The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 19, 1995
Filed:
Jul. 29, 1994
B A Babu, Lewisville, TX (US);
Del Norte Technology, Inc., Euless, TX (US);
Abstract
A method and system for accurately determining the position coordinates of a mobile GPS receiver by resolving the double difference GPS carrier phase integer ambiguity. A reference station is provided at precisely known coordinates and carrier phase data and pseudoranges for each received GPS satellite are calculated at both the reference station and the mobile GPS receiver. A communications link couples carrier phase data, pseudorange data and the known reference station position from the reference station to the mobile GPS receiver. A first Kalman filter within the mobile GPS receiver operates on GPS satellite ephemeris parameters and the calculated pseudoranges to obtain an error state vector for position and time. The GPS satellite ephemeris parameters and calculated carrier phase data are then applied to a second Kalman filter to obtain a predicted vector of velocity and clock rate error. Line of sight range and range rates are then estimated utilizing the outputs of both Kalman filters and utilized, together with double difference phase measurements, to resolve the double difference carrier wave integer ambiguity providing an accurate set of coordinates for the mobile GPS receiver.