Assessment of Network-based Positioning Performance Using GPS Alone versus GPS and GLONASS Combined

摘要

As it is anticipated that the full operational capability ofrnGLONASS will be achieved in the very near future,rnGLONASS is now attracting surveyors’ attention, withrnquestions being asked on how much improved accuracyrncan be obtained if GPS and GLONASS were usedrntogether. Such a performance assessment has beenrnundertaken in the past; however, most of the tests werernconducted with a limited number of available (at therntime) GLONASS satellites. It is timely to re-assess thernperformance because most networks of continuouslyrnoperating reference stations (CORS) are now equippedrnwith receivers that can track both GPS and GLONASSrnsatellites, and therefore network-based positioning withrncombined GPS and GLONASS observations is possible.rnThis paper compares the network-based positioningrnresults with GPS measurements only versus the use ofrncombined GPS and GLONASS measurements, underrnvarious sky view conditions.rnThe benefit of adding GLONASS measurements to GPSrnmeasurements is more obvious when a limited number ofrnsatellites are available due to the fact that sky view isrnpartially blocked. Comparing the GPS-only solution withrnthe GPS+GLONASS solution, the accuracy improves byrnapproximately 2mm and 3mm in the 2-dimensional andrn3-dimensional coordinates, respectively. However, therncombined solution shows its clear advantage whenrnGLONASS-only solutions are considered.