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:
Oct. 24, 2000
Filed:
Sep. 09, 1998
Jin Dai, San Diego, CA (US);
Nadav Levanon, Ramat-Gan, IL;
Bill Ames, Poway, CA (US);
Ed Victor, Louisville, CO (US);
Jim Determan, Encinitas, CA (US);
Qualcomm Incorporated, San Diego, CA (US);
Abstract
The present invention is a system and method for accurately determining the distance (range) between one or more satellites and a user terminal and the rate of change (range rate) of that distance. When accurately determined according to the present invention, these quantities can be used to determine the location of the user terminal with a high degree of accuracy. When one satellite is available, the present invention determines the range and range rate based on the Doppler frequency shift that a signal experiences between the satellite and the user terminal, the round trip delay a signal experiences during transmission from the satellite to the user terminal and back via a satellite to a gateway, the Doppler frequency shift a signal experiences between the satellite and the gateway, and the timestamps of the measurements. When a second satellite is available, the present invention determines the range and range rate between the second satellite and the user terminal based on the round trip delay, the Doppler frequency shift that a signal experiences between the second satellite and the user terminal, and the difference in arrival times at the user terminal of the signals from the satellites.