06055477 is referenced by 74 patents and cites 30 patents.

Methods for GPS-assisted determination of location coordinates of a mobile user or selected position on or adjacent to the Earth's surface with improved accuracy. Elevation readings from an altimeter or barometer are integrated with readings of the GPS-determined elevation coordinate for that location, using Kalman filter techniques, minimum least square techniques, or comparison of certain statistically defined parameters associated with the altimeter and GPS variables, such as the standard deviation of the expected errors in these variables. The resulting elevation coordinate may be a statistical blend or filtered blend of the altimeter value and a GPS-determined value for the elevation coordinate; or this resulting elevation coordinate can be chosen to be one or the other of these values, based upon comparison of time varying statistical parameters corresponding to the altimeter and the GPS.

Title
Use of an altitude sensor to augment availability of GPS location fixes
Application Number
414443
Publication Number
6055477
Application Date
July 3, 1997
Publication Date
April 25, 2000
Inventor
Paul Braisted
San Jose
CA, US
Paul McBurney
Palo Alto
CA, US
Agent
John Schipper
Assignee
Trimble Navigation
CA, US
IPC
G05D 1/00
G01S 5/00
View Original Source