A Smart Realtime Service to Broadcast the Precise Orbits of GPS Satellite and Its Performance on Precise Point...

Area of Science:

• Geodesy and Satellite Navigation
• Global Navigation Satellite Systems (GNSS) Engineering

Background:

• Current Global Position System (GPS) navigation ephemeris offers meter-level precision, insufficient for evolving real-time precise point positioning (PPP) demands.
• Real-time PPP requires convenient, continuous, and reliable access to precise satellite orbit data.

Purpose of the Study:

• To propose and validate an 18-parameter ephemeris for broadcasting ultra-rapid precise predicted orbits with centimeter-level accuracy for real-time PPP.
• To evaluate the performance of the 18-parameter ephemeris against traditional precise orbit broadcasting methods.

Main Methods:

• Developed an 18-parameter ephemeris model to broadcast precise predicted GPS orbits.
• Compared PPP results using precise orbits versus orbits broadcasted from the 18-parameter ephemeris.
• Assessed the accuracy and reliability of the proposed method against Radio Technical Commission for Maritime Services (RTCM) standards.

Main Results:

• The 18-parameter ephemeris achieved centimeter-level precision for real-time PPP, with root mean square (RMS) offsets of 0.0098 m during the 2-hour validity period.
• Post-validity period, predicted orbits maintained 2 cm accuracy for up to 15 minutes, with an RMS offset of 0.0057 m.
• The new method reduced broadcast parameters 20-fold and expanded validity periods 120-fold compared to RTCM standards.

Conclusions:

• The 18-parameter ephemeris is a feasible and effective solution for broadcasting precise predicted orbits for real-time PPP applications.
• This approach significantly enhances convenience, continuity, and reliability in accessing precise orbit data.
• The method offers improved performance and data reduction compared to traditional RTCM-based precise orbit corrections.