Real-time orbit determination of Beidou satellite based on square root information filtering

Continuous, stable and high-precision real-time satellite orbit products are essential for the international, scale and intelligent application of the BeiDou system. Current BDS real-time precise orbit products, which rely on “batch processing solution + orbit prediction”, suffer from poor continuity, low stability and low accuracy. Therefore, we introduce the square root information filtering method to perform real-time epoch-by-epoch solutions for the precise orbit of BeiDou satellites. Experimental results demonstrate that the BDS orbits generated by real-time filtering method outperform the ultra-rapid orbit products by effectively avoiding boundary jumps, improving continuity and stability. Moreover, the real-time filtering precise orbit determination method can significantly improve the orbit accuracy of BeiDou satellites, reducing the 3D orbit errors of MEO and IGSO satellites by 46% and 68%, respectively. Also, the validation by satellite laser ranging shows that the orbit accuracy of real-time filtering method is generally better than that of the predicted orbit.