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Opportunistic navigation: finding your way with AM signals of opportunity / J. Mcellroy in GPS world, vol 18 n° 7 (July 2007)

Public [article]  inGPS world > vol 18 n° 7 (July 2007) . - pp 44 - 49 Titre : Opportunistic navigation: finding your way with AM signals of opportunity Type de document : Article/Communication Auteurs : J. Mcellroy, Auteur ; J.F. Raquet, Auteur ; M.A. Temple, Auteur Année de publication : 2007 Article en page(s) : pp 44 - 49 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement [Termes IGN] GPS assisté pour la navigation (technologies) [Termes IGN] modulation du signal [Termes IGN] positionnement par GPS Résumé : (Auteur) In last month's column, we took a brief look at some of the technologies that might be used for UbiPos - ubiquitous positioning - to supplement conventional GPS in environments where it performs poorly or not at all such as in concrete canyons and inside buildings. One of the technologies mentioned involves using signals of opportunity radio signals whose primary purpose is for communications or broadcasting but which could be used for positioning and navigation. Potential signals of opportunity include the amplitude modulated (AM) broadcast stations in the medium wave band. Invented just over 100 years ago by the Canadian radio pioneer Reginald Fessenden, AM broadcasting covers large parts of the globe. Despite the recent tendency of AM stations to move to the FM band, most large metropolitan areas still boast a dozen or more stations on the "AM dial." The signals from AM stations can be used to determine the position of a mobile receiver with respect to a reference receiver using time difference of arrival (TDOA) measurements and a supplementary link between the two receivers. Measurements on one transmitter establish a hyperbolic line of position for the mobile receiver and the intersection of this line with another from measurements on a second transmitter establishes the receiver's position. Measurements on additional transmitters can improve the position accuracy and estimate unsynchronized receiver clock differences through a multi-lateration approach. It matters not whether the stations are "talk radio" or "country and western," as it is the carrier phase of the signals which provides the TDOA measurements. Of course, the proposed use of AM radio broadcasts for positioning and navigation is not a new idea. Measurements of the angle of arrival of AM broadcasts have long been used for position fixing in marine and other environments. In this month's column, a team of authors from the U.S. Air Force Institute of Technology describe the simulations and real-world experiments they carried out using a software-defined radio receiver to test the feasibility of AM radio TDOA measurements for positioning and navigation.Copyright Questex Media Group Inc Numéro de notice : A2007-148 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28511 [article]

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