Sequence Analysis Of High-speed Frequency Hopping Communication Signals

Frequency hopping communication controls the carrier frequency constantly changing through the frequency hopping sequence generated by a pseudo-random sequence to ensure the security of the communication process. The confidentiality and anti-jamming performance of frequency hopping communication mainly depends on the design mechanism of frequency hopping sequence. On the other hand, the frequency hopping synchronization is the key to keep the frequency hopping pattern of the transmitter and receiver consistent to achieve effective operation of frequency hopping communication. With the development of frequency hopping communication system,the jump speed and bandwidth of frequency hopping communication are increasing and the complexity of frequency hopping sequence is increasing day by day. It brings huge of challenge for non-partners to achieve communications reconnaissance and interference as well.Under such a background, this thesis conducts exploratory research from the frequency hopping communication signal analysis and the frequency point sequence analysis two aspects, which takes the high-speed frequency hopping communication signal as the research object, realizing the frequency hopping signal sequence analysis as the research goal and takes the frequency hopping sequence synchronization characteristic as the starting point. The main contents of this thesis are as follows:1) The basic theory and key technologies of frequency hopping communication are introduced briefly. Combining the theory of frequency hopping synchronization and frequency hopping sequence, the characteristics of frequency sequence of high-speed frequency hopping communication are studied.2) The signal analysis method of frequency hopping communication is studied.The time-frequency analysis theory of non-stationary signal is introduced in detail.Taking frequency hopping signal as the object of analysis, several common time-frequency analysis methods are simulated and compared. Then, the frequency hopping signal analysis method in complex electromagnetic environment is studied,which focuses on the semi-blind identification and parameter estimation of frequency hopping signals based on the digital channelization detection matching algorithm under multi-signal interleaving conditions. Considering the influence of fading in shortwave channels on frequency hopping signals, the above model and algorithm are improved and modified. At the same time, the above algorithm is used to analyze the data of the frequency hopping station.3) Taking the synchronization feature of the frequency hopping sequence as the starting point, the method of analyzing the frequency hopping frequency sequence is studied deeply. In this thesis, a special code recognition method based on anomaly detection is studied and a quantitative analysis model is established based on the analysis of the principle of frequency statistics and position difference method; The matrix rearrangement algorithm and the mapping-convolution algorithm are proposed by the research of the frame synchronization analysis method based on periodic detection; The application of the correlation matching method and the Apriori algorithm in the synchronization frequency identification of the frequency hopping sequence is studied with the idea of frequent pattern mining.4) At last, this thesis studies the frequency hopping sequence analysis method of this paper combined with the simulation of frequency hopping data. The simulation results of matrix hopping and mapping-convolution algorithm are compared. Then the algorithm based on Apriori synchronization frequency identification algorithm is used to analyze the simulation frequency hopping data and the setting of the support threshold and its application range are studied. Finally, a variety of frequency hopping sequence analysis methods are used to analyze the data of simulated frequency hopping station to realize the recognition of synchronization jump and analysis of frame structure.