基于Starlink机会信号/INS的组合导航方法

Integrated navigation method based on Starlink opportunity signal/INS

关键词:  星链机会信号  惯性导航  组合导航  快速最大似然  扩展卡尔曼滤波

Key words:  Starlink opportunity signals  Inertial navigation  Integrated navigation  Fast maximum likelihood estimation  Extended Kalman filter

摘要:

针对全球卫星导航系统(GNSS）因频点单一、落地功率低、易受电磁干扰以及存在覆盖较差区域等潜在的被拒止或被干扰导致的导航系统性能降低甚至失效的问题，提出了一种基于星链(Starlink）机会信号融合惯性导航系统(INS）的飞行器动态组合导航方法。首先分析了星链信号体制，建立了基于星链星座卫星下行机会信号的瞬时多普勒定位观测模型，设计了一种基于频率细分的快速最大似然多普勒频率估计方法，然后建立了基于扩展卡尔曼滤波(EKF）的Starlink机会信号/INS的组合导航模型，并对该导航方法进行了实验及分析。结果表明，该方法可为飞行器提供长航时、连续、高精度的导航。动态飞行情况下，该方法可实现平均优于25 m的三维定位精度和平均优于0.1 m/s的速度估计精度，比相同观测时间下的惯导精度提高了1~2个数量级，显著提高了飞行器的导航精度，可为战略导航提供方法和技术支撑。

Abstract:

To address the potential issues of global navigation satellite systems (GNSS), such as singleness of frequency, low landing power, susceptibility to electromagnetic interference, and limited coverage in some areas, leading to navigation system performance degradation or failure, an aircraft dynamic integrated navigation method is proposed based on Starlink opportunity signals and inertial navigation systems (INS). Firstly, the Starlink signal structure is analyzed and an observation model for instantaneous Doppler positioning of downlink opportunity signals from Starlink satellite constellations is established. Then, a fast maximum likelihood Doppler frequency estimation method based on frequency subdivision is designed. Subsequently, a combined navigation model for Starlink opportunity signals/INS based on the extended Kalman filter (EKF) is established and experiments and analyses of the navigation method are conducted. The results indicate that the proposed method can provide high precision navigation for extended and continuous periods of flight. In dynamic flight scenarios, this method achieves an average three-dimensional navigation positioning accuracy of better than 25 meters and an average velocity estimation accuracy of better than 0.1 meters per second. This accuracy improvement is 1 to 2 orders of magnitude better than the inertial navigation under the same observation time, significantly enhancing navigation accuracy for aircraft. Thus, the proposed method can offer a methodological and technical support for strategic navigation.