Ulrich Vollath

Trimble's RTK and DGPS Solutions in Comparison with Precise Point Positioning

Differential GPS (DGPS) and Real-Time- Kinematic (RTK) solutions are widely accepted meth- ods for accurate positioning and navigation. Initially these methods were based on single reference stations. A big breakthrough in performance and accuracy was achieved by the introduction of network solutions. To- day, the use of the Virtual Reference Station method is a standard technology applied in a large number of regional RTK networks all over the world, to pro- vide a positioning service with centimetre accuracy. DGPS techniques are used for marine, airborne and land applications and provide accuracies in the sev- eral decimetre range. The DGPS and RTK methods are based on regional reference station networks or nearby single stations. In contrast, the Precise Point Position- ing (PPP) method is providing position accuracy of several centimetres to decimetres based on a globally distributed tracking network. Precise satellite orbit and clock information is derived from the network process- ing. The achievable accuracy with PPP is impressive, but this method suffers from long convergence times of the order of more than 20-30 min to achieve acceptable