Research On Frequency Measurement And Direction Finding Technology Based On Single Bit Receiver

Recently,electronic warfare signal environment is complex and signal receivers need to improve their performance to accommodate the complex war environment,especially in reconnaissance and anti-reconnaissance,interference and anti-interference and so on.The growing demands for electronic warfare has been a serious challenge for traditional receivers.As a new generation of receiver,the single-bit receiver has the advantages of large instantaneous bandwidth,real-time processing,high sensitivity,small size and so on,and is widely used in the field of electronic warfare.But the instantaneous dynamic range of the single-bit receiver isn't large enough,which makes the single-bit receiver to result a quite large error in frequency measurement and direction finding when two different amplitude signals come into the single-bit receiver.To solve this problem,the main research of the thesis is to increase the instantaneous dynamic range of the single-bit receiver while ensuring that the other performances of the single-bit receiver aren't affected.The main work of this thesis is as follows:The DFT frequency measurement algorithm and the threshold setting algorithm in the single-bit receiver are studied.The threshold setting algorithm includes high and low threshold method,proportional threshold method,compensation matrix method and so on.On the basis,the traditional single-bit quantization method is improved by using the single-bit quantization method based on incremental modulation.The single-bit quantization method based on incremental modulation is combined with the DFT algorithm to complete the frequency measurement of the signal.The single-bit frequency measurement method based on incremental modulation has lower harmonic component than traditional single-bit quantization method,and the instantaneous dynamic range of single-bit receiver can be expanded to improve the detection probability of weak signal.This thesis completes the simulation and analysis of the single-bit frequency measurement based on incremental modulation.The simulation results show that the proposed method has better performance than the traditional single-bit quantization frequency measurement algorithm.The amplitude direction finding algorithm,comparing phase direction finding algorithm,comparing amplitude and phase direction finding algorithm,The frequency domain multi-beam direction finding algorithm is studied.and the beamforming method in the frequency domain multi-beam direction finding algorithm is introduced in detail,including two-dimensional DFT beamforming and ISM.Based on this,the frequency domain multi-beam direction finding algorithm suitable for single bit receiver is studied.The frequency measurement of the received signal is completed by the incremental modulation single bit frequency measurement method,and the corresponding frequency of confidence is used to complete the frequency domain multi-beam direction finding.The thesis gives the concrete implementation steps,simulates the algorithm and verifies the validity of the algorithm.