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, 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 at said mobile receiver;
obtaining expected line-of-sight data to said plurality of satellites at said mobile receiver;
measuring pseudoranges from said mobile receiver to said plurality of satellites at said mobile receiver; and
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 at said mobile receiver.
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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.
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Citations
19 Claims
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1. A method of determining time-of-day in a mobile receiver, 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 at said mobile receiver; obtaining expected line-of-sight data to said plurality of satellites at said mobile receiver; measuring pseudoranges from said mobile receiver to said plurality of satellites at said mobile receiver; and 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 at said mobile receiver. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. Apparatus for determining time-of-day in a mobile receiver, comprising:
the mobile receiver, said mobile receiver comprising; 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; and 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. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
Specification