融合调频遥测和伪码测距的寄生调制技术

Parasitical modulation technique of combining FM telemetry and PN ranging

针对飞行器测控系统将高码率遥测数据和伪码测距信号分流传输的不足,提出一种全新遥外测体制,将测距伪码(pseudo-noise,PN)寄生在调频(frequency modulation,FM)遥测信号中,生成一种融合调频遥测和伪码测距的寄生调制信号,实现高码率遥测数据和测距信号的单流传输。研究FM+PN体制的调制、解调原理,从理论上分析信号频谱及遥外测性能,并通过仿真得到不同参数下的频谱特性、遥测解调误码率和测距精度,给出了调制参数选择建议。仿真结果表明,将FM+PN体制应用到飞行器测控系统中,可将所需带宽降低为现有测控体制的40%,大大提高带宽利用率,而遥测误码率性能损失很小。

Considering that there exist some disadvantages in the current telemetry and ranging system where high rate telemetry data and ranging signals are transmitted on two different frequency bands, a new technique based on frequency modulation＋pseudo-noise （FM＋PN） is proposed to achieve simultaneous trans- mission for high rate telemetry data and ranging signals on one frequency band. The novelty lies in the fact that the PN ranging code is parasitic upon the FM telemetry signal so as to generate a parasitical modulated signal. The modulation and demodulation algorithms are first presented, and the signal spectrum and bit error rate performance of telemetry data and ranging precision are then analyzed in theory. The performance of the new FM＋ PN technique is acquired by simulation and appropriate parameters are recommended by comparing these results. The simulation results demonstrate that the proposed FM＋PN technique can improve band efficiency obviously with just a little cost of bit error rate performance of telemetry data.