Research On Key Techniques Of DS/FH Hybrid Spread Spectrum TT&C Transponder

Direct Sequence Spread Spectrum technology has been widely used in TT&C system because of its good anti-jamming capability and higher range accuracy. With the increasingly complex electromagnetic environment of space and the development of military electronic warfare technology, the security of TT&C links gets attention and the DS/FH hybrid spread spectrum TT&C system is presented based on the needs. DS/FH hybrid spread spectrum transponder as the satellite platform equipment is one of the key components of the system. Its core function is measuring and data transmission, the introduction of DS/FH hybrid spread spectrum technology is to enhance the anti-jamming performance of the system, but it will brings some problems to system design. Under the limited processing capacity constraint on the stars, how to ensure range accuracy of DS/FH hybrid spread spectrum TT&C transponder is the basic problem of this paper. Around the basic problem, this paper must solve the following three key problems:1. DS/FH hybrid spread spectrum TT&C transponder's scheme problem. Range accuracy and anti-jamming performance of DS/FH hybrid spread spectrum TT&C transponder is a pair of contradiction. The introduction of DS/FH hybrid spread spectrum technology increased the system and technical complexity and the complexity makes the system difficult to achieve signal synchronization, signal synchronization is the premise for range. The success of signal synchronization depends on the signal system, reasonable hardware structure. Therefore, scheme design issues of DS/FH hybrid spread spectrum TT&C transponder is the first key technical problem.2. DS/FH hybrid spread spectrum TT&C transponder's synchronization problem. Signal synchronization is restricted by system scheme, and related to the synchronization method of the system. Under the constraints of the signal system and hardware architecture, how to design an effective synchronization method to solve the problem of signal synchronization is the second key technical problem.3. Ionosphere dispersion effect DS/FH hybrid spread spectrum signal problem. Since the characteristics of the ionosphere, the characteristic of DS/FH hybrid spread spectrum signal will change, reducing the system range accuracy. Therefore, reducing the impact of ionosphere effects and protect the measurement accuracy is the third key technical problem.To solve these three key technical problems, this paper designs a DS/FH hybrid spread spectrum TT&C transponder's scheme, analyzes the synchronization method of system and solves the additional delay affect of the ionosphere to improve the range accuracy of the system. Simulation and experimental results verify the effectiveness of the design and achieve the requirement of the system design.