Enhancement of signal-detection capability of GPS systems
First Claim
1. A method for processing GPS signals modulated with navigation data, comprising the steps of:
- (a) recovering navigation data from a first GPS signal transmitted by a first satellite of a GPS system;
(b) generating estimated navigation data based on the recovered navigation data; and
(c) performing, at a wireless terminal, a data wipe-off operation on a subsequent GPS signal, received by the wireless terminal, wherein the data wipe-off operation is based on the estimated navigation data.
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Accused Products
Abstract
Estimated Global Position System (GPS) navigation data is used to increase the signal integration interval. In one embodiment, a WAG (wireless assisted GPS) server receives GPS signals and demodulates the navigation data modulated onto the GPS signals. The WAG server utilizes known features of the demodulated navigation data to generate estimated navigation data for the satellite. This estimation can be made several seconds or even minutes ahead of time. The wireless terminal uses this estimated navigation data to perform a data wipe-off operation to enable the integration interval to be increased (e.g., beyond 20 ms), thereby increasing overall signal-detection sensitivity at the wireless terminal. In another embodiment, information from strong GPS signals is used to detect weak GPS signals from other satellites. In this embodiment, strong GPS signals are received directly by the wireless terminal from the satellites. After strong GPS signals have been detected, the strong GPS signals are demodulated to compute satellite ephemerides including navigation data. The demodulated navigation data is then matched with known features of the navigation data to estimate the navigation data for weak GPS signals. The estimated navigation data is then used to increase the integration interval for weak GPS signals so that weak GPS signals can also be detected at the wireless terminal.
73 Citations
32 Claims
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1. A method for processing GPS signals modulated with navigation data, comprising the steps of:
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(a) recovering navigation data from a first GPS signal transmitted by a first satellite of a GPS system;
(b) generating estimated navigation data based on the recovered navigation data; and
(c) performing, at a wireless terminal, a data wipe-off operation on a subsequent GPS signal, received by the wireless terminal, wherein the data wipe-off operation is based on the estimated navigation data. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A server for a GPS system, comprising:
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(a) a GPS receiver configured to receive a first GPS signal modulated with navigation data and transmitted from a first satellite of the GPS system;
(b) a demodulator configured to recover the navigation data from the received first GPS signal; and
(c) an estimator configured to generate estimated navigation data from the recovered navigation data, wherein the server is configured to transmit the estimated navigation data for receipt by a wireless terminal configured to perform a data wipe-off operation based on the estimated navigation data. - View Dependent Claims (19, 20)
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21. A wireless terminal for a GPS system, comprising:
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(a) a GPS receiver configured to receive GPS signals modulated with navigation data; and
(b) a data wipe-off processor configured to perform a data wipe-off operation on a GPS signal transmitted by a satellite in the GPS system based on estimated navigation data. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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Specification