The influnce of different processing parameters on estimated variation of GPS positioning

Abstract

Throughout the past decades, GPS has been responsible much of the present infrastructure and thusbeing widely used covering from the diverse low cost and recreational uses to highly accurate and professional applications. Level of performance produce by this ingenious space-based positioning system however, is often a function of equipment suitability, measurement technique, error modelling and satellite signal geometry. Data processing complexity is also one of the main factors contributing to the erroneous and discrepancies in the GPS derived positions. This paper highlights the influence of three different processing parameters namely ephemeris type, elevation cut-off angle and earth rotation parameter towards the estimated variation of GPS positioning discrepancies. As each station experiencing low multipath conditions and excellent views of all available satellites, series of RINEX data retrieved from five continuously operating Malaysian Real-time Kinematic Network (MyRTKnet) stations namely JHJY, KLUG, JUML, MERU and LGKW were used. Based on the results, it is suggested that GPS derived positions varies with variation on the ephemeris type and elevation cutoff angle. As far as earth rotation parameter is concerned, it is totally ignorable in most practical cases as no variation detected throughout the observation period.