Abstract: A method of modifying calibration data used to geo-locate a mobile station located in an indoor environment is disclosed. When a mobile station is located indoors, the signal strength of signals received and/or transmitted by the mobile station have the tendency to be lower than the strength of the signals received by a mobile station located outdoors. As a result of these lower signal strengths, geo-location efforts which rely on signal strengths may result in unsatisfactory location accuracy. Modifying pre-existing calibration data obtained outdoors may provide a way to simulate indoor calibration data characteristics.

Abstract: A novel system and method for a network overlay geolocation system operating in a host wireless communication system with repeaters is disclosed. Embodiments of the novel system and method enable the geolocation system to determine if signals being received by the geolocation system arrive directly from a target mobile appliance or if the signals are passing through a repeater and therefore are subject to a known time delay. Embodiments of the novel system and method provide a more accurate geolocation of mobiles served by repeater stations than capable in the prior art.

Abstract: A method of modifying calibration data used to geo-locate a mobile station located in an indoor environment is disclosed. When a mobile station is located indoors, the signal strength of signals received and/or transmitted by the mobile station have the tendency to be lower than the strength of the signals received by a mobile station located outdoors. As a result of these lower signal strengths, geo-location efforts which rely on signal strengths may result in unsatisfactory location accuracy. Modifying pre-existing calibration data obtained outdoors may provide a way to simulate indoor calibration data characteristics.

Abstract: A method and apparatus for correcting position error in a navigation system. A first set of positioning measurements of a device are determined from signals received from a first plurality of sources and a second set of positioning measurements of the device are determined from signals received from a second plurality of sources. A database comprising map-related information of a predetermined region is provided and a location of the device as a function of the first and second set of positioning measurements and selected map-related information is estimated. Errors in future estimated locations in a navigational system may be compensated by determining a divergence of the second set from the first set of positioning measurements. A navigational system that refines its accuracy over time is demonstrated whereby current estimates of location may be improved and data mapping utilized for future location estimates may be updated.

Abstract: A method and apparatus for estimating a location of a device. For each of a plurality of locations of a device, a set of positional data is determined from signals received from a plurality of satellites. The positional data is filtered and compared with data from a road network database. This comparison may be a function of a distance from at least one point defined by a set of the filtered positional data to a road in the road network database and an angle between a line representing a best fit for plural points defined by corresponding plural sets of the filtered positional data to a line defined by a road in the road network database.

Abstract: A novel system and method for a network overlay geolocation system operating in a host wireless communication system with repeaters (350a, 350b) is disclosed. Embodiments of the novel system and method enable the geolocation system to determine if signals being received by the geolocation system arrive directly from a target mobile appliance or if the signals are passing through a repeater (350a, 350b) and therefore are subject to a known time delay. Embodiments of the novel system and method provide a more accurate geolocation of mobiles served by repeater stations than capable in the prior art.

Abstract: An input filter is provided for a superheterodyne receiver for image frequency suppression and a method for operating a superheterodyne receiver. The input filter for a superheterodyne receiver includes a first filter circuit with bandpass characteristics and a center frequency that can be preset as a function of a desired receive frequency, the circuit having a varactor diode and a first filter inductor that are connected in parallel and form a parallel-resonant circuit, wherein the center frequency can be preset by application of a control voltage to the varactor diode, and a second filter circuit with band stop characteristics that includes the varactor diode and a second filter inductor, these being connected in series and forming a series-resonant circuit, and that has a maximum attenuation in the vicinity of an image frequency belonging to the desired receive frequency. The input filter may be used in, for example, DAB receivers.

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.

Abstract: A system and method of applying a known modification to a signal to enable a determination of a signal received by a first node is received directly from a second node or indirectly through a repeater. The repeater receives a primary signal and creates a secondary signal as a function of the primary signal and a known modification, wherein the known modification identifies the repeater. The primary signal is transmitted and injected with the secondary signal as the first signal to the primary receiver.

Abstract: A method for enabling a system to enhance the accuracy of a location estimate modifies weights in a weight matrix associated with receiver station measurements in parallel with successive refinements of the location estimate. In a typical location estimation scenario, several receiving stations simultaneously derive measurements of a signal from the emitter. Any one of these measurements is in general some function of the emitter location and the receiving station location. The aggregate of these measurements is often in excess of the minimum number of measurements required to provide an estimate of the emitter location. Where such an excess exists, the method proceeds by modifying the weights associated with the measurements in parallel with successive refinements of the location estimate. The method can be implemented over various cellular protocols with a consistent and significant enhancement in the accuracy of location estimates.

Abstract: A method for enabling a system to enhance the accuracy of a location estimate modifies weights in a weight matrix associated with receiver station measurements in parallel with successive refinements of the location estimate. In a typical location estimation scenario, several receiving stations simultaneously derive measurements of a signal from the emitter. Any one of these measurements is in general some function of the emitter location and the receiving station location. The aggregate of these measurements is often in excess of the minimum number of measurements required to provide an estimate of the emitter location. Where such an excess exists, the method proceeds by modifying the weights associated with the measurements in parallel with successive refinements of the location estimate. The method can be implemented over various cellular protocols with a consistent and significant enhancement in the accuracy of location estimates.

Abstract: A system and method to re-calibrate an area of a wireless communications network that has been exposed to one or more network configuration changes is disclosed. When one or more attributes of the wireless network undergo a change which impairs the geo-location capability to locate a mobile station, it can be detrimental to the safety and well being of the network users. Geo-location calculations rely on accurate and updated calibration data to correctly locate a mobile station. In some instances, it may be necessary to update the calibration data for areas of the network that have been exposed to network configuration changes. Modifying previously collected calibration data to account for changes that have occurred in the network may increase the accuracy of mobile station location estimation.

Abstract: The location of a wireless mobile device may be estimated using, at least in part, one or more pre-existing Network Measurement Reports (“NMRs”) which include calibration data for a number of locations within a geographic region. The calibration data for these locations is gathered and analyzed so that particular grid points within the geographic region can be determined and associated with a particular set or sets of calibration data from, for example, one or more NMRs. Regions may be defined as a function of any number of parameters and respective predetermined ranges thereof in the NMRs. An intersection of these defined regions may be determined and the location of a mobile device may be estimated as a function of the intersection.

Abstract: A method for calibrating an antenna and signal processing system enabling angle of arrival (AOA) determination for a frequency hopping signal, in which a calibration coefficient is determined in response to one or more calibration signals injected into the system at one or more of the frequencies in the hopping sequence and proximate in time to reception of the communication signal. The calibration coefficients are reflective of a frequency and time dependent parameter of a path between the antenna and wireless location sensor. The AOA is determined as a function of the calibration coefficient and the radio frequency energy of the received communication signal. Several embodiment of the method are illustrated.

Abstract: A method is described that enables a system to estimate the individual times of arrival of multi-path signals components in a received signal while blind to the particular angular response characteristics of an antenna array. Additionally, a system is described that estimates the impulse response of the modulation channel. The impulse response is used to generate impulse response estimates for all multi-path signal components without reference to the actual angle of arrival of the signal. The impulse responses for the multi-path constituents are directly associated with the time delays on each path, providing delay estimates for each path.

Abstract: A method of modifying calibration data used to geo-locate a mobile station located in an indoor environment is disclosed. When a mobile station is located indoors, the signal strength of signals received and/or transmitted by the mobile station have the tendency to be lower than the strength of the signals received by a mobile station located outdoors. As a result of these lower signal strengths, geo-location efforts which rely on signal strengths may result in unsatisfactory location accuracy. Modifying pre-existing calibration data obtained outdoors may provide a way to simulate indoor calibration data characteristics.

Abstract: The location of a wireless mobile device may be estimated using, at least in part, one or more pre-existing Network Measurement Reports (“NMRs”) which include calibration data for a number of locations within a geographic region. The calibration data for these locations is gathered and analyzed so that particular grid points within the geographic region can be determined and associated with a particular set or sets of calibration data from, for example, one or more NMRs. Sets of grid points may be evaluated as a function of parameters of the calibration data, and a set of grid points may be selected as a function of a predetermined criteria. The location of a mobile device in the geographic region may then be determined as a function of the predetermined criteria.

Abstract: The location of a wireless mobile device may be estimated using, at least in part, one or more pre-existing Network Measurement Reports (“NMRs”) which include calibration data for a number of locations within a geographic region. The calibration data for these locations is gathered and analyzed so that particular grid points within the geographic region can be determined and associated with a particular set or sets of calibration data from, for example, one or more NMRs. Received signal level measurements reported by a mobile device for which a location estimate is to be determined may be compared with the data associated with the various grid points to estimate the location of the mobile device.

Abstract: The location of a wireless mobile device may be estimated using, at least in part, one or more pre-existing Network Measurement Reports (“NMRs”) which include calibration data for a number of locations within a geographic region. The calibration data for these locations is gathered and analyzed so that particular calibration points within the geographic region can be determined and associated with a particular set or sets of calibration data from, for example, one or more NMRs. Sets of calibration points may be evaluated as a function of parameters of the calibration data, and a set of calibration points may be selected as a function of a predetermined criteria. Signal reception in the region may be estimated as a function of mobile device location in the region and an approximate statistical accuracy of a signal strength pattern determined as a function of the estimated signal reception.

Abstract: The location of a wireless mobile device may be estimated using, at least in part, one or more pre-existing Network Measurement Reports (“NMRs”) which include calibration data for a number of locations within a geographic region. The calibration data for these locations is gathered and analyzed so that particular grid points within the geographic region can be determined and associated with a particular set or sets of calibration data from, for example, one or more NMRs. Embodiments of the present subject matter also provide a method of improving a location estimate of a mobile device. Received signal level measurements reported by a mobile device for which a location estimate is to be determined may be evaluated and/or compared with the characteristics associated with the various grid points to estimate the location of the mobile device.