GPS Satellite Orbit Prediction at User End for Real-Time PPP System

Area of Science:

• Geodesy and Satellite Navigation
• Orbital Mechanics and Astrodynamics

Background:

• Real-time precise point positioning (PPP) systems require accurate satellite orbit predictions.
• Existing methods may have limitations in user-end prediction accuracy and timeliness.

Purpose of the Study:

• To develop and validate a high-precision satellite orbit prediction process at the user end for real-time PPP.
• To assess the accuracy and effectiveness of user-end orbit prediction for various positioning modes.

Main Methods:

• Introduced a new real-time PPP system structure.
• Generated satellite initial parameters (position, velocity, SRP) at the server end.
• Implemented user-end orbit prediction using dynamic models (Earth's gravity, lunar, solar, SRP) and numerical integrators (Runge-Kutta, Adams-Bashforth-Moulton).

Main Results:

• Achieved prediction accuracy within 0.033 m for radial, along-track, and cross-track directions over 12 hours.
• Static PPP using predicted orbits yielded RMSEs of 0.012 m (North), 0.015 m (East), and 0.021 m (Vertical).
• Kinematic PPP using predicted orbits resulted in RMSEs of 0.031 m (North), 0.069 m (East), and 0.167 m (Vertical).

Conclusions:

• The proposed user-end satellite orbit prediction method maintains high accuracy for several hours.
• The validated prediction accuracy supports reliable real-time precise point positioning in both static and kinematic scenarios.