Abstract: A technique for estimating the location of a wireless terminal at an unknown location in a geographic region is disclosed. The technique is based on the recognition that there are traits of electromagnetic signals that are dependent on topography, the receiver, the location of the transmitter, and other factors. For example, if a particular radio station is known to be received strongly at a first location and weakly at a second location, and a given wireless terminal at an unknown location is receiving the radio station weakly, it is more likely that the wireless terminal is at the second location than at the first location.

Abstract: A process and machine for estimating the location of a wireless terminal is disclosed. The illustrative embodiment of the present invention is based on the observation that the signal strength of a signal from a transmitter is different at some locations, and, therefore, the location of a wireless terminal can be estimated by comparing the signal strength it currently observes against a map or database that correlates locations to signal strengths. In accordance with a first example, if a particular radio station is known to be received well at a first location and poorly at a second location, and a given wireless terminal at an unknown location is receiving the radio station poorly, it is more likely that the wireless terminal is at the second location than it is at the first location.

Abstract: A method for determining the location of a mobile unit (MU) in a wireless communication system and presenting it to a remote party. The location of a remote MU is determined by comparing a snapshot of a predefined portion of the radio-frequency (RF) spectrum taken by the MU to a reference database containing multiple snapshots taken at various locations. The result of the comparison is used to determine if the MU is at a specific location. The comparison may be made in the MU, or at some other location situated remotely from the MU. In the latter case, sufficient information regarding the captured fingerprint is transmitted from the MU to the remote location. The database may be pre-compiled or generated on-line.

Abstract: A technique for estimating the location of a wireless terminal at an unknown location in a geographic region is disclosed. The technique is based on the recognition that there are traits of electromagnetic signals that are dependent on topography, the receiver, the location of the transmitter, and other factors. For example, if a particular radio station is known to be received strongly at a first location and weakly at a second location, and a given wireless terminal at an unknown location is receiving the radio station weakly, it is more likely that the wireless terminal is at the second location than at the first location.

Abstract: A technique for estimating the location of a wireless terminal at an unknown location in a geographic region is disclosed. The technique is based on the recognition that there are traits of electromagnetic signals that are dependent on topography, the receiver, the location of the transmitter, and other factors. For example, if a particular radio station is known to be received strongly at a first location and weakly at a second location, and a given wireless terminal at an unknown location is receiving the radio station weakly, it is more likely that the wireless terminal is at the second location than at the first location.

Abstract: A method for determining the location of a mobile unit (MU) in a wireless communication system and presenting it to a remote party. The location of a remote MU is determined by comparing a snapshot of a predefined portion of the radio-frequency (RF) spectrum taken by the MU to a reference database containing multiple snapshots taken at various locations. The result of the comparison is used to determine if the MU is at a specific location. The comparison may be made in the MU, or at some other location situated remotely from the MU. In the latter case, sufficient information regarding the captured fingerprint is transmitted from the MU to the remote location. The database may be pre-compiled or generated on-line.

Abstract: A technique for improving location accuracy based on a priori geographical location density information is disclosed. In accordance with the illustrative embodiment, geographical location density information is derived from historical wireless location data such as the locations of prior E911 emergency calls, Location Based Services (LBS) sessions, conventional voice calls, packet data sessions, vehicle routes, and so forth. The geographical location density information is represented by a probability distribution function, and is incorporated into an existing location technique. Advantageously, the technique of the present invention can be employed in conjunction with any existing location technology; moreover, the historical location data can be obtained via any technology, and from any wireless network, including those that are different than that of the future location estimates.

Abstract: A method of estimating the location of a wireless terminal is disclosed that is ideally suited for use with legacy systems. The illustrative embodiment of the present invention is based on the observation that the signal strength of a signal from a transmitter is different at some locations, and, therefore, the location of a wireless terminal can be estimated by comparing the signal strength it currently observes against a map or database that correlates locations to signal strengths. For example, if a particular radio station is known to be received well at a first location and poorly at a second location, and a given wireless terminal at an unknown location is receiving the radio station poorly, it is more likely that the wireless terminal is at the second location than it is at the first location.

Abstract: A method of using a non-GPS-derived technique to estimate the location of an Assisted-GPS-enabled wireless terminal for the purposes of generating location-specific assistance data for the wireless terminal is disclosed. The wireless terminal then uses the assistance data to acquire and process one or more GPS signals and to derive information that is probative of the wireless terminal's location. The GPS-derived location information is then combined with non-GPS-derived location to form an estimate of the location of the wireless terminal that is better than can be derived from either alone. This combination of GPS-derived and non-GPS techniques is particularly useful when the wireless terminal can only acquire one or two GPS signals because it is not possible to determine the location of the wireless terminal with only two GPS signals alone.

Abstract: A method of estimating the location of a wireless terminal is disclosed that is ideally suited for use with legacy systems. The illustrative embodiment of the present invention is based on the observation that the signal strength of a signal from a transmitter is different at some locations, and, therefore, the location of a wireless terminal can be estimated by comparing the signal strength it currently observes against a map or database that correlates locations to signal strengths. For example, if a particular radio station is known to be received well at a first location and poorly at a second location, and a given wireless terminal at an unknown location is receiving the radio station poorly, it is more likely that the wireless terminal is at the second location than it is at the first location.

Abstract: A method of using a non-GPS-derived technique to estimate the location of an Assisted-GPS-enabled wireless terminal for the purposes of generating location-specific assistance data for the wireless terminal is disclosed. The wireless terminal then uses the assistance data to acquire and process one or more GPS signals and to derive information that is probative of the wireless terminal's location. The GPS-derived location information is then combined with non-GPS-derived location to form an estimate of the location of the wireless terminal that is better than can be derived from either alone. This combination of GPS-derived and non-GPS techniques is particularly useful when the wireless terminal can only acquire one or two GPS signals because it is not possible to determine the location of the wireless terminal with only two GPS signals alone.

Abstract: A generalized framework is disclosed in which a wide variety of propagation models can be cast in a matrix-based format using arbitrary matrix coefficients. Casting propagation models in the matrix-based framework enables efficient computer implementation and calculation, ease of tuning, admissibility, and aggregating multiple propagation models into a single matrix-based model. Matrix-based propagation models based on transmitter-receiver azimuth orientation, transmitter antenna height, terrain elevation, and clutter are also disclosed. The propagation models can be used in conjunction with automated data acquisition from information sources such as topographic maps, clutter maps, etc.

Abstract: A method of using a non-GPS-derived technique to estimate the location of an Assisted-GPS-enabled wireless terminal for the purposes of generating location-specific assistance data for the wireless terminal is disclosed. The wireless terminal then uses the assistance data to acquire and process one or more GPS signals and to derive information that is probative of the wireless terminal's location. The GPS-derived location information is then combined with non-GPS-derived location to form an estimate of the location of the wireless terminal that is better than can be derived from either alone. This combination of GPS-derived and non-GPS techniques is particularly useful when the wireless terminal can only acquire one or two GPS signals because it is not possible to determine the location of the wireless terminal with only two GPS signals alone.

Abstract: A method and apparatus are disclosed for estimating whether or not a wireless terminal is in a geographic zone. The illustrative embodiment employs a pattern classifier that is trained on traits of electromagnetic signals at various locations. A computer-executable program is then generated based on the trained pattern classifier, and the program is installed and executed on a subscribed identity module of the terminal.

Abstract: A method for estimating whether or not a wireless terminal is in a zone is described. The method is based on the following observation: when a wireless terminal is at a particular location, the values of the traits of the ambient electromagnetic signals that vary with location represent a “fingerprint” or “signature” for that location. This enables the location of a wireless terminal to be estimated by comparing the observed values of the traits of the ambient electromagnetic signals with the fingerprint for each potential location for the wireless terminal.

Abstract: A method for determining the location of a mobile unit (mobile unit) in a wireless communication system is disclosed. The illustrative embodiment provides a computationally-efficient technique for reducing the number of possible positions that have to be analyzed. In particular, the illustrative embodiment eliminates possible positions for the mobile unit from consideration by considering which signals the mobile unit can—and cannot—receive and the knowledge of where those signals can and cannot be received.

Abstract: A technique for designing and testing drive-test plan for gathering location-dependent RF data is disclosed. In accordance with some embodiments of the present invention, one candidate drive-test plan is chosen for implementation over a second based on an economic cost-benefit analysis of both plans. This is in marked contrast to, for example, a selection of drive-test plans, or the design of a drive-test plan, based on a calibration-cost analysis, in which the data estimated to be the most effective to calibrate a radio-frequency tool is sought for a given cost or the least cost. Although a data-estimated-to-be-most-effective-to-calibrate-a-radio-frequency-tool vs. cost analysis is a species of cost-benefit analyses in general, it is not an economic cost-benefit analysis because a data-estimated-to-be-most-effective-to-calibrate-a-radio-frequency-tool vs. cost analysis has deficiencies that an economic cost-benefit analysis does not.

Abstract: A technique for designing and testing drive-test plan for gathering location-dependent RF data is disclosed. In accordance with some embodiments of the present invention, one candidate drive-test plan is chosen for implementation over a second based on an economic cost-benefit analysis of both plans. This is in marked contrast to, for example, a selection of drive-test plans, or the design of a drive-test plan, based on a calibration-cost analysis, in which the data estimated to be the most effective to calibrate a radio-frequency tool is sought for a given cost or the least cost. Although a data-estimated-to-be-most-effective-to-calibrate-a-radio-frequency-tool vs. cost analysis is a species of cost-benefit analyses in general, it is not an economic cost-benefit analysis because a data-estimated-to-be-most-effective-to-calibrate-a-radio-frequency-tool vs. cost analysis has deficiencies that an economic cost-benefit analysis does not.

Abstract: A technique for designing and testing drive-test plan for gathering location-dependent RF data is disclosed. In accordance with some embodiments of the present invention, one candidate drive-test plan is chosen for implementation over a second based on an economic cost-benefit analysis of both plans. This is in marked contrast to, for example, a selection of drive-test plans, or the design of a drive-test plan, based on a calibration-cost analysis, in which the data estimated to be the most effective to calibrate a radio-frequency tool is sought for a given cost or the least cost. Although a data-estimated-to-be-most-effective-to-calibrate-a-radio-frequency-tool vs. cost analysis is a species of cost-benefit analyses in general, it is not an economic cost-benefit analysis because a data-estimated-to-be-most-effective-to-calibrate-a-radio-frequency-tool vs. cost analysis has deficiencies that an economic cost-benefit analysis does not.

Abstract: A method and apparatus for estimating the location of a wireless terminal are disclosed. The location of the wireless terminal is estimated based on one or more signal strength measurements in conjunction with: (i) one or more angle-of-arrival measurements, (ii) one or more time-of-arrival measurements, or (iii) a combination of (i) and (ii). At each measurement time, the illustrative embodiment (a) determines the candidate locations for the wireless terminal, (b) computes a measurement likelihood function for any signal strength measurements that are available at that time, (c) computes a measurement likelihood function for any geometry-of-arrival measurements that are available at that time, (d) computes a joint likelihood function for all measurements available at that time, and (e) updates the location probability distribution for the wireless terminal with the joint measurement likelihood function. Estimates of the location of the wireless terminal are obtained from the location probability distribution.