CN109597070B - Method and device for spiral scanning type arc array microwave imaging - Google Patents
Method and device for spiral scanning type arc array microwave imaging 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
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- G01S13/89—Radar or analogous systems specially adapted for specific applications for mapping or imaging
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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
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
- G01S7/41—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00 using analysis of echo signal for target characterisation; Target signature; Target cross-section
Abstract
The application provides a method and a device for microwave imaging of a spiral scanning type arc array. The method comprises the following steps: s1, acquiring a microwave signal according to the preset working mode; s2, in the uniform motion, controlling the arc array antenna to continuously radiate the microwave signals outwards, wherein the track for radiating the microwave signals is spiral; s3, acquiring post-echo data associated with the microwave signal through the arc array antenna; and S4, acquiring continuous microwave images according to the back echo data. According to the method, continuous high-resolution observation imaging can be carried out on large-area scenes around the platform when the platform moves linearly, the arc array antenna can be observed in a large-range large-view angle along with the uniform linear flight of the platform, and the advantage of all-dimensional imaging of a conventional arc array radar can be reserved.
Description
Technical Field
The application relates to the field of microwave imaging, in particular to a method and a device for spiral scanning type arc array microwave imaging.
Background
Microwave imaging refers to an imaging means using microwave as information carrier, and substantially belongs to the problem of electromagnetic backscattering. It is also called microwave holographic imaging because it uses both the amplitude information scattered by the imaged object and its phase information. The principle is to irradiate the object to be measured with microwaves and then reconstruct the shape or (complex) permittivity distribution of the object from the measurements of the scattered field outside the object.
In the existing array imaging technology for wide-area observation, electromagnetic waves are mainly transmitted and received through an arc array antenna, 360-degree observation of scenes around a platform can be achieved, and compared with a conventional linear array SAR, the array imaging method can only perform single forward-looking, side-looking and rear-looking imaging, and the observation visual angle of the scenes is greatly increased.
However, the existing arc array microwave imaging method can only realize observation of a circular area scene with a fixed center.
Disclosure of Invention
The application provides a method for microwave imaging of a spiral scanning arc array, in particular to a device for microwave imaging of the spiral scanning arc array; the problem of 360-degree large-visual-angle high-resolution continuous observation imaging during uniform linear motion of the platform is solved.
In order to solve the above technical problem, an embodiment of the present application provides the following technical solutions:
the application provides a method for microwave imaging of a spiral scanning type arc array, which comprises the following steps:
s1, acquiring a microwave signal according to the preset working mode;
s2, in the uniform motion, controlling the arc array antenna to continuously radiate the microwave signals outwards, wherein the track for radiating the microwave signals is spiral;
s3, acquiring post-echo data associated with the microwave signal through the arc array antenna;
and S4, acquiring continuous microwave images according to the back echo data.
Preferably, the acquiring of the continuous microwave image according to the post-echo data includes:
s41, dividing the back echo data along the azimuth direction, performing sub-aperture imaging and generating a plurality of sub-aperture imaging data blocks;
s42, generating a two-dimensional image according to the sub-aperture imaging data block;
s43, performing geometric correction on the two-dimensional image to generate a corrected two-dimensional image;
and S44, splicing the plurality of corrected two-dimensional images to generate continuous microwave images.
Preferably, the generating a two-dimensional image from the sub-aperture imaging data block includes:
s421, performing inverse Fourier transform on the sub-aperture imaging data block along the distance direction and removing the residual video phase to obtain first data;
s422, carrying out distance-to-Fourier transform on the first data to obtain distance frequency domain data;
s423, discretizing the image space corresponding to the sub-aperture imaging data block in two dimensions to obtain a two-dimensional image space;
s424, acquiring a matched filter function of each pixel position according to each pixel position of the two-dimensional image space;
s425, obtaining each pixel value of the two-dimensional image space according to the distance frequency domain data and the matched filter function;
s426, a two-dimensional image is generated from each pixel value of the two-dimensional image space.
Preferably, the inverse fourier transforming the sub-aperture imaging data block along the distance direction and removing the residual video phase to obtain the first data includes:
s421-1, imaging the sub-aperture data block S re (t, x, y, z) inverse Fourier transforming along the distance direction to obtain distance compressed data:
S IFT_re (R n ,x,y,z)＝IFT t [S re (t,x,y,z)]；
wherein IFT t Indicating an inverse fourier transform along the distance to the time variable t,
R n representing the arc array equivalent sampling point at (x, y, z) and the target P n (x n ,y n ,z n ) The distance between them;
s421-2, removing the data S after distance compression IFT_re (R n X, y, z) acquires the first data:
S IFT_rvp (R n ,x,y,z)＝S IFT_re (R n ,x,y,z)×H rvp (R n )；
wherein the compensation function:
preferably, the distance-to-fourier transforming the first data obtains distance frequency domain data:
wherein, FT represents the Fourier transform,
f c in order to obtain the frequency of the radar working center,
R n representing the arc array equivalent sampling point at (x, y, z) and the target P n (x n ,y n ,z n ) The distance between them.
Preferably, the two-dimensional discretization of the image space corresponding to the sub-aperture imaging data block to obtain a two-dimensional image space includes:
performing two-dimensional discretization on the sub-aperture imaging data block along the arc array direction and the distance direction respectively according to the pixel sizes of delta theta and delta r to obtain a two-dimensional image space I 0 (n θ Δθ,n r Δr)；
Wherein n is θ ＝1,…,N θ ，n r ＝1,…,N r ，N θ And N r Discretizing along the arc array direction and the distance direction respectivelyThe number of pixels of (c);
θ min and theta max Respectively the start angle and the end angle of the sub-aperture imaging area,
r max and r min The farthest ground distance and the nearest ground distance illuminated by the antenna respectively.
Preferably, the obtaining a matched filter function according to each pixel position in the two-dimensional image space includes:
according to the two-dimensional image space I 0 (n θ Δθ,n r Δ r) th (n) θ ,n r ) Coordinate position (n) corresponding to pixel θ Δθ,n r Δ R) distance R to equivalent sampling point P (x, y, z) of the arc array antenna m Obtaining a matched filter function:
wherein the content of the first and second substances,
z 0 the height of the ground surface plane is shown,
n θ and n r A pixel count number is represented and,
n θ ＝1,…,N θ ，
n r ＝1,…,N r ，
N θ and N r The number of pixels discretized along the arc array direction and the distance direction is respectively.
Preferably, the obtaining each pixel value of the two-dimensional image space according to the distance frequency domain data and the matched filter function includes:
traversing each pixel position of the two-dimensional image space according to a preset traversal rule, and acquiring a pixel value of the pixel position through the distance frequency domain data and the matched filtering function;
wherein the formula for each pixel value is calculated:
θ max and theta min Respectively, the range of array-wise integration.
Preferably, the controlling the arc-shaped array antenna to continuously radiate the microwave signal to the outside includes:
and controlling the transmitting array elements of the arc array antenna to radiate the microwave signals outwards according to a preset radiation sequence, wherein the track of each transmitting array element for radiating the microwave signals is in a fan-ring shape.
The application provides a device of spiral scanning formula arc array microwave formation of image includes:
the acquisition unit is used for acquiring microwave signals according to the preset working mode;
the radiation unit is used for controlling the arc-shaped array antenna to continuously radiate the microwave signals outwards in uniform motion, and the track for radiating the microwave signals is spiral;
the receiving unit is used for acquiring post-echo data associated with the microwave signal through the arc array antenna;
and the imaging unit is used for acquiring continuous microwave images according to the back echo data.
Based on the disclosure of the above embodiments, it can be known that the embodiments of the present application have the following beneficial effects:
the application provides a method and a device for microwave imaging of a spiral scanning type arc array. The method comprises the following steps: s1, acquiring a microwave signal according to the preset working mode; s2, in the constant-speed motion, controlling an arc-shaped array antenna to continuously radiate the microwave signals outwards, wherein the track for radiating the microwave signals is spiral; s3, acquiring post-echo data associated with the microwave signal through the arc array antenna; and S4, acquiring continuous microwave images according to the back echo data. According to the method, continuous high-resolution observation imaging can be carried out on large-area scenes around the platform when the platform moves linearly, the method not only can realize large-range large-view-angle observation of the arc array antenna along with the uniform-speed linear flight of the platform, but also can retain the advantage of all-around imaging of a conventional arc array radar, and imaging observation can be carried out all day long without being influenced by dust, cloud, rain and fog; the method and the system fill the vacancy problem of the spiral scanning type arc array microwave imaging system and method when the platform moves linearly, and realize the capability of acquiring high-resolution imaging data and continuously imaging and processing large-area scenes around the flying platform.
Drawings
FIG. 1 is a geometric schematic diagram of a helical scanning arc array microwave imaging system provided in an embodiment of the present application;
FIG. 2 is a flowchart of a method for microwave imaging with a helical scan arc array according to an embodiment of the present disclosure;
fig. 3 is a block diagram of a device for microwave imaging with a helical scanning arc array according to an embodiment of the present application.
Detailed Description
Specific embodiments of the present application will be described in detail below with reference to the accompanying drawings, but the present application is not limited thereto.
It will be understood that various modifications may be made to the embodiments disclosed herein. Accordingly, the foregoing description should not be construed as limiting, but merely as exemplifications of embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the application.
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the application and, together with a general description of the application given above and the detailed description of the embodiments given below, serve to explain the principles of the application.
These and other characteristics of the present application will become apparent from the following description of preferred forms of embodiment, given as non-limiting examples, with reference to the attached drawings.
It should also be understood that, although the present application has been described with reference to some specific examples, a person of skill in the art shall certainly be able to achieve many other equivalent forms of application, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.
The above and other aspects, features and advantages of the present application will become more apparent in view of the following detailed description when taken in conjunction with the accompanying drawings.
Specific embodiments of the present application are described hereinafter with reference to the accompanying drawings; however, it is to be understood that the disclosed embodiments are merely examples of the application, which can be embodied in various forms. Well-known and/or repeated functions and constructions are not described in detail to avoid obscuring the application of unnecessary or unnecessary detail. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present application in virtually any appropriately detailed structure.
The specification may use the phrases "in one embodiment," "in another embodiment," "in yet another embodiment," or "in other embodiments," which may each refer to one or more of the same or different embodiments in accordance with the application.
In the prior art, electromagnetic waves are transmitted and received mainly through an arc array antenna, 360-degree range observation of scenes around a platform can be achieved, and compared with a conventional linear array SAR, the imaging device can only perform single forward-looking, side-looking and rear-looking imaging, and the observation visual angle of the scenes is greatly increased.
However, the existing arc array microwave imaging method can only realize observation of a fixed-center annular region scene.
The application provides a method and a device for microwave imaging of a spiral scanning arc array. The purpose is that the spiral scanning type arc array microwave imaging flies through the platform straight line. The imaging area can be greatly enlarged to realize continuous high-resolution observation imaging, and the advantages of the conventional imaging are also kept. Please refer to fig. 3.
The method is explained in conjunction with the microwave imaging geometry of the helical scanning arc array. As shown in FIG. 1, the position coordinates of the arc array transceiver antenna when the platform moves are (x, y, z), R arc The radius of the arc array is, the incident angle and the pitch direction of the receiving and transmitting antenna are respectively phi and 3dB wave beam width in And phi -3dB Target P n Corresponding coordinate position is P n (x n ,y n ,z n ) And the radar platform flies linearly at a constant speed, and the arc array antenna beams scan. As the beam scans, the ground scatter points sequentially enter the beam irradiation area, and the beam footprints are distributed in a spiral shape on the ground. Continuous imaging of scenes around the motion platform is realized through spiral scanning type arc array microwave imaging, so that the imaging observation range is enlarged.
Details are described in the following examples one by one.
The first embodiment provided by the application is an embodiment of a method for microwave imaging of a spiral scanning arc array.
The present embodiment will be described in detail with reference to fig. 1 to 2.
Referring to fig. 1, the whole helical scanning type arc array microwave imaging system is powered and initialized, a flight platform carries the imaging system, an arc array antenna is fixed at the belly position of a helicopter, a system controller is started, and system parameters are set.
And S1, acquiring a microwave signal according to the preset working mode.
Preferably, the preset working mode includes: frequency modulated continuous wave mode or chirp mode. For example, the preset operation mode is a frequency modulation continuous wave operation mode.
The microwave signals are synthesized by the signal generating module, then transmitted to the signal transmitting module, modulated by the waveform modulator, subjected to multi-path division and power amplification by the power divider and the power amplifying unit, and then transmitted to the arc array antenna.
And S2, controlling the arc array antenna to continuously radiate the microwave signals outwards in the constant-speed motion, wherein the track for radiating the microwave signals is spiral.
The arc array antenna includes: an arc array transmitting antenna and an arc array receiving antenna.
The arc array transmitting antenna consists of transmitting array elements which are arrayed in an arc direction.
The arc array receiving antenna consists of receiving array elements which are arrayed in an arc direction.
And each channel of the transmitting array element or the receiving array element is controlled by a rapid microwave switch network, so that the arc array antenna units work in a time-sharing mode according to a preset working mode, and spiral scanning type observation is realized along with the movement of the platform.
Preferably, the controlling the arc-shaped array antenna to continuously radiate the microwave signal to the outside includes:
and controlling the transmitting array elements of the arc array antenna to radiate the microwave signals outwards according to a preset radiation sequence, wherein the track of the microwave signals radiated by each transmitting array element is in a fan-ring shape.
For example, the transmission signal of the Frequency Modulated Continuous Wave (FMCW) operating system is:
wherein, K r In order to adjust the frequency of the frequency,
f c in order to be the operating frequency of the radar,
t is the distance to the time and,
j is an imaginary component.
And S3, acquiring post-echo data associated with the microwave signal through the arc array antenna.
And the receiving array element receives scattered echoes of surrounding scenes, amplifies the power of the acquired echoes through a signal receiving module, and then performs frequency mixing and filtering processing to generate the back echo data.
Specifically;
echo data acquired by the arc array receiving antenna passes through a signal receiving and processing module of the system, and the signal receiving and processing module is expressed as follows:
wherein, delta n (x n ,y n ,z n ) For observing a target P in a scene n (x n ,y n ,z n ) The scattering coefficient of (a) is,
R n representing the arc array equivalent sampling point at (x, y, z) and the target P n (x n ,y n ,z n ) A distance therebetween, and
(x, y, z) is the coordinate position of the equivalent sampling point of the arc array antenna when the platform moves linearly at a constant speed,
c represents the electromagnetic wave propagation speed.
And S4, acquiring continuous microwave images according to the back echo data. The method comprises the following specific steps:
and S41, dividing the back echo data along the azimuth direction, performing sub-aperture imaging and generating a plurality of sub-aperture imaging data blocks.
And S42, generating a two-dimensional image according to the sub-aperture imaging data block. The method comprises the following specific steps:
step S421, inverse fourier transform is performed on the sub-aperture imaging data block along the distance direction, and the residual video phase is removed to obtain first data. The method comprises the following specific steps:
step S421-1, imaging the sub-aperture data block S re (t, x, y, z) inverse Fourier transforming along the distance direction to obtain distance compressed data:
S IFT_re (R n ,x,y,z)＝IFT t [S re (t,x,y,z)]；
wherein IFT t Indicating an inverse fourier transform along the distance to the time variable t,
R n representing the arc array equivalent sampling point at (x, y, z) and the target P n (x n ,y n ,z n ) The distance between them;
step S421-2, removing the distance compressed data S IFT_re (R n X, y, z) acquires the first data:
S IFT_rvp (R n ,x,y,z)＝S IFT_re (R n ,x,y,z)×H rvp (R n )；
wherein the compensation function:
step S422, perform distance-to-fourier transform on the first data to obtain distance frequency domain data:
wherein, FT represents the Fourier transform,
f c in order to obtain the frequency of the radar working center,
R n representing the arc array equivalent sampling point at (x, y, z) and the target P n (x n ,y n ,z n ) The distance between them.
Step S423, discretizing the image space corresponding to the sub-aperture imaging data block in two dimensions to obtain a two-dimensional image space.
Performing two-dimensional discretization on the sub-aperture imaging data block along the arc array direction and the distance direction respectively according to the pixel sizes of delta theta and delta r to obtain a two-dimensional image space I 0 (n θ Δθ,n r Δr)；
Wherein n is θ ＝1,…,N θ ，n r ＝1,…,N r ，N θ And N r The number of pixels discretized along the arc array direction and the distance direction is respectively;
θ min and theta max Respectively the start angle and the end angle of the sub-aperture imaging area,
r max and r min The farthest ground distance and the nearest ground distance illuminated by the antenna respectively.
Step S424, obtaining a matched filter function of each pixel position according to each pixel position of the two-dimensional image space.
According to the two-dimensional image space I 0 (n θ Δθ,n r Δ r) th (n) θ ,n r ) Coordinate position (n) corresponding to pixel θ Δθ,n r Δ R) to the equivalent sampling point P (x, y, z) of the arc array antenna m Obtaining a matched filtering function:
wherein, the first and the second end of the pipe are connected with each other,
z 0 the height of the ground surface plane is shown,
n θ and n r A pixel count number is indicated and,
n θ ＝1,…,N θ ，
n r ＝1,…,N r ，
N θ and N r The number of pixels discretized along the arc array direction and the distance direction is respectively.
Step S425, obtaining each pixel value of the two-dimensional image space according to the distance frequency domain data and the matched filter function.
The obtaining each pixel value of the two-dimensional image space according to the distance frequency domain data and the matched filter function includes:
traversing each pixel bit of the two-dimensional image space according to a preset traversal rule, and acquiring a pixel value of the pixel bit through the distance frequency domain data and the matched filtering function;
wherein the formula for each pixel value is calculated:
θ max and theta min Respectively, the range of array-wise integration.
Step S426, generating a two-dimensional image I (n) from each pixel value of the two-dimensional image space θ Δθ,n r Δr)。
And S43, performing geometric correction on the two-dimensional image to generate a corrected two-dimensional image.
And transforming the distance-angle image in the polar coordinate format to a Cartesian rectangular coordinate system, performing accurate coordinate transformation on the distance-angle image through a sinc interpolation value, performing geometric correction on the obtained sub-aperture image, and splicing the sub-aperture image to realize continuous observation imaging.
And S44, splicing the plurality of corrected two-dimensional images to generate continuous microwave images.
According to the method, continuous high-resolution observation imaging can be carried out on large-area scenes around the platform when the platform moves linearly, the method can realize large-range large-view-angle observation of the arc array antenna along with the uniform-speed linear flight of the platform, the advantage of omnibearing imaging of a conventional arc array radar can be reserved, and imaging observation can be carried out all day round without being influenced by dust, cloud, rain and fog; the method and the system fill the vacancy problem of the spiral scanning type arc array microwave imaging system and method when the platform moves linearly, and realize the capability of acquiring high-resolution imaging data and continuously imaging and processing large-area scenes around the flying platform.
The application also provides a second embodiment, namely a device for microwave imaging of the spiral scanning arc array, corresponding to the first embodiment provided by the application. Since the second embodiment is basically similar to the first embodiment, the description is simple, and the relevant portions should be referred to the corresponding description of the first embodiment. The device embodiments described below are merely illustrative.
Fig. 3 shows an embodiment of an apparatus for microwave imaging of a helical scanning arc array provided by the present application. Fig. 3 is a block diagram of a device for microwave imaging with a helical scanning arc array according to an embodiment of the present application.
Referring to fig. 3, the present application provides a spiral scanning arc array microwave imaging apparatus, including: an acquisition unit 201, a radiation unit 202, a receiving unit 203, an imaging unit 204;
an obtaining unit 201, configured to obtain a microwave signal according to the preset working mode.
Preferably, the preset working mode includes: frequency modulated continuous wave mode or chirp mode.
And the radiation unit 202 is configured to control the arc-shaped array antenna to continuously radiate the microwave signal outwards in uniform motion, where a track of the radiated microwave signal is spiral.
A receiving unit 203, configured to acquire post-echo data associated with the microwave signal through the arc array antenna.
And the imaging unit 204 is configured to acquire a continuous microwave image according to the post-echo data.
Preferably, the imaging unit 204 includes:
a sub-aperture imaging data block generating subunit, configured to divide the post-echo data along an azimuth direction, perform sub-aperture imaging, and generate a plurality of sub-aperture imaging data blocks;
a generating two-dimensional image subunit, configured to generate a two-dimensional image according to the sub-aperture imaging data block;
a generating correction two-dimensional image subunit, configured to perform geometric correction on the two-dimensional image to generate a correction two-dimensional image;
and the continuous microwave image generating subunit is used for splicing the plurality of corrected two-dimensional images to generate a continuous microwave image.
Preferably, the generating two-dimensional image subunit includes:
the first data acquisition subunit is used for performing inverse Fourier transform on the sub-aperture imaging data block along the distance direction and removing residual video phases to acquire first data;
a distance frequency domain data obtaining subunit, configured to perform distance-to-fourier transform on the first data to obtain distance frequency domain data;
the two-dimensional image space acquisition subunit is used for discretizing the image space corresponding to the sub-aperture imaging data block in two dimensions to acquire a two-dimensional image space;
the matched filter function acquiring subunit is used for acquiring a matched filter function of each pixel position according to each pixel position of the two-dimensional image space;
the acquiring pixel value subunit is used for acquiring each pixel value of the two-dimensional image space according to the distance frequency domain data and the matched filter function;
and generating a two-dimensional image slave subunit for generating a two-dimensional image according to each pixel value of the two-dimensional image space.
Preferably, the inverse fourier transforming the sub-aperture imaging data block along the distance direction and removing the residual video phase to obtain the first data includes:
obtaining a distance-compressed data sub-unit for imaging the sub-aperture data block S re (t, x, y, z) performing inverse Fourier transform along the distance direction to obtain distance-compressed data:
S IFT_re (R n ,x,y,z)＝IFT t [S re (t,x,y,z)]；
wherein IFT t Indicating an inverse fourier transform along the distance to the time variable t,
R n representing the arc array equivalent sampling point at (x, y, z) and the target P n (x n ,y n ,z n ) The distance between them;
obtaining a first data slave subunit for removing the distance-compressed data S IFT_re (R n X, y, z) acquires first data:
S IFT_rvp (R n ,x,y,z)＝S IFT_re (R n ,x,y,z)×H rvp (R n )；
wherein the compensation function:
preferably, in the obtaining distance frequency domain data subunit, the distance frequency domain data:
wherein, FT represents the Fourier transform,
f c in order to obtain the frequency of the radar operating center,
R n representing the arc array equivalent sampling point at (x, y, z) and the target P n (x n ,y n ,z n ) The distance between them.
Preferably, in the obtaining a two-dimensional image space subunit, the method includes:
obtaining a two-dimensional image space slave unit for performing two-dimensional discretization on the sub-aperture imaging data block along the arc array direction and the distance direction respectively according to the pixel sizes of delta theta and delta r to obtain a two-dimensional image space I 0 (n θ Δθ,n r Δr)；
Wherein n is θ ＝1,…,N θ ，n r ＝1,…,N r ，N θ And N r The number of pixels discretized along the arc array direction and the distance direction respectively;
θ min and theta max Respectively the start angle and the end angle of the sub-aperture imaging area,
r max and r min The farthest ground distance and the nearest ground distance irradiated by the antenna respectively.
Preferably, in the obtaining matched filter function subunit, the method includes:
obtaining a matched filter function slave subunit for obtaining a matched filter function from the two-dimensional image space I 0 (n θ Δθ,n r Δ r) th (n) θ ,n r ) Coordinate position (n) corresponding to pixel θ Δθ,n r Δ R) to the equivalent sampling point P (x, y, z) of the arc array antenna m Obtaining a matched filter function:
wherein the content of the first and second substances,
Z 0 the height of the ground surface plane is shown,
n θ and n r A pixel count number is represented and,
n θ ＝1,…,N θ ，
n r ＝1,…,N r ，
N θ and N r The number of pixels discretized along the arc array direction and the distance direction is respectively.
Preferably, the pixel value obtaining subunit includes:
the pixel value slave subunit is used for traversing each pixel bit of the two-dimensional image space according to a preset traversal rule and acquiring the pixel value of the pixel bit through the distance frequency domain data and the matched filtering function;
wherein the formula for each pixel value is calculated:
θ max and theta min Respectively, the range of array-wise integration.
Preferably, in the radiation unit 202, it includes:
and the radiation subunit is used for controlling the transmitting array elements of the arc-shaped array antenna to externally radiate the microwave signals according to a preset radiation sequence, wherein the track of the microwave signals radiated by each transmitting array element is in a fan-ring shape.
According to the method, continuous high-resolution observation imaging can be carried out on large-area scenes around the platform when the platform moves linearly, the method can realize large-range large-view-angle observation of the arc array antenna along with the uniform-speed linear flight of the platform, the advantage of omnibearing imaging of a conventional arc array radar can be reserved, and imaging observation can be carried out all day round without being influenced by dust, cloud, rain and fog; the method and the system fill the vacancy problem of the spiral scanning type arc array microwave imaging system and method when the platform moves linearly, and realize the capability of acquiring high-resolution imaging data and continuously imaging and processing large-area scenes around the flying platform.
The above embodiments are only exemplary embodiments of the present application, and are not intended to limit the present application, and the protection scope of the present application is defined by the claims. Various modifications and equivalents may be made by those skilled in the art within the spirit and scope of the present application and such modifications and equivalents should also be considered to be within the scope of the present application.
Claims (9)
1. A method of microwave imaging of a helical scanning arc array, comprising:
s1, acquiring a microwave signal according to a preset working mode; the preset working mode comprises a frequency modulation continuous wave working mode or a linear frequency modulation pulse working mode;
s2, in the uniform linear motion, controlling the arc array antenna to continuously radiate the microwave signals outwards, wherein the track for radiating the microwave signals is spiral,
the control arc array antenna radiates the microwave signal to the outside continuously, including: controlling the transmitting array elements of the arc array antenna to radiate the microwave signals outwards according to a preset radiation sequence, wherein the track of the microwave signals radiated by each transmitting array element is in a fan-shaped ring shape;
s3, acquiring post-echo data associated with the microwave signal through the arc array antenna;
s4, acquiring continuous microwave images according to the back echo data, including,
s41, dividing the back echo data along the azimuth direction, performing sub-aperture imaging and generating a plurality of sub-aperture imaging data blocks;
s42, generating a two-dimensional image according to the sub-aperture imaging data block;
s43, performing geometric correction on the two-dimensional image to generate a corrected two-dimensional image;
and S44, splicing the plurality of corrected two-dimensional images to generate a continuous microwave image.
2. The method of claim 1, wherein generating a two-dimensional image from the sub-aperture imaging data block comprises:
s421, performing inverse Fourier transform on the sub-aperture imaging data block along the distance direction and removing the residual video phase to obtain first data;
s422, carrying out distance-to-Fourier transform on the first data to obtain distance frequency domain data;
s423, discretizing the image space corresponding to the sub-aperture imaging data block in two dimensions to obtain a two-dimensional image space;
s424, acquiring a matched filter function of each pixel position according to each pixel position of the two-dimensional image space;
s425, obtaining each pixel value of the two-dimensional image space according to the distance frequency domain data and the matched filter function;
s426, a two-dimensional image is generated from each pixel value of the two-dimensional image space.
3. The method of claim 2, wherein said inverse fourier transforming the sub-aperture imaging data block along a distance direction and removing residual video phases to obtain first data comprises:
s421-1, imaging the sub-aperture data block S re (t, x, y, z) inverse Fourier transforming along the distance direction to obtain distance compressed data:
S IFT_re (R n ,x,y,z)＝IFT t [S re (t,x,y,z)]；
wherein IFT t Indicating an inverse fourier transform along the distance to the time variable t,
R n representing the arc array equivalent sampling point at (x, y, z) and the target P n (x n ,y n ,z n ) The distance between them;
s421-2, removing the data S after distance compression IFT_re (R n X, y, z) acquires the first data:
S IFT_rvp (R n ,x,y,z)＝S IFT_re (R n ,x,y,z)×H rvp (R n )；
wherein the compensation function:
c represents the propagation speed of the electromagnetic wave,
kr is the frequency modulation rate of the mixed gas,
t is the distance versus time.
4. The method of claim 3, wherein the distance-to-Fourier transforming the first data obtains distance frequency domain data:
wherein, FT represents the Fourier transform,
f c in order to obtain the frequency of the radar operating center,
R n representing the arc array equivalent sampling point at (x, y, z) and the target P n (x n ,y n ,z n ) The distance between them.
5. The method of claim 4, wherein discretizing the image space corresponding to the sub-aperture imaging data block in two dimensions to obtain a two-dimensional image space comprises:
performing two-dimensional discretization on the sub-aperture imaging data block along the arc array direction and the distance direction respectively according to the pixel sizes of delta theta and delta r to obtain a two-dimensional image space I 0 (n θ Δθ,n r Δr)；
Wherein n is θ ＝1,…,N θ ，n r ＝1,…,N r ，N θ And N r The number of pixels discretized along the arc array direction and the distance direction respectively;
θ min and theta max Respectively the start angle and the end angle of the sub-aperture imaging area,
r max and r min The farthest ground distance and the nearest ground distance illuminated by the antenna respectively.
6. The method of claim 5, wherein obtaining a matched filter function from each pixel location of the two-dimensional image space comprises:
according to said two-dimensional image space I 0 (n θ Δθ,n r Δ r) th (n) θ ,n r ) Coordinate position (n) corresponding to pixel θ Δθ,n r Δ R) distance R to equivalent sampling point P (x, y, z) of the arc array antenna m Get the PMatching a filter function:
wherein the content of the first and second substances,
z 0 the height of the ground surface plane is shown,
n θ and n r A pixel count number is indicated and,
n θ ＝1,…,N θ ，
n r ＝1,…,N r ，
N θ and N r The number of pixels discretized along the arc array direction and the distance direction is respectively.
7. The method of claim 6, wherein said obtaining each pixel value of the two-dimensional image space from the distance frequency domain data and the matched filter function comprises:
traversing each pixel bit of the two-dimensional image space according to a preset traversal rule, and acquiring a pixel value of the pixel bit through the distance frequency domain data and the matched filtering function;
wherein the formula for each pixel value is calculated:
θ max and theta min Respectively, the range of array-wise integration.
8. The method of claim 1, wherein said controlling the arcuate array antenna to continuously radiate the microwave signal outward comprises:
and controlling the transmitting array elements of the arc array antenna to radiate the microwave signals outwards according to a preset radiation sequence, wherein the track of the microwave signals radiated by each transmitting array element is in a fan-ring shape.
9. A helical scanning type arc array microwave imaging device is characterized by comprising:
the device comprises an acquisition unit, a processing unit and a processing unit, wherein the acquisition unit is used for acquiring a microwave signal according to a preset working mode, and the preset working mode comprises a frequency modulation continuous wave working mode or a linear frequency modulation pulse working mode;
a radiation unit for controlling the arc array antenna to continuously radiate the microwave signal outwards in uniform motion, wherein the track for radiating the microwave signal is spiral,
the control arc array antenna radiates the microwave signal to the outside continuously, including: controlling the transmitting array elements of the arc array antenna to radiate the microwave signals outwards according to a preset radiation sequence, wherein the track of the microwave signals radiated by each transmitting array element is in a fan-shaped ring shape;
a receiving unit, configured to acquire post-echo data associated with the microwave signal through the arc array antenna;
an imaging unit for acquiring continuous microwave images from the post-echo data, comprising,
s41, dividing the back echo data along the azimuth direction, performing sub-aperture imaging and generating a plurality of sub-aperture imaging data blocks;
s42, generating a two-dimensional image according to the sub-aperture imaging data block;
s43, performing geometric correction on the two-dimensional image to generate a corrected two-dimensional image;
and S44, splicing the plurality of corrected two-dimensional images to generate continuous microwave images.
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Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7034746B1 (en) * | 2005-03-24 | 2006-04-25 | Bettelle Memorial Institute | Holographic arrays for threat detection and human feature removal |
| KR20100126979A (en) * | 2009-05-25 | 2010-12-03 | 한국지질자원연구원 | Imaging method for arc synthetic aperture radar system using polar coordinates |
| CN102540185A (en) * | 2011-12-30 | 2012-07-04 | 北京华航无线电测量研究所 | Imaging method for millimeter waves imaging system with arc-scanning antenna array |
| CN103018738A (en) * | 2011-09-20 | 2013-04-03 | 中国科学院电子学研究所 | Microwave three-dimensional imaging method based on rotary antenna array |
| CN104090277A (en) * | 2014-07-21 | 2014-10-08 | 中国科学院电子学研究所 | Method for imaging sliding circumferential synthetic aperture radar |
| CN104269658A (en) * | 2014-10-21 | 2015-01-07 | 内蒙古工业大学 | Arc array antenna for MIMO-SAR imaging |
| CN104280735A (en) * | 2014-10-21 | 2015-01-14 | 内蒙古工业大学 | MIMO-SAR imaging method and device based on arc-shaped array antenna |
| CN106054182A (en) * | 2016-05-13 | 2016-10-26 | 北京工业大学 | Terahertz imaging system |
| CN106556874A (en) * | 2016-10-31 | 2017-04-05 | 华讯方舟科技有限公司 | A kind of closely microwave imaging method and system |
| CN107121670A (en) * | 2017-04-12 | 2017-09-01 | 东南大学 | A kind of anti-unmanned plane system of defense based on synthetic aperture radar |
| CN107645068A (en) * | 2017-09-15 | 2018-01-30 | 中南大学 | A kind of circular array design method for rotating circular polarisation array element and producing OAM wave beams |
| CN108107431A (en) * | 2017-11-20 | 2018-06-01 | 西安电子科技大学 | A kind of cylinder ScanSAR three-dimensional imaging Fast implementation |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2109416C1 (en) * | 1994-12-09 | 1998-04-20 | Институт ядерной физики им.Г.И.Будкера СО РАН | Device for release of electron beam into atmosphere |
| US9715012B2 (en) * | 2013-04-25 | 2017-07-25 | Battelle Memorial Institute | Footwear scanning systems and methods |
-
2018
- 2018-12-29 CN CN201811634739.2A patent/CN109597070B/en active Active
Patent Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7034746B1 (en) * | 2005-03-24 | 2006-04-25 | Bettelle Memorial Institute | Holographic arrays for threat detection and human feature removal |
| KR20100126979A (en) * | 2009-05-25 | 2010-12-03 | 한국지질자원연구원 | Imaging method for arc synthetic aperture radar system using polar coordinates |
| CN103018738A (en) * | 2011-09-20 | 2013-04-03 | 中国科学院电子学研究所 | Microwave three-dimensional imaging method based on rotary antenna array |
| CN102540185A (en) * | 2011-12-30 | 2012-07-04 | 北京华航无线电测量研究所 | Imaging method for millimeter waves imaging system with arc-scanning antenna array |
| CN104090277A (en) * | 2014-07-21 | 2014-10-08 | 中国科学院电子学研究所 | Method for imaging sliding circumferential synthetic aperture radar |
| CN104269658A (en) * | 2014-10-21 | 2015-01-07 | 内蒙古工业大学 | Arc array antenna for MIMO-SAR imaging |
| CN104280735A (en) * | 2014-10-21 | 2015-01-14 | 内蒙古工业大学 | MIMO-SAR imaging method and device based on arc-shaped array antenna |
| CN106054182A (en) * | 2016-05-13 | 2016-10-26 | 北京工业大学 | Terahertz imaging system |
| CN106556874A (en) * | 2016-10-31 | 2017-04-05 | 华讯方舟科技有限公司 | A kind of closely microwave imaging method and system |
| CN107121670A (en) * | 2017-04-12 | 2017-09-01 | 东南大学 | A kind of anti-unmanned plane system of defense based on synthetic aperture radar |
| CN107645068A (en) * | 2017-09-15 | 2018-01-30 | 中南大学 | A kind of circular array design method for rotating circular polarisation array element and producing OAM wave beams |
| CN108107431A (en) * | 2017-11-20 | 2018-06-01 | 西安电子科技大学 | A kind of cylinder ScanSAR three-dimensional imaging Fast implementation |
Non-Patent Citations (3)
| Title |
|---|
| "MIMO-SAR imaging technology for helicopter-borne based on ARC antenna array";Huang Pingping 等;《2015 IEEE International Geoscience and Remote Sensing Symposium (IGARSS)》;20151231;第1801-1804页 * |
| "The statistics of radio frequency interference propagating from long distances to the Murchison radio-astronomy observatory";Marcin Sokolowski 等;《2016 Radio Frequency Interference (RFI)》;20161231;第105-110页 * |
| "直升机载弧形阵列MIMO微波成像技术研究";黄平平 等;《雷达学报》;20150320;第11-19页 * |
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