Reseach On Design And Detection Of Anti-interception Waveform In Satellite Communication

With the diversified development of detection technologies,the issue of signal security at the physical layer has drawn more and more attention.Due to the openness of its channels,satellite communications have poor concealment of communication signals and are easily intercepted by electronic reconnaissance.The traditional anti-interception technology mainly uses the spread spectrum method,but with the research on the LPI(low-probability interception)signal detection problem,the anti-interception ability of the traditional spread spectrum signal is greatly reduced.Therefore,only a single design of the spread spectrum signal itself to ensure its anti-interception is not enough,but also needs to design the transmission signal in many aspects,to improve the signal waveform stealth capabilities in non-cooperative common detection algorithms.The large-signal masking technique uses large power and significant parameter features to mask the useful signals in the channel,increases the difficulty of intercepting useful signals by non-cooperative parties and ensures the interception resistance of useful signals.This thesis studies the design and detection techniques of anti-interception waveform for satellite communications,focuses on the design of anti-interception waveform based on large-signal masking techniques,synchronous detection of anti-interception waveform under large signal masking,and the problem of secret signal demodulation loss under large signal masking.This thesis combines large-signal masking technology with direct sequence spread spectrum technology,proposes a large-signal masking anti-interception waveform design method based on data classification,and a non-stationary design technique for confidential signal waveform based on large-signal masking.And the simulation results verified that the design waveform has better anti-blind detection ability,and correspondingly has better anti-acquisition ability.For the designed anti-interception waveform based on large-signal masking,we studied the interference condition of large signals for weak signal synchronization detection and weak signal detection based on large signal masking,and proposed a full-bit frequency domain parallel algorithm based on joint processing of interference cancellation and FFT accumulation,then simulated and analyzed the performance of the algorithm and verified that the algorithm could effectively suppress the interference of large signals to synchronous detection.For the designed anti-interception signal,we analyzed the receiving performance of cooperative receivers,analyzed the weak signal demodulation loss in the presence of large signals and the influence of weak signals on large signal demodulation,and found that reasonable design of the waveform parameters can guarantee that the loss of demodulation is within an acceptable range.