Use of a Covariance Analysis Technique for Predicting Performance of Regional-Area Differential Code and Carrier-Phase Networks*

Abstract

ABSTRACT: There is currently great interest in using regional-area reference receiver networks (on the order of hundreds of kilometers) to perform precise (10 cm or better) kinematic positioning using GPS carrier-phase measurements. When designing or using such a network, it is important to be able to determine design trade-offs by predicting what the errors will be under various network configurations (e.g., number/geometry of receivers, ionospheric levels). This paper presents a method for predicting the level of differential (double-difference) code and carrier-phase errors that is capable of taking all these considerations into account. This method uses a covariance analysis technique, which is based on a network differential algorithm that minimizes the differential error variances (the NetAdjust method). After validation, this method is applied to a number of what-if scenarios, demonstrating the usefulness of the approach when designing or using a regional-area differential GPS network for precise positioning.