基于改进码环鉴别器的航天器间多径抑制方法

Inter-spacecraft multipath mitigation method based on improved loop discriminator

针对现有多径抑制方法在航天器间测距系统短时延多径场景下性能下降的问题,提出了一种基于改进码环鉴别器的多径抑制方法.通过对短时延多径情况下的超前、滞后和对准相关器进行分析,定义了一种改进的对准支路.所设计的鉴别器通过比较改进的对准支路相关值和滞后支路相关值,保证了当本地估计码相位与直达信号码相位同步时鉴别器输出为零,克服了传统鉴别器过零点偏移的缺陷.通过理论分析和仿真,证实改进的码环鉴别器的短时延多径抑制性能优于现有的多径抑制方法的,提高了航天器间测距场景下接收机的测距精度.

The performance of existing algorithms degrades in the inter‐spacecraft microwave ranging system with short‐delay multipath ,and therefore a multipath mitigation algorithm was proposed based on improved loop discriminator .First ,a modified prompt signal was presented through analyzing the early ,late ,and prompt correlators in the short delay scenario .By comparing the correlations of the modified prompt signal and late signal ,it was ensured that the output of discriminator was zero when the code phase of the local estimated signal was fully synchronized with that of the direct signal .It o‐vercame the zero migration in traditional discriminators .The theory analysis and simulation results prove that the suppression performance for short‐delay multipath of the improved loop discriminator is superior to that of the existing methods and the ranging precision of the receiver in inter‐spacecraft ranging system is improved .