velocity；
And then the echo-signal two dimension wave-number spectrum simplification result of Na wave position after three rank Taylor expansions is calculated
Its expression formula is：
4. a kind of Terahertz radar foresight imaging method based on reflecting antenna as claimed in claim 3, which is characterized in that
In step 3, the echo-signal two dimension wave-number spectrum of Na wave position, the process of obtaining are after the quadravalence Taylor expansion：
Result is simplified to the echo-signal two dimension wave-number spectrum of Na wave position after three rank Taylor expansionsAlong distance into
Row Fast Fourier Transform (FFT) obtains the echo-signal two dimension wave-number spectrum S of distance Na wave position after Fast Fourier Transform (FFT) FFT
(y,KX), expression formula is：
Wherein, y is represented to △ KRCarry out the result output that Fast Fourier Transform (FFT) obtains, △ KR=a+KR, a is sets constant, KR
Represent the echo-signal distance dimension wave-number spectrum of Na wave position, sinc represents sinc function, A (y, KX) represent distance in quick Fu
The echo-signal voltage of Na wave position after leaf transformation FFT；
And then the echo-signal two dimension wave-number spectrum of Na wave position after quadravalence Taylor expansion is calculatedIts expression formula is：
Wherein, A (KX) represent quadravalence Taylor expansion after Na wave position echo-signal voltage.
5. a kind of Terahertz radar foresight imaging method based on reflecting antenna as claimed in claim 4, which is characterized in that
In step 4, the echo-signal two dimension wave-number spectrum of Na wave position is after the phase compensationIts expression formula is：
Wherein,R represent target to phase shift reflecting antenna aperture vertical range,fcRepresent every
The pulse signal carrier frequency of a wave position transmitting, △ KR=a+KR, the C expression lighies velocity, RB=R-Rs, RBRepresent target to Terahertz radar area
The vertical range at scape center, RsRepresent phase shift reflecting antenna aperture to the vertical range of Terahertz radar imagery scene center, n=
1,2 ..., M, XnRepresent that n-th of scattering point arrives the distance of Terahertz radar, K in orientationXRepresent the echo letter of Na wave position
Number azimuth dimension wave-number spectrum, exp represent exponential function, and j represents imaginary unit, and y is represented to △ KRFast Fourier Transform (FFT) is carried out to obtain
The result output arrived, △ KR=a+KR, a is sets constant, KRRepresent the echo-signal distance dimension wave-number spectrum of Na wave position.
6. a kind of Terahertz radar foresight imaging method based on reflecting antenna as claimed in claim 5, which is characterized in that
In step 5, the echo-signal two dimension wave-number spectrum of the orientation against Na wave position after Fast Fourier Transform IFFT is S (y, x),
Its expression formula is：
Wherein, x represents the echo-signal two dimension wave-number spectrum to Na wave position after phase compensationAlong KXIt carries out in quick Fu
The result output obtained after leaf transformation FFT, KXRepresent the echo-signal azimuth dimension wave-number spectrum of Na wave position,fcRepresent the pulse signal carrier frequency of each wave position transmitting, R represents that target reflects day to phase shift
The vertical range of string holes diameter.
7. a kind of Terahertz radar foresight imaging method based on reflecting antenna as claimed in claim 6, which is characterized in that
In step 6, the echo-signal two dimension wave-number spectrum of Na wave position is after the orientation is gone tiltedlyIts expression formula is：
Wherein, R represent target to phase shift reflecting antenna aperture vertical range,fcRepresent every
The pulse signal carrier frequency of a wave position transmitting, n=1,2 ..., M, XnRepresent that n-th of scattering point arrives Terahertz radar in orientation
Distance, x represented to the echo-signal two dimension wave-number spectrum of Na wave position after phase compensationAlong KXCarry out fast Fourier
The result output obtained after transformation FFT, KXRepresent the echo-signal azimuth dimension wave-number spectrum of Na wave position.
8. a kind of Terahertz radar foresight imaging method based on reflecting antenna as claimed in claim 7, which is characterized in that
In step 7, after the Fast Fourier Transform (FFT) FFT echo-signal orientation of Na wave position go tiltedly two-dimentional wave-number spectrum be
Its expression formula is：
Wherein, L represents phase shift reflecting antenna aperture length, n=1,2 ..., M, XnRepresent n-th of scattering point in orientation to too
The distance of hertz radar, y are represented to △ KRCarry out the result output that Fast Fourier Transform (FFT) obtains, △ KR=a+KR, a is setting
Constant, KRRepresent the echo-signal distance dimension wave-number spectrum of Na wave position, fcRepresent each wave
The pulse signal carrier frequency of position transmitting, R represent target to the vertical range in phase shift reflecting antenna aperture, KXRepresent time of Na wave position
Wave aspect ties up wave-number spectrum.
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| CN111273289A (en) * | 2020-01-20 | 2020-06-12 | 中南大学 | Desert parameter inversion method, device, equipment and storage medium |
| CN111273289B (en) * | 2020-01-20 | 2022-01-25 | 中南大学 | Desert parameter inversion method, device, equipment and storage medium |
| CN112255600A (en) * | 2020-10-17 | 2021-01-22 | 中国电波传播研究所（中国电子科技集团公司第二十二研究所） | Airborne motion simulation method based on receiving-transmitting co-located multi-channel radar |
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