Design Of Small-sized Broadband Passive Radar Receiver

Passive radar exploits the electromagnetic signal emitted by the opportunity illumination to detect and locate targets.Nowadays several illumination sources are available for use in passive radar,include FM broadcast,digital audio broadcast(DAB),digital video broadcast(DVB-T,CMMB,DTMB),global positioning system signal GPS,Wi Fi signal,and fourth-generation mobile communication(LTE),etc.These illumination sources covers multiple frequency bands such as HF,VHF and UHF.However,most mature passive radar are customized experimental systems which mainly work on a single frequency band.Only single frequency channel can be used for target detection.The detection range of the system is constrained by the geometric position of the transceiver station.and there is a detection blind area.In fact,there are usually multiple transmitting stations in one area for different kinds of illumination sources.These transmitting station can transmit signals of different frequencies.Target detection in passive radar using the multi-frequency broadcast illumination sources from one or more transmitters can improve the radar coverage area and enhance the target detection capability.Based on the multi-frequency target detection for passive radar,this paper designs a miniaturized broadband passive radar receiving system.The receiving system mainly consists of the highly integrated AD9371 RF chip,field programmable gate array(FPGA)and 10 Gigabit Ethernet data transmission interface.The system operates at300MHz?6GHz.The maximum receiving bandwidth can be up to 100 MHz.It can cover most illumination sources frequency bands and give full consideration to the unique advantages of different frequency band illumination sources in terms of regional,distance and velocity resolution.The system has high integration,small size and low cost.In practical application,multiple systems can be equipped simultaneously to realize distributed cooperative networking,so as to further expand the detection range of radar.Firstly,this paper introduces the basic theory of radar receiver,including common radar receiver architecture and receiver performance parameters.Then,the overall architecture of the system and the design and implementation of the hardware and software of the key modules are introduced in detail.A series of functional tests and performance tests are carried out for the system,and the basic performance indicators of the system are given.Finally,the field experiment of dual-frequency DTMB signal target detection is introduced.The experimental results show that the system can complete multi-frequency broadband signal acquisition and transmission.Compared with single frequency,multi-frequency detection scheme can significantly improve the target detection ability and enhance the robustness of external emitter radar detection.