A Novel SBAS-Assisted Single-Frequency Precise Point Positioning Method

Satellite-based augmentation systems (SBAS) can provide positioning services of 1 m accuracy level by broadcasting real-time error correction products. However, the positioning accuracy of SBAS based on pseudorange has limitation in satisfying high precision navigation service, such as 1-dm accuracy. In view of this situation, one option is the utilization of precise point positioning (PPP) to achieve the global high precision positioning results. However, the accuracy of PPP depends on the quality of various correction products normally difficult to obtain in real-time. It is therefore difficult to acquire real-time PPP resolution. Through combining the real-time characteristics of SBAS with the characteristics of the high precision of PPP, the real-time wide-area PPP can be realized. Although the accuracy of SBAS broadcast ephemeris correction information is little lower than precise ephemeris data, they belong to the corrections of satellite clock and orbit, and can be obtained in real-time. Furthermore, in order to meet the requirement of dynamic navigation, the extended Kalman filter was applied to improve the positioning accuracy. To sufficiently verify the effectiveness of proposed algorithm, the proposed method is compared with the traditional SBAS and PPP methods by using single-frequency GPS data in static and dynamic mode, respectively. The experimental results show that, the static positioning accuracy in horizontal is better than 50 cm, and the dynamic positioning accuracy in horizontal is better than 90 cm, increased by 42 and 40 %, respectively, compared with traditional SBAS method.