A NEW HIGH-PRECISION WIDE AREA DGPS SYSTEM

This paper describes an advanced method, and the corresponding algorit hms, which could provide a high precision Wide Area Differential GPS ( WADGPS). The service would be suitable for single or dual frequency us ers, and could be introduced with very few reference stations. The two main components of the service are a precise, near real-time orbit de termination of the GPS satellites, and an accurate estimation and mode lling of ionospheric and tropospheric effects. Broad principles of the processing algorithms and results of both simulation and real data te sts are described. User positioning accuracies of better than 2.5 m (r .m.s.) in plan and 3.0 m (r.m.s.) in height are achieved by both singl e and dual frequency scenarios.