Ocean decimeter-level real-time BDS precise point positioning based on short message communication

Decimeter-level positioning accuracy is the premise for most ocean applications, such as ocean development and ocean engineering construction. Although the existing real-time precise point positioning method can achieve economical decimeter to centimeter-level positioning accuracy based on Global Beidou Short Message Communication, they can only broadcast limited satellites for regional users. This is because the above method maintains minimum resolution of real-time precise satellite orbit and clock corrections using a single-card GBSMC. We proposed an ocean decimeter-level real-time BDS PPP method based on dual-card GBSMC to implement global positioning service. First, the encoding ranges of real-time precise satellite orbit and clock corrections were redefined to reduce occupied digits based on 2-month data. Second, the resolution adjustment strategy for real-time precise satellite orbit and clock corrections at the service-end was proposed to broadcast 24 global BDS-3 Middle Earth Orbit (MEO) satellites based on dual-card GBSMC device. Last, aiming at the frequency limitation of GBSMC, the real-time correction method at the user-end was employed due to the change of equivalent distance within 1 min at the centimeter-level. The proposed method was verified by six static stations around the world, and the average positioning accuracy was 0.089 m and 0.103 m in the horizontal and vertical directions, respectively. Meanwhile, compared with the original SSR scheme, the proposed method had a longer convergence time. Furthermore, the real-time kinematic ocean multi-users experiment with reference to XP service of Kongsberg DPS 132 receiver was carried out. The results showed that the positioning accuracy was 0.132 m and 0.217 m in the horizontal and vertical directions after converged.