A long-range dynamic GPS positioning system and its test results

The proposed long range dynamic (LRD) prototype system delivers online positioning accurate to a few decimetres, while the off line processing provides a uniformly accurate output of 10 cm level for precise navigation challenges. This is achieved without on-the-fly ambiguity resolutions. This paper addresses the two theoretical aspects for the LRD system. First, the LRD system detects and repairs carrier phase cycle-slips and small data gaps in real-time by using proper combinations of L1 and L2 carrier phase and code measurements. The system then outputs 3D delta position and position solutions from the phase and code measurements respectively, then uses optimal filtering and smoothing approaches to reprocess the obtained solutions in real time for decimetre positioning or post processing for better accuracy. This technique allows the system to initialise the solutions at any moving points with 4 satellites. The system is robust and reliable to use for dynamically positioning any moving platforms or aircraft a few hundred kilometres away from a base station either in real time or off line. A set of airborne dynamic test data collected by Trimble Geodesist IIP receivers in 1992 over the range of 130 km is analysed.