直扩测控系统抗多址能力分析与验证

为了防止多址干扰造成接收机出现误捕和假锁,改善直接序列扩频测控系统抗多址干扰性能,在Gold码特性和扩频接收机性能分析的基础上,结合最大似然原理,对采用扩频体制测控系统的抗干扰能力进行了分析。为契合工程应用,采用仿真遍历结合理论分析的方式,对Gold码的互相关抑制能力理论值进行了工程修正。在分析捕获阶段的抗干扰捕获门限后,还分析了载噪比估计结果在正常锁定和假锁两种状态下的差异,给出了接收机对假锁状态的判决方法和门限。根据分析和仿真的结果,给出了系统设计约束条件和优化的接收机设计流程,作为测控系统和接收机设计的参考。

Analysis and Verification of the Anti Multi Address Jamming Performance of Spread Spectrum TT&C Systems

To prevent false detection and false locking caused by multi address jamming and to improve the anti multi address jamming performance of direct sequence spread spectrum TT&C (Tracking, Telemetry and Command) systems, the anti jamming performance of spread spectrum TT&C systems is analyzed with maximum likelihood theory based on analysis of the characteristics of Gold code sequence and spread spectrum receivers.In order to meet the needs of engineering applications, the theoretical value of the cross correlation suppression capability of Gold codes is modified by using simulation results in combination with theoretical analysis.Following analysis of the anti multi address jamming threshold in capture phase, the difference of carrier to noise ratio estimation results between normal locking and false lock states is also analyzed and this yields the judgment method and threshold of false lock state.Based on the results of analysis and simulation, the constraints of system design and optimization of receiver design process are given for reference to design of TT&C systems and receivers.