The Signal Acquisition And Anti-jamming Performance Analyzing Of The Unified Spread Spectrum TT&C System

Space TT&C system holds important responsibility on promoting the development of space cause of our country. The general level of TT&C technology of our country needs more improvement to meet the need of TT&C system from possible space missions in the future.This paper is on the bases of analyzing the disparity between missions of our space TT&C system and current space TT&C technology, and combines the understandings on the future developing tendency of international nowadays space TT&C technology, proposes a preliminary imaginations of Unified Spread Spectrum TT&C system that based on the technology of Direct Sequence Spread Spectrum.This paper has mainly discussed that acquisition and tracing of the spread spectrum signals in high dynamic environment. First the expression of time-domain and frequency-domain Max Likelihood Estimation is given which is derived from K~L expanding method, the some solutions on the PN code acquisition under the high dynamic environment is given. After comparing these solutions, it can reach a conclusion that as it usually has prior knowledge of Doppler frequency shifting, the frequency domain parallel searching method may give a better performance, and this method will has the convenience for receiver digitization. Carrier tracing can employ MLE method or compound software loop with Extend Kalman Filter.Then the anti-jamming performance is"considered and the simulation is carried out. The outcomes show that the DS-based TT&C has improved anti-jamming performance greatly comparing with traditional PMmode. But it can' t confront all kinds of jams yet. So the occasion, in which the security of TT&C is highly considered, it must adopt many kinds of means to improve the anti-jamming performance.It has the advantage of anti-jamming performance, reliability, equipments predigesting and conveniently encrypting, comparing with now existing TT&C technology, it overcomes the shortage of sub-carrier inter-modulation interfere, and has convenience to realizemulti-objects telemeter and telecommand. The USS TT&C system will also be advantageous for interfacing with the space-based TT&C system.The scheme presented in this paper has certain significance for the development of our country' s next generation TT&C system.