Inter-satellite ranging enhancement-based satellite formation GPS (global positioning system) relative navigation system and method

Abstract

The invention discloses an inter-satellite ranging enhancement-based satellite formation GPS (global positioning system) relative navigation system and an inter-satellite ranging enhancement-based satellite formation GPS relative navigation system method, and relates to the technical field of satellite formation relative navigation. The system consists of a GPS receiver module, an inter-satellite ranging module and a relative navigation module, wherein the inter-satellite ranging module consists of two RF (radio frequency) sensors, and is used for acquiring an inter-satellite ranging pseudo code and a carrier phase observable by combining a composite pseudo code and a double-frequency two-way forwarding ranging system; the relative navigation module consists of an orbit determination module, an inter-satellite ranging calculation module and a combined navigation module, and is used for calculating inter-satellite relative distance and speed data by an extended Kalman filter method by virtue of observation data acquired by the GPS receiver module and the inter-satellite ranging module. The system and the method are applicable to inter-satellite formation at an inter-satellite distance of 0 to 30Km, and compared with a purely differential-GPS-based relative navigation system, have the advantage that the real-time relative navigation accuracy is higher than 1mm; required relative position and speed data can still be continuously output by the system in case of interruption of a GPS signal; the initialization time of the system is reduced from dozens of epochs of the differential-GPS-based relative navigation system to a single point.

Description

technical field [0001] The invention relates to the technical field of satellite formation relative navigation, in particular to a satellite formation GPS relative navigation system and method based on enhanced inter-satellite ranging. Background technique [0002] The relative navigation between satellites in the formation of micro-satellites is the basis of the cooperative work of the formation, and the level of relative navigation accuracy determines the application level that the formation can achieve. The relative navigation system based on differential GPS is currently the main means of satellite formation navigation. Representative applications include: the GRACE double-satellite formation launched in 2002, the inter-satellite baseline determination accuracy of the ground post-processing has reached mm level; the PRISMA launched in 2010 Double-star formation, GPS real-time relative navigation accuracy reaches cm level, post-processing can reach sub-cm level; Canadian ...

AI Technical Summary

Problems solved by technology

[0004] (1) The ability of continuous navigation is limited. The formation satellites cannot obtain enough GPS observations due to the lack of common-view GPS satellites and the implementation of maneuvers in formation missions. They only rely on the orbital dynamics model for calculation, and the error will decrease after 1 minute. has become more obvious

[0005] (2) The navigation accuracy is limited. The post-processing on the ground has reached the accuracy limit of mm level, while the real-time navigation accuracy can only reach cm level.

[0006] (3) The real-time performance of navigation is limited, and the reinitialization process after formation initialization or observation data interruption and recovery often requires dozens of epochs

However, there are some problems that are difficult to improve in the KBR system. In essence, it is only a measurement method for distance changes, and it cannot provide real-time relative distance data between formation satellites. Therefore, KBR data cannot be used to assist CDGPS relative navigation, and its system is complex. , it is difficult to apply to microsatellites

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