Evaluation of Two Integer Ambiguity Resolution Methods for Real Time GPS Positioning

Abstract:- The Global Positioning System (GPS) is a satellite-based navigation system which allows the user to determine position and time with high precision. However, phase measurements has an inherent difficulty, which is the ambiguity determination in number of signal wavelengths. Once ambiguities are resolved to an integer value, positioning can reach sub-meter level in accuracy. Sub-meter positioning accuracy is required in many applications, such as aircraft navigation and landing, attitude and orbit determination of satellites, navigating agricultural vehicles, among others applications. The purpose of this work is to evaluate performance of LSAST and LAMBDA methods for real time integer ambiguity resolution in situations of static and kinematic positioning. Position coordinates of a GPS receiver (“user”) are estimated using data of another receiver placed on a landmark with known coordinates (“base”), using phase double difference positioning technique, and an iterated least-squares as float solution estimator. Positioning errors are shown with half meter level for static and less than meter level for kinematic positioning