Wireless assisted GPS using a reference location
First Claim
1. A method of assisting location comprising the steps of:
- estimating a PRN synchronization and a Doppler shift for a satellite signal at a reference location and a reference time in the future for a wireless terminal, the reference time being a time in the future that is greater than a time required for demodulation and decoding of the PRN synchronization and Doppler shift estimates by the wireless terminal; and
transmitting the PRN synchronization and Doppler shift estimates to the wireless terminal.
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Accused Products
Abstract
The invention is directed towards a method for estimating a PRN synchronization and Doppler shift of a satellite signal at a reference location within a cell and sector of where a wireless terminal or WAG client is located. The estimates are based on information conveyed by a GPS signal acquired by an auxiliary system or WAG server, which may be at a location different from the wireless terminal or WAG client. The PRN synchronization and Doppler shift estimates are also based on some reference time, which is a time that is sufficiently far into the future to allow the WAG client to demodulate and decode the PRN synchronization and Doppler shift estimates from an assisting message transmitted by the WAG server and to use such estimates to acquire GPS signals, wherein the assisting message indicates the PRN synchronization and Doppler shift estimates.
61 Citations
13 Claims
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1. A method of assisting location comprising the steps of:
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estimating a PRN synchronization and a Doppler shift for a satellite signal at a reference location and a reference time in the future for a wireless terminal, the reference time being a time in the future that is greater than a time required for demodulation and decoding of the PRN synchronization and Doppler shift estimates by the wireless terminal; and
transmitting the PRN synchronization and Doppler shift estimates to the wireless terminal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of assisting location comprising the steps of:
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estimating a PRN synchronization and Doppler shift for a reference event in the future; and
transmitting the PRN synchronization and Doppler shift estimates at regular intervals to a client based on the reference event, the reference event including a reference time in the future that is greater than a time required for demodulation and decoding of the transmitted PRN synchronization and Doppler shift estimates by the client. - View Dependent Claims (10, 11, 12, 13)
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Specification