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The GPS L2C signal: a preliminary analysis of data quality / Rodrigo Figueiredo Leandro in GPS world, vol 19 n° 10 (October 2008)

Public [article]  inGPS world > vol 19 n° 10 (October 2008) . - pp 42 - 47 Titre : The GPS L2C signal: a preliminary analysis of data quality Type de document : Article/Communication Auteurs : Rodrigo Figueiredo Leandro, Auteur ; R.B. Langley, Auteur ; et al., Auteur Année de publication : 2008 Article en page(s) : pp 42 - 47 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] longueur d'onde [Termes IGN] qualité des données [Termes IGN] signal GPS [Termes IGN] utilisateur civil Résumé : (Auteur) 56 and counting. That's the number of GPS satellites that have been launched over the past thirty years beginning with the first prototype {Block I) satellite, space vehicle number 1, in February 1978. Ten Block I satellites were successfully launched between 1978 and 1985 to demonstrate the feasibility of GPS. The first satellite of the Block II operational constellation was launched in February 1989. The four year hiatus in launches was due, in part, to the Space Shuttle Challenger disaster as it had been planned to launch the operational satellites using the Shuttle. Following the accident, it was decided to continue with expendable rockets for GPS launches but to switch to the newly designed Delta II rocket. The pace of Block II launches was rapid with five launches of the original Block II design in 1989 and four in 1990 a modified, version of the Block II satellite - the IIA - was develloped, and between 1990 and 1997,19 Block IIAs were launched. The Block II and IIA satellites established the operational GPS constellation. Full operational capability was declared on April 27,1995. A new satellite was developed for replenishing the constellation as the earlier satellites were retired. Following an initial launch failure, twelve of the Block lIR satellites were launched between 1997 and 2004. All of the satellites in the Block I, Block II, Block IIA, and Block llR, constellations transmitted what are now called the legacy signals : tne C/A-code on the L1 frequency of 1575.42 MHz and the P-code on L1 and the L2 frequency of 1227.60 MHz.The P-code has been encrypted to yield the Y-code since January 1994, denying its direct access by most civil users. Since the C/A-code was only transmitted on the L1 frequency, civil users have had to rely on suboptimal semicodeless techniques for the dual-frequency operation necessary for direct cancellation of ionospheric biases. In 1998, Vice-President Al Gore announced that a new civil signal on L2 would be transmitted by future GPS satellites. This new signal-L2C-joined the legacy signals beginning with the launch of modernized Block llR satellite. Six of these blockllR-M satellites have been launched to date. In this month's column, we'll overview the characteristics of the new L2C signal and take a look at some of the analyses of received signals carried out by a team of researchers from the University of New Brunswick. Copyright Questex Media Group Inc Numéro de notice : A2008-397 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29390 [article]

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