Titre du document / Document title
What is the accuracy of DGPS?
Auteur(s) / Author(s)
SARDINHA MONTEIRO Luis (1 2) ;
MOORE Terry (1) ;
HILL Chris (1) ;
Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)
(1) Institute of Engineering Surveying and Space Geodesy (IESSG), The University of Nottingham, ROYAUME-UNI
(2) Portuguese Hydrographic Office, PORTUGAL
Résumé / Abstract
In general, a Reference Station calculates differential corrections which are valid for that exact location (zero baseline) at that particular epoch (age of corrections zero). However, DGPS users may be located as far as 200 nm away from the Reference Station and some of the errors compensated for by the Reference Station vary with space, namely satellite ephemeris, tropospheric and ionospheric errors. Therefore, the corrections calculated at the Reference Station suffer certain accuracy degradation as the separation distance increases, because of a decreasing relevance of the Reference Station data to the user. The error growth with increasing distance to the beacon is accentuated by the inability of Reference Station and user to see the same satellites, commonly termed the lack of intervisibility. The error growth with distance is the most important factor determining DGPS accuracy, but surprisingly very little has been done to assess it. US official documents and IALA state that the achievable accuracy degrades at an approximate rate of 1 in for each 150 km (80 nm) distance from the broadcast site, but this value is based on a theoretical prediction, made back in 1993. To estimate the error growth with real data, 6 DGPS receivers were placed along the Portuguese coastline at approximately 50 nm intervals from Sagres Broadcast Station, in a South - North direction. This paper describes the results of the trial.
Revue / Journal Title
Journal of Navigation
ISSN
0373-4633
CODEN JONVAL
Source / Source
Congrès
European Navigation Conference GNSS 2004, Rotterdam
, PAYS-BAS
(16/05/2004)
2005, vol. 58, n
o2, pp. 207-225 [19 page(s) (article)] (13 ref.)
Langue / Language
Anglais
Editeur / Publisher
Cambridge University Press, Cambridge, ROYAUME-UNI
(1972)
(Revue)
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Localisation / Location
INIST-CNRS, Cote INIST : 5718, 35400012462322.0050
Nº notice refdoc (ud4) : 16778223
