UAV-borne microwave vision 3D SAR system

Abstract

The present invention provides an unmanned aerial vehicle-mounted microwave vision three-dimensional SAR system, which belongs to the field of radar technology and includes a micro-sized SAR system, an unmanned aerial vehicle platform, and a navigation system, wherein the micro-sized SAR system includes a radar host, which is a core unit of the system, and also includes a storage module for recording and storing collected radar echo data, and a fully polarized transceiver antenna for transmitting electromagnetic wave signals in a corresponding polarized transmitting antenna according to control, and receiving echo signals in a corresponding polarized receiving antenna, and a switch combination for opening / closing the passage of the corresponding polarized antenna according to a control signal to form a specific polarization combination of multiple antennas. The present invention has low cost and miniaturization of the system, and can realize SAR three-dimensional imaging by using only four array interference channels; by combining the working mode of time-sharing full polarization with four channels at the same time, the technical problems of insufficient acquisition channels and excessive storage rate are solved, and the full polarization three-dimensional information acquisition capability is realized.

Description

Technical Field

[0001] The invention belongs to the field of radar technology, and in particular relates to an unmanned aerial vehicle-borne microwave vision three-dimensional SAR system. Background Art

[0002] In recent years, with the rapid development of UAV technology, using UAVs equipped with various sensors to achieve earth observation has become one of the current hot topics. In particular, miniaturized UAVs can complete observation tasks with the advantages of speed, flexibility, and low cost, and have great commercial and practical value. Synthetic aperture radar (SAR) can achieve all-day and all-weather earth observation, especially the currently popular three-dimensional SAR, which can achieve third-dimensional resolution through array interference, and obtain a three-dimensional point cloud or model of the observation scene in just one flight.

[0003] However, the traditional array interferometric SAR system requires at least more than ten antenna elements to ensure the third-dimensional resolution. Due to the limited load and volume of miniaturized UAVs, it is difficult to carry a large number of antenna elements, which makes the design of miniaturized UAV-mounted 3D SAR very complex and difficult. The French Space Agency has carried out the development of a UAV-mounted 3D SAR system (DRIVE system), which is a 3D SAR working in the Ka band. Its carrier is a glider with a wingspan of 23m and a weight of about 600kg. The miniaturized design has not yet been reported. Germany began to develop an unmanned array 3D SAR system in 2005. It uses a frequency modulated continuous wave Ka-band radar that can achieve low energy consumption and small size, but it did not report the design related to polarization switching, and only achieved single-polarization imaging. In China, the development of an airborne array 3D SAR system began in 2005, using a rigid large antenna array with a length of 2m and a weight of 150kg to ensure the stability of the baseline. In 2015, the world's first 3D scene imaging result was obtained. However, none of the current related studies have reported a small UAV-mounted 3D SAR system with full polarization capability. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides an unmanned aerial vehicle-mounted microwave vision three-dimensional SAR system, including a micro-SAR system, an unmanned aerial vehicle platform, and a navigation system, wherein the micro-SAR system includes a radar host, which is the core unit of the system, and also includes a storage module for recording and storing the collected radar echo data, and a fully polarized transceiver antenna for transmitting electromagnetic wave signals in the corresponding polarized transmitting antenna according to a control signal, and receiving echo signals in the corresponding polarized receiving antenna, and a switch combination for opening / closing the passage of the corresponding polarized antenna according to the control signal to form a specific polarization combination of multiple antennas. The present invention has low cost and miniaturization of the system, and can realize SAR three-dimensional imaging by using only four array interference channels; by combining the simultaneous four-channel and time-sharing full polarization working mode, the technical problems of insufficient acquisition channels and excessive storage rate are solved, and the full polarization three-dimensional information acquisition capability is realized.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] A UAV-mounted microwave vision 3D SAR system, including a micro-SAR system, a UAV platform, and a navigation system;

[0007] The micro SAR system comprises:

[0008] A storage module, used for recording and storing collected radar echo data;

[0009] The radar host is used to generate electromagnetic waves, sample echo signals and supply power, and includes a radio frequency module, a digital module, a PCS module and a power module; the digital module is connected to the radio frequency module and the storage module, and the PCS module is connected to the navigation system; the power module provides the required power for the radio frequency module, the digital module and the PCS module; the radio frequency module includes a power amplifier module and a T / R module;

[0010] A fully polarized transceiver antenna, consisting of five independent fully polarized microstrip antennas, one of which is connected to the power amplifier module of the radio frequency module as a transmitting antenna for transmitting signals outward, and the other four fully polarized microstrip antennas are connected to four receiving channels in the T / R module of the radio frequency module as receiving antennas, respectively, to form a 1-transmit 4-receive visual three-dimensional SAR working mode, for transmitting electromagnetic wave signals in the corresponding polarized transmitting antenna according to the control signal, and receiving echo signals in the corresponding polarized receiving antenna;

[0011] A switch combination, used to open or close the path of the corresponding polarized antenna according to the control signal, to form a polarized combination of multiple antennas;

[0012] The navigation system records the flight trajectory and attitude of the UAV during flight operation, and forms flight data, which is recorded for use by the micro SAR system.

[0013] Furthermore, the RF module also includes a frequency source module and a receiving intermediate frequency module; the T / R module receives the signal generated by the digital module, obtains a broadband RF radar signal after amplification, filtering, up-conversion, and frequency multiplication, and after amplification, filtering, and conditioning, it is amplified by the power amplifier module and sent to the transmitting antenna for radiation, and the echo signal obtained from the receiving antenna is connected to the receiving intermediate frequency module after low noise amplifier, RF gain control, and down-conversion; the frequency source module generates the clock signal and local oscillator signal required by the RF module; the receiving intermediate frequency module transmits the signal to the digital module for sampling and processing after DC isolation filtering, signal amplification, and RF gain control.

[0014] Furthermore, the digital module includes a DA module, an AD module, a timing module, and a control module; the DA module is connected to the T / R module of the RF module to generate a digital broadband intermediate frequency signal; the AD module is connected to the receiving intermediate frequency module of the RF module to complete the intermediate frequency sampling of the received echo signal; the timing module provides a synchronization trigger signal for the DA module and the AD module, and performs high-precision timing on the DA module and the AD module; the control module completes the functional control of the DA module, the AD module, and the timing module.

[0015] Furthermore, the PCS module serves as a navigation board to realize inertial measurement, satellite positioning and navigation data storage of the navigation system.

[0016] Furthermore, the switch combination controls the transmission and reception time of the transmitting channel and the receiving channel in the fully polarized transceiver antenna to realize the 4-channel combined with time-sharing fully polarized working mode of the microwave visual three-dimensional SAR, so that the radar's transmitting signal cycles once every 4 cycles, and transmits H signal, H signal, V signal, and V signal in sequence. The 4 receiving antennas receive signals at the same time and cycle once every 4 cycles, and receive HH1 signal-HH4 signal, HV1 signal-HV4 signal, VH1 signal-VH4 signal, VV1 signal-VV4 signal in sequence, where H represents the horizontal polarization mode and V represents the vertical polarization mode.

[0017] Furthermore, the radar host operates in the Ku frequency band, and the radar operating system is a linear frequency modulation continuous wave system.

[0018] Furthermore, the UAV platform is a multi-rotor UAV with a load greater than 15kg.

[0019] Furthermore, the navigation system is composed of a GPS module and a micro inertial measurement unit module, wherein the track measurement accuracy of the GPS module is ≤0.05m, and the attitude measurement accuracy of the micro inertial measurement unit module is ≤0.02°.

[0020] Furthermore, the micro-SAR system and the navigation system are fixed on a mounting platform made of a metal plate, the radar host, storage module, switch combination and navigation system of the micro-SAR system are installed on the mounting platform, the fully polarized transceiver antenna is installed on the bottom of the mounting platform, and the mounting platform is fixedly connected to the UAV platform.

[0021] Furthermore, the angle between the array plane of the fully polarized transceiver antenna and the horizontal plane of the installation platform is 60°, and the spacing between the five fully polarized microstrip antennas in the fully polarized transceiver antenna can be arbitrarily adjusted within the length range of the installation platform according to the baseline length.

[0022] Beneficial effects:

[0023] (1) The present invention can design the system in a low-cost and miniaturized manner, and realize the SAR three-dimensional imaging capability using only four array interferometer channels;

[0024] (2) The present invention solves the technical problems of insufficient acquisition channels and excessive storage rate through the working mode of "simultaneous 4 channels + time-sharing full polarization", and realizes the ability to acquire full polarization three-dimensional information. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The present invention is a block diagram of a micro-SAR system in a microwave vision 3D SAR system carried by an unmanned aerial vehicle according to an embodiment of the present invention.

[0026] Figure 2 It is a structural connection diagram of a microwave vision 3D SAR system carried by an unmanned aerial vehicle shown in one embodiment of the present invention.

[0027] Figure 3 This is a full polarization time-sharing operation timing diagram of an unmanned aerial vehicle-mounted microwave vision three-dimensional SAR system shown in one embodiment of the present invention.

[0028] Figure 4 It is a schematic diagram of the design method of sparse antenna array.

[0029] Among them, the figure markings are: 1-micro SAR system; 2-UAV platform; 3-navigation system; 11-radar host; 12-storage module; 13-full-polarization transceiver antenna; 14-switch combination; 111-RF module; 112-digital module; 113-PCS module; 114-power module. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0031] like Figure 1 , Figure 2 , Figure 3 As shown, an exemplary embodiment of the present invention provides an unmanned aerial vehicle-mounted microwave visual three-dimensional SAR system. The system includes a micro-SAR system 1, an unmanned aerial vehicle platform 2, a navigation system 3, a radar installation platform, a battery, a whole machine cable, and a power supply cable. Generally, for airborne SAR, the micro-SAR system 1 is defined as a system with a load weight not exceeding 15 kg. The unmanned aerial vehicle platform 2 includes an unmanned aerial vehicle mounting bracket.

[0032] The micro SAR system 1 includes:

[0033] The radar host 11 is the core unit of the micro-SAR system 1, which is used to generate electromagnetic waves, sample echo signals and provide power;

[0034] The storage module 12 is used to record and store the collected radar echo data;

[0035] The fully polarized transceiver antenna 13 includes a plurality of fully polarized antennas, which are used to transmit electromagnetic wave signals in the corresponding polarized transmitting antennas according to control, and receive echo signals in the corresponding polarized receiving antennas;

[0036] The switch assembly 14 includes a plurality of polarization switches, which are used to open / close the paths of corresponding polarization antennas according to control signals to form a specific polarization combination of multiple antennas.

[0037] The radar host 11, storage module 12, and switch assembly 14 are fixedly connected to the mounting platform on the upper side of the mounting platform, and the fully polarized transceiver antenna 13 is fixedly connected to the mounting platform on the lower side of the mounting platform. The fully polarized transceiver antenna 13 is designed with a fixed tilt angle according to the application scenario requirements so that it can illuminate the detection scene according to the angle.

[0038] The UAV platform 2 is connected to the micro-SAR system 1 through a UAV mounting bracket, and is used to provide a flexible flight platform for the micro-SAR system 1 to meet flexible flight operation requirements.

[0039] The navigation system 3 and the micro-SAR system 1 are installed together on the UAV platform 2 through the UAV mounting bracket to record the flight trajectory and posture of the UAV during flight operation, and record the flight data for use by the micro-SAR system.

[0040] In some embodiments of the present invention, the navigation system 3 is an inertial navigation unit (IMU) device, which is fixedly connected to the mounting platform on the upper side of the mounting platform.

[0041] In some embodiments of the present invention, the radar host 11 of the micro SAR system 1 integrates a radio frequency module 111, a digital module 112, a PCS module 113 and a power module 114, and also includes a fan and a heat sink. Among them, the radio frequency module 111, the digital module 112, the PCS module 113, and the power module 114 are highly integrated and designed in the radar host 11, and a casing is installed outside; the fan and the heat sink are fixed on the casing; the fan is used to dissipate heat from the radar host 11, the heat sink is attached to the outside of the digital module 112, connected to it through a thermal pad, and the heat generated by the digital module is dissipated through the thermal plate by the fan. PCS represents a navigation data processing computer system.

[0042] The RF module 111 includes a T / R module, a frequency source module, a receiving intermediate frequency module, and a power amplifier module. The T / R module receives the signal generated by the digital module 112, and obtains a broadband RF radar signal after amplification, filtering, up-conversion, and frequency multiplication. After amplification, filtering, and conditioning, it is amplified by the power amplifier module and sent to the transmitting antenna for radiation; the echo signal obtained from the receiving antenna is connected to the receiving intermediate frequency module after a low noise amplifier, RF gain control (MGC), and down-conversion; the frequency source module generates the clock signal and local oscillator signal required by the RF module 111 to drive each module; the receiving intermediate frequency module transmits the signal to the digital module 112 for sampling and processing after DC isolation filtering, signal amplification, and MGC control.

[0043] In some embodiments of the present invention, the power module 114 uses a battery to provide a 28V DC power supply for powering the micro SAR system 1 and the navigation system 3, and the power module 114 also receives power from the outside; the battery is connected to the micro SAR system 1 through a power supply cable; the micro SAR system 1 (including internal modules) and the navigation system 3 are connected through a whole machine cable.

[0044] In some embodiments of the present invention, the digital module 112 is connected to the RF module 111, and includes a DA module, an AD module, a timing module, and a control module. The DA module is connected to the T / R module of the RF module 111 to generate a digital broadband intermediate frequency signal; the AD module is connected to the receiving intermediate frequency module of the RF module 111 to complete the intermediate frequency sampling of the received echo signal; the timing module provides a synchronous trigger signal for the DA module and the AD module, and performs high-precision timing on them; and the control module completes the functional control of each module.

[0045] In some embodiments of the present invention, the PCS module 113 is connected to the navigation system 3 and serves as a navigation board to implement the inertial measurement, satellite positioning and navigation data storage functions of the navigation system.

[0046] In some embodiments of the present invention, Figure 2 As shown, the fully polarized transceiver antenna 13 is composed of five independent fully polarized microstrip antennas, one of which is connected to the power amplifier module of the RF module 111 as a transmitting antenna for transmitting signals outward, and the other four fully polarized microstrip antennas are connected to the four receiving channels in the T / R module of the RF module 111 as receiving antennas, respectively, to form a "1 transmit 4 receive" visual three-dimensional SAR working mode.

[0047] In some embodiments of the present invention, the switch combination 14 controls the polarization channel receiving and transmitting time in the full polarization receiving and transmitting antenna 13 to realize the working mode of "simultaneous 4 channels + time-sharing full polarization" of the visual 3D SAR, and controls the total cycle so that the radar transmits the signal once every 4 cycles, and transmits H, H, V, V signals in sequence, and the 4 receiving antennas receive the signal at the same time, and once every 4 cycles, and receive HH1-HH4 signals, HV1-HV4 signals, VH1-VH4 signals, and VV1-VV4 signals in sequence. The full polarization time-sharing working timing diagram is as follows: Figure 3 As shown, TTL represents transistor logic level regulations, H represents horizontal polarization, V represents vertical polarization, H polarization signal is transmitted or received when the level is low, V polarization signal is transmitted or received when the level is high, and PRT represents pulse repetition time.

[0048] In some embodiments of the present invention, the drone-borne microwave visual three-dimensional SAR system operates in the Ku frequency band, and the operating system is a linear frequency modulation continuous wave system.

[0049] In some embodiments of the present invention, the drone platform 2 of the drone-mounted microwave vision 3D SAR system uses a multi-rotor drone, and the maximum load should be more than 15 kg.

[0050] In some embodiments of the present invention, the navigation system 3 of the unmanned aerial vehicle-mounted microwave visual three-dimensional SAR system is composed of a GPS module and a micro inertial measurement unit (MIMU) module; optionally, the track measurement accuracy of the GPS module should be ≤0.05m, and the attitude measurement accuracy of the MIMU module should be ≤0.02°.

[0051] In some embodiments of the present invention, each module in the micro-SAR system 1 of the unmanned aerial vehicle microwave vision three-dimensional SAR system and the navigation system 3 are fixed on a mounting platform made of a metal plate; optionally, other modules in the micro-SAR system 1 except the fully polarized transceiver antenna 13 and the navigation system 3 are installed on the mounting platform, the fully polarized transceiver antenna 13 is installed under the mounting platform, and the mounting platform is fixedly connected to the unmanned aerial vehicle platform 2.

[0052] In some embodiments of the present invention, the angle between the array plane of the fully polarized transceiver antenna 13 of the drone-mounted microwave visual 3D SAR system and the horizontal plane of the installation platform is 60° (i.e., the viewing angle below the antenna is 60°), and the spacing between the five independent fully polarized microstrip antennas in the fully polarized transceiver antenna 13 can be arbitrarily adjusted within the length range of the installation platform according to the baseline length required in the actual test. Optionally, the length of the installation platform is 1.29 meters.

[0053] Optional, such as Figure 4 The sparse antenna array design shown can achieve high-precision three-dimensional imaging capabilities. Figure 4 middle, represents the transmitting antenna, Indicates 4 receiving antennas, represents the four equivalent antenna phase centers, represents the baseline configuration, and the numerical axis [0 107 214 321 428 535 642 749 856 963 1070 11771284] mm represents the coordinates of the holes drilled on the mounting platform, and the fully polarized microstrip antenna can be flexibly mounted on these holes.

[0054] The system parameters are set as follows:

[0055] In this embodiment, the radar host operates in the Ku band, and the radar working system is a linear frequency modulation continuous wave system, wherein the range resolution is achieved by using a broadband linear frequency modulation continuous wave signal to de-frequency modulate the received pulse and then compress it; the azimuth resolution is achieved by using an unmanned aerial vehicle platform to drive the radar to move along the heading to form a synthetic aperture; and the elevation resolution is achieved by using a cross-heading baseline interference formed by the phase centers of multiple antennas across the heading.

[0056] 1) Working frequency band:

[0057] The unmanned aerial vehicle-borne microwave vision three-dimensional SAR system of the present invention operates in the Ku frequency band, and the center frequency is 15.2 GHz.

[0058] 2) Distance resolution:

[0059] When the drone-borne microwave vision 3D SAR system of the present invention is used for imaging, a linear frequency modulation continuous wave signal with a certain bandwidth is used to perform frequency modulation reception to realize range pulse compression, and its range resolution is The calculation formula is:

[0060] ;

[0061] in, is the speed of light, is the linear frequency modulated continuous wave signal bandwidth, is the main lobe widening factor during windowing. , , substitute the distance resolution The calculation formula can be obtained: .

[0062] 3) Azimuth resolution:

[0063] When the unmanned aerial vehicle microwave vision 3D SAR system of the present invention is used for imaging, azimuth resolution is achieved by forming a synthetic aperture along the heading motion. The size depends on the azimuth beamwidth of the antenna , and its calculation formula is:

[0064] ;

[0065] in, is the wavelength of radar electromagnetic wave, is the azimuth beamwidth of the antenna, is the main lobe widening factor during windowing, is the radar center frequency. , , substitute the azimuth resolution The calculation formula can be obtained: .

[0066] 4) Altitude resolution:

[0067] When the unmanned aerial vehicle microwave vision 3D SAR system of the present invention is used for imaging, multiple antenna array elements along the oblique height direction are used to form a synthetic aperture to achieve oblique height resolution. The calculation formula is as follows:

[0068] ;

[0069] in, is the wavelength of radar electromagnetic wave, is the slope length, is the maximum vertical baseline length.

[0070] In summary, the present invention provides an unmanned aerial vehicle-mounted microwave vision three-dimensional SAR system, which can overcome the shortcomings of other technical systems such as optics and infrared, and achieve uninterrupted operation around the clock and in all weather conditions; the system can be designed in a low-cost and miniaturized manner, and only four array interference channels are used to achieve the SAR three-dimensional imaging capability; the system solves the technical problems of insufficient acquisition channels and excessive storage rate through the "simultaneous four channels + time-sharing full polarization" working mode, and achieves the full polarization three-dimensional information acquisition capability.

[0071] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An unmanned aerial vehicle-mounted microwave vision three-dimensional SAR system, characterized in that: Including micro-SAR systems, UAV platforms, and navigation systems; The micro SAR system comprises: A storage module, used for recording and storing collected radar echo data; The radar host is used to generate electromagnetic waves, sample echo signals and supply power, and includes a radio frequency module, a digital module, a PCS module and a power module; the digital module is connected to the radio frequency module and the storage module, and the PCS module is connected to the navigation system; the power module provides the required power for the radio frequency module, the digital module and the PCS module; the radio frequency module includes a power amplifier module and a T / R module; A fully polarized transceiver antenna, consisting of five independent fully polarized microstrip antennas, one of which is connected to the transmitting channel of the power amplifier module of the radio frequency module as a transmitting antenna, and is used to transmit signals outward, and the other four fully polarized microstrip antennas are connected to the four receiving channels in the T / R module of the radio frequency module as receiving antennas, respectively, to form a 1-transmit 4-receive microwave visual three-dimensional SAR working mode, and are used to transmit electromagnetic wave signals in the corresponding polarized transmitting antenna according to the control signal, and receive echo signals in the corresponding polarized receiving antenna; A switch combination, used to open or close the path of the corresponding polarized antenna according to the control signal, to form a polarized combination of multiple antennas; The navigation system records the flight trajectory and attitude of the UAV during flight operation, and forms flight data, which is recorded for use by the micro-SAR system; The switch combination controls the transmitting and receiving time of the transmitting channel and the receiving channel in the fully polarized transmitting and receiving antenna to realize the 4-channel combined with time-sharing fully polarized working mode of the microwave visual three-dimensional SAR, so that the radar's transmitting signal cycles once every 4 cycles, and transmits H signal, H signal, V signal, and V signal in sequence, and the 4 receiving antennas receive signals at the same time, and cycle once every 4 cycles, and receive HH1 signal-HH4 signal, HV1 signal-HV4 signal, VH1 signal-VH4 signal, VV1 signal-VV4 signal in sequence, wherein H represents the horizontal polarization mode and V represents the vertical polarization mode.

2. The unmanned aerial vehicle-mounted microwave visual three-dimensional SAR system according to claim 1, characterized in that: The RF module also includes a frequency source module and a receiving intermediate frequency module; the T / R module receives the signal generated by the digital module, obtains a broadband RF radar signal after amplification, filtering, up-conversion, and frequency multiplication, and after amplification, filtering, conditioning, amplification by the power amplifier module, and then sends it to the transmitting antenna for radiation. The echo signal obtained from the receiving antenna is connected to the receiving intermediate frequency module after low noise amplifier, RF gain control, and down-conversion; The frequency source module generates the clock signal and local oscillator signal required by the RF module; the receiving intermediate frequency module transmits the signal to the digital module for sampling and processing after DC isolation filtering, signal amplification and RF gain control.

3. The unmanned aerial vehicle-mounted microwave visual 3D SAR system according to claim 2, characterized in that: The digital module includes a DA module, an AD module, a timing module, and a control module; the DA module is connected to the T / R module of the RF module to generate a digital broadband intermediate frequency signal; the AD module is connected to the receiving intermediate frequency module of the RF module to complete the intermediate frequency sampling of the received echo signal; the timing module provides a synchronous trigger signal for the DA module and the AD module, and performs high-precision timing on the DA module and the AD module; the control module completes the functional control of the DA module, the AD module, and the timing module.

4. The unmanned aerial vehicle-mounted microwave visual three-dimensional SAR system according to claim 1, characterized in that: The PCS module serves as a navigation board to realize inertial measurement, satellite positioning and navigation data storage of the navigation system.

5. The unmanned aerial vehicle-mounted microwave visual 3D SAR system according to claim 1, characterized in that: The radar host operates in the Ku frequency band, and the radar operating system is a linear frequency modulation continuous wave system.

6. The unmanned aerial vehicle-mounted microwave visual three-dimensional SAR system according to claim 1, characterized in that: The UAV platform is a multi-rotor UAV with a load greater than 15kg.

7. The unmanned aerial vehicle-mounted microwave visual 3D SAR system according to claim 1, characterized in that: The navigation system consists of a GPS module and a micro inertial measurement unit module, wherein the track measurement accuracy of the GPS module is ≤0.05m, and the attitude measurement accuracy of the micro inertial measurement unit module is ≤0.02°.

8. The unmanned aerial vehicle-mounted microwave visual three-dimensional SAR system according to claim 1, characterized in that: The micro-SAR system and the navigation system are fixed on a mounting platform made of a metal plate. The radar host, storage module, switch combination and navigation system of the micro-SAR system are installed on the mounting platform, and the fully polarized transceiver antenna is installed under the mounting platform. The mounting platform is fixedly connected to the UAV platform.

9. The unmanned aerial vehicle-mounted microwave visual three-dimensional SAR system according to claim 8, characterized in that: The angle between the array plane of the fully polarized transceiver antenna and the horizontal plane of the installation platform is 60°, and the spacing between the five fully polarized microstrip antennas in the fully polarized transceiver antenna can be arbitrarily adjusted within the length range of the installation platform according to the baseline length.

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