Method and system for all-in-view coherent GPS signal PRN codes acquisition and navigation solution determination
First Claim
1. A method for rapidly acquiring and using a plurality of satellite ranging signals having satellite codes to rapidly determine a real time position of a user receiver, the method comprising:
- using a wireless assist link to transmit to the user receiver, from a base station, a set of initialization data and base-station-location data to limit a search space grid, in which the user receiver is located, to predetermined geographic dimensions;
wherein using wireless link to transmit said initialization data and said base-station-location data includes using the base station to transmit to the user receiver;
a time synch function to enable the user receiver to synchronize a user receiver clock associated with the user receiver, andsatellite ranging data at an epoch time, the satellite ranging data having been previously received at the base station;
using the user receiver to search a plurality of grid points locations making up the search space grid based on the base-station-location data and acquire simultaneously at least one of the satellite codes from a plurality of satellites in view of the user receiver; and
when a plurality of satellite codes are received at any one or more of the grid point locations, using the user receiver to coherently combine the power outputs of the received satellite codes at each one of said grid points, and to detect therefrom a probable location of the user receiver.
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Accused Products
Abstract
A method and system of the present disclosure allow for a more robust detection of GPS satellite ranging signals based on a simultaneous, all-in-view coherent PRN code signal processing scheme rather than acquisition of GPS signals one at a time. Additionally, the method and system may enable 10 dB or more improvement in signal-to-ratio (SNR) acquisition performance of the combined signals when compared to conventional acquisition approaches of acquiring GPS PRN code signals one at a time. The method and system also automatically enables removal of ranging errors common to both the user and base station and minimizes the introduction of multi-path errors into code phase measurements.
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Citations
19 Claims
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1. A method for rapidly acquiring and using a plurality of satellite ranging signals having satellite codes to rapidly determine a real time position of a user receiver, the method comprising:
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using a wireless assist link to transmit to the user receiver, from a base station, a set of initialization data and base-station-location data to limit a search space grid, in which the user receiver is located, to predetermined geographic dimensions; wherein using wireless link to transmit said initialization data and said base-station-location data includes using the base station to transmit to the user receiver; a time synch function to enable the user receiver to synchronize a user receiver clock associated with the user receiver, and satellite ranging data at an epoch time, the satellite ranging data having been previously received at the base station; using the user receiver to search a plurality of grid points locations making up the search space grid based on the base-station-location data and acquire simultaneously at least one of the satellite codes from a plurality of satellites in view of the user receiver; and when a plurality of satellite codes are received at any one or more of the grid point locations, using the user receiver to coherently combine the power outputs of the received satellite codes at each one of said grid points, and to detect therefrom a probable location of the user receiver. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for determining a position of a user receiver using satellite ranging signals, comprising:
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transmitting to a user receiver, from a base station via a wireless assist link, initialization data including time synchronization data to enable said user receiver to synchronize to a clock of said base station, and base-station-location data to limit a search by the user receiver for a plurality of satellite ranging signals to a predetermined geographic area circumscribing a present location of the user terminal; using the user receiver to search within the predetermined geographic area having a plurality of grid point locations for each of the plurality of satellite ranging signals from each spaced-based GPS satellite that is within view of the user receiver; using the user receiver to combine, coherently, a power output of all received ones of said ranging signals at each of the plurality of grid point locations within the predetermined geographic area, to determine a maximum power output value; and having the user receiver use the maximum power output value to determine a probable location of the user terminal. - View Dependent Claims (11, 12, 13, 14, 15, 16, 18, 19)
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17. A global positioning system (GPS) for rapidly determining a position of a user receiver from satellite ranging signals from a plurality of satellites in view of the user receiver, comprising:
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a plurality of GPS satellites configured to produce a plurality of GPS satellite ranging signals having a pseudo random code; a base station having a base station receiver clock, and configured to generate a set of initialization data including a time synch function, and base-station-location data to limit a search space grid to predetermined geographic dimensions, the base station is further configured to receive the plurality of GPS satellite ranging signals to produce time aiding data to synchronize a user receiver clock to reduce time error for the search space grid and aid acquisition of the plurality of GPS ranging signals and to transmit the time aiding data and the set of initialization data; and a user receiver in wireless communication with the base station and is configured to receive the set of initialization data and the time aiding data, the user receiver is further configured to receive the time synch function to synchronize a user receiver clock with the base station receiver clock, and ranging data associated with said ranging signals, at an epoch time, the user receiver configured to search a plurality of grid points within the search space grid based on the base-station-location data and to acquire simultaneously each of the ranging signals at each said grid point from the plurality of satellites in view of the user receiver, and the user receiver being further configured to coherently sum power outputs of the received ranging signals from satellites that are received at each of one said grid points, to determine a maximum power output at each said grid point, and to use said maximum power output to detect therefrom a probable location of the user receiver.
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Specification