A Beidou Based Multiple-GNSS Positioning Algorithm for Mission Critical Applications

With the development of the Global Navigation Satellite Systems (GNSS), countries that own a GNSS have realised that critically national infrastructures using Position Navigation and Timing (PNT) services and a portion of the national economy associated with GNSS applications should not be over reliant on other countries. Recently, both China and Russia have made their systems mandatory for some applications. This paper addresses this issue and proposes a Beidou based multiple-GNSS positioning algorithm. It involves three stages: (1) Understanding of the quality of Beidou solutions. This was achieved by Receiver Autonomous Integrity Monitoring (RAIM) embedded in the Beidou positioning algorithm. (2) A real time validation and modelling algorithm for the measurements from the other constellations if Beidou solution is proved good in stage 1. The measurement residual errors relative to the Beidou position solution are assessed. (3) Introduction of measurements from the other constellations if there is not enough Beidou measurements. At this stage, the models derived in stage 2 are applied to the non-Beidou measurements. The tests were carried out using the Beidou and GPS data from a reference station. The signal blockage of Beidou and GPS constellation is simulated. The test results show that the proposed methods can benefit from the validated measurements from the GPS constellation. The performance can be significantly improved in terms of accuracy, continuity, integrity and availability in difficult environments. It can be extended for critical applications where any constellation is mandated.