Study On Techniques Of Detection And Parameter Estimation Oriented To Frequency Hopping Datalink Signal

As the important part of C4 ISR system, datalink is the effective means to satisfy operational information exchange requirements and the key of improving weapon system imformation level and collective combat ability. As the typical representative of the datalink family, frequency hopping datalink has extremely high noise immunity and security. Furthermore, frequency hopping datalink is efficiently and safely exchange the information, at the same time,it also put the challenges to the non-cooperation communication.then developing actively detection and parameter estimation of the frequency hopping datalink signals has greatly theoretical and practical significance.Study on the frame format and key technology of frequency-hopping datalink is the premise of the subsequent technology research which include the detection technique, parameter estimation technique and coding parse technique.On the research of the frame format of frequency hopping datalink, packet structure, message structure, message category, message pulse and message packaging have been researched.On the research of the key technology of frequency hopping datalink, RS coding technique, tamed spread spectrum, frequency hopping technology and modulation technique have been researched. the detection technique,the parameter estimation technique and the coding parse technique is the emphatically part in this paper.On the research of the detection technique, the existence detection and the modulation classification technique of the frequency hopping datalink signal has been emphatically carried out. On the research of the parameter estimation technique and coding parse technique, carrier estimation, hopping speed estimation, hop duration estimation and coding parse technique has been emphatically carried out.Furthermore, according to the study of the detection technique of the frequency hopping datalink signal, STFT has been used to realize the existence detection of it, cyclic spectrum has been used to identify the modulation of it. Simulation results show that existence of the frequency hopping datalink signal could be successfully detected by STFT when the SNR is-13, the modulation of the signal could be successfully identified by cyclic spectrum when the SNR is-1. According to the study of the parameter estimation technique and coding parse technique, improved square frequency doubling method and cyclic spectrum has been used to realize the carrier frequency estimation,SPWVD has been used to realize the hopping speed estimation and the hop duration estimation. Simulation results show that carrier-frequency of the radio frequency signal could be successfully estimated by the improved square frequency doubling method which has lower SNR-tolerance than traditional square frequency doubling method, carrier-frequency of the medium-frequency signal could be successfully estimated by cyclic spectrum when the SNR is-10, the hopping speed estimation and the hop duration estimation could be successfully estimated by SPWVD, the estimation accuracy becomes higher and higher as the estimation times increased.At last based on the theory of frame format standard and parameter estimation completed, the frequency hopping pattern has been generated to finished de-hopping and demodulation of the frequency hopping datalink signal for the research of the coding parse.