The use of GNSS, especially GPS, is a standard technique for geroreferencing spatial data. Its precision is depends on receiver types and on the methods to eliminate systematic errors. The runtime solutions for Single Point Positioning and positioning with differential corrections (e.g. DGPS) can be used world wide in real time depending on the methods for broadcasting pseudo range (run time) corrections. Users reference stations only can bridge limited distances (some km) and precise commercial services are costly (e.g. OmniStar).

Precise differential methods based on carrier phase observations are limited to certain distances and determine only coordinate differences (baselines) between receivers. So a reference frame is necessary to get positions related to a geodetic datum. Compared with the solutions above, the Precise Point Positioning (PPP) method has two main advantages:

1. A single GNSS receiver can be used to get cm accuracy

2. The positions are related to a well defined geodetic datum valid globally

Disadvantages by achieving cm accuracy are long observation times, restriction to post processing, and costs for dual frequency receivers. The presentation will compare PPP with the well known methods to use GNSS and discuss fields for using PPP. First experiences in using the method at HFT Stuttgart will be shown and explained.

REFERENCES

Martin Giese et.a: Berechnungsdienste für Precise Point Positioning (PPP), AVN 3/2011.

Katrin Huber et.al: PPP: Precise Point Positioning - Constraints and Opportunities, FIG Congress 2010, http://www.fig.net/pub/fig2010/ppt/ts10c/ts10c_huber_heuberger_et_al_ppt_4040.pdf. [Accessed Juli 15th, 2011]

John Vint: GNSS PPP (Precise Point Positioning), A New Development for High Precision Navigation and Positioning, NNF -E-Nav Conference, Bergen, 6 March 2009, http://img3.custompublish.com. [Accessed Juli 15th, 2011]

Yang Gao: Precise Point Positioning and its Challenges, InsideGPS, November/December 2006,
http://www.insidegnss.com/auto/NovDec06GNSSSolutions.pdf. [Accessed Juli 15th, 2011]

Sunil B. Bisnath, Yang Gao: Innovation: Precise Point Positioning, GPS World, April 2009,   
http://www.gpsworld.com/gnss-system/algorithms-methods/innovation-precise-point-positioning-7040. [Accessed Juli 15th, 2011]

Zumberge, J. F., M. B. Heflin, D. C. Jefferson, M. M. Watkins, and F. H. Webb (1997), Precise point positioning for the efficient and robust analysis of GPS data from large networks, J. Geophys. Res., 102(B3), 5005-5017, doi:10.1029/96JB03860.