A UAV detection radar mechanism

Abstract

The utility model discloses a human-machine detection radar mechanism, which relates to the technical field of drone detection, including an FPGA chip, the FPGA chip signal is connected to a DDS module, the DDS module signal is connected to an analog switch, the analog switch signal is connected to an up-converter, the up-converter signal is connected to a frequency synthesizer, the frequency synthesizer signal is connected to a down-converter, the up-converter signal is connected to a power divider, the power divider signal is connected to a synthesis network module, the synthesis network module is connected to a down-converter signal, the synthesis network module signal is connected to a T / R module, the T / R module is connected to an FPGA chip signal, the frequency synthesizer signal is connected to an FPGA chip, the FPGA chip signal is connected to an A / D converter, and the signal between the A / D converter and the down-converter is connected to a frequency conditioning circuit. The utility model can realize pulse-variable linear frequency modulation of radar, and the linear frequency modulation pulse can resist interference through frequency diversity and broadband signal processing.

Description

Technical Field

[0001] The utility model relates to the technical field of detection radars, and in particular to a detection radar mechanism for an unmanned aerial vehicle. Background Art

[0002] As the domestic low-altitude airspace is gradually opened up, drones have also gradually developed and are widely used in civil fields such as intelligent traffic monitoring, aerial imaging, and film and television shooting, playing a positive role. However, due to the lack of unified industry standards and specifications, a large number of drones are flying without supervision, which has become a prominent problem in air traffic control. At present, radars for monitoring aircraft use pulse Doppler. The transmission and reception of radars in this system are time-sharing, with high isolation. Simple pulses are used as transmission signals. Since the time-bandwidth product of simple pulses is approximately one, it cannot have both distance resolution and velocity resolution.

[0003] The Chinese patent with the announcement number CN212111767U discloses a drone detection radar. The technical solution disclosed in the patent document is as follows: it includes a radar body and a heat dissipation component, the radar body and the heat dissipation component are stacked, a cover plate is provided between the radar body and the heat dissipation component, the various functional components of the radar body are independent of each other, and each functional component is provided with an input and output interface, and a thermal pad in contact with the functional component is provided inside the radar body, and the thermal pad is in contact with the cover plate for heat dissipation, and the heat received by the cover plate is dissipated through the heat dissipation component. In order to solve the problems of heavy weight, large volume, inconvenient transportation and installation, and difficult detection and maintenance of the existing drone detection radar, in the drone detection radar of the utility model of the present application, the radar body and the heat dissipation component are stacked, the various functional components of the radar body are independent of each other, and each functional component is provided with an input and output interface, so that the same type of components can be reused or interchangeable, and the problems of chaotic layout and interlaced wiring of the radar body are solved. The structure is compact, the volume is small, the weight is light, and the off-site installation is convenient, and it is also convenient for assembly, debugging and later maintenance. However, this technical solution also has the problem that the radar cannot perform linear frequency modulation with variable pulses. Utility Model Content

[0004] A technical problem solved by the utility model is that a radar for detecting unmanned aerial vehicles cannot perform pulse variable linear frequency modulation.

[0005] The technical solution adopted by the utility model is:

[0006] A drone detection radar mechanism includes an FPGA chip, wherein the FPGA chip signal is connected to a DDS module, wherein the DDS module signal is connected to an analog switch, wherein the analog switch signal is connected to an up-converter, wherein the up-converter signal is connected to a frequency synthesizer, wherein the frequency synthesizer signal is connected to a down-converter, wherein the up-converter signal is connected to a power divider, wherein the power divider signal is connected to a synthesis network module, wherein the synthesis network module is connected to a down-converter signal, wherein the synthesis network module signal is connected to a T / R module, wherein the T / R module is connected to an FPGA chip signal, wherein the frequency synthesizer signal is connected to an FPGA chip, wherein the FPGA chip signal is connected to an A / D converter, wherein the signal between the A / D converter and the down-converter is connected to a frequency conditioning circuit. Thus, the radar can be subjected to pulse-variable linear frequency modulation.

[0007] As a further improvement of the present invention, the T / R module signal is connected to the transceiver antenna array, so that it can be used to send radar signals and receive echo signals.

[0008] As a further improvement of the utility model, the FPGA chip signal is connected to the memory, so as to extract target distance, speed, signal-to-noise ratio, azimuth, pitch angle and other information from the echo, and transmit the data to the terminal for display through the gigabit network port.

[0009] As a further improvement of the utility model, the chip of the DDS module adopts the AD9910 chip, the chip of the A / D chip adopts the AD9653 chip, the FPGA chip adopts the XC7K480T-1FFG901I chip, and the drone detection radar mechanism is connected to a power supply. The AD9910 chip can achieve the blind spot filling effect by combining long and short pulses, the AD9653 chip can sample the intermediate frequency echo, and the XC7K480T-1FFG901I chip can achieve the advantages of fast calculation speed, strong application flexibility, many interface resources, short design cycle and relatively low cost.

[0010] As a further improvement of the utility model, the up-converter and down-converter adopt image suppression harmonic mixers, and the synthesis network module adopts microstrip circuit design. Harmonic suppression mixers can effectively reduce or eliminate image frequency interference in the mixer output, and improve the performance and output quality of the mixer.

[0011] As a further improvement of the utility model, the power divider is used to amplify the frequency synthesizer signal and the up-converter signal, and the frequency synthesizer adopts a frequency multiplication design.

[0012] The utility model has the following beneficial effects: 1. Through the DDS module, up-converter, down-converter and frequency synthesizer, the DDS module and the frequency synthesizer will generate microwave signals after passing through the up-converter, and the frequency synthesizer and the down-converter will receive the signals, so as to achieve pulse-variable linear frequency modulation of the radar. The linear frequency modulation pulse can resist interference through frequency diversity and broadband signal processing. Since the linear frequency modulation pulse has a high signal-to-noise ratio, the radar can work in a complex electromagnetic environment. Moreover, the linear frequency modulation pulse can improve the target resolution of the radar. By frequency modulating the radar pulse signal, the radar system can be made more sensitive to the speed and distance of the target, thereby improving the detection performance of the target. The frequency modulation pulse can also enable the radar system to resist different types of interference, which helps to improve the anti-interference performance of the radar system.

[0013] 2. Through the DDS module and FPGA chip, the DDS module generates a composite waveform of long pulses and short pulses through linear frequency modulation, which can achieve higher speed measurement accuracy and meet the detection requirements of low-speed targets. The UAV echo signal is processed using advanced digital signal processing technology, and the target distance, target speed, azimuth, and pitch angle are analyzed through the processing of the FPGA chip signal algorithm. Compared with the existing detection radar system, it has better detection performance and greatly improves the radar's detection performance and anti-interference ability. And this design makes the radar compact in structure, high in stability, reliable in circuit performance, relatively low in cost, and easier to mass produce. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the principle of the utility model.

[0015] Figure 2 It is a composite waveform diagram of DDS in the utility model. DETAILED DESCRIPTION

[0016] The utility model is further described below in conjunction with the accompanying drawings.

[0017] As shown in the figure, a drone detection radar mechanism includes a transceiver antenna array, a T / R module, a synthesis network module, a frequency synthesizer, up-conversion, down-conversion, a frequency conditioning circuit for amplification and conditioning, an A / D converter, a DDS module, an analog switch, a power divider for power division and amplification, an FPGA chip, a gigabit network port, a terminal display, and a power supply.

[0018] The composite pulse signal modulated by the DDS module is up-converted in the up-converter through the analog switch and the frequency synthesizer, thereby generating a microwave signal. After being amplified by the power divider, it is sent to the transmitting component in the T / R module through the synthesis network to output power, and then radiated outward through the antenna array. When the radar is in the receiving state, the signal radiated by the antenna array is reflected back to the antenna array after encountering the drone. After the array receives it, it is received by the T / R module receiving component. After passing through the synthesis network module, the received signal is down-converted in the down-converter through the synthesis network and the frequency synthesizer. The generated intermediate frequency signal is amplified and conditioned by the frequency conditioning circuit and sent to the A / D converter. The FPGA chip performs an algorithm to filter out interference clutter, and extracts target distance, speed, signal-to-noise ratio, azimuth, pitch angle and other information from the echo. Finally, the data is transmitted to the terminal display through the Gigabit network port.

[0019] The DDS module uses the AD9910 chip, which uses serial SPI to accurately control linear frequency modulation, generates digital waveforms through sine lookup table addressing, and finally converts them into analog signals through DAC. Under the premise that the radar signal processing guarantees a certain signal-to-noise ratio, the larger the DDS signal width, the higher the speed resolution; so the waveform generated by DDS is the core of the radar. The waveform generated by the linear frequency modulation pulse contains long pulses and short pulses. The long pulse mainly tests the information of long-distance drones, and the short pulse tests the information of short-distance drones. The combination of long and short pulses can achieve the effect of blind spot filling. The analog switch mainly increases the isolation of the DDS module waveform output. By controlling the switch to isolate the transmit signal and the receive signal, the interference information brought by the transmit signal is reduced, the detection performance of the drone detection radar is improved, and the anti-interference ability of the radar is increased.

[0020] The frequency synthesizer can generate a clock signal for the FPGA chip, and can control the time synchronization of the T / R module and the FPGA signal processing. The frequency synthesizer can also generate microwave signals, and transmit the signal generated by the DDS module through the up-converter, while the received signal is converted into an intermediate frequency signal through the down-converter. The power divider amplifies the frequency synthesizer signal and the up-converter signal, and then sends them to the synthesis network through the power divider and then to the T / R module again. The power divider uses the Wilkinson power divider, which has high isolation, low insertion loss, good phase consistency and amplitude balance, to ensure high distribution and good isolation performance of each branch.

[0021] Furthermore, the synthesis network can perform power division on the transmitted signal and synthesize the received signal at the same time. The transceiver antenna array is used to radiate and receive electromagnetic waves into the airspace, transmit high-power microwave signals through the TR component in a direction, and receive drone targets in the corresponding direction. The array surface can determine the detection direction through FPGA control, and transmit and receive electromagnetic waves in a fixed direction. The T / R module (transceiver module) amplifies, shifts phase and attenuates the microwave signal according to the FPGA chip control signal. The system completes the antenna beam pointing by configuring the internal phase shifter of the T / R module component. Since there is a circulator inside the T / R component, the transmission of electromagnetic waves can only circulate in a single direction, so the transmission and reception are time-division, and the transceiver component is integrated, which can effectively reduce the size, reduce the cost and improve its stability. The up-converter and down-converter use image suppression harmonic mixers to add and subtract the frequencies generated on the frequency synthesizer to obtain the upper sideband and lower sideband, and move the spectrum of the input signal to the intermediate frequency without distortion. The amplification and conditioning of the frequency conditioning circuit is mainly to process the weak intermediate frequency signal after down-conversion. Since the signal obtained after down-conversion is small, it is filtered and amplified. When the amplitude of the echo signal is large, it needs to be input into the conditioning circuit before sampling the echo signal. The conditioning circuit has the following two purposes: first, the conditioning circuit can act as a buffer to protect the back-end circuit; second, the echo input signal is a single-ended analog signal, and the conditioning circuit can convert it into a differential analog signal to meet the input requirements of the chip before entering the A / D signal sampling, and can also suppress noise crosstalk.

[0022] The advantages of the utility model are: 1) The radar is subjected to pulse variable linear frequency modulation, and the linear frequency modulation pulse can resist interference through frequency diversity and broadband signal processing. Since the linear frequency modulation pulse has a high signal-to-noise ratio, the radar can work in a complex electromagnetic environment. 2) The composite waveform of long pulses and short pulses can achieve higher speed measurement accuracy and meet the detection requirements of low-speed targets. The UAV echo signal is processed by advanced digital signal processing technology. 3) Microstrip integrated circuit integration technology, a signal generation method combining monolithic integrated circuits and microstrip hybrid integrated circuits, reduces the volume of the system, reduces electromagnetic interference, and thus enhances stability and reliability. 4) The electronic components in the frequency synthesizer, up-converter, down-converter and T / R module all use components with smaller packaging forms, which can effectively reduce the volume, reduce costs and improve their stability, making the entire UAV detection radar more integrated. 5) The linear frequency modulation signal is isolated by an analog switch; the transmit signal and the receive signal are isolated by controlling the switch, reducing the interference signal caused by the transmit signal, improving the detection performance of the UAV detection radar, and thus increasing the radar's anti-interference ability.

[0023] Those skilled in the art should be aware that the protection scheme of the present utility model is not limited to the above-mentioned embodiments, and various arrangements, combinations and transformations can be made on the basis of the above-mentioned embodiments. Without violating the spirit of the present utility model, various transformations of the present utility model fall within the protection scope of the present utility model.

Claims

1. A drone detection radar mechanism, comprising an FPGA chip, characterized in that: The FPGA chip signal is connected to the DDS module, the DDS module signal is connected to the analog switch, the analog switch signal is connected to the up-converter, the up-converter signal is connected to the frequency synthesizer, the frequency synthesizer signal is connected to the down-converter, the up-converter signal is connected to the power divider, the power divider signal is connected to the synthesis network module, the synthesis network module is connected to the down-converter signal, the synthesis network module signal is connected to the T / R module, the T / R module is connected to the FPGA chip signal, the frequency synthesizer signal is connected to the FPGA chip, the FPGA chip signal is connected to the A / D converter, and the signal between the A / D converter and the down-converter is connected to the frequency conditioning circuit.

2. The drone detection radar mechanism according to claim 1, characterized in that: The T / R module signal is connected to the transceiver antenna array.

3. The drone detection radar mechanism according to claim 1, characterized in that: The FPGA chip signal is connected to the memory.

4. The drone detection radar mechanism according to claim 1, characterized in that: The chip of the DDS module adopts the AD9910 chip, the chip of the A / D chip adopts the AD9653 chip, the FPGA chip adopts the XC7K480T-1FFG901I chip, and the drone detection radar mechanism is connected to a power supply.

5. The drone detection radar mechanism according to claim 1, characterized in that: The up-converter and the down-converter adopt image suppression harmonic mixers, and the synthesis network module adopts microstrip circuit design.

6. The drone detection radar mechanism according to claim 1, characterized in that: The power divider is used to amplify the frequency synthesizer signal and the up-converter signal, and the frequency synthesizer adopts a frequency multiplication design.

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