FIG Peer Review Journal


Accurate High-Sensitivity GPS (3349)

Volker Schwieger (Germany)
Dr.-Ing. habil. Volker Schwieger
Head of Metrology Department
University Stuttgart
Inst. for Applications of Geodesy to Engineering
Geschwister-Scholl-Str. 24D
Corresponding author Dr.-Ing. habil. Volker Schwieger (email: volker.schwieger[at], tel.: + 49 7116854064)

[ abstract ] [ handouts ] [ handouts ]

Published on the web 2009-02-16
Received 2008-12-01 / Accepted 2009-02-16
This paper is one of selection of papers published for the FIG Working Week 2009 in Eilat, Israel and has undergone the FIG Peer Review Process.

FIG Working Week 2009
ISBN 978-87-90907-73-0 ISSN 2307-4086


Efficiency improvement for positioning tasks is an important responsibility for geodesists. In the context of this paper efficiency means the achievement of the same position quality with minor spending of money. If it would be possible to use low-cost receivers like navigation type receivers for the geodetic accuracy levels, the spend of money could be fairly reduced. The only available high-sensitivity GPS receiver, that may output phase data, available on the market is the u-blox LEA-4T. This paper presents the first results obtained using an u-blox LEA-4T and a notebook for storing the data sent via the USB interface. The baselines ranging from 150 m to 7.7 km distance were determined using a receiver of geodetic accuracy level as reference station. This paper will show that the u-blox LEA-4T may be used to determine coordinates in post-processing. The observation span has to be minimum 20 minutes. To get a higher reliability and accuracy 30 minutes have to be preferred. The reached accuracy levels are 2.5 cm for horizontal and 8 cm for vertical components. The baseline length between 150 m and 7.7 km is of minor importance; only the height component gets worst. In a multipath and shadowing free environment the accuracy level is better than 2 cm for 20 minutes observation time. This is already a level usable for geodetic applications.
Keywords: GNSS/GPS; Positioning; Low cost technology; High-Sensitivity GPS