GPS and GIS: Enhanced Accuracy in Map Matching through Effective Filtering of Autonomous GPS Points

Road Reduction Filtering for GPS‐GIS Navigation

“…If the length of the connected route through a network from the present position on one particular road segment to the next position on another potential road segment is outside the possible range of distance travelled so far, that potential road segment is rejected. Carstensen (1998) has looked at the effects of filtering autonomous GPS points by number of satellites tracked, Dilution of Position (DOP) values or satellite geometry, and velocity and acceleration of the vehicle between positions. Filtering of potential road segments may be achieved using some of these measures and other criteria such as distance travelled and change of heading between vehicle positions, both criteria are used here.…”

“…If the distance from the present position to a position on another potential road segment is greater than possible distance travelled, that road segment is rejected. Carstensen (1998) has looked at the effects of filtering autonomous GPS points by number of satellites tracked, DOP values or satellite geometry, and velocity and acceleration of the vehicle between positions. Carstensen (1998) found that`filters make different types of errors', and concludes that filter methods must be appropriate to the application at hand.…”

“…The accurate location of a vehicle on a highway network model is fundamental to any in-car-navigation system, personal navigation assistant, fleet management system, National Mayday System (Carstensen, 1998) and many other applications that provide a current vehicle location, a digital map and perhaps directions or route guidance. A great many of these systems use the Global Positioning System (GPS) to initially determine the position of a vehicle.…”

GIS and GPS integration and mobile handset positioning

“…Location Based Services (LBS), personal navigation assistant, tourist information system, National Mayday System [2], and many other applications that provide a current location, a digital map and perhaps directions or route guidance. A great many of these systems could use the Global Positioning System (GPS) to determine the position of a telephone handset.…”

“…Often data can be combined from multiple sources integrating GPS with other navigational tools, attitude sensors such as the gyrocompass, vehicle odometer, flux gate compass and other dead reckoning methods [2] and [3]. This use of multiple data sources again helps to correct for the error (noise) on the GPS position output.…”