Hamid Reza Nankali - National Cartographic Center Of Iran(Research-Institute) Dept of Geodesy and Geodynamics

Global Positioning System (GPS) , which is a world-wide precise positioning system has become a popular and very useful device for geodetic survey and crustal deformation observation such as velocity filed of tectonic plate and station coordinates and their velocities. For precise measurements, differential positioning technique is used. Two antenna located a part , receive the signals data simultaneously and the collected datasets are processed together in order to obtain relative location between to observation points. To keep the computational burden associated with the such data feasible, one technique is to determine precise ephemerid from a global distributed network(IGS). Then data from local network are analyzed by estimating receiver parameters, satellite parameter are held fix (precise ephemerid). This Precise Point ositioning(PPP) is simple and very efficient method that must be applied with dual frequency receivers and 24h observation and independent of base station and the reference frame cab be free of distortion imposed by erroneous fiducially constraint on any sites. This paper outlines the use of PPP for processing GPS data(advantages-and disadvantages)with Bernese V5 software and compare the results with relative positioning in the same point of Iranian permanent GPS observation network for crusal deformation monitoring that process with Gamit/Globk software in relative mode.