Budget Analysis and Realization of Precise RTK-GPS Via Compact Correction Messages Applied to Commercial GPS Receivers
Jeonghan Kim, Byungwoon Park, Changdon Kee, Allen Cleveland, M. Parsons, D. B. Wolfe · 2004
The SNUR-2000 v. 2.2 consists of several types of compact RTK-GPS messages whose main components are pseudorange and carrier phase corrections. Using these messages, we can carry out precise RTK-GPS positioning using low-rate data-link. In this paper, we analyze the effect of latency on RTK-GPS positioning error and determine minimum baud-rate of data-link for compact correction messages applied to commercial GPS receivers. We also evaluate the performance of the SNUR-2000 by applying converted correction messages to commercial GPS receivers. Commercial GPS receivers can identify their own proprietary RTK-GPS messages, but not the correction messages of the SNUR-2000 v. 2.2. In order to make RTK-GPS receivers identify the SNUR-2000 messages, we converted the compact correction data to proprietary RTK-GPS data which commercial GPS receivers can identify. For this purpose, we converted compact correction messages to CMR (Compact Measurement Records), which is one of the widely-known RTK-GPS data format. The RTK-GPS receivers decode the converted messages, estimate DD integer ambiguities, then compute RTK-GPS position internally. Test results show that the converted compact correction messages of the SNUR-2000 make it possible to resolve integer ambiguities and to compute precise RTK-GPS position autonomously without performance degradation (Initial test results have been demonstrated in the plenary meeting of the RTCM SC-104 version 3 working group).