Geodetski Vestnik (Jan 2004)
Izračun položaja GPS-satelita iz podatkov oddanih efemerid : GPS-Orbit Computation from Broadcast Ephemeris Data
Abstract
The article describes the theoretical point of view of the GPS-broadcast ephemerides application. Beside the raw GPS observations, any kind of GPS ephemerides represents indispensable data in the GPS processing engine. Broadcast ephemerides have been produced in the central Control Station in Colorado Springs and interposed from GPS satellites to the users as part of the GPS navigation message. The article focuses on the theoretical broadcast-ephemeris-data treatment for computing the position of a GPS satellite. The reason for the orbit-problem explanation is that anyone who uses any GPS measurement methods should be aware of the advantages and disadvantages of the ephemeris data. Thus, numerical examples of GPS-satellite position computation for 4-hour time span from broadcast ephemerides and deviations of the results regarding the IGS ultra-rapid and IGS final precise ephemerides are presented in the article.
