Through-Wall Imaging Radar Digital Processing Technology

Through-wall imaging radar(TWIR),which can penetrate non-metallic walls and other obstacles for imaging,detecting,and tracking targets behind walls,has been widely used in both military(Counter-terrorism,mine detection,target detection behind walls)and civil applications(security,disaster relief).As a key module of TWIR,the digital signal processing subsystem has great effects on the performance and efficiency of the whole system.With the continuous development of TWIR technology and the demands for high real-time processing performance,the digital signal processing subsystem is now faceing complex structure,huge data flow and great computation burden.All these bring greater challenge to the implementation of the system.Traditional monolithic single-core digital processor cannot meet the requirements of TWIR system for its relative poor processing power.In this paper,a noval processor architecture based on the DSP(Digital Signal Processor)and FPGA(Field Programmable Gate Array)has been proposed to meet the actual demand of a real TWIR system.Software including transceiver system control,echo data acquisition,high-speed serial interface data transmission,and multi-core parallel processing has been successfully designed.Actual measurements on a real TWIR system show the performance improvements.Specific work contents are as follows:1.Combined with the data flow and the processing burden of TWIR,a digital processor system scheme has been proposed to meet the specific demands of TWIR.2.A software module has been designed and implemented in FPGA which consists of the implementation of a data acquisition module,the design of transceiver system control logic and design of high-speed serial interface.In addition,a new step frequency scanning method has been designed for stepped frequency TWIR system.3.A multi-core parallel processing implementation of TWIR imaging algorithm has been designed.Based on the analysis of data flow and the processing burden in each step of TWIR imaging,the processing task was evenly segmented and distributed to the cores.Then an inter-core communication mechanism has been designed to ensure synchronization and effective communication of subtasks between multi-cores.4.The designed digital system has been successfully used on a real TWIR system.Series experiments have been carried out to test and verify the system's real-time processing and imaging performance.The results proved that the proposed digital signal processing subsystem is effective and efficient.