07020555 is referenced by 29 patents and cites 12 patents.

A GPS information service system for providing supplemental GPS correction and signal acquisition information to subscribers. A GPS information server broadcasts GPS aiding information encrypted with subscription keys. A remote GPS subscription unit receives the key enablers for the subscription keys in service activation (SAM) messages for the services for which they have subscribed and then uses the subscription keys to decrypt the GPS aiding information. In order to prevent unauthorized access to the information, unsymmetrical signature generation and authentication algorithms are used for generating and authenticating signatures for the SAM messages.

Title
Subscription GPS information service system
Application Number
10/744925
Publication Number
7020555 (B1)
Application Date
December 23, 2003
Publication Date
March 28, 2006
Inventor
Ann Ciganer
San Mateo
CA, US
David G Bird
Thornton
CO, US
James M Janky
Los Altos
CA, US
Agent
David R Gildea
Menlo Patent Agency
Assignee
Trimble Navigation
CA, US
IPC
G01C 21/00
G01S 5/02
H04B 7/185
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