NovAtel's RT20 - A Real Time Floating Ambiguity Positioning System

Abstract

Over the past 10 years, the thrust of many GPS programs has been towards solving the precise positioning problem with a fmed integer carrier solution. Progress has been made in this area, but an uncertain multipath environment and decorrelated ionospheric delays have made this technology problematic for a single frequency receiver. The nature of the solution requires an excess of computing resources and a lot of time, if special initialization methods are not used. NovAtel has developed a high performance floating ambiguity differential positioning package on a single board which promises to be as robust as a differential pseudorange system but approaches the accuracy achievable with a f&d ambiguity single frequency system. The process is described in this paper, including its features, data stream, positioning filters and test methods and results.