Performances and Applications Using TERRASTAR® Precise Point Positioning Service

J. Van Hees, L. LeThuaut, P. Nemry

Abstract:	One of the most recent entrants into the land PPP business is TERRASTAR®. The parent company has been around since 1989 and has been extremely successful in their marine business. TERRASTAR® was launched to focus specifically on the land market. The paper and presentation will focus on key differentiating elements from infrastructure in place to accuracy and robustness characteristics that make TERRASTAR® one outstanding performer. Attention is put on use-case experiments and actual results measured in the field including near-shore in dredging operations. TERRASTAR® provides two correction services: –M is meter level and –D is decimeter. All current and projected reference sites around the world have dual frequency Septentrio GPS/GLONASS receivers, and there are plans to add Galileo and even Beidou in the future. TERRASTAR® owns controls and operates its own fully independent DGNSS reference network. Dual redundant processing centers in Aberdeen and Singapore along with dual redundant network servers ensure uninterrupted distribution of GPS and GLONASS orbit and clock corrections enabling decimeter accuracy to users. TERRASTAR® distributes corrections from four global uplink stations over all seven Inmarsat Geostationary Communications Satellites (GEOs), providing most land users with redundant L-band visibility. The service is geo-gated to provide service to land areas plus about 6km beyond the coastline. Correction quality and availability is largely dependent on the number of reference stations which track the same GNSS satellite. For the TERRASTAR® ground network there are often more than 30 stations tracking the same satellite. This makes for high-quality orbit and clock set of corrections, allowing consistent horizontal 5-10 cm and vertical 10-15 cm accuracy. TERRASTAR-M® (meter level corrections) and TERRASTAR-D® (decimetre level corrections) services are available world-wide for use on land and in the air. Septentrio receivers are available which include hardware and embedded software to receive and decode the TERRASTAR® L-band augmentation signals. Subscriptions control is also embedded within the receivers and can be activated remotely. The Septentrio dual-frequency AsteRx2eL OEM and the packaged HDC unit are the first TERRASTAR® enabled for any PPP application using either –M or –D correction service on the market. Septentrio OEM boards with L-band capability are also powering all Altus survey instruments. The receivers can be switched between PPP and RTK mode and can therefore be used to operate beyond conventional RTK range with only minimal loss of accuracy which can be recovered by post processing if required. Merged RTK/PPP algorithms and unique techniques are implemented into the receivers to reduce or remove convergence time. Septentrio Satellite Navigation NV also has long term technology development relationships in place with TERRASTAR®. TERRASTAR® provides services for specialist and demanding land activities: • Agriculture and Forestry • Transportation • Mining • Oil and Gas Exploration • Survey • Construction • Aerial • Near-shore TERRASTAR® coverage is extended to near-shore land areas plus about a few kilometers beyond the coastline. So they have been able to capture near-shore dredging and construction business in Europe that otherwise might have to use more expensive marine corrections services. DEME, a world leading group of dredging and land reclamation companies, has selected the TERRASTAR-D® service to work with its Septentrio GNSS receivers. The Belgian dredging and environmental group is employing this service using AsteRx2eL GNSS positioning and AsteRx2eH GNSS heading receivers to support its near-shore dredging and construction operations worldwide. DEME evaluated and used the service for several months before selecting TERRASTAR-D® and Septentrio GNSS receivers for accuracy, stability and consistent performance. While the engineering and GNSS expertise behind TERRASTAR® has been around since 1989, TERRASTAR® is relatively new to the market. However, a number of other significant customer applications are already underway. In addition, new customers are using TERRASTAR® for Airborne Geophysical applications in oil & gas and land exploration/survey applications. There are also on-going trials on excavators in road-construction, on trains, in oil and gas and with integrated agricultural sprayer-control and harvesters. TERRASTAR® and Septentrio have a long term relationship for receivers, and Septentrio also retails the TERRASTAR® service.
Published in:	Proceedings of the 26th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2013) September 16 - 20, 2013 Nashville Convention Center, Nashville, Tennessee Nashville, TN
Pages:	2221 - 2227
Cite this article:	Van Hees, J., LeThuaut, L., Nemry, P., "Performances and Applications Using TERRASTAR® Precise Point Positioning Service," Proceedings of the 26th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2013), Nashville, TN, September 2013, pp. 2221-2227.
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