Method and apparatus for generating time of arrival estimates for use in determining a location
First Claim
1. A method of generating time of arrival estimates for use in determining the location of a mobile unit within a wireless communication network comprising:
- receiving a plurality of data bursts from a group of base sites during a burst collection period;
determining a time of arrival value for each of the data bursts;
selecting the time of arrival values, which more closely correspond to a line of sight path;
estimating a drift value of a reference clock for each of the base sites from the selected time of arrival values; and
generating a time of arrival estimate for each of the base sites corresponding to a particular time during the burst collection period.
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Abstract
The present invention provides a method and apparatus for generating time of arrival estimates for use by a wireless communication network for locating the position of a wireless or mobile source (102) within the service area of the wireless communication network. The mobile source generates time of arrival estimates from data bursts received from base sites (100) operating within the network. In at least one embodiment, the mobile source (102), then, communicates the time of arrival estimates for each of the base sites (100) to the network, from which the location of the mobile source (102) is determined. In at least some instances, the mobile units additionally determine a variance estimate for each time of arrival estimates, which is representative of the degree of confidence in the time of arrival information being supplied to the network.
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Citations
37 Claims
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1. A method of generating time of arrival estimates for use in determining the location of a mobile unit within a wireless communication network comprising:
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receiving a plurality of data bursts from a group of base sites during a burst collection period;
determining a time of arrival value for each of the data bursts;
selecting the time of arrival values, which more closely correspond to a line of sight path;
estimating a drift value of a reference clock for each of the base sites from the selected time of arrival values; and
generating a time of arrival estimate for each of the base sites corresponding to a particular time during the burst collection period. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
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34. A processor unit for use in a wireless communication device, coupled to a receiver, which generates a time of arrival estimate for each of a group of base sites, said processor unit comprising:
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a processor;
an interface circuitry coupled to said processor and the receiver for configuring the receiver to receive signals corresponding to the group of base sites, and for receiving a plurality of data bursts;
a storage unit coupled to said processor for storing sampling data of the plurality of data bursts and one or more sets of instructions for execution by the processor including prestored instructions for receiving a plurality of data bursts from a group of base sites during a burst collection period and determining a time of arrival value for each of the data bursts, prestored instructions for selecting the time of arrival values, which more closely correspond to a line of sight path and estimating a drift value of a reference clock for each of the base sites from the selected time of arrival values, and prestored instructions for generating a time of arrival estimate for each of the base sites corresponding to a particular time during the burst collection period.
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35. A wireless communication device comprising:
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an antenna;
a receiver coupled to said antenna;
a processor unit coupled to said receiver including a processor;
an interface circuitry coupled to said processor and the receiver for configuring the receiver to receive signals corresponding to the group of base sites, and for receiving a plurality of data bursts;
a storage unit coupled to said processor for storing sampling data of the plurality of data bursts and one or more sets of instructions for execution by the processor including prestored instructions for receiving a plurality of data bursts from a group of base sites during a burst collection period and determining a time of arrival value for each of the data bursts, prestored instructions for selecting the time of arrival values, which more closely correspond to a line of sight path and estimating a drift value of a reference clock for each of the base sites from the selected time of arrival values, and prestored instructions for generating a time of arrival estimate for each of the base sites corresponding to a particular time during the burst collection period. - View Dependent Claims (36)
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37. A processor unit for use in a wireless communication device, coupled to a receiver, which generates a time of arrival estimate for each of a group of base sites, said processor unit comprising:
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a sampling circuit for producing multiple sampling points from a received signal;
a correlator coupled to the sampling circuit for correlating the sampling points with a corresponding predetermined data pattern and determining a time of arrival value for each data burst;
a discriminator circuit coupled to the correlator for selecting the time of arrival values, which most closely correspond to a line of sight path;
a drift estimator coupled to the discriminator circuit for estimating an estimated drift value of a reference clock for each of the base stations from the selected time of arrival values;
a time of arrival estimator coupled to the drift estimator for estimating a time of arrival value from the estimated drift calculation for each of the base stations for a selected substantially consistent point in time; and
a variance calculator coupled to the time of arrival estimator for computing a variance value corresponding to the accumulated degree of deviation of the time of arrival value determined by the time of arrival estimator.
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Specification