Mapping Dilution of Precision (MDOP) and map-matched GPS

A novel method of map matching using the Global Positioning System (GPS) has been developed which uses digital mapping and height data to augment point position computation. This method reduces the error in position, which is a sum from several sources, including signal delay due to the ionosphere and atmosphere and until recently from `selective availability' (S/A). S/A was imposed by the US military to degrade purposefully the accuracy of GPS, but was switched oOEon 2 May 2000, and is to be replaced with `regional denial capabilities in lieu of global degradation' (Interagency GPS Executive Board, 2000). Taylor et al. (2001) describe the Road Reduction Filter (RRF) in detail. RRF is a method of detecting the correct road on which a vehicle is travelling. In the work described here, the position error vector is estimated in a formal least squares procedure, as the vehicle is moving. This estimate is a map-matched correction, that provides an autonomous alternative to DGPS fo...

• Type: Journal
• Year: 2002
• Where: GIS
• Authors: Geoffrey Blewitt, George E. Taylor
• Keywords: Automated Reasoning, Digital Mapping, GIS 2002, Interagency GPS Executive Board, Map-matched Corrections