Comparison of Beidou autonomous navigation performance using the SRP model and onboard accelerometers

The Autonomous Navigation (AutoNav) mode of a Global Navigation Satellite System (GNSS) utilizes Inter-Satellite Links (ISLs) to maintain satellite operations without the service from the ground control segment. The newly launched Beidou satellites are capable of conducting ISLs for orbit determination to improve their autonomy, integrity, reliability, and robustness. However, the satellite orbit errors can increase over time due to various force model errors, particularly that of Solar Radiation Pressure (SRP). Accelerometers aboard satellites can measure non-conservative forces directly and have been successfully used in satellite missions for gravity recovery and atmosphere study (i.e., GRACE, CHAMP, and GOCE). This study investigates the feasibility to use accelerometers aboard Beidou satellites to improve AutoNav accuracy and service span. The results show that in a simulated 180-day AutoNav period, the orbit accuracy with the aid of accelerometers is two times better than that of using ISL data only.