Mobile station location determination in a radio communication system
First Claim
1. A method for position location by a mobile station in a radio communication system, the method comprising the steps of:
- receiving at the mobile station satellite position curve fit data transmitted from a base station of the radio communication system; and
determining a position of the mobile station using the satellite position curve fit data.
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Accused Products
Abstract
A method and apparatus for location determination of a mobile station (304) in a fixed radiocommunication system having at least one base station (302) reduces the computational load on the mobile station. Satellite ephemeris information and clock correction information are received at a base station and periodically used to calculate satellite position data. The satellite position data are conveyed to the mobile station. At other times, the satellite ephemeris data is used to calculate curve fit data at the base station. The curve fit data is transmitted to the mobile station, reducing the amount of data conveyed over the communication link and the computation load on the mobile station.
185 Citations
33 Claims
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1. A method for position location by a mobile station in a radio communication system, the method comprising the steps of:
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receiving at the mobile station satellite position curve fit data transmitted from a base station of the radio communication system; and
determining a position of the mobile station using the satellite position curve fit data. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
receiving at the mobile station from the base station clock correction curve fit data; and
determining the position of the mobile station using the clock correction curve fit data.
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3. The method of claim 1 wherein receiving the satellite position curve fit data comprises the steps of:
receiving data related to position and velocity of a plurality of earth orbiting satellites.
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4. The method of claim 3 wherein determining the position of the mobile station comprises the steps of:
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determining positions of each satellite of the plurality of satellites using the data; and
determining the position of the mobile station using the positions of each satellite.
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5. The method of claim 4 further comprising the steps of:
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receiving a signal at the mobile station from at least some satellites of the plurality of satellites;
in response to the signal, determining pseudo-ranges between the mobile station and the at least some satellites; and
determining the position of the mobile station using the positions of each satellite and the pseudo-ranges.
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6. The method of claim 1 wherein receiving the satellite position curve fit data comprises:
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receiving a broadcast transmission of the base station; and
detecting the satellite position curve fit data in the broadcast transmission.
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7. The method of claim 6 wherein receiving the broadcast transmission comprises the step of:
detecting a paging channel transmitted by the base station for all mobile stations in a geographic area served by the base station.
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8. The method of claim 1 wherein receiving the satellite position and clock correction curve fit data comprises:
detecting a point-to-point transmission from the base station intended for the mobile station.
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9. The method of claim 8 further comprising the steps of:
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transmitting from the mobile station to the base station a request for position data; and
receiving the satellite position curve fit data in response to the request.
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10. A method for mobile station location determination in a radio communication system which includes a plurality of base stations configured for radio communication with at least one mobile station, the method comprising the steps of:
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(a) receiving at a base station of the radio communication system satellite ephemeris information and clock correction information for at least one earth orbiting satellite;
(b) transmitting from the base station at predetermined intervals satellite position curve fit data and clock correction data;
(c) at a mobile station, receiving the satellite position curve fit data and the clock correction data; and
(d) at the mobile station, determining a position for the at least one satellite using the satellite position curve fit data and clock correction data. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
(e) at the mobile station, determining a position of the mobile station using the position for the at least one satellite.
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12. The method of claim 11 further comprising the steps of:
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(f) at the mobile station, receiving next satellite position curve fit data and clock correction data after a predetermined interval; and
(g) updating the position of the mobile station in response to the next satellite position and curve fit data.
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13. The method of claim 10 wherein step (a) comprises:
receiving the satellite ephemeris information and clock correction information at the base station directly from the at least one earth orbiting satellite.
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14. The method of claim 10 wherein step (a) comprises:
receiving the satellite ephemeris information and clock correction information at the base station from another location in the radio communication system.
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15. The method of claim 10 wherein step (b) comprises a step of:
broadcasting the data for reception by all mobile stations in a geographic area served by the base station.
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16. The method of claim 10 wherein step (b) comprises a step of:
transmitting the data on a paging channel of the radio communication system.
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17. The method of claim 10 further comprising the step of:
(e) transmitting data indicative of the position of the mobile station to a base station of the radio communication system.
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18. A radiotelephone comprising:
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a transceiver configured for two-way communication with a remote base station and to receive satellite position curve fit data transmitted from the base station;
a satellite receiver configured to receive satellite signals from one or more satellites and produce pseudo-range data in response to the satellite signals; and
a processor coupled with the transceiver and the satellite receiver and configured to compute satellite positions of the one or more satellites in response to the satellite position curve fit data and the pseudo-range data. - View Dependent Claims (19, 20)
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21. A base station for a radio communication system, the base station comprising:
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means for receiving satellite ephemeris information and clock correction information;
a processor configured to compute satellite position curve fit data in response to the satellite ephemeris data and clock correction information; and
a transmitter coupled to the processor and configured to transmit the satellite position curve fit data at predetermined intervals. - View Dependent Claims (22, 23)
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24. A method of position location by a mobile station in a radio communication system, the method comprising the steps of:
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receiving raw satellite ephemeris and clock correction data for a plurality of satellites at a base station of the radio communication system;
using the raw satellite ephemeris, computing the true satellite position and velocity data points for the plurality of satellites at at least three periods of time over a predetermined interval;
using the clock correction data, computing clock corrections at the at least three periods of time over the predetermined interval;
selecting a reference point that is near the mobile station;
projecting the satellite position and velocity data points away from the reference point by an amount corresponding to the propagation delay associated with the clock correction data at each of the at least three periods of time;
determining curve fit parameters for the projected satellite position and velocity data points;
transmitting the curve fit parameters to the mobile station; and
at the mobile station, using the curve fit parameters for the projected satellite position and velocity data points to compute position of the mobile station. - View Dependent Claims (25, 26)
in response to the satellite signals, determining pseudo-ranges between the mobile station and the at least some satellites; and
determining the position of the mobile station using the positions of each satellite and the pseudo-ranges.
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27. A global positioning system (GPS) station comprising:
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a local receiver configured to receive satellite position curve fit data for one or more satellites from a local transmitter; and
a processor configured to determine positions of the one or more satellites using the satellite position curve fit data. - View Dependent Claims (28, 29)
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30. A method of assisting satellite acquisition by a mobile radio, the method comprising the steps of:
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receiving at the mobile radio satellite position curve fit data for one or more satellites transmitted from a local transmitter; and
at the mobile radio, determining a restricted range of satellite Doppler and code phase search to reduce acquisition time of the one or more satellites. - View Dependent Claims (31, 32, 33)
receiving at the mobile radio satellite signals broadcast by the one or more satellites;
searching the restricted range of satellite Doppler and code phase; and
locating at least some of the satellite signals.
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32. The method of claim 31 further comprising the step of using the satellite position curve fit data, determining positions of the one or more satellites.
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33. The method of claim 32 further comprising the steps of:
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receiving at the mobile radio clock correction data for the one or more satellites transmitted from the local transmitter; and
using the clock correction data and the positions of the one or more satellites, determining position of the mobile radio.
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Specification