Design Of Radar Signal Processor For Low-altitude Moving Target Detection

The dramatic increase in the number of low-altitude flying targets has brought potential security risks to production,life,society and national security.Compared with the optical method or the method of capturing communication signals to detect,supervise and intercept low altitude moving targets,the radar method is more adaptable and effective.And the design of radar signal processor is the difficulty and key lying in the low-altitude moving target detection radar design.Based on the principle of radar signal processor,this thesis chose both the two-dimensional Fast Fourier Transformation(FFT)for Range-Doppler accumulation and the clutter map cancellation for clutter suppression as the core procedure of the signal processing algorithm,according to the characteristics of low echo intensity,strong clutter background and low moving speed of low altitude moving target radar.Then the hardware and software prototype of multi-channel software-defined radio signal processor was developed.Finally the actual scene verification was carried out.The architecture of linear frequency modulation continuous wave(LFMCW)radar was adopted,due to the low complexity and low design difficulty.Based on the LFMCW architecture,the basic parameters of the signal processor were designed firstly.The transmitter used Numerically Controlled Oscillator(NCO)to generate the LFMCW waveform,while the receiver adopted the dechirp method to achieve the matched filtering,and used the two-dimensional FFT to realize the two-dimensional accumulation in the range and doppler domains according to the characteristics of strong clutter,small reflection cross section(RCS)and low moving speed of lowaltitude moving target echo.Meanwhile,the clutter map was used to implement the clutter cancellation with the constant false alarm(CFAR)detection adopted.In the hardware architecture,the signal processor prototype to implement the radar signal processing algorithms was developed by using the latest digital signal processing device and the software defined radio transceiver.The proposed multi-channel signal processor contains a single ZYNQ series heterogeneous processor and multiple AD9361 RF agile transceiver chips.According to the different requirements of complexity and real-time performance of the different algorithm procedures,the higher real-time part of the low-altitude moving target detection algorithm was allocated to the programmable logic of the ZYNQ chip,while the part with lower real-time performance and more complicated control flow was allocated to the ARM dual-core processor.The software was designed by the modularization and structuration methods.Experiments show that the algorithm is reasonable,the scheme is feasible and the prototype equipment is effective.With the latest heterogeneous signal processing devices and software designed radio technology,the proposed radar signal processor has the characteristics of high integration,reconfiguration,good scalability and strong adaptability,which makes a certain application prospects.