Subscription system for GPS information
First Claim
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1. A global positioning system (GPS) information server system, comprising:
- at least one GPS correction reference station for generating GPS correction information for improving a GPS-based position estimate;
a GPS acquisition processor for generating GPS acquisition information for reducing time for acquiring a GPS signal; and
a subscription encrypter for encrypting items of said GPS correction and acquisition information according to subscriptions, respectively, procured for remote subscription units; and
disposing said items into a GPS aiding signal where only said remote subscription units having procured said subscriptions are enabled to decrypt said items.
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Abstract
A GPS information service system for providing supplemental GPS location correction and signal acquisition information to subscribers. A GPS information server broadcasts GPS information encrypted with subscription keys. Remote GPS subscription unit receive the key enablers for the subscription keys in service activation (SAM) messages for the services for which they have subscribed and then use the subscription keys to decrypt the GPS information. In order to prevent unauthorized use, the SAM messages have signatures derived from identifications of the remote GPS subscription units using an unsymmetrical signature algorithm.
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Citations
22 Claims
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1. A global positioning system (GPS) information server system, comprising:
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at least one GPS correction reference station for generating GPS correction information for improving a GPS-based position estimate; a GPS acquisition processor for generating GPS acquisition information for reducing time for acquiring a GPS signal; and a subscription encrypter for encrypting items of said GPS correction and acquisition information according to subscriptions, respectively, procured for remote subscription units; and
disposing said items into a GPS aiding signal where only said remote subscription units having procured said subscriptions are enabled to decrypt said items. - View Dependent Claims (2, 3)
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4. A global positioning system (GPS) information server system, comprising:
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at least one GPS correction reference station for generating GPS correction information; a GPS acquisition processor for providing information for a sequence of expected GPS data bits for a certain future time for a GPS signal; and a remote GPS subscription unit for receiving a GPS aiding signal having said expected data bit sequence information and said GPS correction information;
using said expected data bit sequence for acquiring a GPS signal with coherent integration of said GPS signal over a time period greater than a GPS data bit; and
then using said GPS correction information for improving accuracy of a GPS-based position estimate.
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5. A global positioning system (GPS) information server system, comprising:
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at least one GPS correction reference station for generating GPS correction information; a GPS acquisition processor for providing a sequence of GPS data bits received at a certain past time; and a remote GPS subscription unit for storing a representation of said GPS signal;
receiving a GPS aiding signal having said past GPS data bit sequence;
using said past GPS data bit sequence for coherent integration of said GPS signal representation over a time period greater than a GPS data bit; and
then using said GPS correction information for improving accuracy of a GPS-based position estimate.
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6. A global positioning system (GPS) information server system, comprising:
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at least one GPS correction reference station for generating GPS correction information for improving a GPS-based position estimate; a GPS acquisition processor for generating GPS acquisition information for reducing time for acquiring a GPS signal; a subscription encrypter for encrypting portions of said GPS correction and acquisition information with subscription keys, respectively; and several remote subscription units for receiving a GPS aiding signal having said encrypted portions of said GPS correction and acquisition information, each of said subscription units having a GPS information decrypter for decrypting said portions of said GPS correction and acquisition information in said remote subscription units having possession of said respective subscription keys. - View Dependent Claims (7, 8, 9, 10, 11)
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12. A method for aiding the operation of a global positioning system (GPS) receiver, comprising:
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generating GPS correction information for correcting a GPS-based position estimate; generating GPS acquisition information for increasing speed of acquisition of a GPS signal; encrypting items of said GPS correction and acquisition information according to subscriptions, respectively, procured for remote subscription units; and disposing said items in a GPS aiding signal for receipt by said remote subscription units where only said remote subscription units having procured said subscriptions are enabled to decrypt said items. - View Dependent Claims (13, 14)
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15. A method for aiding the operation of a global positioning system (GPS) receiver, comprising:
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generating GPS correction information for correcting a GPS-based position estimate; providing information for a sequence of expected GPS data bits for a certain future time for a GPS signal; in a remote GPS receiver, receiving a GPS aiding signal having said expected data bit sequence information and said GPS correction information; using said expected data bit sequence for coherent integration of said GPS signal over a time period greater than a GPS data bit for acquiring said GPS signal in said remote GPS receiver; and using said GPS correction information for improving accuracy of a GPS-based position estimate of said remote GPS receiver.
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16. A method for aiding the operation of a global positioning system (GPS) receiver, comprising:
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generating GPS correction information for correcting a GPS-based position estimate; determining a sequence of GPS data bits for a certain past time; in a remote GPS receiver, receiving a GPS aiding signal having said GPS correction information and said past data bit sequence; storing a representation of said GPS signal in said remote GPS receiver; using said past data bit sequence in said remote GPS subscription unit for coherent integration of said GPS signal representation over a time period greater than a GPS data bit; and using said GPS correction information for improving accuracy of a GPS-based position estimate of said remote GPS receiver.
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17. A method for aiding the operation of a global positioning system (GPS) receiver, comprising:
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generating GPS correction information for correcting a GPS-based position estimate; generating GPS acquisition information for increasing speed of acquisition of a GPS signal; encrypting portions of said GPS correction and acquisition information with subscription keys, respectively; receiving a GPS aiding signal in several remote subscription units, said GPS aiding signal having said encrypted portions of said GPS correction and acquisition information; and decrypting said portions of said GPS correction and acquisition information in said remote subscription units having possession of said respective subscription keys. - View Dependent Claims (18, 19, 20, 21, 22)
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Specification