The Usefulness of GLONASS for Positioning in the Presence of GPS in the Indian Subcontinent
Abstract: The effort to integrate the use of GPS and GLONASS constellations resulted in the production of a special receiver, which can use both constellations in combination. These receivers may be used in GPS only mode, GLONASS mode and combined (both GPS and GLONASS) mode. Utilising this type of receiver, GPS and GLONASS signals were monitored for one calendar year simultaneously in different places in India to study the status of visibility of satellites and the positioning accuracy. The number of satellites in GLONASS constellation gradually depleted from 16 to 7 during the course of this study. So a 3-D solution was rarely possible using only GLONASS satellites. However, appreciable improvement in PDOP was observed in the combined mode. Before the withdrawal of GPS Selective Availability (SA), significant improvement of position accuracy could be observed in the combined mode. After the removal of GPS-SA, the accuracies of the combined mode and that of GPS-only mode have been found to be of the same order. While this does not apparently reflect any advantage, it indirectly confirms that both the GPS and the GLONASS systems have similar limits of accuracy and also confirms that optimal interoperability of two systems has been achieved. These studies reveal that the combined use of GLONASS and GPS will always be beneficial to a varying degree depending on different applications and circumstances.
Cites background or methods from "The Usefulness of GLONASS for Posit..."
...3-dimensional solution errors of instantaneous solutions were calculated following Banerjee et al., 2002....
...First GLONASS satellite was launched in 1982; an operational constellation was available from early January 1996, (Website of University of New Brunswick 2004-2016) providing the users an active and useful alternative to GPS, operating with Selective Availability during the period (Banerjee et al. 2002)....
...…GLONASS satellite was launched in 1982; an operational constellation was available from early January 1996, (Website of University of New Brunswick 2004-2016) providing the users an active and useful alternative to GPS, operating with Selective Availability during the period (Banerjee et al. 2002)....
...The situation was short-lived, and the constellation gradually degraded (Holmes et al. 1998); it was observed, from 14 useable GLONASS satellites during May 1998, the number of satellites reduced to 06 in April 2001 (Rooney et al. 1999, and Banerjee et al. 2002) in the constellation....
...…Centre 2004-2016, Website of The affiliated branch Precision Navigation and Ballistic Support of OJSC, University of New Brunswick (2004-2016), Banerjee et al. 2002, Bose et al. 2008, 2010, 2013, Shengyue et al. 2010, Russian system of differential correction and monitoring (SDCM)…...
"The Usefulness of GLONASS for Posit..." refers background in this paper
...…desired accuracy, it is not only necessary to track a sufficient number of satellites with sufficient signal strength, but it is equally important that the geometrical configuration of the tracked satellites is favourable NO. 3 THE USEFULNESS OF GLONASS FOR POSITIONING 467 (Banerjee et al., 1997)....