| Millimeter wave active and passive detection system is a kind of detection system wich combines the advantages of active sensor and passive sensor. In the first.this paper explains the development of technology of domestic and foreign detection weapons for war. analyzes the present situation of millimeter wave research technique to probe the necessity and development. The proposed detection scheme wich combines3mm band active FM wave ranging and passive radiometer target recognition. Then it introduces the principle of frequency modulation wave active and passive compound detection system, and selects fractional active and passive detection system as the research project. Method of active FM ranging is used constant difference frequency. And frequency domain and the time domain on the FM ranging signal is analyzed, through the analysis of frequency modulation in time domain ranging distance equation is derived. According to the distance equation how to select parameters in the FM ranging. We use the full power radiometer as passive detection, the influence of noise which is come from the detection sensitivity of the system is discussed. According to the characteristics of detecting system.we are going to design the active used FPGA and the passive used DSP in engineering implementation. Active in the hardware design mainly use analog and analog digital conversion circuit, while the DSP of passive part with AD function. This combination of flexibility of FPGA’s hardware and processing time and efficiency of DSP for the data is used to design a FM passive compound detection signal processing system. The whole system is desiged and finished, according to the designed hardware to design the corresponding software. At last finally the system signal processing system design are validated by experiment, we verified the feasibility of the detection system and the correctness of the hardware and software design through the analysis on the experimental results. |
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