FIG Peer Review Journal


Positioning in Environments Where GPS Fails (4357)

Binghao Li, Andrew G. Dempster and Chris Rizos (Australia)
Dr. Binghao Li
University of New South Wales, NSW, Australia
School of Surveying and SIS, UNSW
Corresponding author Dr. Binghao Li (email:[at], tel.: + 61 2 93854189)

[ abstract ] [ paper ] [ handouts ]

Published on the web 2010-01-14
Received 2009-11-19 / Accepted 2010-01-14
This paper is one of selection of papers published for the FIG Congress 2010 in Sydney, Australia and has undergone the FIG Peer Review Process.

FIG Congress 2010
ISBN 978-87-90907-87-7 ISSN 2308-3441


The development of the global navigation satellite system (GNSS) over the last three decades has revolutionised positioning, navigation and timing (PNT). The U.S. developed global positioning system (GPS) is of course the classic exemplar of this technology, being the only fully operational (since 1995) GNSS currently available. The applications of GPS can be found across almost all of a nation’s economic, scientific and social activities, from spacecraft navigation and geodesy, to land surveying and mapping, to precise agriculture and vehicle fleet management, to emergency services and professional navigation, to mass market applications such as in mobile devices (cars and smartphones) and location based services (LBS). The success of GPS (and increasingly also the revitalised GLONASS) has encouraged the development of more satellite navigation systems, such as the E.U.’s Galileo and China’s Compass. However, the major shortcoming of GNSS is that it is usable everywhere where there is clear sky, and hence fails to operate where it's impossible or difficult to receive the satellite signals such as inside most buildings, in urban canyon environments, in caves, tunnels and other subterranean locations, and underwater. However, in some difficult signal environments – principally where the satellite signals are weak (<-142 dBm) and multipath is severe – so-called “high sensitivity” GPS/GNSS and/or assisted-GPS/GNSS (A-GPS/A-GNSS) can be used to improve PNT availability. Other sensors can also be integrated with GPS/GNSS to improve positioning. In environments where GPS/GNSS completely fails alternative positioning technologies based on WiFi signals or ultrasound etc. could be used. In this paper, some of the research carried out in the School of Surveying and Spatial Information Systems, University of New South Wales, into positioning in environments where standard GPS fails is described.
Keywords: GNSS/GPS; Positioning; WiFi; cellular phone network