Method and apparatus for assisted GPS
First Claim
1. A method for maintaining the integrity of a mobile handset'"'"'s location determination in a system comprising the mobile handset, radio communication infrastructure and a Differential Global Positioning System (DGPS) reference receiver coupled to the radio communication infrastructure and installed at a predetermined location, the DGPS reference receiver receiving GPS information from a plurality of GPS satellites, the method comprising:
- said radio communication infrastructure receiving DGPS information from the DGPS reference receiver;
deriving differential correction data from said DGPS information;
determining whether one or more of said plurality of GPS satellites have failed/are failing, based on the differential correction data;
generating a failed satellite message when it is determined that one or more of said plurality of GPS satellites have failed/are failing, said failed satellite message identifying the one or more of said plurality of GPS satellites that have failed/are failing; and
transmitting the failed satellite message identifying the one or more of said plurality of GPS satellites that have failed/are failing when it is determined that the one or more of said plurality of GPS satellites has failed/are failing.
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Accused Products
Abstract
A cellular network protocol that maintains the reliability of assisted GPS based positioning is taught. An Integrity Monitor (IM) informs mobile stations, their users, or networks of measurement quality and it warns them of failing and failed GPS satellites by isolating them from the effects of these failures. Whenever an unhealthy satellite is detected, its corresponding assistance data will be excluded for delivery or for position determination. In other words, there are two specific aspects to the Integrity Monitor (IM). For DGPS users, it predicts the reliability or quality of the DGPS corrections. For all users, it isolates the mobile position calculation from the effects of GPS satellite failures. The UDRE parameter, nominally output by a reference DGPS receiver, is used to communicate the DGPS quality information, and DGPS corrections are simply excluded for failed satellites. For autonomous GPS users, a special integrity message is required and defined to communicate the satellite failure status information.
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Citations
25 Claims
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1. A method for maintaining the integrity of a mobile handset'"'"'s location determination in a system comprising the mobile handset, radio communication infrastructure and a Differential Global Positioning System (DGPS) reference receiver coupled to the radio communication infrastructure and installed at a predetermined location, the DGPS reference receiver receiving GPS information from a plurality of GPS satellites, the method comprising:
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said radio communication infrastructure receiving DGPS information from the DGPS reference receiver;
deriving differential correction data from said DGPS information;
determining whether one or more of said plurality of GPS satellites have failed/are failing, based on the differential correction data;
generating a failed satellite message when it is determined that one or more of said plurality of GPS satellites have failed/are failing, said failed satellite message identifying the one or more of said plurality of GPS satellites that have failed/are failing; and
transmitting the failed satellite message identifying the one or more of said plurality of GPS satellites that have failed/are failing when it is determined that the one or more of said plurality of GPS satellites has failed/are failing. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for maintaining the integrity of a mobile handset'"'"'s location determination in a radio communication system, the method comprising:
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determining whether one or more of said plurality of GPS satellites have failed/are failing within a specified after failure;
generating an integrity message identifying which of said plurality of GPS satellites have failed/are failing; and
transmitting the integrity message to said mobile handset. - View Dependent Claims (9, 10, 11, 12, 13, 15, 16, 17, 18, 20, 21, 22, 23, 24, 25)
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14. A satellite positioning system integrity maintenance method in a mobile handset, comprising:
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receiving differential correction data for said mobile handset;
determining whether any satellite of the satellite positioning system has failed, including whether any satellite is failing, based on the differential correction data;
excluding information from any failed and failing satellites from mobile handset position solution determinations.
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19. A method for maintaining integrity of a satellite positioning system based location fix in a cellular communications network, comprising:
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determining whether any satellite of the satellite positioning system has failed, including whether any satellite is failing;
if a satellite has failed, including if any satellite is failing, generating an integrity message identifying the satellite that has failed/is failing; and
transmitting the integrity message from the cellular communications network.
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Specification