Requirements analysis of differential GPS for Singapore

The use of GPS system is gradually and steadily increasing throughout the world. The degraded performance of the commercial/civilian GPS system due to the incorporation of selective availability (SA) feature of the system has provided significant impetus to the utilization of the concept of differential GPS. Successful implementations of the DGPS concept for non-military applications have been analyzed, designed and tested. Currently, emphasis is directed towards reducing the complexity and expense of the operational DGPS system for large areas such as the United States by the application of WADGPS (wide area DGPS). The goal of the research reported in this paper is to determine if a similar SADGPS (small area DGPS) implementation is possible for small nations like Singapore. Specifically, the approach to define constant GPS position corrections for commercial GPS receivers has been investigated The results indicate that such a simple model may be feasible for simple applications and more elaborate formulations may be needed to model general DGPS implementation. The results reported also indicate that the simple DGPS model will have to be a function of the equipment category