面向星链机会信号的多星信号检测与隔离方法

Multi-satellite signal detection and isolation method for starlink satellites’ signals of opportunity

  • 摘要: 目前,利用宽波束、低增益天线接收星链机会信号(signal of opportunity,SOP),可以实现多星信号的同时跟踪,有助于缩短定位收敛时间并提高定位精度. 在此场景下,高动态、弱信号的检测通常依赖于对多普勒频移及其变化率的补偿剥离. 然而,现有方法未充分考虑卫星星历误差对多普勒变化率估计造成的偏差影响,导致信号相干积分增益不足、部分单音信号无法检测,进而减少单次观测可获取的有效观测量. 此外,现有星链多星跟踪方法缺乏完善的多星区分与隔离机制. 针对上述问题,本文提出了在剥离多普勒及其变化率的基础上,引入多普勒变化率寻优搜索策略,有效克服了由星历误差引起的积分增益降低问题,显著提升了单音信号检测能力. 同时,设计了基于星链信号体制的单历元信号初步筛选方法,并结合基于卫星多普勒变化率特征的多历元联合判决策略,实现了多星信号的可靠区分与隔离. 实验结果表明,采用所提多普勒变化率寻优搜索方法后,单音信号检测数量提升约35.88%;在5 min内可成功识别并区分15颗卫星;定位精度方面,可获得优于10 m的2D定位精度与优于15 m的3D定位精度.

     

    Abstract: Currently, utilizing wide-beam and low-gain antennas to receive starlink satellites signals of opportunity (SOP) enables the simultaneous tracking of multiple satellites, which contributes to reducing positioning convergence time and enhancing positioning accuracy. In this scenario, the detection of high-dynamic, weak signals typically relies on the compensation and stripping of Doppler shift and its rate of change. However, existing methods inadequately account for the bias in Doppler rate estimation introduced by satellite ephemeris errors. This limitation results in insufficient coherent integration gain for signals and the inability to detect certain tone signals, consequently reducing the number of valid observations obtainable in a single measurement epoch. Furthermore, current multi-satellite tracking methods for starlink lack a robust mechanism for satellite signal differentiation and isolation. To address these issues, this paper proposes an optimized Doppler rate search strategy implemented after stripping the Doppler shift and Doppler rate. This approach effectively mitigates the degradation of integration gain caused by ephemeris errors, significantly improving the detection capability for tone signals. Simultaneously, we design a single-epoch signal preliminary screening method based on the starlink signal structure, combined with a multi-epoch joint decision strategy leveraging the characteristic Doppler rates of individual satellites. This dual approach achieves reliable differentiation and isolation of signals from multiple satellites. Experimental results demonstrate that the proposed optimized Doppler rate search method increases the number of detected tone signals by approximately 35.88%. Within a 5 min observation window, the system successfully identifies and distinguishes signals from 15 satellites. In terms of positioning accuracy, it achieves a 2D positioning accuracy better than 10 m and a 3D positioning accuracy better than 15 m.

     

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