Design And Implementation Of MTD In Radar Signal Processing

As an important part of radar system, the radar signal processor determines the approach and results of radar signal detection, whose performance has greatly promoted the development of the radar system. With the rapid development of digital signal processing technology and VLSI technology, the generation and processing of radar signals are developing towards digital direction, which makes radar signal processor develop towards the directions of systematization, miniaturization and high-speed. Moving target detection is one of the key technologies of radar signal processing system. Through the coherent processing of multiplesets of echos in a coherent processing interval, the echo signal to noise ratio improves, and the ability of detecting targets in a complex background is improved.There are two common implementations of moving target detection, which are based on FFT and FIR filters. By considering the advantages and disadvantages of the two implementations, a combination of FFT and FIR processing mode in moving target detection is proposed, which can meet the technical requirements to achieve moving target detection with limited hardware consumption, which is also herein goal.Based on the basic theory of digital signal processing, the Fast Fourier Transform algorithm and the basic principles of the decimation in time FFT were firstly studied. And then two operational flow diagram of in situ calculation and fixed structure, and three implementation structures of fixed structure were analyzed. Finally, the RTL design of 8 to 4096 point FFT using ping-pang operation was completed. This design of the variable-point FFT was finished with double butterfly structure, and two-stage continuous process of the butterfly operation. Data were stored in cache in other stage and data is stored in ping-pang structure, which greatly reduces the consumption of hardware.Based on the basic theory of radar signal processing, the basic theories of moving target detection, including the Doppler frequency, fast and slow time dimension sampling, pulse Doppler processing etc, were firstly studied. Then the two approaches of FIR and FFT were combined to complete the RTL design of the configurable MTD circuit. In the paper, a configurable and storage-reused MTD circuit was presented, which has reduced the contradictions between detection capability and cost, and the unity of testing methods, which has gradually improved the anti-jamming capability and applications of the radar signal processor.By establishing the corresponding algorithm model in MATLAB software, the processing results of the hardware circuit and the model in MATLAB were compared, thereby the functional verification of the variable point FFT circuit and the two detecting modes of the configurable MTD circuit were completed. Verification results show that the variable-point FFT functions properly, the relative error in magnitude is under 10-4; moving target detection based on FFT and FIR functions properly, its radial velocity measurement error is less than 0.6 m/s. Performance analysis shows the maximum operating frequency of the variable-point FFT is 182.993 MHz; the maximum operating frequency of the overall circuit is 204.300 MHz. Finally, the logic synthesis of the variable point FFT was completed in the SMIC 0.13 um process conditions, and the maximum operating frequency is 250 MHz.