Software Defined Radio Based Cognitive Anti-jamming Through-wall Radar Design

Through-wall radar(TWR)has been widely used in a wide range of areas such as earthquake relief,security protection and anti-terrorist.However,the traditional TWR is only equipped with target detection function and is susceptible to interferences from electronic devices such as mobile communication base stations,and WIFI.Multifunctional TWR integrated with target detection and spectrum awareness capabilities can recognize the interference signals,and adopt anti-interference strategies to improve the target detection performance of TWR in complicated electromagnetic environments.Electronic systems based on software defined radio(SDR)technology have the advantages of configurable operating parameters,reconfigurable operating modes and high system integration,which are suitable to develop multifunctional TWR.In this thesis,a cognitive anti-interference TWR is implemented using an integrated SDR transceiver chip.The main contents of the thesis are as follows.Firstly,the working mode of step-frequency TWR is investigated and improved in the framework of SDR technology.The oppressive and deceptive interferences and antiinterference strategies are investigated.The impact of oppressive multipoint frequency interference on the target detection performance of TWR is analyzed.Based on the above analysis,the TWR system solution is given.Secondly,device selection is carried out according to the function and performance requirements of the TWR.The schematic diagrams and printed circuit board designs of the TWR power supply,radio frequency(RF)transceiver link,system control and clock distribution modules are completed to integrate the TWR hardware system,which enables the TWR to obtain the spectrum awareness and anti-interference capabilities.Next,the control procedures of system configuration,RF transceiver link control,data acquisition and data transmission are designed based on the devised hardware platform.The signal processing of target detection,spectrum awareness and antiinterference is implemented on the host computer.Finally,the software and hardware debugging of TWR modules is completed.The target detection,spectrum cognition function and anti-interference strategy of the TWR are verified by field tests.The development of the SDR based cognitive anti-interference TWR system is completed in this thesis,which provides technical support for the development of multifunctional radar based on SDR technology.