一种INS辅助GNSS高动态弱信号标量跟踪方法

A High Dynamic Tracking Method of INS-Aided GNSS Receiver for a Scalar-Based Weak Signal Tracking Loop

为提高恶劣电磁环境下的高动态卫星导航接收机的干扰抑制能力,提出一种低成本INS自适应辅助标量跟踪环路方法。该方法以INS辅助二阶锁频环(IFLL2)算法为核心,采用INS/GNSS紧组合结果提高外部辅助跟踪环路的多普勒频率估计精度,以降低动态应力对跟踪环路的影响。建立了INS辅助锁相环和锁频环性能分析模型,基于该模型可知IFLL2对本地振荡器的抖动噪声抑制能力更强,可更多地降低跟踪环路带宽,故其性能优于INS辅助锁相环(IPLL)的性能。高动态仿真试验结果表明高动态环境下独立式三阶锁相环可跟踪载噪比为28dBHz的GPS L1 C/A卫星信号,INS辅助最优带宽二阶锁频环算法可跟踪载噪比为19dB-Hz的卫星信号,基于本算法的接收机的干扰抑制能力提高了9dB,与理论分析结果相当。

In order to improve anti-jamming, a low-cost INS-aided scalar tracking method based EKF and the INS- aided second order FLL （IFLL2） is presented. Doppler derived from INS/GNSS tight-integration can improve the performance of the tracking loop under dynamic circumstances. And performance analysis models for INS-aided scalar tracking are established. Analysis shows that the FLL2 can more suppress the noise induced by the local oscillator and can be more reduced tracking loop bandwidth, so it outperforms the INS-aided PLL. Experiment under dynamic circumstances shows that the third order phase locked loop of stand-alone GPS can track carrier-to-noise ratio 28dB-Hz satellite signal, while the INS-aided second order FLL can track carrier-to-noise ratio 19dB-Hz satellite signal, and the increase is 9dB which is in accordance with the analysis.