Small low-speed target detection radar and use method

Abstract

The invention discloses a small low-speed target detection radar and a use method, and the radar comprises a radio frequency front-end cascade module which is used for generating a first wave band radio frequency signal when the radar works in a first wave band and generating a second wave band radio frequency signal when the radar works in a second wave band; the antenna array plane module is connected with the radio frequency front-end cascade module; the antenna array plane module comprises a first wave band transmitting antenna unit used for transmitting a first wave band radio frequency signal to a target; the second wave band transmitting antenna unit is used for transmitting a second wave band radio frequency signal to the target; the dual-band receiving antenna unit is used for receiving a first echo signal corresponding to the first-band radio-frequency signal and a second echo signal corresponding to the second-band radio-frequency signal; and the radar signal processing module is connected with the dual-band receiving antenna unit and is used for calculating the distance, the speed, the horizontal angle and the pitching angle of the target according to the first echo signal or the second echo signal so as to efficiently and reliably detect the target.

Description

Technical Field

[0001] The present invention relates to the technical field of target detection, and in particular to a small-sized low-speed target detection radar and a use method thereof. Background Art

[0002] With the rapid development of science and technology, the requirements for refined management and security of key areas are getting higher and higher, and the corresponding monitoring technology is also being put forward. For example, in key parks, airports, prisons and other places, there are often illegal intrusions or random intrusions by drones; for small and low-speed targets such as drones, existing technical means have problems such as high detection difficulty, high detection equipment cost and easy false alarms.

[0003] At present, the commonly used technical means mainly include the use of infrared cameras or active phased array radars for detection. However, the above technical means all have certain application limitations. For example, infrared cameras are expensive, and it is difficult to effectively balance the distance and field of view. Currently, they are only used for target type verification and confirmation, and are not suitable for search. Active phased array radars have defects such as high cost, short mechanical life, high failure rate, and high false alarm rate. They mainly work in a fixed frequency band and have insufficient anti-interference capabilities. From the above, it can be seen that for small, low-speed targets, the current effective detection methods are extremely limited and generally have the problem of high cost, which is not convenient for large-scale deployment and industrial application. Summary of the invention

[0004] The object of the present invention is to provide a small low-speed target detection radar and a use method thereof, which can detect targets efficiently and reliably.

[0005] In order to achieve the above object, the present invention is implemented by the following technical solutions:

[0006] A small low-speed target detection radar, comprising:

[0007] A radio frequency front-end cascade module, used to generate a first-band radio frequency signal when operating in the first band and to generate a second-band radio frequency signal when operating in the second band;

[0008] An antenna array module is connected to the RF front-end cascade module; the antenna array module includes: a first band transmitting antenna unit, used to transmit the first band RF signal to the target, and the target reflects a first echo signal corresponding to the first band RF signal; a second band transmitting antenna unit, used to transmit the second band RF signal to the target, and the target reflects a second echo signal corresponding to the second band RF signal; a dual-band receiving antenna unit, used to receive the first echo signal and the second echo signal;

[0009] A radar signal processing module is connected to the dual-band receiving antenna unit and is used to calculate the distance, speed, horizontal angle and pitch angle of the target according to the first echo signal or the second echo signal to detect the target.

[0010] Optionally, the RF front-end cascade module includes:

[0011] A local oscillator unit, used to generate a first local oscillator signal and a second local oscillator signal with different frequencies;

[0012] A radio frequency front end unit, comprising: a first software defined radio chip connected to the first band transmitting antenna unit; a second software defined radio chip connected to the second band transmitting antenna unit;

[0013] a power division network unit connected to the local oscillator unit, the first software defined radio chip and the second software defined radio chip, and configured to transmit the first local oscillator signal or the second local oscillator signal to the first software defined radio chip and the second software defined radio chip, so as to synchronize the radio frequencies of the first software defined radio chip and the second software defined radio chip;

[0014] The first software defined radio chip is used to generate a linear frequency modulation continuous wave waveform sequence when operating in the first band and mix the linear frequency modulation continuous wave waveform sequence with the first local oscillator signal to obtain the first band radio frequency signal;

[0015] The second software defined radio chip is used to generate the linear frequency modulation continuous wave waveform sequence when operating in the second band and mix the linear frequency modulation continuous wave waveform sequence with the second local oscillator signal to obtain the second band radio frequency signal.

[0016] Optionally, the first band transmitting antenna unit comprises a first transmitting antenna and a second transmitting antenna connected to the first software defined radio chip;

[0017] The second band transmitting antenna unit comprises a third transmitting antenna and a fourth transmitting antenna connected to the second software defined radio chip;

[0018] The dual-band receiving antenna unit includes a first receiving antenna, a second receiving antenna, a third receiving antenna and a fourth receiving antenna; and the first receiving antenna, the second receiving antenna, the third receiving antenna and the fourth receiving antenna are all connected to the first software defined radio chip and the second software defined radio chip to feed back the first echo signal to the first software defined radio chip and feed back the second echo signal to the second software defined radio chip.

[0019] Optionally, the first software defined radio chip is further used to mix the first echo signal with the first local oscillator signal to obtain a first echo mixed signal;

[0020] The second software defined radio chip is further configured to mix the second echo signal with the second local oscillator signal to obtain a second echo mixed signal.

[0021] Optionally, the RF front-end cascade module further includes: an analog-to-digital converter, connected to the first software defined radio chip and the second software defined radio chip, and configured to perform complex sampling on the first echo mixing signal or the second echo mixing signal to obtain a first complex sampling signal or a second complex sampling signal;

[0022] The radar signal processing module includes: a signal processing unit connected to the analog-to-digital converter, the first software defined radio chip and the second software defined radio chip, and configured to digitally mix the first complex sampled signal or the second complex sampled signal with the linear frequency modulation continuous wave waveform sequence to obtain a first digital intermediate frequency signal or a second digital intermediate frequency signal;

[0023] The signal processing unit is also used to perform fast Fourier transform on the first digital intermediate frequency signal to obtain a first range Doppler two-dimensional map; and use constant false alarm detection to perform target search on the first range Doppler two-dimensional map to obtain a range index value and a Doppler dimension index value of the target when the first band is working;

[0024] The signal processing unit is also used to perform fast Fourier transform on the second digital intermediate frequency signal to obtain a second range Doppler two-dimensional map; and use the constant false alarm detection to perform target search on the second range Doppler two-dimensional map to obtain the range index value and Doppler dimension index value of the target when the second band is working;

[0025] The signal processing unit is also used to calculate the distance of the target based on the distance index value of the target when the first band is working or the distance index value of the target when the second band is working; and calculate the speed of the target based on the Doppler dimension index value of the target when the first band is working or the Doppler dimension index value of the target when the second band is working.

[0026] Optionally, when working in the first band, the first transmitting antenna and the second transmitting antenna work in time sharing, and the first transmitting antenna, the second transmitting antenna and the first receiving antenna, the second receiving antenna, the third receiving antenna and the fourth receiving antenna form eight first virtual receiving channels;

[0027] The signal processing unit is further used to extract the first echo phase data of the eight first virtual receiving channels from the first range-Doppler two-dimensional map according to the range index value and the Doppler dimension index value of the target when working in the first band;

[0028] Performing digital beam synthesis on the first echo signal to obtain a horizontal angle range and a pitch angle range when the first band is working;

[0029] generating a first steering vector corresponding to the first virtual receiving channel according to the horizontal angle range and the elevation angle range when the first band is working and the coordinates of the virtual antennas corresponding to the eight first virtual receiving channels; and

[0030] The first steering vector is multiplied and accumulated with the first echo phase data corresponding to the first virtual receiving channel to obtain a first spatial power spectrum, and the horizontal angle and the pitch angle corresponding to the peak in the first spatial power spectrum are the horizontal angle and the pitch angle of the target.

[0031] Optionally, when working in the second band, the third transmitting antenna and the fourth transmitting antenna work in time-sharing mode, and the third transmitting antenna, the fourth transmitting antenna, the first receiving antenna, the second receiving antenna, the third receiving antenna and the fourth receiving antenna form eight second virtual receiving channels;

[0032] The signal processing unit is also used to extract the second echo phase data of the eight second virtual receiving channels from the second range-Doppler two-dimensional map according to the range index value and the Doppler dimension index value of the target when working in the second band;

[0033] Performing digital beam synthesis on the second echo signal to obtain a horizontal angle range and a pitch angle range when the second band is operating;

[0034] According to the horizontal angle range and the elevation angle range when the second band is working and the coordinates of the virtual antennas corresponding to the eight second virtual receiving channels, obtaining a second steering vector corresponding to the second virtual receiving channel; and

[0035] The second steering vector is multiplied and added with the second echo phase data corresponding to the second virtual receiving channel to obtain a second spatial power spectrum, and the horizontal angle and pitch angle corresponding to the peak in the second spatial power spectrum are the horizontal angle and pitch angle of the target.

[0036] Optionally, the RF front-end cascade module further includes:

[0037] a clock synchronization unit connected to the first software defined radio chip and the second software defined radio chip, and configured to transmit a clock signal to the first software defined radio chip and the second software defined radio chip so as to synchronize the clocks of the first software defined radio chip and the second software defined radio chip;

[0038] A power amplifier, arranged between the first band transmitting antenna unit and the first software defined radio chip and between the second band transmitting antenna unit and the second software defined radio chip, for amplifying the power of the first band radio frequency signal and the second band radio frequency signal;

[0039] A low noise amplifier is provided between the dual-band receiving antenna unit and the first software defined radio chip and between the dual-band receiving antenna unit and the second software defined radio chip, and is used for amplifying the first echo signal and the second echo signal.

[0040] On the other hand, the present invention also provides a method for using the small low-speed target detection radar as described above, comprising:

[0041] When there is no interference with the target, the small low-speed target detection radar is operated in the first band to detect the target;

[0042] If the target has interference in the first band, the small low-speed target detection radar is operated in the second band to detect the target;

[0043] If the target has interference in the second band, the small low-speed target detection radar is made to work alternately between the first band and the second band frames to detect the target.

[0044] Optionally, the method for using the small low-speed target detection radar further includes:

[0045] The working airspace of the small low-speed target detection radar is divided into a monitoring area and a danger area according to the distance; and the distance from any point in the monitoring area to the small low-speed target detection radar is greater than the distance from any point in the danger area to the small low-speed target detection radar;

[0046] When the target enters the dangerous area from the monitoring area and continues to approach the small low-speed target detection radar, the RF front-end cascade module generates an active interference signal and transmits it to the target through the first band transmitting antenna unit and the second band transmitting antenna unit to increase active interference to the target;

[0047] When the target continues to move away from the small low-speed target detection radar, the RF front-end cascade module stops generating the active interference signal.

[0048] The present invention has at least one of the following advantages:

[0049] The present invention provides a small low-speed target detection radar and a method of using the same. The radio frequency front-end cascade module can generate a first-band radio frequency signal when working in the first band and generate a second-band radio frequency signal when working in the second band. The first-band transmitting antenna unit of the antenna array module can transmit the first-band radio frequency signal to the target, the second-band transmitting antenna unit can transmit the second-band radio frequency signal to the target, and the dual-band receiving antenna unit can receive the first echo signal corresponding to the first-band radio frequency signal and the second echo signal corresponding to the second-band radio frequency signal. The radar signal processing module can calculate the distance, speed, horizontal angle and pitch angle of the target according to the first echo signal or the second echo signal to detect the target. The present invention adopts a dual-band antenna design, so that the small low-speed target detection radar has multiple working modes, such as a fast search mode (i.e., working in the first band), a standby search mode (i.e., working in the second band) and a complex anti-interference mode (i.e., interlaced working between the first band and the second band frames), so that the appropriate working mode can be selected according to different application scenarios, thereby efficiently and reliably detecting the target.

[0050] The RF front-end cascade module in the present invention can also generate an active interference signal and transmit the active interference signal to the target through the first band transmitting antenna unit and the second band transmitting antenna unit to increase active interference to the target.

[0051] The present invention realizes FMCW (frequency modulated continuous wave) system detection through dual-band design based on low-cost SDR (software defined radio, Standard Dynamic Range) chip cascading, and adds power amplifiers and low-noise amplifiers at the same time, which can improve the effective range for low-speed small targets and effectively reduce costs.

[0052] The present invention provides an efficient, reliable, low-cost integrated solution for detection, anti-interference and active interference of low-speed small targets in the field of anti-UAV. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a schematic structural diagram of a small low-speed target detection radar provided by one embodiment of the present invention;

[0054] Figure 2 is a schematic diagram of the position of a small low-speed target provided by an embodiment of the present invention;

[0055] Figure 3It is a structural schematic diagram of an antenna array module in a small-sized low-speed target detection radar provided by one embodiment of the present invention;

[0056] Figure 4 It is a schematic diagram of an array of virtual antennas of a small-sized low-speed target detection radar provided by an embodiment of the present invention when operating in the first band;

[0057] Figure 5 It is a schematic diagram of an array of virtual antennas of a small-sized low-speed target detection radar provided by an embodiment of the present invention when operating in the second band;

[0058] Figure 6 This is a working mode state diagram of a small low-speed target detection radar provided by one embodiment of the present invention. DETAILED DESCRIPTION

[0059] The following is a further detailed description of a small low-speed target detection radar and a method of use proposed by the present invention in conjunction with the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the present invention will be clearer. It should be noted that the accompanying drawings are in a very simplified form and use non-precise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. In order to make the purposes, features and advantages of the present invention more obvious and easy to understand, please refer to the accompanying drawings. It should be noted that the structure, proportion, size, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no technical substantive significance. Any modification of the structure, change in the proportional relationship or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope of the technical content disclosed by the present invention.

[0060] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0061] Combined with Figures 1 to 5As shown, this embodiment provides a small low-speed target detection radar, including: a radio frequency front-end cascade module 10, an antenna array module 20 and a radar signal processing module 30. The radio frequency front-end cascade module 10 is used to generate a first-band radio frequency signal when working in the first band and to generate a second-band radio frequency signal when working in the second band. Optionally, the first band is the S band, the second band is the C band, and the frequency of the first band is 2.75 GHz, and the frequency of the second band is 5.5 GHz.

[0062] The antenna array module 20 is connected to the RF front-end cascade module 10; specifically, the antenna array module 20 includes: a first band transmitting antenna unit 201, a second band transmitting antenna unit 202 and a dual-band receiving antenna unit 203; the first band transmitting antenna unit 201 is used to transmit to a target (such as Figure 2 The radar signal processing module 30 is connected to the dual-band receiving antenna unit 203, and is used to calculate the distance, speed, horizontal angle and pitch angle of the target according to the first echo signal or the second echo signal, so as to detect the target.

[0063] The small low-speed target detection radar in this embodiment adopts a dual-band antenna design, so that the small low-speed target detection radar has multiple working modes, such as a fast search mode, a backup search mode and a complex anti-interference mode, so that the appropriate working mode can be selected according to different application scenarios, and the target can be detected efficiently and reliably. Specifically, when there is no interference to the target, the small low-speed target detection radar can work in the first band, and the fast search mode is used to detect the target. If there is interference in the first band of the target, the small low-speed target detection radar can work in the second band, and the backup search mode is used to detect the target; if there is interference in the second band of the target, the small low-speed target detection radar can work in the first band and the second band frame interlaced, and the complex anti-interference mode is used to detect the target.

[0064] In addition, in this embodiment, the working airspace of the small low-speed target detection radar can be divided into a monitoring area and a dangerous area according to the distance; wherein the distance from any point in the monitoring area to the small low-speed target detection radar is greater than the distance from any point in the dangerous area to the small low-speed target detection radar. When the target enters the dangerous area from the monitoring area and continues to approach the small low-speed target detection radar, the RF front-end cascade module 10 can also generate an active interference signal and transmit the active interference signal to the target through the first band transmitting antenna unit 201 and the second band transmitting antenna unit 202 to increase active interference to the target; at this time, the small low-speed target detection radar will enter the active interference mode from the original working mode (one of the fast search mode, the standby search mode and the complex anti-interference mode). When the target continues to move away from the small low-speed target detection radar, the RF front-end cascade module 10 stops generating active interference signals, and the small low-speed target detection radar reverts to the original working mode.

[0065] Please continue to refer to Figure 1 The RF front-end cascade module 10 includes: a RF front-end unit 106; the RF front-end unit 106 includes: a first software defined radio chip (i.e., a first SDR chip), connected to the first band transmitting antenna unit 201; a second software defined radio chip (i.e., a second SDR chip), connected to the second band transmitting antenna unit 202.

[0066] It can be understood that the RF front-end cascade module 10 also includes: a clock synchronization unit 105; the clock synchronization unit 105 is connected to the first software defined radio chip and the second software defined radio chip, and is used to transmit a clock signal to the first software defined radio chip and the second software defined radio chip to synchronize the clocks of the first software defined radio chip and the second software defined radio chip.

[0067] Specifically, the clock signal output from the same clock crystal is divided into two clock signals by the clock synchronization unit 105, and respectively sent to the clock input pins of the first software defined radio chip and the second software defined radio chip, so as to achieve clock synchronization of the first software defined radio chip and the second software defined radio chip, so as to ensure the accuracy and correctness of the data of both the first software defined radio chip and the second software defined radio chip. Optionally, the clock synchronization unit 105 adopts the LMK00804B chip, and the first software defined radio chip and the second software defined radio chip adopt the AD9361 chip, but the present invention is not limited thereto.

[0068] Please continue to refer to Figure 1The RF front-end cascade module 10 further includes: a local oscillator unit 101 and a power division network unit 102. The local oscillator unit 101 is used to generate a first local oscillator signal and a second local oscillator signal with different frequencies. Optionally, the first local oscillator signal f c1 The frequency of the second local oscillator signal f c2 The power division network unit 102 is connected to the local oscillator unit 101, the first software defined radio chip and the second software defined radio chip, and is used to transmit the first local oscillator signal or the second local oscillator signal to the first software defined radio chip and the second software defined radio chip, so as to synchronize the radio frequencies of the first software defined radio chip and the second software defined radio chip.

[0069] Specifically, the first software defined radio chip is used to generate a linear frequency modulation continuous wave waveform sequence when operating in a first band and mix the linear frequency modulation continuous wave waveform sequence with the first local oscillator signal to obtain a first band radio frequency signal. The second software defined radio chip is used to generate the linear frequency modulation continuous wave waveform sequence when operating in a second band and mix the linear frequency modulation continuous wave waveform sequence with the second local oscillator signal to obtain a second band radio frequency signal.

[0070] Please continue to refer to Figure 1 The radar signal processing module 30 includes a radar control unit 303, and the radar control unit 303 is connected to the local oscillator unit 101, the first software defined radio chip and the second software defined radio chip.

[0071] Specifically, the radar control unit 303 sends a first driving instruction to the local oscillator unit 101 through the PS end SPI interface when working in the first band, and sends a second driving instruction to the local oscillator unit 101 through the SPI interface when working in the second band; wherein the first driving instruction controls the local oscillator unit 101 to generate the first local oscillator signal, and the second driving instruction controls the local oscillator unit 101 to generate the second local oscillator signal. Further, when working in the first band, the power division network unit 102 sends the first local oscillator signal to the local oscillator input pins of the first software defined radio chip and the second software defined radio chip, or when working in the second band, the power division network unit 102 sends the second local oscillator signal to the local oscillator input pins of the first software defined radio chip and the second software defined radio chip, so as to achieve radio frequency synchronization between the first software defined radio chip and the second software defined radio chip. Optionally, the main processor of the radar signal processing module 30 adopts MPSOC XCZU3EG; the local oscillator unit 101 is composed of ADF4158 device and HMC431LP4 device; the power division network unit 102 is mainly composed of a three-port Wilkinson power divider, but the present invention is not limited to this.

[0072] Specifically, the radar control unit 303 sends the third driving instruction to the first software defined radio chip through the SPI interface when working in the first band, and sends the fourth driving instruction to the second software defined radio chip when working in the second band. More specifically, after receiving the third driving instruction, the first software defined radio chip completes the parameter configuration of its own chip, generates the linear frequency modulation continuous wave waveform sequence, and mixes the linear frequency modulation continuous wave waveform sequence with the received first local oscillator signal, thereby obtaining the first band radio frequency signal. After receiving the fourth driving instruction, the second software defined radio chip completes the parameter configuration of its own chip, generates the linear frequency modulation continuous wave waveform sequence, and mixes the linear frequency modulation continuous wave waveform sequence with the received second local oscillator signal, thereby obtaining the second band radio frequency signal. Optionally, the linear frequency modulation continuous wave waveform sequence consists of M=1024 linear sawtooth frequency modulations, the frequency modulation bandwidth is B=50MHz, and each linear sawtooth duration period is T c =75us, the effective accumulation time of each linear sawtooth frequency modulation is T N =64us.

[0073] Optionally, according to the frequency of the first waveband (i.e., 2.75 GHz) and the wave velocity of the first waveband (i.e., 3×10 8m / s) can be used to calculate the wavelength of the radio frequency signal in the first band, and the frequency of the second band (i.e., 5.5 GHz) and the wave speed of the second band (i.e., 3×10 8 m / s) can be used to calculate the wavelength of the second band radio frequency signal. Further, combined with the formula Where V max is the maximum unambiguous speed measurement value, λ is the wavelength of the RF signal (the first band RF signal when working in the first band, or the second band RF signal when working in the second band), and according to the wavelength of the first band RF signal and the wavelength of the second band RF signal, it can be obtained that the maximum unambiguous speed measurement value of the small low-speed target detection radar when working in the first band is 363.63m / s, and the maximum unambiguous speed measurement value of the small low-speed target detection radar when working in the second band is 181.81m / s.

[0074] Please continue to refer to Figure 1 , the RF front-end cascade module 10 also includes: a power amplifier 104 and a low noise amplifier 103. The power amplifier 104 is arranged between the first band transmitting antenna unit 201 and the first software defined radio chip and between the second band transmitting antenna unit 202 and the second software defined radio chip, and is used to power amplify the first band radio frequency signal and the second band radio frequency signal. Optionally, the power amplifier connected to the first band transmitting antenna unit 201 is recorded as a first power amplifier, and the power amplifier connected to the second band transmitting antenna unit 202 is recorded as a second power amplifier. The low noise amplifier 103 is arranged between the dual-band receiving antenna unit 203 and the first software defined radio chip and between the dual-band receiving antenna unit 203 and the second software defined radio chip, and is used to amplify the first echo signal and the second echo signal.

[0075] Specifically, the RF front-end unit 106 contains 4 independent transmitting channels and 4 independent receiving channels; wherein the first software defined radio chip has a first transmitting channel and a second transmitting channel for sending the first band RF signal and a first receiving channel and a second receiving channel for receiving the first echo signal; the second software defined radio chip has a third transmitting channel and a fourth transmitting channel for transmitting the second band RF signal and a third receiving channel and a fourth receiving channel for receiving the second echo signal.

[0076] Specifically, the first band transmitting antenna unit 201 includes a first transmitting antenna TX1 and a second transmitting antenna TX2 connected to the first software defined radio chip to transmit the first band radio frequency signal; and the first transmitting channel of the first software defined radio chip is connected to the first transmitting antenna TX1 via the first power amplifier, and the second transmitting channel is connected to the second transmitting antenna TX2 via the first power amplifier. In this embodiment, the number of the first power amplifiers is two; optionally, the model of the first power amplifier is QPA1003D, and the maximum output power P of the first power amplifier is t1 =40dBm. Optionally, the gain G of the first transmitting antenna TX1 and the second transmitting antenna TX2 is txs =11dBi.

[0077] The second band transmitting antenna unit 202 includes a third transmitting antenna TX3 and a fourth transmitting antenna TX4 connected to the second software defined radio chip to transmit the second band radio frequency signal; and the third transmitting channel of the second software defined radio chip is connected to the third transmitting antenna TX3 via the second power amplifier, and the fourth transmitting channel is connected to the fourth transmitting antenna TX4 via the second power amplifier. In this embodiment, the number of the second power amplifiers is two; optionally, the model of the second power amplifier is QPA1003D, and the maximum output power P of the second power amplifier is t2 =38dBm. Optionally, the gain G of the first transmitting antenna TX3 and the second transmitting antenna TX4 is txc =10dBi.

[0078] The dual-band receiving antenna unit 203 is composed of 4 S-composite C-band dual-band antennas, specifically including a first receiving antenna RX1, a second receiving antenna RX2, a third receiving antenna RX3 and a fourth receiving antenna RX4; and the first receiving antenna RX1, the second receiving antenna RX2, the third receiving antenna RX3 and the fourth receiving antenna RX4 are all connected to the first software defined radio chip and the second software defined radio chip to feed back the first echo signal to the first software defined radio chip and the second echo signal to the second software defined radio chip. Optionally, the first receiving channel and the second receiving channel of the first software defined radio chip, and the third receiving channel and the fourth receiving channel of the second software defined radio chip are all connected to the first receiving antenna, the second receiving antenna, the third receiving antenna and the fourth receiving antenna through the low noise amplifier 103. In this embodiment, the number of the low noise amplifiers 103 is four; optionally, the model of the low noise amplifier 103 is QPL9504, and the noise coefficient F of the low noise amplifier is n =0.76dB. Optionally, the dual-band receiving antenna unit 203 is a dual-band antenna, the main operating frequencies are 2.75GHz (i.e., the frequency of the first band) and 5.5GHz (i.e., the frequency of the second band), and the gain of the receiving antennas (i.e., the first receiving antenna, the second receiving antenna, the third receiving antenna, and the fourth receiving antenna) when working in the first band is G rxs =8dBi, the gain of the receiving antenna when working in the second band is G rxc =10dBi. Optionally, the first band or the second band is virtualized by 2-transmitter and 4-receiver MIMO (multiple input multiple output) to form 8 virtual transceiver channels, then the non-channel coherent accumulation gain G N =4.51dB, but the present invention is not limited thereto.

[0079] Specifically, when working in the first band, the first band radio frequency signal is radiated to space and illuminates the target through the power amplifier 104 and the first band transmitting antenna unit 201, and the target reflects the first echo signal, and the first echo signal is input to the first software defined radio chip through the dual-band receiving antenna unit 203 and the low noise amplifier 103; the first software defined radio chip mixes the first echo signal with the first local oscillator signal to obtain a first echo mixing signal. When working in the second band, the second band radio frequency signal is radiated to space and illuminates the target through the power amplifier 104 and the second band transmitting antenna unit 202, and the target reflects the second echo signal, and the second echo signal is input to the second software defined radio chip through the dual-band receiving antenna unit 203 and the low noise amplifier 103; the second software defined radio chip mixes the second echo signal with the second local oscillator signal to obtain a second echo mixing signal.

[0080] It can be understood that the RF front-end cascade module further includes: an analog-to-digital converter for complex sampling the first echo mixing signal to obtain a first complex sampling signal; and complex sampling the second echo mixing signal to obtain a second complex sampling signal. Optionally, the number of sampling points during complex sampling is N=512 points, and the complex sampling frequency is f N =N / T N =8Msps.

[0081] Optionally, combine the formula Where R max is the maximum unambiguous ranging value, c is the speed of light, and according to the complex sampling frequency, the maximum unambiguous ranging value of the small low-speed target detection radar can be obtained to be 1800m; to ensure effective detection of the target, the actual working guarantee distance R of the small low-speed target detection radar is taken as 1500m. Optionally, the effective accumulation time within a single frame, i.e., the signal accumulation gain T val =M×T N =65.536ms, but the present invention is not limited thereto.

[0082] Further, all values ​​are converted into decibel values ​​according to the minimum signal-to-noise ratio radar equation Where SNR is the minimum detectable signal-to-noise ratio required for a target with a radar cross-sectional area (RCS) of σ at a corresponding distance R, P t is the transmission power (in this embodiment, it is the output power of the power amplifier), G r is the gain of the receiving antenna, G tis the gain of the transmitting antenna (the first transmitting antenna and the second transmitting antenna when working in the first band, or the third transmitting antenna and the fourth transmitting antenna when working in the second band), λ is the wavelength of the RF signal, σ is the radar reflection cross-sectional area of ​​the target, R is the distance of the target, L s is the system loss, k is the Boltzmann constant, T0 is the working environment temperature, F n is the noise figure of the low noise amplifier, T val is the signal accumulation gain, G N For the non-channel coherent accumulation gain, it can be calculated that for a target with σ=-20dBsm, the detection distance is guaranteed to be 1500m, the signal-to-noise ratio in the first band is 21.64dB, and the signal-to-noise ratio in the second band is 16.68dB. The signal-to-noise ratio condition meets the radar system's minimum detection signal-to-noise ratio requirement of 15dB, which can ensure that the target is effectively detected.

[0083] Please continue to refer to Figure 1 , the radar signal processing module 30 includes: a signal processing unit 301, connected to the analog-to-digital converter, the first software defined radio chip and the second software defined radio chip, and configured to digitally mix the first complex sampling signal with the linear frequency modulation continuous wave waveform sequence to obtain a first digital intermediate frequency signal; and digitally mix the second complex sampling signal with the linear frequency modulation continuous wave waveform sequence to obtain a second digital intermediate frequency signal;

[0084] The signal processing unit is also used to perform fast Fourier transform on the first digital intermediate frequency signal to obtain a first range Doppler two-dimensional map; and perform target search on the first range Doppler two-dimensional map using constant false alarm detection to obtain a range index value and a Doppler dimension index value of the target in the first band;

[0085] The signal processing unit is also used to perform fast Fourier transform on the second digital intermediate frequency signal to obtain a second range Doppler two-dimensional map; and use the constant false alarm detection to perform target search on the second range Doppler two-dimensional map to obtain the range index value and Doppler dimension index value of the target in the second band;

[0086] The signal processing unit is also used to calculate the distance of the target according to the distance index value of the target in the first band or the distance index value of the target in the second band; and calculate the speed of the target according to the Doppler dimension index value of the target in the first band or the Doppler dimension index value of the target in the second band.

[0087] Specifically, Figure 2As shown, it is assumed that there is a target T, the distance R = 500m from the small low-speed target detection radar (located at the origin O), the speed V = 10m / s, the horizontal angle θ0 = 10°, the pitch angle

[0088] In this embodiment, the signal processing unit 301 performs two-dimensional FFT (fast Fourier transform) and CFAR (constant false alarm detection) on the obtained first digital intermediate frequency signal or the second digital intermediate frequency signal, and the number of points of the two-dimensional FFT is P=512 (when P is not equal to an integer power of 2, N is taken as an integer power of 2 as possible) and M=1024. After the two-dimensional FFT processing, the first distance Doppler two-dimensional map or the second distance Doppler two-dimensional map is obtained, and CFAR is used to search for the target on the first distance Doppler two-dimensional map or the second distance Doppler two-dimensional map, and the distance index value p and the Doppler dimension index value m of the target are respectively 143 and 15 when the first band is working, and the distance index value p and the Doppler dimension index value m of the target are respectively 143 and 29 when the second band is working. According to the formula The distances of the targets when the first band is working and the second band is calculated to be And according to the formula It is calculated that the speed of the target when the first band is working and the second band is working is 9.94m / s, specifically It can be seen that the small low-speed target detection radar described in this embodiment has extremely high accuracy in detecting the distance and speed of the target.

[0089] Please continue to refer to Figure 3 , the horizontal spacing between the first transmitting antenna TX1 and the second transmitting antenna TX1 is 6D, the horizontal spacing between the third transmitting antenna TX3 and the fourth transmitting antenna TX4 is D, and D is a positive number. The horizontal spacing between the first receiving antenna RX1 and the second receiving antenna RX2, between the second receiving antenna RX2 and the third receiving antenna RX3, and between the third receiving antenna RX3 and the fourth receiving antenna RX4 is 2D, and the vertical spacing between the fourth receiving antenna RX4 and the first receiving antenna RX1, the second receiving antenna RX2 and the third antenna RX3 is H, and H is a positive number. Optionally, D=27.273mm, H=109.092mm, but the present invention is not limited thereto.

[0090] Specifically, when the first band is working, the first transmitting antenna TX1 and the second transmitting antenna TX2 work in time sharing, and the first transmitting antenna TX1, the second transmitting antenna TX2 and the first receiving antenna RX1, the second receiving antenna RX2, the third receiving antenna RX3 and the fourth receiving antenna RX4 virtually form 8 first virtual receiving channels through MIMO (multiple input multiple output); Figure 4 As shown, the coordinates (x i ,y i ) are (0, 0), (2D, 0), (4D, 0), (6D, H), (6D, 0), (8D, 0), (10D, 0), and (12D, H), respectively; where i = 1, ..., 8.

[0091] When the second band is working, the third transmitting antenna TX3 and the fourth transmitting antenna TX4 work in time division, and the third transmitting antenna TX3, the fourth transmitting antenna TX4 and the first receiving antenna RX1, the second receiving antenna RX2, the third receiving antenna RX3 and the fourth receiving antenna RX4 form 8 second virtual receiving channels through MIMO (multiple input multiple output); Figure 5 As shown, the coordinates (x i ,y i ) are (0, 0), (2D, 0), (4D, 0), (6D, H), (D, 0), (3D, 0), (5D, 0), and (7D, H), respectively; where i = 1, ..., 8.

[0092] Furthermore, when the first band and the second band are working, the echo phase data of each channel can be expressed as Where i = 1...8, x i and i represents the horizontal and vertical coordinates of the virtual antenna, j is an imaginary unit, θ0 and are the horizontal angle and pitch angle of the target respectively.

[0093] Specifically, the signal processing unit 301 is also used to extract the echo phase data of the eight first virtual receiving channels from the first band range-Doppler two-dimensional map according to the distance index value and the Doppler dimension index value of the target when the first band is working; perform digital beam synthesis on the first echo signal to obtain the horizontal angle range and the pitch angle range when the first band is working; according to the horizontal angle range and the pitch angle range when the first band is working, the coordinates of the virtual antennas corresponding to the eight first virtual receiving channels and the formula In the formula is the steering vector, θ∈[-θ max,θ max ]、 Generate a steering vector corresponding to the first band; multiply and accumulate the first band steering vector and the echo phase data corresponding to the first band virtual receiving channel to obtain a first band spatial power spectrum, and the horizontal angle and pitch angle corresponding to the peak in the first band spatial power spectrum are the horizontal angle and pitch angle of the target.

[0094] The signal processing unit 301 is also used to extract the echo phase data of the eight second virtual receiving channels from the second band range-Doppler two-dimensional map according to the range index value and Doppler dimension index value of the target when the second band is working; perform digital beam synthesis on the second echo signal to obtain the horizontal angle range and the elevation angle range when the second band is working; according to the horizontal angle range and the elevation angle range when the second band is working, the coordinates of the eight virtual antennas corresponding to the second virtual receiving channels and the formula In the formula is the steering vector, θ∈[-θ′ max ,θ′ max ]、 Generate a steering vector corresponding to the second band; multiply and accumulate the second band steering vector and the second echo phase data corresponding to the second band virtual receiving channel to obtain a second band spatial power spectrum, and the horizontal angle and pitch angle corresponding to the peak in the second band spatial power spectrum are the horizontal angle and pitch angle of the target.

[0095] The above can obtain the distance, speed, horizontal angle, and pitch angle of the target, and then convert the spherical coordinate system into a Cartesian coordinate system to obtain the X, Y, and Z three-dimensional spatial coordinates and speed value of the target.

[0096] In addition, in some embodiments, Kalman tracking filtering can also be performed on the target, and for the target with established stable tracking track, micro-Doppler information can be extracted from the speed Doppler map through p and m index information; and multiple frames are continuously extracted to establish a micro-Doppler time-frequency map. The convolutional neural network classifier in the signal processing unit 301 identifies the micro-Doppler time-frequency map, completes target classification, obtains the category information of the target, and finally obtains the X, Y, Z three-dimensional spatial coordinate information, speed information and category information of the target, but the present invention is not limited to this.

[0097] In other embodiments, the radar signal processing module 30 also includes a radar communication interface 302, which is connected to the signal processing unit 301; the radar communication interface 302 includes an Ethernet interface and a CAN communication interface; and the Ethernet interface and the CAN communication interface can independently send the X, Y, Z three-dimensional spatial coordinate information, speed information, and category information of the target obtained by the signal processing unit 301 to the user end for staff to view, but the present invention is not limited to this.

[0098] Combined with Figure 6 As shown, based on the same inventive concept, this embodiment also provides a method for using the small-sized low-speed target detection radar as described above, including: when there is no interference to the target, the small-sized low-speed target detection radar is operated in the first band, and a fast search mode is used to detect the target; if there is interference in the first band to the target, the small-sized low-speed target detection radar is operated in the second band, and a backup search mode is used to detect the target; if there is interference in the second band to the target, the small-sized low-speed target detection radar is operated in an interlaced manner between frames of the first band and the second band, and a complex anti-interference mode is used to detect the target, and coded frequency hopping is performed between modulated sawtooth waveforms in each frame.

[0099] Optionally, the radar signal processing module 30 also includes a radar interference detection unit 304, which is connected to the RF front-end cascade module 10 and is used to detect whether the target has first-band interference and second-band interference; if the target does not have first-band interference and second-band interference, the radar interference detection unit 304 controls the RF front-end cascade module 10 to generate the first-band RF signal; if the target has first-band interference, the radar interference detection unit 304 controls the RF front-end cascade module 10 to generate the second-band RF signal; if the target has second-band interference, the radar interference detection unit 304 controls the RF front-end cascade module 10 to interleave the generation of the first-band RF signal and the second-band RF signal between frames.

[0100] Specifically, the small low-speed target detection radar enters the fast search mode by default when it is turned on, that is, it works in the first band. When the radar interference detection unit does not detect interference with the target for a continuous period of time (i.e., within a preset time length), the small low-speed target detection radar enters the fast search mode, but the present invention is not limited thereto.

[0101] Specifically, the method for using the small low-speed target detection radar also includes: dividing the working airspace of the small low-speed target detection radar into a monitoring area and a dangerous area according to the distance; wherein the distance from any point in the monitoring area to the small low-speed target detection radar is greater than the distance from any point in the dangerous area to the small low-speed target detection radar. When the target enters the dangerous area from the monitoring area and continues to approach the small low-speed target detection radar, the RF front-end cascade module 10 generates an active interference signal and transmits the active interference signal to the target through the first band transmitting antenna unit 201 and the second band transmitting antenna unit 202 to increase active interference to the target; at this time, the small low-speed target detection radar will enter the active interference mode from the original working mode (one of the fast search mode, the standby search mode and the complex anti-interference mode). When the target continues to move away from the small low-speed target detection radar, the RF front-end cascade module 10 stops generating the active interference signal, and the small low-speed target detection radar reverts to the original working mode.

[0102] Furthermore, the RF front-end cascade module 10 also includes an interference signal generating unit, which is connected to the radar control unit 303; when the target enters the dangerous area from the monitoring area and continues to approach the small low-speed target detection radar, the radar control unit 303 generates a fifth driving instruction, and the fifth driving instruction controls the interference signal generating unit to generate the active interference signal and transmit it to the target through the first band transmitting antenna unit 201 and the second band transmitting antenna unit 202, but the present invention is not limited to this.

[0103] In summary, the present embodiment provides a small low-speed target detection radar and a method of use, wherein the RF front-end cascade module can generate a first-band RF signal when working in the first band and generate a second-band RF signal when working in the second band. The first-band transmitting antenna unit of the antenna array module can transmit a first-band RF signal to the target, the second-band transmitting antenna unit can transmit a second-band RF signal to the target, and the dual-band receiving antenna unit can receive a first echo signal corresponding to the first-band RF signal and a second echo signal corresponding to the second-band RF signal. The radar signal processing module can calculate the distance, speed, horizontal angle and pitch angle of the target according to the first echo signal or the second echo signal to detect the target. The present embodiment adopts a dual-band antenna design, so that the small low-speed target detection radar has multiple working modes, such as a fast search mode (i.e., working in the first band), a standby search mode (i.e., working in the second band) and a complex anti-interference mode (i.e., working in the first band and the second band inter-frame interleaving), so that the appropriate working mode can be selected according to different application scenarios, thereby efficiently and reliably detecting the target. In this embodiment, the RF front-end cascade module can also generate an active interference signal and transmit the active interference signal to the target through the first band transmitting antenna unit and the second band transmitting antenna unit to increase active interference to the target. In addition, this embodiment uses a dual-band design to realize FMCW (frequency modulated continuous wave) system detection based on low-cost SDR (software defined radio, Standard Dynamic Range) chip cascade, and adds a power amplifier and a low-noise amplifier at the same time, which can increase the range of low-speed small targets and effectively reduce costs, thereby providing an efficient and reliable low-cost detection, anti-interference, and active interference integrated solution for low-speed small targets in the field of anti-UAV.

[0104] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.

Claims

1. A small low-speed target detection radar, characterized in that: include: A radio frequency front-end cascade module, used to generate a first-band radio frequency signal when operating in the first band and to generate a second-band radio frequency signal when operating in the second band; An antenna array module is connected to the RF front-end cascade module; the antenna array module includes: a first band transmitting antenna unit, used to transmit the first band RF signal to the target, and the target reflects a first echo signal corresponding to the first band RF signal; a second band transmitting antenna unit, used to transmit the second band RF signal to the target, and the target reflects a second echo signal corresponding to the second band RF signal; a dual-band receiving antenna unit, used to receive the first echo signal and the second echo signal; A radar signal processing module is connected to the dual-band receiving antenna unit and is used to calculate the distance, speed, horizontal angle and pitch angle of the target according to the first echo signal or the second echo signal to detect the target.

2. The small low-speed target detection radar according to claim 1, characterized in that: The radio frequency front-end cascade module comprises: A local oscillator unit, used to generate a first local oscillator signal and a second local oscillator signal with different frequencies; A radio frequency front end unit, comprising: a first software defined radio chip connected to the first band transmitting antenna unit; a second software defined radio chip connected to the second band transmitting antenna unit; a power division network unit connected to the local oscillator unit, the first software defined radio chip and the second software defined radio chip, and configured to transmit the first local oscillator signal or the second local oscillator signal to the first software defined radio chip and the second software defined radio chip, so as to synchronize the radio frequencies of the first software defined radio chip and the second software defined radio chip; The first software defined radio chip is used to generate a linear frequency modulation continuous wave waveform sequence when operating in the first band and mix the linear frequency modulation continuous wave waveform sequence with the first local oscillator signal to obtain the first band radio frequency signal; The second software defined radio chip is used to generate the linear frequency modulation continuous wave waveform sequence when operating in the second band and mix the linear frequency modulation continuous wave waveform sequence with the second local oscillator signal to obtain the second band radio frequency signal.

3. The small low-speed target detection radar according to claim 2, characterized in that: The first band transmitting antenna unit comprises a first transmitting antenna and a second transmitting antenna connected to the first software defined radio chip; The second band transmitting antenna unit comprises a third transmitting antenna and a fourth transmitting antenna connected to the second software defined radio chip; The dual-band receiving antenna unit includes a first receiving antenna, a second receiving antenna, a third receiving antenna and a fourth receiving antenna; and the first receiving antenna, the second receiving antenna, the third receiving antenna and the fourth receiving antenna are all connected to the first software defined radio chip and the second software defined radio chip to feed back the first echo signal to the first software defined radio chip and feed back the second echo signal to the second software defined radio chip.

4. The small low-speed target detection radar according to claim 3, characterized in that: The first software defined radio chip is further used for mixing the first echo signal with the first local oscillator signal to obtain a first echo mixed signal; The second software defined radio chip is further configured to mix the second echo signal with the second local oscillator signal to obtain a second echo mixed signal.

5. The small low-speed target detection radar as claimed in claim 4, characterized in that: The RF front-end cascade module further includes: an analog-to-digital converter connected to the first software defined radio chip and the second software defined radio chip, and configured to perform complex sampling on the first echo mixing signal or the second echo mixing signal to obtain a first complex sampling signal or a second complex sampling signal; The radar signal processing module includes: a signal processing unit connected to the analog-to-digital converter, the first software defined radio chip and the second software defined radio chip, and configured to digitally mix the first complex sampled signal or the second complex sampled signal with the linear frequency modulation continuous wave waveform sequence to obtain a first digital intermediate frequency signal or a second digital intermediate frequency signal; The signal processing unit is also used to perform fast Fourier transform on the first digital intermediate frequency signal to obtain a first range Doppler two-dimensional map; and use constant false alarm detection to perform target search on the first range Doppler two-dimensional map to obtain a range index value and a Doppler dimension index value of the target when the first band is working; The signal processing unit is also used to perform fast Fourier transform on the second digital intermediate frequency signal to obtain a second range Doppler two-dimensional map; and use the constant false alarm detection to perform target search on the second range Doppler two-dimensional map to obtain the range index value and Doppler dimension index value of the target when the second band is working; The signal processing unit is also used to calculate the distance of the target based on the distance index value of the target when the first band is working or the distance index value of the target when the second band is working; and calculate the speed of the target based on the Doppler dimension index value of the target when the first band is working or the Doppler dimension index value of the target when the second band is working.

6. The small low-speed target detection radar according to claim 5, characterized in that: When working in the first band, the first transmitting antenna and the second transmitting antenna work in time sharing, and the first transmitting antenna, the second transmitting antenna and the first receiving antenna, the second receiving antenna, the third receiving antenna and the fourth receiving antenna form eight first virtual receiving channels; The signal processing unit is further used to extract the first echo phase data of the eight first virtual receiving channels from the first range-Doppler two-dimensional map according to the range index value and the Doppler dimension index value of the target when working in the first band; Performing digital beam synthesis on the first echo signal to obtain a horizontal angle range and a pitch angle range when the first band is operating; Generate a first steering vector corresponding to the first virtual receiving channel according to the horizontal angle range and the elevation angle range when the first band is working and the coordinates of the virtual antennas corresponding to the eight first virtual receiving channels; as well as The first steering vector is multiplied and accumulated with the first echo phase data corresponding to the first virtual receiving channel to obtain a first spatial power spectrum, and the horizontal angle and the pitch angle corresponding to the peak in the first spatial power spectrum are the horizontal angle and the pitch angle of the target.

7. The small low-speed target detection radar according to claim 5, characterized in that: When working in the second band, the third transmitting antenna and the fourth transmitting antenna work in time-sharing mode, and the third transmitting antenna, the fourth transmitting antenna, the first receiving antenna, the second receiving antenna, the third receiving antenna and the fourth receiving antenna form eight second virtual receiving channels; The signal processing unit is also used to extract the second echo phase data of the eight second virtual receiving channels from the second range-Doppler two-dimensional map according to the range index value and the Doppler dimension index value of the target when working in the second band; Performing digital beam synthesis on the second echo signal to obtain a horizontal angle range and a pitch angle range when the second band is operating; According to the horizontal angle range and the elevation angle range of the second band operation and the coordinates of the virtual antennas corresponding to the eight second virtual receiving channels, obtaining a second steering vector corresponding to the second virtual receiving channel; and The second steering vector is multiplied and added with the second echo phase data corresponding to the second virtual receiving channel to obtain a second spatial power spectrum, and the horizontal angle and pitch angle corresponding to the peak in the second spatial power spectrum are the horizontal angle and pitch angle of the target.

8. The small low-speed target detection radar according to claim 2, characterized in that: The RF front-end cascade module also includes: a clock synchronization unit connected to the first software defined radio chip and the second software defined radio chip, and configured to transmit a clock signal to the first software defined radio chip and the second software defined radio chip so as to synchronize the clocks of the first software defined radio chip and the second software defined radio chip; A power amplifier, arranged between the first band transmitting antenna unit and the first software defined radio chip and between the second band transmitting antenna unit and the second software defined radio chip, for amplifying the power of the first band radio frequency signal and the second band radio frequency signal; A low noise amplifier is provided between the dual-band receiving antenna unit and the first software defined radio chip and between the dual-band receiving antenna unit and the second software defined radio chip, and is used for amplifying the first echo signal and the second echo signal.

9. A method for using the small low-speed target detection radar as claimed in any one of claims 1 to 8, characterized in that: include: When there is no interference with the target, the small low-speed target detection radar is operated in the first band to detect the target; If the target has interference in the first band, the small low-speed target detection radar is operated in the second band to detect the target; If the target has interference in the second band, the small low-speed target detection radar is made to work alternately between the first band and the second band frames to detect the target.

10. The method for using the small low-speed target detection radar according to claim 9, characterized in that: Also includes: The working airspace of the small low-speed target detection radar is divided into a monitoring area and a danger area according to the distance; and the distance from any point in the monitoring area to the small low-speed target detection radar is greater than the distance from any point in the danger area to the small low-speed target detection radar; When the target enters the dangerous area from the monitoring area and continues to approach the small low-speed target detection radar, the RF front-end cascade module generates an active interference signal and transmits it to the target through the first band transmitting antenna unit and the second band transmitting antenna unit to increase active interference to the target; When the target continues to move away from the small low-speed target detection radar, the RF front-end cascade module stops generating the active interference signal.

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