Research On Processing Of Non- Cooperative Frequency Hopping Signals

Frequency hopping communication has been widely applied in military and civil communications, due to its low probability of interception and detection, anti-jamming performance, and networking capability. So it is very important for us to study the processing of FH signals. This dissertation focuses on the non-cooperative FH signals processing. Processing methods of FH signals based on time-frequency analysis and phase difference are the main research works.Time-frequency analysis is one of the most effective methods in processing of FH signals. The performance of several common time-frequency analysis methods is analyzed. For single FH signal, a method about estimation of FH signal parameters that based on Spectrogram is proposed; For multi-FH signals, a method about estimation of asynchronous multi-FH signals parameters and multi-FH signals sorting based on STFT is proposed, Simulation results demonstrate the efficiency of the new method when SNR is over 2dB; A method about the recognition of FH signals modulation pattern is proposed in the paper.The method about recognition and parameters estimation of FH signals based on phase difference is proposed, Firstly, We can get the instantaneous frequency of FH signals by phase difference, the FH signal parameters can be estimated by processing the instantaneous frequency; It can also recognize the FH signals from fixed frequency signals, MFSK signals and LFM signals by the difference of instantaneous frequency, Simulation results demonstrate the efficiency of the new method when SNR is over 3dB, the method is simple and with less calculation.The FH signals simulation and processing software is designed. The validity of proposed methods is verified by processing simulate and real FH data successfully.