Event location determination
First Claim
1. A method of determining a location of an event of interest by processing signals from a satellite positioning system, the method comprising:
- periodically recording, in a storage-device, blocks of data samples of a satellite broadcast, wherein said blocks of data samples are generated by an RF front end of a portable battery-operated device;
in response to a request for a position determination at a particular time, processing, using a processor, a most recent block of data samples in an attempt to obtain a position fix,wherein if the attempt to obtain a position fix is unsuccessful, the method further comprises processing, using the processor, blocks of data samples which were recorded further back in time in a sequence to make further attempts to obtain a position fix, until a position fix is obtained successfully,wherein the blocks of data samples used for the further attempts relate to time instants which are irregularly spaced before the particular time.
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Accused Products
Abstract
A method of determining a location of an event of interest by processing signals from a satellite positioning system comprises periodically recording blocks of data samples of a satellite broadcast. In response to a request for a position determination at a particular time, a most recent block of data samples is processed in an attempt to obtain a position fix. If unsuccessful, the method further comprises processing blocks of data samples which were recorded further back in time in a sequence to make further attempts to obtain a position fix, until a position fix is obtained. The blocks of data samples used for the further attempts are irregularly spaced in time, for example more densely populated in relatively recent time than in relatively ancient time with respect to the particular time. This enables the processing resource in attempting to obtain a position fix to be allocated efficiently, thereby reducing power consumption.
5 Citations
18 Claims
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1. A method of determining a location of an event of interest by processing signals from a satellite positioning system, the method comprising:
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periodically recording, in a storage-device, blocks of data samples of a satellite broadcast, wherein said blocks of data samples are generated by an RF front end of a portable battery-operated device; in response to a request for a position determination at a particular time, processing, using a processor, a most recent block of data samples in an attempt to obtain a position fix, wherein if the attempt to obtain a position fix is unsuccessful, the method further comprises processing, using the processor, blocks of data samples which were recorded further back in time in a sequence to make further attempts to obtain a position fix, until a position fix is obtained successfully, wherein the blocks of data samples used for the further attempts relate to time instants which are irregularly spaced before the particular time. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A computer program embodied on a computer readable storage medium, comprising computer program code which when executed by a computer performs the steps of:
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periodically recording, in a storage-device, blocks of data samples of a satellite broadcast, wherein said blocks of data samples are generated by an RF front end of a portable battery-operated device; in response to a request for a position determination at a particular time, processing, using a processor, a most recent block of data samples in an attempt to obtain a position fix, wherein if the attempt to obtain a position fix is unsuccessful, the program further comprises processing, using the processor, blocks of data samples which were recorded further back in time in a sequence to make further attempts to obtain a position fix, until a position fix is obtained successfully, wherein the blocks of data samples used for the further attempts relate to time instants which are irregularly spaced before the particular time.
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18. Apparatus for determining a location of an event of interest by processing signals from a satellite positioning system, the apparatus comprising:
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first receiving means, adapted to periodically record blocks of data samples of a satellite broadcast; a processor which is adapted; in response to a request for a position determination at a particular time, to process a most recent block of data samples in an attempt to obtain a position fix, if the attempt to obtain a position fix is unsuccessful, to process blocks of data samples which were recorded further back in time in a sequence to make further attempts to obtain a position fix, until a position fix is obtained, wherein the blocks of data samples used for the further attempts relate to time instants which are irregularly spaced before the particular time.
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Specification