CN113625270B - Three-dimensional imaging radar combining MIMO and ArcSAR and imaging method thereof - Google Patents
Three-dimensional imaging radar combining MIMO and ArcSAR and imaging method thereof Download PDFInfo
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- 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
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- 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
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- G01S13/90—Radar or analogous systems specially adapted for specific applications for mapping or imaging using synthetic aperture techniques, e.g. synthetic aperture radar [SAR] techniques
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Abstract
The invention is applicable to the technical field of radar three-dimensional imaging, and relates to an imaging method of a three-dimensional imaging radar combining MIMO and ArcSAR, which comprises the following steps: s10, mounting a MIMO array antenna and a radial arm; s20, receiving and transmitting signals at a single angle by the MIMO array antenna to form a one-dimensional virtual aperture linear array; s30, repeating the step S20 for all rotation angles, and forming a two-dimensional virtual area array for two-dimensional scanning of the detection area; s40, performing pulse compression on array element radar echoes of the two-dimensional virtual area array to obtain a one-dimensional range profile; s50, imaging network division is carried out on the detection space, and delay of each array element is calculated; s60, projecting a certain array element in the step S40 to a corresponding imaging grid according to delay of the certain array element to obtain a three-dimensional sub-image corresponding to the virtual array element; and S70, traversing all the virtual array elements in the process of the step S60, and performing coherent superposition on the sub-images to obtain a three-dimensional image. The invention can realize the large-scale three-dimensional imaging of any scene and the extraction of deformation fields under the condition of lower hardware complexity.
Description
Technical Field
The invention belongs to the technical field of radar three-dimensional imaging, and particularly relates to a three-dimensional imaging radar combining MIMO and ArcSAR and an imaging method thereof.
Background
The foundation interferometric radar is an effective slope stability monitoring remote sensing technical means, and has the advantages of long-distance non-contact monitoring, high deformation measurement precision, high data update rate, no influence of weather illumination and the like compared with the means such as spaceborne and airborne interferometric synthetic aperture radar, three-dimensional laser, photogrammetry and the like. The foundation interference monitoring radar is divided into a plurality of systems such as linear orbit synthetic aperture imaging, pen-shaped beam real aperture two-dimensional scanning, fan-shaped beam real aperture one-dimensional scanning, circular arc orbit synthetic aperture (group-based arc-scanning syntheticaperture radar) imaging, multiple input multiple output (Multiple input multiple output) and the like according to the antenna form and the scanning mode.
Since the monitoring object of the foundation slope stabilizing radar is three-dimensional scenes such as a slope, a dam, a mine pit and the like, whether three-dimensional terrain data can be generated and a deformation field of the three-dimensional scene can be acquired is particularly important. In the working modes, a true three-dimensional image can be formed by the pen-shaped beam real-aperture two-dimensional scanning radar system, namely, when the radar scans a monitored scene, the azimuth angle and the pitch angle of the two-dimensional turntable and the radar echo range profile can directly generate three-dimensional scattering and deformation field data for the terrain, but the working mode has long time for scanning the whole scene and low working efficiency because the antenna beam only covers a small angle; in other working radar systems, elevation information is estimated by adding an elevation base line, then processing two radar images with different heights by using an interference synthetic aperture (Interferometric Synthetic Aperture Radar) algorithm, but these three-dimensional terrain reconstructions all adopt InSAR to perform elevation estimation, on one hand, reconstruction errors are large for areas with severe terrain changes and scenes with nearly vertical relative radar gradients, and on the other hand, although the terrain is reconstructed, the extracted deformation field is still two-dimensional, and the three-dimensional deformation field cannot be obtained.
In recent years, in the field of slope stability monitoring radars, more researches are carried out on extraction of three-dimensional deformation fields at home and abroad, the existing three-dimensional deformation field is generally extracted in two forms, firstly, a scene is monitored by a plurality of radars from different view angles, the three-dimensional deformation quantity of a PS point is calculated through a triangular projection relation, a plurality of radars are required to work together, more equipment is needed, the clock and the data among the radars are difficult to synchronize to a certain extent, and only three-dimensional deformation of a certain PS point is acquired, three-dimensional topography reconstruction and three-dimensional scene deformation field acquisition cannot be carried out, and in addition, the monitoring scene range is limited; secondly, three-dimensional imaging is carried out on a local area through a two-dimensional MIMO area array, deformation monitoring is carried out, then a larger area is covered through two-dimensional rotation of a rotary table, more transmitting and receiving antennas are needed in the mode to form enough two-dimensional array size (or the number of array elements when array element intervals are fixed) required by high resolution, and the complexity of the system is high.
Therefore, how to provide a three-dimensional imaging radar capable of being applied to large-scale three-dimensional imaging of any scene and deformation field extraction is a problem to be solved by those skilled in the art.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide an imaging method of a three-dimensional imaging radar combining MIMO and ArcSAR, thereby realizing large-scale three-dimensional imaging and deformation field extraction of any scene; in addition, the invention also provides a three-dimensional imaging radar combining MIMO and ArcSAR.
In order to solve the technical problems, the invention adopts the following technical scheme:
in a first aspect, the present invention provides an imaging method of a three-dimensional imaging radar combining MIMO and ArcSAR, comprising the steps of:
s10, mounting the MIMO array antenna at the front end of a radial arm with a certain length and being perpendicular to the radial arm, wherein the radial arm drives the MIMO array antenna to rotate at a certain angular speed in a plane taking the MIMO array antenna as a normal line;
s20, when the radial arm rotates to a certain angle, all receiving and transmitting antennas of the MIMO array antenna complete sequential receiving and transmitting of signals, and a one-dimensional virtual aperture linear array is formed;
s30, repeating the step S20 when the radial arm traverses all rotation angles, and obtaining two-dimensional scanning of a detection area by the system, namely forming a two-dimensional virtual area array;
s40, carrying out pulse compression on the radar echo obtained by the array elements of the two-dimensional virtual area array formed in the step S30 to obtain a one-dimensional range profile of the radar echo to a detection area;
s50, carrying out imaging network division on a detection space, and calculating delay of each imaging grid and each array element of the two-dimensional virtual area array;
s60, projecting the one-dimensional distance image of a certain array element in the step S40 to a corresponding imaging grid according to the delay corresponding to the step S50 to obtain a three-dimensional sub-image corresponding to the virtual array element;
and S70, traversing all the virtual array elements in the process of the step S60, and performing coherent superposition on all the obtained sub-images to finally obtain the three-dimensional image of the detection area.
Further, in the step S10, when the MIMO array antenna is horizontally placed, the radial arm rotates in a pitch direction; when the MIMO array antenna is placed vertically, the radial arm rotates in the horizontal direction.
Further, in step S20, the electric scanning of the MIMO array antenna and the rotation of the rotating arm are in a time-sharing working mode, and the MIMO array antenna completes the electric scanning to form a virtual aperture once when the rotating arm rotates to a certain angle, thereby forming a one-dimensional virtual aperture linear array.
Further, in the step S20, the three-dimensional imaging radar combined with MIMO and ArcSAR transmits a frequency modulated continuous wave signal S T (t) is represented by the following formula:
wherein T is the fast time, T p To transmit signal pulse width, f c For transmitting signal carrier frequency, K r Frequency modulation for the signal;
further, the transmitting antenna A of the MIMO array antenna T，m And receiving antenna A R，n The corresponding echo signal is represented by the following equation:
wherein R is m，p For radial distance of transmitting antenna from target, R n，p Radial distance from the target for the receiving antenna;
R m，p and R is n，p Represented by the formula:
wherein x is p ，y p ，z p Is the three-dimensional coordinates of the target point, x T，m ，y T，m ，z T，m Transmitting antenna A being said MIMO array antenna T，m Three-dimensional coordinates, x R，n ，y R，n ，z R，n For the MIMO array antennaIs a receiving antenna a of (1) R，n Is a three-dimensional coordinate of (c).
Further, the transmitting antenna A of the MIMO array antenna T，m Is represented by the following formula:
receiving antenna A of MIMO array antenna R，n Is represented by the following formula:
wherein L is the length of the radial arm of the array,the half beam angle is panned for the transmit and receive antenna.
Further, in the step S30, after the radial arm continues to rotate to the next angle, the MIMO array antenna performs an electric scan again, and the step S20 is repeated until all the MIMO array antennas under the set angles of the radial arm are electrically scanned, where each virtual aperture formed forms an arc aperture in the array normal plane due to the rotation of the radial arm, so as to form a two-dimensional virtual area array.
Further, in the step S40, the one-dimensional distance profile is represented by the following formula:
further, the three-dimensional imaging algorithm applied by the two-dimensional virtual area array of the three-dimensional imaging radar combining the MIMO and the ArcSAR comprises a polar wave number domain algorithm, a back projection algorithm and a beam synthesis algorithm.
In a second aspect, the present invention also provides a three-dimensional imaging radar combining MIMO and ArcSAR, comprising:
MIMO array antennas and radial arms;
the MIMO array antenna is arranged at the front end of the radial arm and is vertical to the radial arm;
the rotating arm can drive the MIMO array antenna to rotate in all directions to transmit and receive signals.
Compared with the prior art, the three-dimensional imaging radar combining MIMO and ArcSAR and the imaging method thereof have at least the following beneficial effects:
the invention can realize the large-scale three-dimensional imaging of any scene and the extraction of deformation fields under the condition of lower hardware complexity.
Drawings
In order to more clearly illustrate the solution of the invention, a brief description will be given below of the drawings required for the description of the embodiments, it being apparent that the drawings in the following description are some embodiments of the invention and that other drawings may be obtained from these drawings without inventive effort for a person skilled in the art.
Fig. 1 is an imaging geometry diagram of a three-dimensional imaging radar for MIMO and ArcSAR according to an embodiment of the present invention;
fig. 2 is a two-dimensional cross-sectional plan view of a single-point target of an imaging method of a three-dimensional imaging radar of MIMO and ArcSAR according to an embodiment of the present invention;
fig. 3 is a one-dimensional cross-sectional graph of a single-point target of an imaging method of a three-dimensional imaging radar of MIMO and ArcSAR according to an embodiment of the present invention;
fig. 4 is a single-point target three-dimensional equivalent surface diagram of an imaging method of a three-dimensional imaging radar of MIMO and ArcSAR according to an embodiment of the present invention;
fig. 5 is a two-dimensional cross-sectional plan view of a multi-point target of an imaging method of a three-dimensional imaging radar of MIMO and ArcSAR according to an embodiment of the present invention;
fig. 6 is a one-dimensional cross-sectional graph of a multi-point target of an imaging method of a three-dimensional imaging radar of MIMO and ArcSAR according to an embodiment of the present invention;
fig. 7 is a three-dimensional contour map of a multi-point target of an imaging method of a three-dimensional imaging radar of MIMO and ArcSAR according to an embodiment of the present invention.
Detailed Description
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs; the terms used in the specification are used herein for the purpose of describing particular embodiments only and are not intended to limit the present invention, for example, the orientations or positions indicated by the terms "length", "width", "upper", "lower", "left", "right", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are orientations or positions based on the drawings, which are merely for convenience of description and are not to be construed as limiting the present invention.
The terms "comprising" and "having" and any variations thereof in the description of the invention and the claims and the description of the drawings above are intended to cover a non-exclusive inclusion; the terms first, second and the like in the description and in the claims or in the above-described figures, are used for distinguishing between different objects and not necessarily for describing a sequential or chronological order. In the description of the invention and the claims and the above figures, when an element is referred to as being "fixed" or "mounted" or "disposed" or "connected" to another element, it can be directly or indirectly on the other element. For example, when an element is referred to as being "connected to" another element, it can be directly or indirectly connected to the other element.
Furthermore, references herein to "an embodiment" mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present invention. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments.
The invention provides an imaging method of a three-dimensional imaging radar combining MIMO and ArcSAR, which is applied to large-scale three-dimensional imaging of any scene and extraction of deformation fields, and comprises the following steps:
s10, mounting the MIMO array antenna at the front end of a radial arm with a certain length and being perpendicular to the radial arm, wherein the radial arm drives the MIMO array antenna to rotate at a certain angular speed in a plane taking the MIMO array antenna as a normal line;
s20, when the radial arm rotates to a certain angle, all receiving and transmitting antennas of the MIMO array antenna complete sequential receiving and transmitting of signals, and a one-dimensional virtual aperture linear array is formed;
s30, when the radial arm traverses all rotation angles, repeating the step S20, and obtaining two-dimensional scanning of the detection area by the system, namely forming a two-dimensional virtual area array;
s40, carrying out pulse compression on the radar echo obtained by the array elements of the two-dimensional virtual area array formed in the step S30 to obtain a one-dimensional range profile of the detection area;
s50, carrying out imaging network division on a detection space, and calculating delay of each imaging grid and each array element of the two-dimensional virtual area array;
s60, projecting the one-dimensional distance image of one array element in the step S40 to a corresponding imaging grid according to the delay corresponding to the step S50 to obtain a three-dimensional sub-image corresponding to the virtual array element;
and S70, traversing all the virtual array elements in the process of the step S60, and performing coherent superposition on all the obtained sub-images to finally obtain the three-dimensional image of the detection area.
The rotating arm can drive the MIMO array antenna to rotate in all directions to transmit and receive signals, and large-scale three-dimensional imaging of any scene and extraction of deformation fields are realized.
In order to make the person skilled in the art better understand the solution of the present invention, the technical solution of the embodiment of the present invention will be clearly and completely described below with reference to the accompanying drawings.
The invention provides an imaging method of a three-dimensional imaging radar combining MIMO and ArcSAR, which adopts the three-dimensional imaging radar combining MIMO and ArcSAR and comprises an MIMO array antenna and a radial arm, wherein the MIMO array antenna is arranged at the front end of the radial arm and is vertical to the radial arm, the radial arm can drive the MIMO array antenna to rotate in all directions to transmit and receive signals, the resolution ratio of the MIMO array antenna and the plane direction of an antenna beam is obtained through a virtual aperture technology, the high resolution ratio of the plane elevation direction of the method is obtained through an arc synthetic aperture technology, and the imaging method is used for large-scale three-dimensional imaging of any scene and extraction of deformation fields, and in the embodiment, the imaging method of the three-dimensional imaging radar combining MIMO and ArcSAR comprises the following steps:
s10, mounting the MIMO array antenna at the front end of a radial arm with a certain length and being perpendicular to the radial arm, wherein the radial arm drives the MIMO array antenna to rotate at a certain angular speed in a plane taking the MIMO array antenna as a normal line;
s20, when the radial arm rotates to a certain angle, all receiving and transmitting antennas of the MIMO array antenna complete sequential receiving and transmitting of signals, and a one-dimensional virtual aperture linear array is formed;
s30, when the radial arm traverses all rotation angles, repeating the step S20, and obtaining two-dimensional scanning of the detection area by the system, namely forming a two-dimensional virtual area array;
s40, carrying out pulse compression on the radar echo obtained by the array elements of the two-dimensional virtual area array formed in the step S30 to obtain a one-dimensional range profile of the detection area;
s50, carrying out imaging network division on a detection space, and calculating delay of each imaging grid and each array element of the two-dimensional virtual area array;
s60, projecting the one-dimensional distance image of one array element in the step S40 to a corresponding imaging grid according to the delay corresponding to the step S50 to obtain a three-dimensional sub-image corresponding to the virtual array element;
and S70, traversing all the virtual array elements in the process of the step S60, and performing coherent superposition on all the obtained sub-images to finally obtain the three-dimensional image of the detection area.
The two-dimensional virtual area array three-dimensional imaging algorithm mainly comprises a polar coordinate wave number domain algorithm, a backward projection algorithm, a beam forming algorithm and the like, wherein the backward projection algorithm has the advantages of being simple in algorithm, high in imaging precision, easy to realize antenna pattern compensation and the like, and is more suitable for the three-dimensional imaging radar combining MIMO and ArcSAR.
Taking a system structure of horizontally placing an antenna of an MIMO array and pitching and rotating a rotating arm as an example, the three-dimensional imaging radar combining the MIMO and the ArcSAR and the one-dimensional distance pulse pressure and the three-dimensional imaging process related to the imaging method of the three-dimensional imaging radar provided by the embodiment of the invention are described in detail as follows:
the imaging geometric model of the three-dimensional imaging radar of the MIMO and the ArcSAR is shown in fig. 1, the two-dimensional cross-section plane view, the one-dimensional cross-section graph and the three-dimensional equivalent surface view of a single-point target are shown in fig. 2, 3 and 4 respectively, the two-dimensional cross-section plane view, the one-dimensional cross-section graph and the three-dimensional equivalent surface view of a multi-point target are shown in fig. 5, 6 and 7 respectively, the transmitting antenna array is divided into 2M units, the receiving antenna array is divided into 2N units uniformly, and the two units are arranged at two ends of the transmitting antenna array. The interval of the receiving antenna is set as D, the interval of the receiving antenna is set as D, the interval of the transmitting antenna is set as 4D, and the interval of the nearest receiving antenna is set as D/2 in order to form a uniform virtual aperture. And establishing a rectangular coordinate system by taking the rear end pivot of the radial arm of the radar MIMO array as the origin of coordinates.
Suppose that there is a target point P (x p ，y p ，z p ) At the moment, the included angle between the rotating arm of the MIMO array and the horizontal direction is theta, and the radar transmits the frequency modulation continuous wave signal s T (t) may be represented by the following formula:
wherein T is the fast time, T p To transmit signal pulse width, f c For transmitting signal carrier frequency, K r The frequency is tuned for the signal.
Transmitting antenna A T，m And receiving antenna A R，n The corresponding echo signal can be obtained byThe formula is:
wherein R is m，p For radial distance of transmitting antenna from target, R n，p For receiving the radial distance of the antenna from the target.
Represented by the formula:
according to imaging geometry, transmitting antenna A T，m The three-dimensional coordinates of (2) are given by:
wherein L is the length of the array radial arm,the half beam angle is panned for the transmit and receive antenna.
Receiving antenna A R，n The three-dimensional coordinates of (2) are given by:
after mixing, ignoring the amplitude term to obtain a difference frequency signal:
the first term represents the phase corresponding to the distance, and the second and third terms are constants:wherein the second term represents the Doppler effect of the echo, which is the azimuthal pulse pressureThe third term that must be handled is unique to the de-chirping method, called residual video phase, both of which need to be compensated during imaging.
Performing fast time t Fourier transform on the formula (6) to obtain a target echo spectrum:
according to the corresponding relation f=2rK of frequency and target distance r And/c, obtaining a one-dimensional range profile of the target echo, wherein the one-dimensional range profile of the target echo is represented by the following formula:
the Lei Dafu scattered image I (x, y, z) of the imaging grid (x, y, z) is a result of phase compensation and coherent accumulation of complex distance values corresponding to one-dimensional distance images of all virtual array elements:
wherein R (x, y, z) is the distance between the imaging grid (x, y, z) and the virtual array element.
The three-dimensional resolution of the MIMO-ArcSAR system is briefly analyzed, and the system is a MIMO array SAR system in a distance-azimuth plane; in the height-distance plane, the system is an ArcSAR system, so the three-dimensional resolution can be calculated according to the corresponding imaging system model, and the following table is detailed:
table 1 system three-dimensional resolution theoretical formula
TABLE 1
Where Θ=atan (L x /2y)，L x For the MIMO array virtual aperture length, y is the distance of the target in the range-azimuth plane,is the angle between the center line of the target-array and the normal line of the array center.
The following is verified by a single point target simulation test, and the simulation related parameters are given in table 2:
TABLE 2
In general, if the array length is smaller than the square of the product of the wavelength and the target distance, the far field condition can be considered as being satisfied, and under this condition, the virtual aperture position of the antenna array can be approximated as the geometric center of the transceiver antenna on the antenna array surface, and the approximation error of the phase center can be ignored. As can be seen from the parameters of table 2, the array length is 0.3175m, and the square of the product of the wavelength and the target distance is 0.6642m, thus satisfying the far field condition.
Table 3 three-dimensional resolution simulation verification
TABLE 3 Table 3
The theoretical value and the simulation value of the distance resolution, the azimuth resolution and the height resolution of table 3 can be known, the theoretical value and the simulation value are very close, and according to the attached drawing of the specification, the imaging method of the three-dimensional imaging radar combining MIMO and ArcSAR provided by the embodiment of the invention can realize the large-scale three-dimensional imaging of any scene and the extraction of deformation fields.
It is apparent that the above-described embodiments are merely preferred embodiments of the present invention, not all of which are shown in the drawings, which do not limit the scope of the invention. This invention may be embodied in many different forms, but rather, embodiments are provided in order to provide a thorough and complete understanding of the present disclosure. Although the invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments described in the foregoing description, or equivalents may be substituted for elements thereof. All equivalent structures made by the content of the specification and the drawings of the invention are directly or indirectly applied to other related technical fields, and are also within the scope of the invention.
Claims (10)
1. An imaging method of a three-dimensional imaging radar combining MIMO and ArcSAR, comprising the steps of:
s10, mounting the MIMO array antenna at the front end of a radial arm with a certain length and being perpendicular to the radial arm, wherein the radial arm drives the MIMO array antenna to rotate at a certain angular speed in a plane taking the MIMO array antenna as a normal line;
s20, when the radial arm rotates to a certain angle, all receiving and transmitting antennas of the MIMO array antenna complete sequential receiving and transmitting of signals, and a one-dimensional virtual aperture linear array is formed;
s30, repeating the step S20 when the radial arm traverses all rotation angles, and obtaining two-dimensional scanning of a detection area by the system, namely forming a two-dimensional virtual area array;
s40, carrying out pulse compression on the radar echo obtained by the array elements of the two-dimensional virtual area array formed in the step S30 to obtain a one-dimensional range profile of the radar echo to a detection area;
s50, carrying out imaging network division on a detection space, and calculating delay of each imaging grid and each array element of the two-dimensional virtual area array;
s60, projecting the one-dimensional distance image of a certain array element in the step S40 to a corresponding imaging grid according to the delay corresponding to the step S50 to obtain a three-dimensional sub-image corresponding to a virtual array element;
and S70, traversing all the virtual array elements in the process of the step S60, and performing coherent superposition on all the obtained sub-images to finally obtain the three-dimensional image of the detection area.
2. The imaging method of a three-dimensional imaging radar combining MIMO and ArcSAR according to claim 1, wherein in said step S10, said radial arm rotates in a pitch direction when said MIMO array antenna is horizontally placed; when the MIMO array antenna is placed vertically, the radial arm rotates in the horizontal direction.
3. The method according to claim 1, wherein in the step S20, the electric scanning of the MIMO array antenna and the rotation of the rotating arm are in a time-sharing operation mode, and the MIMO array antenna completes the electric scanning to form a virtual aperture once when the rotating arm rotates to a certain angle, so as to form a one-dimensional virtual aperture linear array.
4. The method for imaging a three-dimensional imaging radar combining MIMO and ArcSAR according to claim 3, wherein in said step S20, said three-dimensional imaging radar combining MIMO and ArcSAR transmits a frequency modulated continuous wave signal S T (t) is represented by the following formula:
wherein T is the fast time, T p To transmit signal pulse width, f c For transmitting signal carrier frequency, K r The frequency is tuned for the signal.
5. The imaging method of three-dimensional imaging radar combining MIMO and ArcSAR according to claim 4, wherein the transmitting antenna a of the MIMO array antenna T，m And receiving antenna A R，n The corresponding echo signal is represented by the following equation:
wherein R is m，p For radial distance of transmitting antenna from target, R n，p Radial distance from the target for the receiving antenna;
R m，p and R is n，p Represented by the formula:
wherein x is p ，y p ，z p Is the three-dimensional coordinates of the target point, x T，m ，y T，m ，z T，m Transmitting antenna A being said MIMO array antenna T，m Three-dimensional coordinates, x R，n ，y R，n ，z R，n Receiving antenna A being said MIMO array antenna R，n Is a three-dimensional coordinate of (c).
6. The imaging method of three-dimensional imaging radar combining MIMO and ArcSAR according to claim 5, wherein the transmitting antenna a of the MIMO array antenna T，m Is represented by the following formula:
receiving antenna A of MIMO array antenna R，n Is represented by the following formula:
wherein L is the length of the radial arm of the array,the half beam angle is panned for the transmit and receive antenna.
7. The method according to claim 1, wherein in the step S30, after the arm continues to rotate to the next angle, the MIMO array antenna performs an electric scan again, and the step S20 is repeated until all the MIMO array antennas at the set angles of the arm are electrically scanned, and each virtual aperture formed forms an arc aperture in the array normal plane due to the rotation of the arm, so as to form a two-dimensional virtual area array.
8. The method for imaging a three-dimensional imaging radar combining MIMO and ArcSAR according to claim 6, wherein in step S40, the one-dimensional range profile is represented by the following formula:
9. the imaging method of a three-dimensional imaging radar combining MIMO and ArcSAR according to claim 1, wherein the three-dimensional imaging algorithm applied to the two-dimensional virtual area array of the three-dimensional imaging radar combining MIMO and ArcSAR includes a polar-wave number domain algorithm, a back projection algorithm, and a beam forming algorithm.
10. Radar apparatus employing the imaging method of the three-dimensional imaging radar combining MIMO and ArcSAR according to any one of claims 1 to 9, characterized by comprising:
MIMO array antennas and radial arms;
the MIMO array antenna is arranged at the front end of the radial arm and is vertical to the radial arm;
the rotating arm can drive the MIMO array antenna to rotate in all directions to transmit and receive signals.
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