CN113625270A - 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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Abstract
The invention is suitable for 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 the MIMO array antenna and the spiral arm; s20, the MIMO array antenna receives and transmits signals at a single angle to form a one-dimensional virtual aperture linear array; s30, repeating the step S20 for all the rotation angles, and forming a two-dimensional virtual area array by two-dimensional scanning of the detection area; s40, performing pulse compression on the array element radar echo 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 the delay of the 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-range three-dimensional imaging and the extraction of the deformation field of any scene 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 ground interference radar is an effective remote sensing technical means for monitoring slope stability, and has the advantages of long-distance non-contact monitoring, high deformation measurement precision, high data updating rate, no influence of weather illumination and the like compared with satellite-borne and airborne interference synthetic hole radars, three-dimensional laser, photogrammetry and other means. The Ground-based interference monitoring radar is divided into a plurality of systems such as linear track synthetic aperture imaging, pencil-beam real aperture two-dimensional scanning, fan-beam real aperture one-dimensional scanning, circular-arc track synthetic aperture (circular-arc-scanning synthetic aperture) imaging, Multiple-input Multiple-output (Multiple-input Multiple-output) and the like according to the form and the scanning mode of the antenna.
Because the monitoring objects of the ground slope stabilizing radar are three-dimensional scenes such as a side slope, a dam, a mine mining pit and the like, whether three-dimensional terrain data can be generated or not and a deformation field of the three-dimensional scene can be acquired is particularly important. In the working modes, the pencil beam real-aperture two-dimensional scanning radar system can form a true three-dimensional image, namely when the radar scans a monitored scene, the azimuth angle and the pitch angle of the two-dimensional turntable and the radar echo distance image can directly generate three-dimensional scattering and deformation field data on the terrain, but the working mode only covers a small angle due to the antenna beam, so that the time for scanning the whole scene is long, and the working efficiency is low; in other working modes, the elevation information is estimated by increasing the height base line and then processing two Radar images with different heights by using an Interferometric Synthetic Aperture (Interferometric Synthetic Aperture Radar) algorithm, but the elevation estimation is performed by adopting InSAR for three-dimensional terrain reconstruction, so that on one hand, reconstruction errors are large for an area with severe terrain change and a scene with a relative Radar gradient close to vertical, 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 acquired.
In recent years, in the field of slope stability monitoring radars, many researches are carried out at home and abroad aiming at the extraction of a three-dimensional deformation field, the existing three-dimensional deformation field is generally extracted in two forms, firstly, scenes are monitored from different perspectives through a plurality of radars, 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 provided, the synchronization of clocks and data among the radars has certain difficulty, only the three-dimensional deformation of a certain PS point is obtained, the three-dimensional terrain reconstruction cannot be carried out, the deformation field of the three-dimensional scene cannot be obtained, and 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 the rotary table, the mode needs more transmitting and receiving antennas to form enough two-dimensional array size (or the number of array elements when the interval of the array elements is fixed) required by high resolution, and the system complexity is higher.
Therefore, how to provide a three-dimensional imaging radar capable of being applied to large-scale three-dimensional imaging and deformation field extraction of any scene is a problem to be solved urgently 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-range 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 for a three-dimensional imaging radar combining MIMO and ArcSAR, comprising the following steps:
s10, mounting the MIMO array antenna at the front end of a spiral arm with a certain length, wherein the spiral arm is vertical to the spiral arm, and the spiral arm drives the MIMO array antenna to rotate at a certain angular speed in a plane taking the MIMO array antenna as a normal;
s20, when the swing arm rotates to a certain angle, all the receiving and transmitting antennas of the MIMO array antenna complete the sequential receiving and transmitting of signals to form a one-dimensional virtual aperture linear array;
s30, when the swing arm traverses all the 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, performing pulse compression on radar echoes 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 echoes to a detection area;
s50, imaging network division is carried out on the detection space, and delay of each imaging grid and each array element of the two-dimensional virtual area array is calculated;
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 a 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 vertically placed, the radial arm rotates in the horizontal direction.
Further, in step S20, the electrical scanning of the MIMO array antenna and the rotation of the swing arm are in a time-sharing mode, and the MIMO array antenna completes the electrical scanning when the swing arm rotates to a certain angle to form a one-dimensional virtual aperture linear array.
Further, in step S20, the MIMO and ArcSAR combined three-dimensional imaging radar transmits a frequency-modulated continuous wave signal ST(t) is represented by the following formula:
where T is the fast time, TpFor transmitting the pulse width of the signal, fcCarrier frequency, K, for transmitting signalsrFrequency modulation is carried out on the signals;
further, the transmitting antenna A of the MIMO array antennaT，mAnd a receiving antenna AR，nThe corresponding echo signal is represented by:
whereinRm，pRadial distance, R, of transmitting antenna from targetn，pIs the radial distance of the receiving antenna from the target;
Rm，pand Rn，pRepresented by the formula:
wherein xp，yp，zpAs three-dimensional coordinates of the target point, xT，m，yT，m，zT，mA transmitting antenna A being the MIMO array antennaT，mThree-dimensional coordinates of (2), xR，n，yR，n，zR，nA receiving antenna A of the MIMO array antennaR，nThree-dimensional coordinates of (a).
Further, the transmitting antenna A of the MIMO array antennaT，mIs represented by the following formula:
receiving antenna A of the MIMO array antennaR，nIs represented by the following formula:
wherein L is the length of the array arm,
the half-wave beam angle of the pitching antenna is used for receiving and transmitting.
Further, in the step S30, after the swing arm continues to rotate to the next angle, the MIMO array antenna performs once electrical scanning again, and the step S20 is repeated until all the electrical scanning of the MIMO array antenna at the set angle of the swing arm is completed, and each formed virtual aperture forms an arc aperture in the array normal plane due to the rotation of the swing arm, thereby forming a two-dimensional virtual area array.
Further, in step S40, the one-dimensional distance image is represented by the following formula:
further, the three-dimensional imaging algorithm applied to 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, including:
a MIMO array antenna and a radial arm;
the MIMO array antenna is arranged at the front end of the spiral arm and is vertical to the spiral arm;
the spiral arm can drive the MIMO array antenna to transmit and receive signals in an all-around rotating mode.
Compared with the prior art, the three-dimensional imaging radar combining MIMO and ArcSAR and the imaging method thereof provided by the invention at least have the following beneficial effects:
the invention can realize the large-range three-dimensional imaging and the extraction of the deformation field of any scene under the condition of lower hardware complexity.
Drawings
In order to illustrate the solution of the invention more clearly, the drawings that are needed in the description of the embodiments will be briefly described below, it being obvious that the drawings in the following description are some embodiments of the invention, and that other drawings may be derived from these drawings by a person skilled in the art without inventive effort.
Fig. 1 is an imaging geometry diagram of a three-dimensional imaging radar of 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 single-point target one-dimensional cross-sectional graph 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 isosurface 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 multi-point target one-dimensional cross-sectional graph 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 multi-point target three-dimensional isosurface map of the imaging method of the three-dimensional imaging radar of MIMO and ArcSAR provided by the 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 terminology used in the description presented herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention, e.g., the terms "length," "width," "upper," "lower," "left," "right," "front," "rear," "vertical," "horizontal," "top," "bottom," "inner," "outer," etc., refer to an orientation or position based on that shown in the drawings, are for convenience of description only and are not to be construed as limiting of the present disclosure.
The terms "including" and "having," and any variations thereof, in the description and claims of this invention and the description of the above figures are intended to cover non-exclusive inclusions; the terms "first," "second," and the like in the description and in the claims, or in the drawings, are used for distinguishing between different objects and not necessarily for describing a particular sequential order. In the description and claims of the present invention and in the description of the above figures, when an element is referred to as being "fixed" or "mounted" or "disposed" or "connected" to another element, it may be directly or indirectly located 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, reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the invention. The appearances of the phrase 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. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can 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-range three-dimensional imaging and deformation field extraction of any scene, and comprises the following steps:
s10, mounting the MIMO array antenna at the front end of a spiral arm with a certain length, wherein the spiral arm is vertical to the spiral arm, and the spiral arm drives the MIMO array antenna to rotate at a certain angular speed in a plane taking the MIMO array antenna as a normal;
s20, when the rotating arm rotates to a certain angle, all receiving and transmitting antennas of the MIMO array antenna complete the sequential receiving and transmitting of signals to form a one-dimensional virtual aperture linear array;
s30, when the swing arm traverses all the rotation angles, repeating the step S20, and the system obtains two-dimensional scanning of the detection area, namely forming a two-dimensional virtual area array;
s40, performing pulse compression on the radar echo obtained by the array element 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, imaging network division is carried out on the detection space, and delay of each imaging grid and each array element of the two-dimensional virtual area array is calculated;
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 a three-dimensional image of the detection area.
The spiral arm can drive the MIMO array antenna to rotate in all directions to transmit and receive signals, and large-range three-dimensional imaging and deformation field extraction of any scene are achieved.
In order to make the technical solutions of the present invention better understood by those skilled in the art, the technical solutions in the embodiments 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 combined with MIMO and ArcSAR, which adopts a three-dimensional imaging radar combined with MIMO and ArcSAR and comprises an MIMO array antenna and a spiral arm, wherein the MIMO array antenna is arranged at the front end of the spiral arm and is vertical to the spiral arm, the spiral arm can drive the MIMO array antenna to rotate in all directions to send and receive signals, the resolution of the MIMO array antenna and the antenna beam in the plane direction is obtained by a virtual aperture technology, and the high resolution of the plane pitch direction of the method is obtained by an arc synthetic aperture technology and is used for large-range three-dimensional imaging and deformation field extraction of any scene.
S10, mounting the MIMO array antenna at the front end of a spiral arm with a certain length, wherein the spiral arm is vertical to the spiral arm, and the spiral arm drives the MIMO array antenna to rotate at a certain angular speed in a plane taking the MIMO array antenna as a normal;
s20, when the rotating arm rotates to a certain angle, all receiving and transmitting antennas of the MIMO array antenna complete the sequential receiving and transmitting of signals to form a one-dimensional virtual aperture linear array;
s30, when the swing arm traverses all the rotation angles, repeating the step S20, and the system obtains two-dimensional scanning of the detection area, namely forming a two-dimensional virtual area array;
s40, performing pulse compression on the radar echo obtained by the array element 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, imaging network division is carried out on the detection space, and delay of each imaging grid and each array element of the two-dimensional virtual area array is calculated;
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 a 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 back projection algorithm, a beam synthesis algorithm and the like, wherein the back projection algorithm has the advantages of simple algorithm, high imaging precision, easiness in realizing antenna directional diagram compensation and the like, and is more suitable for the three-dimensional imaging radar combining MIMO and ArcSAR provided by the invention.
The following will take the system structure of horizontal placement of MIMO array antenna and pitching rotation of the swing arm as an example, and will describe in detail the one-dimensional range pulse pressure and the three-dimensional imaging process related to the three-dimensional imaging radar and the imaging method thereof in combination with MIMO and ArcSAR provided by the embodiments of the present invention:
an imaging geometry model of a three-dimensional imaging radar of MIMO and ArcSAR provided by an embodiment of the present invention is shown in fig. 1, a single-point target two-dimensional sectional plane view, a one-dimensional sectional graph, and a three-dimensional isosurface view are respectively shown in fig. 2, fig. 3, and fig. 4, a multi-point target two-dimensional sectional plane view, a one-dimensional sectional graph, and a three-dimensional isosurface view are respectively shown in fig. 5, fig. 6, and fig. 7, a transmitting antenna array has 2M units, a receiving antenna array has 2N units, and the receiving antenna arrays are uniformly divided into two groups and disposed at two ends of the transmitting antenna array. Setting the interval of the receiving antenna to be D, setting the interval of the receiving antenna to be D, the interval of the transmitting antenna to be 4D and the interval of the nearest receiving antenna to be D/2 in order to form a uniform virtual aperture. And establishing a rectangular coordinate system by taking the rear end fulcrum of the radar MIMO array spiral arm as the origin of coordinates.
Suppose that there is a target point P (x) far awayp，yp，zp) At the moment, the included angle between the rotary arm of the MIMO array and the horizontal direction is theta, and the radar transmits a frequency modulation continuous wave signal sT(t) may be represented by the following formula:
where T is the fast time, TpFor transmitting the pulse width of the signal, fcCarrier frequency, K, for transmitting signalsrThe signal is frequency modulated.
Transmitting antenna AT，mAnd a receiving antenna AR，nThe corresponding echo signal may be represented by:
wherein R ism，pRadial distance, R, of transmitting antenna from targetn，pIs the radial distance of the receiving antenna from the target.
Represented by the formula:
according to the imaging geometry, the transmitting antenna AT，mIs given by:
wherein L is the length of the array spiral arm,
the half-wave beam angle of the pitching antenna is used for receiving and transmitting.
Receiving antenna AR，nIs given by:
after mixing, neglecting the included 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:
the second term represents the doppler effect of the echo, which must be handled for azimuthal pulse pressure, and the third term is characteristic of the de-chirp method, called residual video phase, both of which need to be compensated during imaging.
Performing Fourier transform of fast time t on equation (6) to obtain a target echo spectrum:
according to the corresponding relation f between the frequency and the target distance, 2rKrAnd/c, obtaining a one-dimensional range image of the target echo, which is shown as the following formula:
and (3) performing phase compensation on the radar complex scattering image I (x, y, z) of the imaging grid (x, y, z) for complex distance values corresponding to all the virtual array element one-dimensional distance images and performing coherent accumulation to obtain a result:
wherein, R (x, y, z) is the distance between the imaging grid (x, y, z) and the virtual array element.
Briefly analyzing the three-dimensional resolution of the MIMO-ArcSAR system, wherein the system is an MIMO array SAR system on a distance-azimuth plane; in the height-distance plane, the system is an ArcSAR system, so that the three-dimensional resolution can be calculated according to a corresponding imaging system model, and the details are shown in the following table:
TABLE 1 theoretical formula of three-dimensional resolution of system
TABLE 1
Wherein Θ is atan (L)x/2y)，LxIs the MIMO array virtual aperture length, y is the distance of the target in the range-azimuth plane,
is the angle between the connecting line of the target and the center of the array and the normal of the center of the array.
The following was verified by single point target simulation experiments, and table 2 gives the simulation related parameters:
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 is considered to be satisfied, and under this condition, the virtual aperture position of the antenna array can be approximated to the geometric center of the transceiving antenna at the antenna array surface, and the phase center approximation error is negligible. From the parameters in table 2, the array length is 0.3175m, and the square of the product of the wavelength and the target distance is 0.6642m, so far field conditions are satisfied.
TABLE 3 three-dimensional resolution simulation verification
TABLE 3
As can be seen from the theoretical values and the simulation values of the range-direction resolution, the azimuth-direction resolution and the altitude-direction resolution in table 3, the theoretical values and the simulation values are very close to each other, and it can be seen from the drawings in the description that the imaging method of the three-dimensional imaging radar combining MIMO and ArcSAR provided by the embodiment of the present invention can realize the extraction of the three-dimensional imaging and the deformation field in a large range of any scene.
It is to be understood that the above-described embodiments are merely preferred embodiments of the present invention, and not all embodiments are shown in the drawings, which are set forth to limit the scope of the invention. This invention may be embodied in many different forms and, on the contrary, these embodiments are provided so that this disclosure will be thorough and complete. Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that various changes in the embodiments and modifications can be made, and equivalents may be substituted for elements thereof. All equivalent structures made by using the contents of the specification and the attached drawings of the invention can be directly or indirectly applied to other related technical fields, and are also within the protection scope of the patent of the invention.
Claims (10)
1. An imaging method of a three-dimensional imaging radar combining MIMO and ArcSAR is characterized by comprising the following steps:
s10, mounting the MIMO array antenna at the front end of a spiral arm with a certain length, wherein the spiral arm is vertical to the spiral arm, and the spiral arm drives the MIMO array antenna to rotate at a certain angular speed in a plane taking the MIMO array antenna as a normal;
s20, when the swing arm rotates to a certain angle, all the receiving and transmitting antennas of the MIMO array antenna complete the sequential receiving and transmitting of signals to form a one-dimensional virtual aperture linear array;
s30, when the swing arm traverses all the 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, performing pulse compression on radar echoes 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 echoes to a detection area;
s50, imaging network division is carried out on the detection space, and delay of each imaging grid and each array element of the two-dimensional virtual area array is calculated;
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 a three-dimensional image of the detection area.
2. The imaging method of the three-dimensional imaging radar combining MIMO and ArcSAR of claim 1, wherein in the step S10, when the MIMO array antenna is horizontally placed, the radial arm is rotated in a pitch direction; when the MIMO array antenna is vertically placed, the radial arm rotates in the horizontal direction.
3. The imaging method of the three-dimensional imaging radar combining the MIMO and the ArcSAR of claim 1, wherein in the step S20, the electrical scanning of the MIMO array antenna and the rotation of the swing arm are in a time-sharing mode, and the MIMO array antenna completes the electrical scanning to form a virtual aperture once when the swing arm rotates to a certain angle, so as to form a one-dimensional virtual aperture linear array.
4. The imaging method of the MIMO and ArcSAR combined three-dimensional imaging radar as claimed in claim 3, wherein in the step S20, the MIMO and ArcSAR combined three-dimensional imaging radar transmits the frequency-modulated continuous wave signal ST(t) is represented by the following formula:
where T is the fast time, TpFor transmitting the pulse width of the signal, fcCarrier frequency, K, for transmitting signalsrThe signal is frequency modulated.
5. The imaging method of the three-dimensional imaging radar combining MIMO and ArcSAR as claimed in claim 4, wherein the transmitting antenna A of the MIMO array antennaT，mAnd a receiving antenna AR，nThe corresponding echo signal is represented by:
wherein R ism，pRadial distance, R, of transmitting antenna from targetn，pIs the radial distance of the receiving antenna from the target;
Rm，pand Rn，pRepresented by the formula:
wherein xp，yp，zpAs three-dimensional coordinates of the target point, xT，m，yT，m，zT，mA transmitting antenna A being the MIMO array antennaT，mThree-dimensional coordinates of (2), xR，n，yR，n，zR，nA receiving antenna A of the MIMO array antennaR，nThree-dimensional coordinates of (a).
6. The imaging method of the three-dimensional imaging radar combining MIMO and ArcSAR as claimed in claim 5, wherein the transmitting antenna A of the MIMO array antennaT，mIs represented by the following formula:
receiving antenna A of the MIMO array antennaR，nIs represented by the following formula:
wherein L is the length of the array arm,
the half-wave beam angle of the pitching antenna is used for receiving and transmitting.
7. The imaging method of the three-dimensional imaging radar combining MIMO and ArcSAR of claim 1, wherein in the step S30, after the swing arm continues to rotate to the next angle, the MIMO array antenna performs one electrical scan again, and the step S20 is repeated until the electrical scans of the MIMO array antenna at all the set angles of the swing arm are completed, and each formed virtual aperture forms a circular arc aperture in the array-normal plane due to the rotation of the swing arm, so as to form a two-dimensional virtual plane array.
8. The imaging method of the three-dimensional imaging radar combining MIMO and ArcSAR of claim 1, wherein in the step S40, the one-dimensional range profile is represented by the following formula:
9. the imaging method of the three-dimensional imaging radar combining the MIMO and the ArcSAR of claim 1, wherein the three-dimensional imaging algorithm applied to 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.
10. A radar apparatus employing the imaging method of the three-dimensional imaging radar combining MIMO and ArcSAR of any one of claims 1 to 9, comprising:
a MIMO array antenna and a radial arm;
the MIMO array antenna is arranged at the front end of the spiral arm and is vertical to the spiral arm;
the spiral arm can drive the MIMO array antenna to transmit and receive signals in an all-around rotating mode.
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