Real-time kinematic positioning with GPS and GLONASS

Abstract

Recently, low-cost dual constellation receivers with simultaneous tracking of GPS and GLONASS satellites and raw carrier phase output have become available. This enables a faster and more reliable ambiguity fixing especially in areas with limited satellite visibility, e.g. street canyons. In this paper, we present a combined GPS/GLONASS RTK positioning with code multipath estimation for low-cost receivers. We use double difference measurements and take the integer property of both the GPS and GLONASS ambiguities into account. For GLONASS, this requires a reparametrization of the double difference ambiguities and a subsequent parameter mapping. The re-parameterized measurement models are used for ambiguity fixing with real measurements from two low-cost dual constellation GNSS receivers. We obtain residuals of a few centimeters for both GPS and GLONASS fixed carrier phases.