Remote subscription unit for GPS information
First Claim
Patent Images
1. A global positioning system (GPS) subscription unit, comprising:
- receiver circuitry for receiving a GPS aiding signal from a GPS information server, said GPS aiding signal having a plurality of items encrypted with a plurality of subscription keys;
a subscription key generator for providing certain ones of said subscription keys corresponding to certain ones of said items for which the unit has subscriptions;
a GPS information decrypter for decrypting said certain items with said certain subscription keys; and
a GPS receiver for using said decrypted items for processing a GPS satellite signal.
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Abstract
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.
44 Citations
24 Claims
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1. A global positioning system (GPS) subscription unit, comprising:
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receiver circuitry for receiving a GPS aiding signal from a GPS information server, said GPS aiding signal having a plurality of items encrypted with a plurality of subscription keys; a subscription key generator for providing certain ones of said subscription keys corresponding to certain ones of said items for which the unit has subscriptions; a GPS information decrypter for decrypting said certain items with said certain subscription keys; and a GPS receiver for using said decrypted items for processing a GPS satellite signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A global positioning system (GPS) subscription unit, comprising:
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receiver circuitry for receiving a GPS aiding signal from a GPS information server, said GPS aiding signal having a plurality of items encrypted with a plurality of subscription keys; a subscription key generator for providing certain ones of said subscription keys corresponding to certain ones of said items for which the unit has subscriptions where the subscription key generator is constructed for providing a one of said certain subscription keys when said certain subscription key is activated by a key enabler, and the subscription key generator has possession of said plurality of subscription keys but only provides said certain subscription key when said key enabler is received from said GPS information server; a GPS information decrypter for decrypting said certain items with said certain subscription keys; and a GPS receiver for using said decrypted items for processing a GPS satellite signal, wherein; the receiver circuitry is constructed for receiving a SAM signal having a service activation message carrying said key enabler from said GPS information server, said message having a signature derived from a subscription unit identification and said message; and
further comprising;a SAM decrypter having possession of said identification for authenticating said signature and providing said key enabler when said signature is authenticated. - View Dependent Claims (11)
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12. A method in a global positioning system (GPS) subscription unit, comprising:
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receiving a GPS aiding signal from a GPS information server, said GPS aiding signal having a plurality of items encrypted with a plurality of subscription keys; providing certain ones of said subscription keys corresponding to certain ones of said items for which the unit has subscriptions; decrypting said certain items with said certain subscription keys; and using said decrypted items for processing a GPS satellite signal. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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21. A method in a global positioning system (GPS) subscription unit, comprising:
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receiving a GPS aiding signal from a GPS information server, said GPS aiding signal having a plurality of items encrypted with a plurality of subscription keys; providing certain ones of said subscription keys corresponding to certain ones of said items for which the unit has subscriptions where providing said certain subscription keys includes activating a one of said certain subscription keys with a key enabler and activating said certain subscription key includes retaining possession of said plurality of subscription keys but only activating said certain subscription key when said key enabler is received from said GPS information server; decrypting said certain items with said certain subscription keys; and using said decrypted items for processing a GPS satellite signal, and wherein; receiving a SAM signal having a service activation message carrying said key enabler from said GPS information server, said message having a signature derived from a subscription unit identification and said message; authenticating said signature according to said identification; and providing said key enabler when said signature is authenticated. - View Dependent Claims (22)
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23. A global positioning system (GPS) subscription unit, comprising:
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receiver circuitry for receiving a GPS aiding signal from a GPS information server, said GPS aiding signal having a plurality of items encrypted with a plurality of subscription keys; a subscription key generator for providing certain ones of said subscription keys corresponding to certain ones of said items for which the unit has subscriptions, at least one of said certain items being precise time or precise frequency information; a time and frequency enabler for using said certain subscription keys for decrypting information for setting said precise time or tuning to said precise frequency; and a GPS receiver for using said precise time or said precise frequency for processing a GPS satellite signal.
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24. A medium readable by a computer for directing a process, comprising steps of:
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receiving a GPS aiding signal from a GPS information server, said GPS aiding signal having a plurality of items encrypted with a plurality of subscription keys; providing certain ones of said subscription keys corresponding to certain ones of said items for which subscriptions have been procured; decrypting said certain items with said certain subscription keys; and using said decrypted items for processing a GPS satellite signal.
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Specification