Method and apparatus for determining absolute time-of-day in a mobile-assisted satellite positioning system
First Claim
1. A method of determining time-of-day in a mobile receiver, the method comprising:
- obtaining expected pseudoranges to a plurality of satellites, said expected pseudoranges based on an initial position of said mobile receiver and an initial time-of-day;
obtaining expected line-of-sight data to said plurality of satellites;
measuring pseudoranges from said mobile receiver to said plurality of satellites;
computing update data for said initial time-of-day using a mathematical model relating said pseudoranges, said expected pseudoranges, and said expected line-of-sight data;
updating said initial time-of-day using said update data to compute a time-tag; and
transmitting said pseudoranges and said time-tag to a server in wireless communication with said mobile receiver.
6 Assignments
0 Petitions
Accused Products
Abstract
A method and apparatus for determining time-of-day in a mobile receiver is described. In one example, expected pseudoranges to a plurality of satellites are obtained. The expected pseudoranges are based on an initial position of the mobile receiver and an initial time-of-day. Expected line-of-sight data to said plurality of satellites is also obtained. Pseudoranges from said mobile receiver to said plurality of satellites are measured. Update data for the initial time-of-day is computed using a mathematical model relating the pseudoranges, the expected pseudoranges, and the expected line-of-sight data. The expected pseudoranges and the expected line-of-sight data may be obtained from acquisition assistance data transmitted to the mobile receiver by a server. Alternatively, the expected pseudoranges may be obtained from acquisition assistance data, and the expected line-of-sight data may be computed by the mobile receiver using stored satellite trajectory data, such as almanac data.
11 Citations
41 Claims
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1. A method of determining time-of-day in a mobile receiver, the method comprising:
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obtaining expected pseudoranges to a plurality of satellites, said expected pseudoranges based on an initial position of said mobile receiver and an initial time-of-day; obtaining expected line-of-sight data to said plurality of satellites; measuring pseudoranges from said mobile receiver to said plurality of satellites; computing update data for said initial time-of-day using a mathematical model relating said pseudoranges, said expected pseudoranges, and said expected line-of-sight data; updating said initial time-of-day using said update data to compute a time-tag; and transmitting said pseudoranges and said time-tag to a server in wireless communication with said mobile receiver. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of determining time-of-day in a mobile receiver, the method comprising:
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obtaining expected pseudoranges to a plurality of satellites, said expected pseudoranges based on an initial position of said mobile receiver and an initial time-of-day; obtaining expected line-of-sight data to said plurality of satellites; measuring pseudoranges from said mobile receiver to said plurality of satellites; computing update data for said initial time-of-day using a mathematical model relating said pseudoranges, said expected pseudoranges, and said expected line-of-sight data; measuring pseudorange rates at said mobile receiver; obtaining almanac data; and computing an approximate position of said mobile receiver using said pseudorange rates and said almanac data, wherein said expected line-of-sight data is obtained in response to said approximate position and said almanac data. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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14. A method of determining time-of-day in a mobile receiver, the method comprising:
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obtaining expected pseudoranges to a plurality of satellites, said expected pseudoranges based on an initial position of said mobile receiver and an initial time-of-day; obtaining expected line-of-sight data to said plurality of satellites; measuring pseudoranges from said mobile receiver to said plurality of satellites; computing update data for said initial time-of-day using a mathematical model relating said pseudoranges, said expected pseudoranges, and said expected line-of-sight data; obtaining almanac data; and obtaining an estimated position of said mobile receiver, wherein said expected line-of-sight data is obtained in response to said estimated position and said almanac data. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21)
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22. An apparatus for determining time-of-day in a mobile receiver, the apparatus comprising:
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a wireless transceiver for obtaining acquisition assistance data from a server, said acquisition assistance data comprising expected pseudoranges to a plurality of satellites based on an initial position of said mobile receiver and an initial time-of-day; a satellite signal receiver for measuring pseudoranges from said mobile receiver to said plurality of satellites; a processor for obtaining expected line-of-sight data to said plurality of satellites and for computing update data for said initial time-of-day using a mathematical model relating said pseudoranges, said expected pseudoranges, and said expected line-of-sight data; and a clock circuit, wherein said processor is further configured to calibrate said clock circuit using said update data. - View Dependent Claims (23, 24, 25, 26, 27)
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28. An apparatus for determining time-of-day in a mobile receiver, the apparatus comprising:
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a wireless transceiver for obtaining acquisition assistance data from a server, said acquisition assistance data comprising expected pseudoranges to a plurality of satellites based on an initial position of said mobile receiver and an initial time-of-day; a memory for storing almanac data associated with a constellation having said plurality of satellites; a satellite signal receiver for measuring pseudoranges from said mobile receiver to said plurality of satellites and for measuring pseudorange rates; and a processor for; obtaining expected line-of-sight data to said plurality of satellites; computing update data for said initial time-of-day using a mathematical model relating said pseudoranges, said expected pseudoranges, and said expected line-of-sight data; computing an approximate position of said mobile receiver using said pseudorange rates and said almanac data; and obtaining said expected line-of-sight data in response to said approximate position and said almanac data. - View Dependent Claims (29, 30, 31, 32, 33)
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34. An apparatus for determining time-of-day in a mobile receiver, the apparatus comprising:
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a wireless transceiver for obtaining acquisition assistance data from a server, said acquisition assistance data comprising expected pseudoranges to a plurality of satellites based on an initial position of said mobile receiver and an initial time-of-day; a memory for storing almanac data associated with a constellation having said plurality of satellites; a satellite signal receiver for measuring pseudoranges from said mobile receiver to said plurality of satellites; and a processor for; obtaining expected line-of-sight data to said plurality of satellites; computing update data for said initial time-of-day using a mathematical model relating said pseudoranges, said expected pseudoranges, and said expected line-of-sight data; computing an approximate position of said mobile receiver using an estimated position of said mobile receiver and said almanac data; and obtaining said expected line-of-sight data in response to said approximate position and said almanac data. - View Dependent Claims (35, 36, 37, 38, 39)
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40. A position location system, comprising:
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a mobile receiver comprising; a wireless transceiver; a satellite signal receiver for measuring pseudoranges from said mobile receiver to a plurality of satellites; and a processor; and a server, in wireless communication with said mobile receiver, for transmitting acquisition assistance data to said mobile receiver, said acquisition assistance data comprising expected pseudoranges to said plurality of satellites based on an initial position of said mobile receiver and an initial time-of-day, wherein said processor is configured to obtain expected line-of-sight data to said plurality of satellites and to compute update data for said initial time-of-day using a mathematical model relating said pseudoranges, said expected pseudoranges, and said expected line-of-sight data; and
wherein said wireless transceiver is configured to transmit said measured pseudoranges and said update data to said server. - View Dependent Claims (41)
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Specification