Working principle of anti UAV radar

Anti UAV radar system is Ku band radar, which adopts pulse Doppler working system. The radar adopts the combination of long and short pulse signals to realize short-range blind compensation and long-range detection in the measurement range; multi beam amplitude comparison is used for angle measurement in azimuth dimension, and mono pulse and difference angle measurement are used for elevation dimension angle measurement in elevation dimension. Radar has organic and frequency scanning function in azimuth dimension and phase scanning function in elevation dimension, which can flexibly switch working mode to meet various scene requirements.

The drone detection radar system mainly includes antenna, TR module, power differential sum difference network, switch assembly, wave controller, transceiver, signal processor, orientation sensor, turntable, power supply, terminal, etc.

In the transmitting stage, the signal is generated by the signal processor and sent to the transceiver, which is amplified and output to the switch assembly through the transmitter channel of the transceiver. After the excitation power in the switch assembly is amplified, it is output to the excitation port P of the power difference and difference network, and then distributed to four tr modules through the network. After the T channel of the TR assembly amplifies the signal of this channel and corrects the initial phase, the signal is transmitted to the channel The antenna radiates the signal into the air, and the electromagnetic waves radiated by all the channel antennas are superimposed in the air vector to synthesize the transmitted beam of the system.

In the receiving stage, the echo signal is received by the antenna array and transmitted to the corresponding T / R module of each channel. After being amplified and phase corrected by the R component, two channels of ∑, △ signals are output to the transceiver through the power differential sum difference network. After being processed by the transceiver, it becomes two IF signals and enters the signal processor for processing. Finally, the position information of the target plot is transmitted through the network The slip rings of the mouth and turntable are sent to the terminal, which is processed and displayed by the terminal. A network port is preset in the terminal to report the target information to the main control system when necessary.

The frequency synthesizer of radar adopts crystal oscillator with high stability and low phase noise as the internal reference source of frequency synthesizer. The internal reference source generates all kinds of coherent signals required by radar through frequency conversion, frequency multiplication, frequency division, DDS and other ways, and outputs them under the synchronous timing control of the signal processor; for example, clock signal, intermediate frequency calibration signal or linear frequency modulation signal, broadband signal source with certain step frequency; the above-mentioned signals can obtain local oscillator signal with low phase noise and high signal purity through mixing and frequency doubling And transmit the excitation signal.

The data (target) processing module of the signal processor controls the phase shifter phase in the T / R module corresponding to the 16 channel waveguide slit sub array through the wave control computer, so that the transmitted beam points to move in time-sharing sequence in the pitch; the data (target) processing module of the signal processor controls the frequency of the transmitted signal through the frequency synthesizer, so that the transmitted beam points to move in the azimuth.

The antenna array is a two-dimensional planar array consisting of multi column slot wave guide sub arrays arranged evenly at a certain spatial distance, while the wave guide slot sub array is a one-dimensional linear array with different oblique slots on the narrow edge of a rectangular wave guide. The wave guide slot is the basic radiation unit on the linear array. Electromagnetic waves transmit to the terminal through the wave guide slot in the linear array, and the terminal of the linear array is connected with a matching load to absorb the remaining microwave power.The ability of the array to be equipped with azimuth scanning by controlling the feed phase of each sub array.

The echo signal reflected by the target is received by an antenna array composed of wave guide crack sub arrays. After low noise amplification by 16 T/R components, the echo signal is synthesized into sum and difference two channels by a power synthesis network and sent to the receiver.

The receiving channel uses a three-channel superheroes receiver, which receives both sum and difference beam signals, and the radar antenna receives the reflected echo of the target, and transmits it to the T/R component for low noise amplification to ensure the sensitivity of the receiver. The mixer mixes the echo signal with the local signal twice to produce a 90MHz intermediate frequency signal.The amplified signal is sent to the signal processor for intermediate frequency sampling.

The A/D converter that receives the channel IF signal and sends it to the signal processor to complete the analog/digital conversion.The mid-frequency sampling data of A/D output is sent to the signal processing module. Digital down-conversion is completed in the signal processing module, and the down-conversion signal is filtered and extracted. Pulse compression, Doppler filter, CFAR processing, automatic threshold detection, normalization, classification combination, and condensation are processed for the digital received Sigma and sigma signals.The state control data in each working mode of radar communicates with wave control, frequency synthesis and receiver through serial port; outputs antenna beam pointing data, frequency synthesis control code, receiver gain control data; completes the control sequence.

The data processing module performs beam position scheduling by starting, associating and terminating tracks on the target data that is output from signal processing, confirming and tracking the target that is found after searching.At the same time, the target information is sent to the control system when needed.

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