Sunday 1 August 2010 by Libadmin2010

10th International Multidisciplinary Scientific GeoConference - SGEM2010, www.sgem.org, SGEM2010 Conference Proceedings/ ISBN 10: 954-91818-1-2, June 20-26, 2010, Vol. 1, 829-836 pp


Global navigation satellite systems (GNSS) introduced revolutionary changes in the
positioning and navigation, but it is well known that the precision, reliability,
availability and integrity of the results obtained by this technology, largely depend on
the number and geometric distribution of the satellites being tracked. This is especially
problem in areas with limited sky visibility, such as urban canyons, dam monitoring in
valleys, deep open-pit mines, larges construction sites. Furthermore, indoors or
underground, such as factory halls, inside buildings and tunnels, positioning is totally
disabled due to unavailability of satellite signals. To overcome these severe limitations,
additional ranging signals transmitted from pseudolites can be include. Pseudolites (the
term derived from pseudo-satellite, often abbreviated PL), are ground-based generators
and transmitters of GPS-like signals, for use in the local area.

Pseudolites can be used to augment the GNSS satellite constellation in case of
inadequate satellites coverage and for improvement the geometry, but also as an
independent measurement system which can completely replace the GNSS, such as
indoors, underground or on the surface of other planets.

The pseudolites may seem like a new measurement technology, but the concept of
ground-based transmitters can be tracked back to the early development of GPS, when
the pseudolites been designed to test the GPS user equipment. Since than, researches
teams around the world continuously improve and develop new pseudolite concepts
and hardware, trying to adapt them to the requirements of certain applications.

This paper presents the theoretical basis, advantages and disadvantages of pseudolite
technology, and its application in some areas of positioning and navigation.

Keywords: pseudolite, GNSS augmentation, indoor positioning and navigation