System and method for estimating the location of a mobile device
First Claim
1. A method for estimating the location of a first mobile station from a plurality of mobile stations that receive signals from a plurality of base stations, comprising:
- (a) determining observed time difference of arrival (“
OTDOA”
) values at said first mobile station and at a second mobile station between a first signal received from a first base station and a second signal received from a second base station;
(b) determining a round trip time (“
RTT”
) values between said first and second mobile stations and said first base station;
(c) selecting an initial locations for said first and second mobile stations that are within a first and second predetermined areas, respectively;
(d) determining an estimated base station time offset (“
BSTO”
) using the selected initial locations, the OTDOA and RTT values, and an iterative search algorithm wherein the iterative search algorithm iterates a predetermined number of steps;
(e) determining an estimated location for said first mobile station jointly with the BSTO;
(f) storing said estimated location if the estimated location is within a third predetermined area;
(g) repeating (a) through (f) within a predetermined time interval; and
(h) determining a calculated location for said first mobile station from the stored estimated locations.
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Accused Products
Abstract
A system and method for estimating the location of a mobile station that receives signals from a plurality of base stations. The base station timing offsets may be estimated utilizing an observed time difference of arrival value at the mobile between a first signal received from a first base station and a second signal received from a second base station. An initial location for the mobile is randomly selected and an estimated location is determined using the selected initial location, the observed time difference of arrival value, and an iterative search algorithm. The estimated location may be stored if the estimated location is within a predetermined area. In addition, for each such estimated location, the applicable base station time offsets that relate to this location may be updated to generate a current best estimate. A calculated location for the mobile may be determined from stored estimated locations and the current base station time offset estimates.
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Citations
47 Claims
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1. A method for estimating the location of a first mobile station from a plurality of mobile stations that receive signals from a plurality of base stations, comprising:
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(a) determining observed time difference of arrival (“
OTDOA”
) values at said first mobile station and at a second mobile station between a first signal received from a first base station and a second signal received from a second base station;(b) determining a round trip time (“
RTT”
) values between said first and second mobile stations and said first base station;(c) selecting an initial locations for said first and second mobile stations that are within a first and second predetermined areas, respectively; (d) determining an estimated base station time offset (“
BSTO”
) using the selected initial locations, the OTDOA and RTT values, and an iterative search algorithm wherein the iterative search algorithm iterates a predetermined number of steps;(e) determining an estimated location for said first mobile station jointly with the BSTO; (f) storing said estimated location if the estimated location is within a third predetermined area; (g) repeating (a) through (f) within a predetermined time interval; and (h) determining a calculated location for said first mobile station from the stored estimated locations. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method for estimating the location of a first mobile station and a second mobile station where each mobile station receives signals from the same plurality of base stations, comprising:
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(a) determining a first observed time difference of arrival (“
OTDOA1”
) value at said first mobile station between a first signal received from a first base station and a second signal received from a second base station;(b) determining a second observed time difference of arrival (“
OTDOA2”
) value at said second mobile station between a third signal received from said first base station and a fourth signal received from said second base station;(c) determining a first round trip time (“
RTT1”
) value between said first mobile station and said first base station;(d) determining a second round trip time (“
RTT2”
) value between said second mobile station and said second base station;(e) selecting a first initial location for said first mobile station that is within a first predetermined area; (f) selecting a second initial location for said second mobile station that is within a second predetermined area; (g) determining an estimated base station time offset (“
BSTO”
) using the selected initial locations, the OTDOA1 value, the OTDOA2 value, the RTT1 value, the RTT2 value, and an iterative search algorithm wherein the iterative search algorithm iterates a predetermined number of steps;(h) determining a first estimated location for said first mobile station and a second estimated location for said second mobile station jointly with the BSTO; (i) storing the first estimated location if said first estimated location is within a third predetermined area; (j) storing the second estimated location if said second estimated location is within a fourth predetermined area; (k) repeating (a) through (j) within a predetermined time interval; and (l) determining a first calculated location for said first mobile station and a second calculated location for said second mobile station from the stored estimated locations. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
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31. A method for estimating the location of a first mobile station and a second mobile station where each mobile station receives signals from the same plurality of base stations, comprising:
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(a) determining a first observed time difference of arrival (“
OTDOA1”
) value at said first mobile station between a first signal received from a first base station and a second signal received from a second base station;(b) determining a second observed time difference of arrival (“
OTDOA2”
) value at said second mobile station between a third signal received from said first base station and a fourth signal received from said second base station;(c) selecting a first initial location for said first mobile station that is within a first predetermined area; (d) selecting a second initial location for said second mobile station that is within a second predetermined area; (e) determining an estimated base station time offset (“
BSTO”
) using the selected initial locations, the OTDOA1 value, the OTDOA2 value, and an iterative search algorithm wherein the iterative search algorithm iterates a predetermined number of steps;(f) determining a first estimated location for said first mobile station and a second estimated location for said second mobile station jointly with the BSTO; (g) storing the first estimated location if said first estimated location is within a third predetermined area; (h) storing the second estimated location if said second estimated location is within a fourth predetermined area; (i) repeating (a) through (h) within a predetermined time interval; and (j) determining a first calculated location for said first mobile station and a second calculated location for said second mobile station from the stored estimated locations. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47)
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Specification