A double-frequency combined positioning algorithm of beidou navigation satellite system

With the second civilian signal B2I announced, Beidou Navigation Satellite System has been into the era of multiple frequency application. In order to improve the accuracy of BDS positioning, an estimation algorithm of BDS positioning based on Particle Swarm Optimization and Square-Root Unscented Kalman Filter is proposed, which could estimate the noise covariance matrix accurately and compensate defects of Extended Kalman Filter and Unscented Kalman Filter. Based on above, a new algorithm of BDS double-frequency combined positioning is proposed. Experimental results show that the proposed method can effectively improve the accuracy and stability of Beidou System positioning.