A millimeter wave radar applied to unmanned aerial vehicle ground obstacle avoidance

Abstract

The utility model relates to belong to unmanned aerial vehicle sensing and barrier avoidance technical field, disclose a kind of millimeter wave radar applied to unmanned aerial vehicle ground barrier avoidance, including cavity structural member and radio frequency circuit board and signal processing circuit board being arranged in parallel in the inside of cavity structural member, radio frequency circuit board is integrated with microstrip antenna, radio frequency front end and first power chip;Signal processing circuit board is integrated with signal acquisition and processing module and second power chip, and microstrip antenna includes transmitting array and receiving array;The transmitting channel of radio frequency front end is connected with the transmitting array of microstrip antenna;The receiving channel of radio frequency front end is connected with the input end of signal acquisition and processing module;Signal acquisition and processing module are connected with radio frequency front end;First power chip and second power chip jointly constitute power module, for radio frequency front end and the power supply of signal acquisition and processing module.The utility model greatly reduces the area occupied by radio frequency part PCB, significantly reduces system complexity and weight.

Description

Technical Field

[0001] This utility model relates to the field of UAV perception and obstacle avoidance technology, specifically to a miniaturized, highly integrated millimeter-wave ground obstacle avoidance radar integrated into a UAV platform. Background Technology

[0002] With the large-scale application of drones in logistics delivery, agricultural plant protection, power line inspection, and security monitoring, the requirements for their autonomous flight capabilities and near-ground safety have reached unprecedented levels. Among these, obstacle avoidance during low-altitude flight and takeoff and landing is a core element in ensuring mission success and flight safety. Currently, the mainstream sensors for achieving this function include visual sensors, lidar, and ultrasonic sensors.

[0003] Millimeter-wave radar, as an active radio frequency sensor, has all-weather operation capability, can penetrate rain, fog, and dust, and can directly and accurately measure the relative distance and radial velocity of targets. These unique advantages make it an ideal choice to make up for the above-mentioned sensor defects and build a reliable UAV obstacle avoidance system.

[0004] Transferring millimeter-wave radar technology from traditional fields such as automobiles to unmanned aerial vehicle (UAV) platforms faces a series of unique challenges arising from the platform's characteristics. Existing technological solutions mainly suffer from the following key limitations:

[0005] Traditional millimeter-wave radars, especially high-performance models, typically employ discrete component solutions for their radio frequency front-ends, and their antennas are often independent waveguides or large PCB boards, making it difficult to control the overall physical size and weight of the device. Unmanned aerial vehicles (UAVs) have extremely stringent requirements regarding the size and weight of their payloads. Radars that are too large or too heavy will significantly shorten the UAV's endurance and affect its flight stability and maneuverability, making it impossible to practically apply many high-performance radars to UAVs.

[0006] In existing discrete component solutions, circuits such as power amplifiers, low-noise amplifiers, mixers, and frequency synthesizers are discrete, requiring complex external circuitry for matching and debugging. This not only increases the system's size and design complexity but also leads to poor production consistency and high costs. Under the harsh operating conditions faced by drones, such as vibration, shock, and temperature variations, the connection reliability and long-term stability of systems composed of a large number of discrete components face severe challenges. Utility Model Content

[0007] This utility model provides a millimeter-wave radar for ground obstacle avoidance in UAVs, addressing two core technical challenges in its application to UAV ground obstacle avoidance:

[0008] 1. To address the issue of excessive size and weight in radar systems, a highly integrated, compact, and lightweight millimeter-wave radar solution is provided, enabling it to meet the stringent payload requirements of mainstream industrial drones.

[0009] 2. To address the complexity and reliability issues of discrete component-based RF systems, a highly integrated chip-level solution is adopted to simplify the system architecture, improve the connection reliability and long-term stability of radar under harsh conditions such as drone vibration and impact, and reduce manufacturing costs.

[0010] This utility model is achieved through the following technical solution:

[0011] A millimeter-wave radar for ground obstacle avoidance in unmanned aerial vehicles (UAVs) includes a cavity structure and a radio frequency (RF) circuit board and a signal processing circuit board arranged side-by-side inside the cavity structure. The RF circuit board integrates a microstrip antenna, an RF front-end, and a first power supply chip. The signal processing circuit board integrates a signal acquisition and processing module and a second power supply chip.

[0012] The microstrip antenna includes a transmitting array and a receiving array;

[0013] The transmitting channel of the radio frequency front end is connected to the transmitting array of the microstrip antenna and is used to transmit radio frequency signals through the transmitting array;

[0014] The receiving channel of the radio frequency front end is connected to the input terminal of the signal acquisition and processing module, and is used to process and output the echo signal received by the receiving array.

[0015] The signal acquisition and processing module is connected to the radio frequency front end and is used to acquire and process the signals output by the radio frequency front end;

[0016] The first power chip and the second power chip together constitute a power module, which is used to supply power to the radio frequency front end and the signal acquisition and processing module.

[0017] As an optimization, the microstrip antenna is integrated on the surface of the radio frequency circuit board in the form of a patch. The microstrip antenna has a size of 80mm×70mm×20mm and an impedance of 50Ω. Both the transmitting array and the receiving array are arranged in a linear array.

[0018] As an optimization, the RF front end specifically includes a crystal oscillator, a phase-locked loop (PLL), a power amplifier (PA), a low-noise amplifier (LNA), a variable gain amplifier, and an analog anti-aliasing filter (AAF).

[0019] The crystal oscillator is connected to the phase-locked loop (PLL) to provide a frequency reference; the PLL includes an integrated phase detector and a voltage-controlled oscillator (VCO).

[0020] The output of the phase-locked loop (PLL) is connected to the power amplifier (PA) and the low-noise amplifier (LNA) via a frequency multiplier and a power divider to provide the local oscillator signal.

[0021] The power amplifier PA has three transmission channels, and the output of each power amplifier PA is connected to one of the transmission arrays to amplify and transmit radio frequency signals.

[0022] The low noise amplifier (LNA) is provided in four parts, and the input terminal of each LNA is connected to one of the receiving arrays to amplify the received echo signal.

[0023] The output of each of the low-noise amplifiers (LNAs) is connected to the corresponding analog anti-aliasing filter (AAF) via the corresponding variable gain amplifier.

[0024] The output of each of the analog anti-aliasing filters constitutes the receiving channel of the radio frequency front end and is connected to the input of the signal acquisition and processing module.

[0025] As an optimization, the signal acquisition and processing module includes an analog-to-digital converter chip, a cache chip, and an FPGA;

[0026] The input terminal of the analog-to-digital converter chip is connected to the receiving channel of the radio frequency front end, and the output terminal of the analog-to-digital converter chip is connected to the FPGA.

[0027] The cache chip is connected to the FPGA and is used to cache point cloud data.

[0028] As an optimization, the analog-to-digital converter chip adopts a dual-balun input design.

[0029] As an optimization, the first power supply chip is a low-dropout linear regulator. The input terminal of the low-dropout linear regulator is connected to the output terminal of the DC / DC chip or the system 12V input. The output terminal of the low-dropout linear regulator is connected to the power supply terminal of the RF front end and the analog power supply terminal of the analog-to-digital converter chip in the signal acquisition and processing module, respectively.

[0030] As an optimization, the second power chip is a DC / DC chip, which is used to convert the 12V input voltage into various voltages to power the digital circuits in the signal acquisition and processing module.

[0031] As an optimization, the cavity structure includes an integrally formed aluminum alloy cavity; the radio frequency circuit board is fixedly connected to the inner wall of the aluminum alloy cavity through a thermally conductive medium.

[0032] As an optimization, the cavity structure also includes a wave-transparent cover disposed on the aluminum alloy cavity. The wave-transparent cover covers and is fixed to the side of the radio frequency circuit board on which the microstrip antenna is disposed, forming a closed space together with the aluminum alloy cavity.

[0033] As an optimization, a CAN interface circuit is also included. One end of the CAN interface circuit is connected to the signal acquisition and processing module, and the other end serves as an external communication interface for communicating with the UAV flight control system to receive external control commands, report processing results, and perform firmware upgrades.

[0034] Compared with the prior art, this utility model has the following advantages and beneficial effects:

[0035] By adopting a structure that integrates the microstrip antenna as a patch on the surface of the RF circuit board, the independent antenna component is eliminated, realizing the integration of antenna and circuit, and fundamentally compressing the vertical space and volume of the whole device.

[0036] By adopting a V-band multifunctional monolithic microwave integrated circuit (MMIC) with seven transceiver channels as the core of the RF front-end, the functions of dozens of discrete components are condensed into a single chip, greatly reducing the PCB area occupied by the RF part and significantly reducing the system complexity and weight.

[0037] By adopting a compact structure with an integrally molded aluminum alloy cavity with dimensions no greater than 100mm×80mm×40mm and a weight no greater than 500g, the whole machine is provided with mechanical support, physical protection and natural heat dissipation path, and ultimately the product is miniaturized and lightweight.

[0038] By adopting a power architecture that uses a DC / DC chip for main power conversion and combines it with an LDO for precise power supply to the analog circuitry, efficient and simple power management is achieved, replacing the complex multi-channel independent power supply design and improving power quality and system stability.

[0039] By combining the synergistic effects of the above-mentioned technologies, the number of system components is significantly reduced, material and assembly costs are lowered, production consistency and yield are improved, and the entire machine has higher connection reliability and long-term stability under harsh operating conditions such as drone vibration and impact. Attached Figure Description

[0040] The accompanying drawings, which are included to provide a further understanding of the embodiments of the present invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0041] Figure 1 This is an external view of the radar of this utility model;

[0042] Figure 2 This is an exploded schematic diagram of the radar of this utility model;

[0043] Figure 3This is a system block diagram for the radar, where the PS terminal is mainly for control and the PL terminal is for programmable logic.

[0044] Figure 4 This is a top view of a microstrip antenna.

[0045] The attached diagram shows the markings and corresponding component names:

[0046] 1- Antenna cover, 2- Cavity cover plate, 3- RF circuit board, 4- Sealing ring, 5- Cavity, 6- Signal processing circuit board, 7- Cavity base plate. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of this utility model are only used to explain this utility model and are not intended to limit this utility model.

[0048] This embodiment 1 provides a millimeter-wave radar for ground obstacle avoidance in unmanned aerial vehicles, such as... Figures 1-2 As shown, it includes a cavity structure and a radio frequency circuit board and a signal processing circuit board 6 arranged side by side inside the cavity structure.

[0049] The radio frequency circuit board integrates a microstrip antenna, a radio frequency front-end, and a first power supply chip (an LDO); the signal processing circuit board integrates a signal acquisition and processing module and a second power supply chip (a DC / DC chip).

[0050] The microstrip antenna includes a transmitting array and a receiving array; the transmitting channel of the radio frequency front-end is connected to the transmitting array of the microstrip antenna for transmitting radio frequency signals through the transmitting array; the receiving channel of the radio frequency front-end is connected to the input terminal of the signal acquisition and processing module for processing and outputting the echo signals received by the receiving array; the signal acquisition and processing module is connected to the radio frequency front-end for acquiring and processing the signals output by the radio frequency front-end; the first power chip and the second power chip together constitute a power module for supplying power to the radio frequency front-end and the signal acquisition and processing module.

[0051] The millimeter-wave radar hardware of this invention adopts a dual-board architecture and a vertically stacked, end-to-end collaborative integration structure. For example... Figure 2As shown, the cavity structure mainly includes a cavity 5, a cavity cover plate 2, and a cavity base plate 7. The radio frequency circuit board 3 and the signal processing circuit board 6 are fixed to the inside of both sides of the cavity 5 by screw interlocking. The microstrip antenna, radio frequency front end, and first power chip are integrated on the radio frequency circuit board 3; the signal acquisition and processing module and the second power chip are integrated on the signal processing circuit board 6, and finally packaged in a compact cavity structure, realizing the miniaturization and lightweight integration of millimeter-wave radar on the UAV platform, greatly improving platform adaptability.

[0052] Next, we will introduce each part in detail with reference to the attached diagram.

[0053] 1. Microstrip antenna and RF circuit board

[0054] In some embodiments, the microstrip antenna is integrated as a patch on the surface of the radio frequency circuit board 3, and its structure is as follows: Figure 4 As shown, this design eliminates the need for a separate antenna component, fundamentally reducing vertical space. The dimensions of the microstrip antenna are... The impedance is 50Ω. Both the transmitting and receiving arrays are arranged in a linear array, which is beneficial for beamforming and angle measurement.

[0055] 2. Radio Frequency Front End

[0056] In some embodiments, the radio frequency front end specifically includes a crystal oscillator, a phase-locked loop (PLL), a power amplifier (PA), a low-noise amplifier (LNA), a variable gain amplifier, and an analog anti-aliasing filter (AAF).

[0057] The crystal oscillator is connected to the phase-locked loop (PLL) to provide a frequency reference; the PLL includes an integrated phase detector and a voltage-controlled oscillator (VCO).

[0058] The output of the phase-locked loop (PLL) is connected to the power amplifier (PA) and the low-noise amplifier (LNA) via a frequency multiplier and a power divider to provide the local oscillator signal.

[0059] The power amplifier PA has three transmission channels, and the output of each power amplifier PA is connected to one of the transmission arrays to amplify and transmit radio frequency signals.

[0060] The low noise amplifier (LNA) is provided in four parts, and the input terminal of each LNA is connected to one of the receiving arrays to amplify the received echo signal.

[0061] The output of each of the low-noise amplifiers (LNAs) is connected to the corresponding analog anti-aliasing filter (AAF) via the corresponding variable gain amplifier.

[0062] The output of each of the analog anti-aliasing filters constitutes the receiving channel of the radio frequency front end and is connected to the input of the signal acquisition and processing module.

[0063] More specifically, the radio frequency front-end is the core of achieving miniaturization, high integration and high reliability. Its core is a V-band multifunctional monolithic microwave integrated circuit chip (MMIC) and an external high-precision crystal oscillator as a frequency reference.

[0064] Core chip: This V-band multi-functional RF chip integrates 7 transceiver channels, condensing numerous functional units such as phase-locked loop (PLL), power amplifier (PA), low-noise amplifier (LNA), variable gain amplifier, and analog anti-aliasing filter (AAF) from traditional discrete solutions into a single chip.

[0065] Frequency generation: The integrated phase-locked loop (PLL) within the chip and the external crystal oscillator together constitute the frequency source. This PLL consists of an integrated phase detector and a voltage-controlled oscillator (VCO) used to generate a stable local oscillator signal. This signal is multiplied to the V-band by a frequency multiplier and then distributed to the various transceiver channels within the chip via a power divider.

[0066] Transmission Link: The chip's integrated power amplifier has three transmission channels. The output of each power amplifier (PA) is directly connected to a transmit antenna patch via a microstrip line on the PCB to amplify and radiate the V-band signal.

[0067] Receive Link: The chip's integrated low-noise amplifiers (LNAs) have four receive channels. The input of each LNA is connected to a receiving antenna patch to amplify the weak waveform signal. The amplified signal is then sequentially passed through an integrated variable gain amplifier for gain adjustment, and then through an analog anti-aliasing filter to remove out-of-band noise and interference. Finally, the outputs of the four analog anti-aliasing filters (AAFs) form the receive channels of the RF front-end, outputting the intermediate frequency (IF) signal.

[0068] Peripheral Circuitry: The peripheral circuitry of this core chip is equipped with necessary passive components such as matching networks and filters, which work together with the chip to fully meet the transmission and reception requirements of V-band signals. It should be noted that the peripheral circuitry can be configured according to specific circumstances; this is common knowledge to those skilled in the art and will not be elaborated upon here.

[0069] 3. Signal acquisition and processing module, located on signal processing circuit board 6.

[0070] In some embodiments, the signal acquisition and processing module includes an analog-to-digital converter (ADC) chip, a buffer chip, and a field-programmable gate array (FPGA).

[0071] The input terminal of the analog-to-digital converter chip is connected to the receiving channel of the radio frequency front end, and the output terminal of the analog-to-digital converter chip is connected to the FPGA.

[0072] The cache chip is connected to the FPGA and is used to cache point cloud data. The analog-to-digital converter chip adopts a dual-balun input design.

[0073] More specifically, this module is responsible for signal digitization and core algorithm processing.

[0074] Data Acquisition: The input of the analog-to-digital converter (ADC) chip is connected to the four receiving channels of the RF front-end. This ADC chip employs a dual-balun input design, which effectively improves the signal-to-noise ratio. After quantizing the analog intermediate frequency (IF) signal into a digital signal, the ADC transmits it to a field-programmable gate array (FPGA) through its digital output.

[0075] Data caching and processing: A cache chip connected to the FPGA is used for high-speed caching of the 128-point cloud data acquired by the ADC, with an access latency of <0.016ms, meeting the requirements of real-time processing. An external SRAM is connected to the FPGA to meet the large memory requirements of the algorithm. The FPGA is programmed to implement all the following hardware logic functions: ADC sampling control, 1D-FFT (distance dimension), 2D-FFT (velocity dimension), 2D-CFAR (constant false alarm rate detection) to extract target points, target clustering algorithm, and Kalman filter tracking algorithm, ultimately outputting stable and reliable target trajectory information. It should be noted that these algorithms are all existing technologies; therefore, this invention does not involve improvements to the algorithms and will not be elaborated upon here.

[0076] Data Interface: A CAN interface circuit or SPI interface connects to the FPGA. One end of this circuit handles communication with the FPGA, while the other end serves as an external communication interface for communicating with the UAV flight control system, enabling control command reception, processing result reporting, and firmware upgrade functions.

[0077] 4. Voltage Module

[0078] The power module of this utility model is composed of power chips disposed on two circuit boards.

[0079] In some embodiments, the second power chip is a DC / DC chip disposed on the signal processing circuit board 6, used to convert the 12V input voltage into various voltages to power the digital circuits and the digital part of the radio frequency front end in the signal acquisition and processing module.

[0080] In some embodiments, the first power supply chip is a low-dropout linear regulator (LDO) disposed on the radio frequency circuit board 3. The input terminal of the LDO is connected to the output terminal of the DC / DC chip or the system 12V input, and its output terminal is connected to the analog power supply terminal of the radio frequency front end and the analog power supply terminal of the analog-to-digital converter (ADC) chip, respectively, to provide clean voltage for these noise-sensitive circuits.

[0081] 5. Cavity structural components

[0082] In some embodiments, the cavity structure includes an integrally formed aluminum alloy cavity 5; the radio frequency circuit board 3 is fixedly connected to the inner wall of the aluminum alloy cavity 5 through a thermally conductive medium.

[0083] In some embodiments, the cavity structure further includes a wave-transparent cover 1 disposed on the aluminum alloy cavity 5, which is sealed by a sealing ring 4. The wave-transparent cover 1 covers and is fixed to the side of the radio frequency circuit board 3 on which the microstrip antenna is disposed, and together with the aluminum alloy cavity 5, forms a closed space.

[0084] More specifically, this structural component achieves physical encapsulation of the entire device, environmental protection, and heat dissipation.

[0085] Heat dissipation and mechanical structure: The radio frequency circuit board 3 and the signal processing circuit board 6 are firmly fixed to the inner wall of the aluminum alloy cavity 5 using thermally conductive media such as thermal grease. This allows the heat generated by the main heat source to be efficiently conducted to the entire cavity, achieving natural heat dissipation through the surface area of ​​the aluminum alloy cavity itself.

[0086] Environmental Protection: A sealing ring 4 is provided between the wave-transparent cover 1, made of low dielectric constant and low loss engineering plastic, and the cavity 5, forming a sealed space to provide physical protection and environmental sealing for the internal circuitry. The wave-transparent cover covers and is fixed to the side of the RF circuit board where the microstrip antenna is located. The wave-transparent cover and the aluminum alloy cavity together form a closed space through a sealing structure, providing physical protection and environmental (rain, dust) sealing for the internal precision circuitry, while ensuring the normal penetration of V-band RF signals.

[0087] The radar system constructed using the above-described specific implementation method has a cavity structure component size of no more than 100mm × 80mm × 40mm and a total weight of no more than 500g. This miniaturized and lightweight design allows it to be directly installed on the landing gear or fuselage bottom of small and medium-sized UAVs. The system boasts high integration, strong reliability, and low production cost, perfectly meeting the stringent payload requirements of UAVs and achieving efficient and reliable ground obstacle avoidance capabilities.

[0088] The system signal workflow is as follows:

[0089] 1. Signal Transmission: The phase-locked loop frequency source generates an intrinsic frequency reference signal and sends it to the voltage-controlled oscillator (VCO). The VCO outputs a signal to the V-band multi-functional RF chip. This signal is frequency-multiplied to the V-band internally and amplified by the internally integrated power amplifier before being radiated into space through the transmission array.

[0090] 2. Signal Reception: The receiving array receives the V-band echo signal reflected from the target. This signal is amplified by the low-noise amplifier integrated within the V-band multi-functional RF chip, down-mixed to intermediate frequency (IF), and then conditioned by a variable gain amplifier and an analog anti-aliasing filter before being output as an IF signal to the analog-to-digital converter chip.

[0091] 3. Data Acquisition: The analog-to-digital converter (ADC) chip quantizes the intermediate frequency (IF) signal into a digital signal and transmits it to the field-programmable gate array (FPGA) through its digital output. Simultaneously, a cache chip caches the data from the ADC at high speed to meet the data access requirements during FPGA processing.

[0092] 4. Signal Processing: The FPGA sequentially performs one-dimensional Fast Fourier Transform (FFT), two-dimensional Fast Fourier Transform (FFT), and two-dimensional Constant False Alarm Rate (CFA) detection on the received digital signal to extract potential target points from the spectrum. Subsequently, the FPGA runs a target clustering algorithm and a Kalman filter tracking algorithm to cluster the target points and form stable and reliable target motion trajectories. It should be noted that the signal processing performed by the FPGA uses existing technologies and does not involve any improvement to the computer program.

[0093] 5. Data Interaction: The CAN interface circuit receives control commands from the UAV flight control system (or taxiing collision avoidance processor) and reports the target trajectory information processed by the FPGA, thereby realizing closed-loop control and information interaction.

[0094] In summary, this invention solves the problem of excessive size and weight of radar systems:

[0095] This invention provides a highly integrated, small, and lightweight millimeter-wave radar solution while ensuring high performance. Through technological innovation, it significantly reduces the physical size and weight of the entire unit, enabling it to meet the stringent payload requirements of mainstream industrial drones. This solves the problem that traditional high-performance millimeter-wave radars cannot be effectively integrated and applied to drones due to their excessive size and weight.

[0096] This invention solves the problems of system complexity, poor production consistency, high cost, and low reliability caused by traditional discrete component solutions:

[0097] This invention simplifies the system architecture and reduces external connections by adopting a highly integrated chip-level solution, thereby improving the connection reliability and long-term stability of the radar under harsh conditions such as UAV vibration and impact, and reducing manufacturing costs.

[0098] In summary, this invention adopts a vertically stacked + screw-interlocked overall architecture, highly integrating the microstrip antenna, RF front-end, acquisition card, FPGA processor, power module, and cavity structure. The microstrip antenna is integrated into the RF board with a patch size of 80mm×70mm×20mm, an impedance of 50Ω, and a linear array arrangement for transmitting and receiving. A V-band multifunctional monolithic microwave integrated circuit (MMIC) chip with 7 transmit and receive channels is used as the core of the RF front-end, replacing the complex discrete component solution. It is paired with a PLL frequency source composed of a crystal oscillator, an integrated phase detector, and a VCO to achieve efficient transmission and reception of 7 V-band signals. At the same time, a DC / DC chip converts the 12V input into multiple voltages to power the RF chip, ADC, and FPGA, while an LDO provides independent power to the analog part of the chip, ensuring stable collaboration among the various hardware modules. In terms of structural design, it adopts a combination of aluminum alloy cavity and wave shield, controlling the cavity size to ≤100mm×80mm×40mm and the weight to ≤500g. Relying on the natural heat dissipation of the cavity, no additional heat dissipation module is required, realizing the miniaturization and lightweight of the whole machine. It is suitable for installation requirements in multiple scenarios such as unmanned vehicles, warehouse robots, and aircraft ground taxiing equipment, while ensuring the system's anti-interference ability and real-time obstacle avoidance response in complex environments.

[0099] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this utility model. It should be understood that the above description is only a specific embodiment of this utility model and is not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A millimeter-wave radar for obstacle avoidance on the ground of unmanned aerial vehicles (UAVs), characterized in that, The system includes a cavity structure and a radio frequency (RF) circuit board and a signal processing circuit board arranged side-by-side inside the cavity structure. The RF circuit board integrates a microstrip antenna, an RF front-end, and a first power supply chip. The signal processing circuit board integrates a signal acquisition and processing module and a second power supply chip. The microstrip antenna includes a transmitting array and a receiving array; The transmitting channel of the radio frequency front end is connected to the transmitting array of the microstrip antenna and is used to transmit radio frequency signals through the transmitting array; The receiving channel of the radio frequency front end is connected to the input terminal of the signal acquisition and processing module, and is used to process and output the echo signal received by the receiving array. The signal acquisition and processing module is connected to the radio frequency front end and is used to acquire and process the signals output by the radio frequency front end; The first power chip and the second power chip together constitute a power module, which is used to supply power to the radio frequency front end and the signal acquisition and processing module.

2. A millimeter-wave radar for ground obstacle avoidance in unmanned aerial vehicles according to claim 1, characterized in that, The microstrip antenna is integrated on the surface of the radio frequency circuit board in the form of a patch, and both the transmitting array and the receiving array are arranged in a linear array.

3. A millimeter-wave radar for ground obstacle avoidance in unmanned aerial vehicles according to claim 1, characterized in that, The radio frequency front end specifically includes a crystal oscillator, a phase-locked loop (PLL), a power amplifier (PA), a low-noise amplifier (LNA), a variable gain amplifier, and an analog anti-aliasing filter (AAF). The crystal oscillator is connected to the phase-locked loop (PLL) to provide a frequency reference; the PLL includes an integrated phase detector and a voltage-controlled oscillator (VCO). The output of the phase-locked loop (PLL) is connected to the power amplifier (PA) and the low-noise amplifier (LNA) via a frequency multiplier and a power divider to provide the local oscillator signal. The power amplifier PA has three transmission channels, and the output of each power amplifier PA is connected to one of the transmission arrays to amplify and transmit radio frequency signals. The low noise amplifier (LNA) is provided in four parts, and the input terminal of each LNA is connected to one of the receiving arrays to amplify the received echo signal. The output of each of the low-noise amplifiers (LNAs) is connected to the corresponding analog anti-aliasing filter (AAF) via the corresponding variable gain amplifier. The output of each of the analog anti-aliasing filters constitutes the receiving channel of the radio frequency front end and is connected to the input of the signal acquisition and processing module.

4. A millimeter-wave radar for ground obstacle avoidance in unmanned aerial vehicles according to claim 1, characterized in that, The signal acquisition and processing module includes an analog-to-digital converter chip, a cache chip, and an FPGA; The input terminal of the analog-to-digital converter chip is connected to the receiving channel of the radio frequency front end, and the output terminal of the analog-to-digital converter chip is connected to the FPGA. The cache chip is connected to the FPGA and is used to cache point cloud data.

5. A millimeter-wave radar for ground obstacle avoidance in unmanned aerial vehicles according to claim 4, characterized in that, The analog-to-digital converter chip adopts a dual-balun input design.

6. A millimeter-wave radar for ground obstacle avoidance in unmanned aerial vehicles according to claim 1, characterized in that, The second power chip is a DC / DC chip, which is used to convert the 12V input voltage into various voltages to power the digital circuits in the signal acquisition and processing module.

7. A millimeter-wave radar for ground obstacle avoidance in unmanned aerial vehicles according to claim 6, characterized in that, The first power supply chip is a low-dropout linear regulator. The input terminal of the low-dropout linear regulator is connected to the output terminal of the DC / DC chip or the 12V input of the system. The output terminal of the low-dropout linear regulator is connected to the power supply terminal of the RF front end and the analog power supply terminal of the analog-to-digital converter chip in the signal acquisition and processing module, respectively.

8. A millimeter-wave radar for ground obstacle avoidance in unmanned aerial vehicles according to claim 1, characterized in that, The cavity structure includes an integrally formed aluminum alloy cavity; the radio frequency circuit board is fixedly connected to the inner wall of the aluminum alloy cavity through a thermally conductive medium.

9. A millimeter-wave radar for ground obstacle avoidance in unmanned aerial vehicles according to claim 8, characterized in that, The cavity structure also includes a wave-transparent cover disposed on the aluminum alloy cavity. The wave-transparent cover covers and is fixed to the side of the radio frequency circuit board on which the microstrip antenna is disposed, forming a closed space together with the aluminum alloy cavity.

10. A millimeter-wave radar for ground obstacle avoidance in unmanned aerial vehicles according to claim 1, characterized in that, It also includes a CAN interface circuit, one end of which is connected to the signal acquisition and processing module, and the other end serves as an external communication interface for communicating with the UAV flight control system.

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