Research On The Unconventional Method Of The Anti-tracking Interference For TT&C And Communication Of Xidian University

With the comprehensive development of electronic warfare, the modern TT&C and communication systems face a growing threat. The security and reliability of the TT&C and communication systems is still a hot research spot in the currently. Especially, the rapid development of modern tracking interference technology, makes the anti- jamming interference methods using conventional jump spread spectrum technology unable to meet the needs of future TT&C and communication systems to some extent. On the deep understanding of signal characteristics and modulation scheme of the conventional frequency hopping anti-tracking interference communication systems, and guided by the theory of “channel is message”, this paper puts forwards two unconventional anti-tracking interference methods carrying effective information by the frequency hopping pattern for TT&C and communication systems.A novel anti-tracking interference method that masquerade the MFSK system as a random frequency hopping system is proposed. Based on the similarity of MFSK systems and random frequency hopping systems in spectral features, the scheme makes the MFSK system disguised as a random frequency hopping system cleverly and carries the real information through frequency hopping patterns. The receiving section demodulates the frequency patterns by detecting transmission frequency to obtain effective information. Firstly, a short-time Fourier transforms spectra and least-squares fitting joint(STFTSP-LS) method is used to estimate the jump speed and transition time. Secondly, a higher accuracy of the single frequency estimation method is introduced to estimate the frequency of the information in each frequency hopping period and to obtain the actual frequency hopping patterns. At last, the real effective information is obtained by some simple regular treatment.A chaotic codes based pattern modulation anti-tracking interference frequency hopping system is proposed. In this scheme, the information is represented directly by the channel, which is, using the corresponding jump point on whether to send the carrier or not to express the effective information. The chaotic codes generated by Logistic-Map is used as the pattern of information symbols in sequence. The receiving section utilize the short-time Fourier transforms spectra and least-squares fitting joint(STFTSP-LS) method to estimatethe jump speed and transition time, then combining with a high accuracy single frequency estimation method to estimate the frequency in each frequency hopping period. After obtaining the sending rule of carrier frequency, t he effective information is easy to obtain by some simple regular treatment.Performance comparison of the anti-tracking interference methods proposed above and the conventional frequency hopping systems under the same parameters are evaluated in the wideband noise interference, partial band interference and tracking interference. Results show that the performance of anti- tracking interference of the two proposed schemes improved obviously compared with the traditional frequency hopping systems. Additionally, the chaotic codes used in the two proposed schemes ensure their anti- interception capability as well, and they are simple and feasible to be deployed to the TT&C and communication systems.