Abstract:
A system and method for determining the location of a wireless device. A boundary for an approximate area in which the wireless device is located is determined and a plurality of satellites may be determined as a function of the boundary. Assistance data is transmitted to the device which includes information from the plurality of satellites, and the location of the wireless device may be determined from the information. In one embodiment, if the number of the plurality of satellites is greater than a predetermined threshold then the number of satellites may be reduced as a function of one or more of the elevation of each satellite above the horizon, a distance between each satellite to one or more other satellites, and an altitude of each satellite.
Abstract:
A system and method for determining whether a wireless device has transmitted one or more forged radio frequency ("RF") measurements. A first set of signals from a plurality of RF sources may be received at a wireless device and transmitted to a location determining system. The location determining system may receive a second set of signals from the plurality of RF sources during substantially the same time period and frequency range. The location determining system may compare information from the second set of signals with information from the first set of signals. Alternatively, the location determining system may determine a location of the wireless device as a function of the first set of signals and compare information from the second set of signals with the determined location. The wireless device may be identified as having transmitted one or more forged RF measurements if the information from the second set of signals does not substantially correspond to the information from the first set of signals and/or the determined location.
Abstract:
A method for a mobile location center (MLC) (120) to determine a location of a mobile device (130) in a wireless communication network includes receiving a request to determine the location of the mobile device; concurrently requesting global navigation satellite system (GNSS) (141-144) measurements from the mobile device and terrestrial measurements from transceivers (116-119) in the wireless communication network, and receiving the GNSS measurements and at least one of the terrestrial measurements. A GNSS location of the mobile device is calculated as a function of the GNSS measurements, and the calculated GNSS location is determined to be the location of the mobile device when the calculated GNSS location meets a predetermined accuracy threshold. A terrestrial location of the mobile device is calculated as a function of the terrestrial measurements, and the calculated terrestrial location is determined to be the location of the mobile device when the calculated terrestrial location meets the predetermined accuracy threshold.
Abstract:
A system and method for determining the location of a mobile device. A first set of signals from a plurality of radio frequency ("RF") sources may be received at a mobile device and then downconverted into a second set of signals. The mobile device may then time stamp the second set of signals and transmit the time stamped signals to a location determining system. The location of the mobile device may be determined at the location determining system as a function of the time stamped signals.
Abstract:
A system and method for detecting one or more forged satellite measurements transmitted from a wireless device. Information may be transmitted to a wireless device, the information including a request that the wireless device provide a portion of a navigation data message from one or more satellites to a location determining system. The one or more satellite measurements and the portion of the navigation data message may be received from the wireless device. The navigation data message may be determined as a function of information from a reference network. The determined navigation data message may then be compared with the received navigation data message portion to thereby determine whether any of the one or more satellite measurements transmitted by the device have been forged.
Abstract:
A system and method for determining whether a wireless device has transmitted one or more forged satellite measurements. An estimated location of a wireless device may be determined as a function of signals from a cellular network. For each one of a first set of satellites from which the wireless device receives a signal, expected frequency information may be determined as a function of the estimated location, actual frequency information may be measured, and the expected frequency information compared with the measured frequency information. One or more satellite measurements received from the wireless device may then be identified as forged if a difference between the expected and measured frequency information is greater than a predetermined threshold.
Abstract:
A system and method for determining whether an estimated location of a wireless device includes one or more forged satellite measurements. An estimated location of the wireless device may be determined from signals received from a first set of satellites, and a set of residuals obtained as a function of the estimated location. The obtained set of residuals may then be compared to a reference set of residuals. If the comparison between the obtained set and reference set of residuals is less than a predetermined threshold, then the estimated location may be identified as having one or more forged satellite measurements.
Abstract:
A system and method for estimating the position of a mobile device using information from a constellation of satellites. A first set of satellites of the constellation may be selected and then a second set of satellites of the constellation may be selected as a function of signals received from the first set of satellites. Data may be transmitted to the mobile device based on signals received from the second set of satellites, and a location of the device estimated based on the data. One embodiment may select the second set as a function of an intersection of coverage areas of ones of the first set of satellites. Another embodiment may select the second set as a function of one or more satellites that are not occluded by the Earth from one or more of the first set of satellites.
Abstract:
A method is provided for determining a location of a mobile device (130) in a wireless network. The method includes receiving global navigation satellite system (GNSS) (141-144) measurements from the mobile device, and receiving terrestrial measurements from corresponding transceivers (111-114) in the wireless network, each terrestrial measurement indicating a distance between the corresponding transceivers and the mobile device. The method further includes selecting at least one terrestrial measurement having an uncertainty value within a predetermined accuracy threshold. The location of the mobile device is determined as a function of the GNSS measurements and the selected terrestrial measurement.
Abstract:
A system and method for determining whether a wireless device has transmitted one or more forged satellite measurements. An estimated location of the wireless device may be determined as a function of information from a cellular network. Acquisition assistance data may be determined for a first set of satellites as a function of the estimated location, the assistance data including an uncertainty window. If measured code phase information in the satellite measurements substantially correlates to the uncertainty window, then the wireless device may be transmitting forged satellite measurements.