Methods and systems for deriving seed position of a subscriber station in support of unassisted GPS-type position determination in a wireless communication system
First Claim
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1. A method comprising:
- obtaining, by a subscriber station, a first value of a parameter from a first received overhead message;
determining by the subscriber station a satellite-based fix position for the subscriber station from a set of signals from a satellite position determination system;
storing by the subscriber station the first value and the determined satellite-based fix position as an entry in a data structure stored in memory of the subscriber station, the data structure including a plurality of entries comprising corresponding stored satellite-based fix positions associated with corresponding values of at least one parameter obtainable from overhead messages; and
using the stored determined satellite-based fix position as a seed position to facilitate searching for one or more satellite transmissions of the satellite position determination system, in order to derive a GPS-type position fix, when a second value is obtained, from a second received overhead message, that matches the stored first value;
wherein the stored determined satellite-based fix position is retrieved from the entry of the data structure in response to a determination that parameter values of the second received overhead message do not indicate a position of a base station or a base station sector in communication with the subscriber station, wherein the retrieved determined satellite-based fix position is used as the seed position in further response to a further determination that a position uncertainty, derived at least in part based on age of the stored determined satellite-based fix position, associated with the stored determined satellite-based fix position is smaller than an other, aged-based, position uncertainty associated with a most-recent satellite-based position estimate obtained for the subscriber station, and wherein the most-recent satellite-based position estimate is used as the seed position when the position uncertainty, associated with the stored determined satellite-based fix position, is larger than the other position uncertainty associated with the most-recent satellite-based position estimate for the subscriber station.
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Abstract
In a method and system for deriving a seed position of a subscriber station in a wireless communications system in supporting unassisted GPS-type position determination is provided, the subscriber station receives overhead messages from the wireless communications system, and derives the seed position from the parameter values. The subscriber station may use a data structure in its memory and map possible parameter values to corresponding positions that may serve as the seed positions.
40 Citations
29 Claims
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1. A method comprising:
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obtaining, by a subscriber station, a first value of a parameter from a first received overhead message; determining by the subscriber station a satellite-based fix position for the subscriber station from a set of signals from a satellite position determination system; storing by the subscriber station the first value and the determined satellite-based fix position as an entry in a data structure stored in memory of the subscriber station, the data structure including a plurality of entries comprising corresponding stored satellite-based fix positions associated with corresponding values of at least one parameter obtainable from overhead messages; and using the stored determined satellite-based fix position as a seed position to facilitate searching for one or more satellite transmissions of the satellite position determination system, in order to derive a GPS-type position fix, when a second value is obtained, from a second received overhead message, that matches the stored first value; wherein the stored determined satellite-based fix position is retrieved from the entry of the data structure in response to a determination that parameter values of the second received overhead message do not indicate a position of a base station or a base station sector in communication with the subscriber station, wherein the retrieved determined satellite-based fix position is used as the seed position in further response to a further determination that a position uncertainty, derived at least in part based on age of the stored determined satellite-based fix position, associated with the stored determined satellite-based fix position is smaller than an other, aged-based, position uncertainty associated with a most-recent satellite-based position estimate obtained for the subscriber station, and wherein the most-recent satellite-based position estimate is used as the seed position when the position uncertainty, associated with the stored determined satellite-based fix position, is larger than the other position uncertainty associated with the most-recent satellite-based position estimate for the subscriber station. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A subscriber station comprising:
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one or more processors; memory comprising computer instructions that, when executed on the one or more processors, cause operations comprising; obtaining a first value of a parameter from a first received overhead message; determining a satellite-based fix position from a set of signals from a satellite position determination system; storing the first value and the determined satellite-based fix position as an entry in a data structure stored in the memory of the subscriber station, the data structure including a plurality of entries comprising corresponding stored satellite-based fix positions associated with corresponding values of at least one parameter obtainable from overhead messages; and using the stored determined satellite-based fix position as a seed position to facilitate searching for one or more satellite transmissions of the satellite position determination system, in order to derive a GPS-type position fix, when a second value is obtained, from a second received overhead message, that matches the stored first value; wherein the stored determined satellite-based fix position being is retrieved from the entry of the data structure in response to a determination that parameter values of the second received overhead message do not indicate a position of a base station or a base station sector in communication with the subscriber station, wherein the retrieved determined satellite-based fix position is used as the seed position in further response to a further determination that a position uncertainty, derived at least in part based on age of the stored determined satellite-based fix position, associated with the stored determined satellite-based fix position is smaller than an other, aged-based, position uncertainty associated with a most-recent satellite-based position estimate obtained for the subscriber station, and wherein the most-recent satellite-based position estimate is used as the seed position when the position uncertainty, associated with the stored determined satellite-based fix position, is larger than the other position uncertainty associated with the most-recent satellite-based position estimate for the subscriber station. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21)
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22. A non-transitory processor readable media programmed with a set of instructions executable on a processor that, when executed, cause operations comprising:
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obtaining a first value of a parameter from a first received overhead message; determining a satellite-based fix position from a set of signals from a satellite position determination system; storing the first value and the determined satellite-based fix position as an entry in a data structure stored in memory of a subscriber station, the data structure including a plurality of entries comprising corresponding stored satellite-based fix positions associated with corresponding values of at least one parameter obtainable from overhead messages; and using the stored determined satellite-based fix position as a seed position to facilitate searching for one or more satellite transmissions of the satellite position determination system, in order to derive a GPS-type position fix, when a second value is obtained, from a second received overhead message, that matches the stored first value; wherein the stored determined satellite-based fix position is retrieved from the entry of the data structure in response to a determination that parameter values of the second received overhead message do not indicate a position of a base station or a base station sector in communication with the subscriber station, wherein the retrieved determined satellite-based fix position is used as the seed position in further response to a further determination that a position uncertainty, derived at least in part based on age of the stored determined satellite-based fix position, associated with the stored determined satellite-based fix position is smaller than an other, aged-based, position uncertainty associated with a most-recent satellite-based position estimate obtained for the subscriber station, and wherein the most-recent satellite-based position estimate is used as the seed position when the position uncertainty, associated with the stored determined satellite-based fix position, is larger than the other position uncertainty associated with the most-recent satellite-based position estimate for the subscriber station. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29)
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Specification