System and method for mass calibration of radio frequency fingerprint (RF-FP) location measurements
First Claim
1. A method for location tracking, comprising:
- in a communication network, which includes base stations that transmit downlink signals to a plurality of subscriber terminals, defining a mapping between geographical locations and respective sets of signal strengths of the downlink signals received from one or more of the base stations at the geographical locations, the communication network further comprising a location system that calibrates the mapping of signal strengths to locations in order to account for changes in the signal environment that may occur over time;
selecting a subset of the subscriber terminals;
for each subscriber terminal in the subset, obtaining first measurements of a geographical location of the subscriber terminal using Uplink Time Difference of Arrival (U-TDOA), and obtaining second measurements of the downlink signals received at the subscriber terminal at the geographical location, wherein any change that affects signal propagation, such as addition or reconfiguration of base stations or a new building or obstacle is used in calibrating the mapping of signal strength;
updating the mapping responsively to the first and second measurements obtained for the subscriber terminals in the subset; and
measuring the geographical locations of at least one of the subscriber terminals in the plurality using the updated mapping.
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Accused Products
Abstract
Systems and methods for location tracking in a communication network. Base stations transmit downlink signals to a plurality of subscriber terminals to define a mapping between geographical locations and respective sets of signal strengths of the downlink signals received from the base stations at the geographical locations. A subset of the subscriber terminals may be selected, and for each subscriber terminal in the subset, first measurements of a geographical location of the subscriber terminal irrespective of the downlink signals is made. Second measurements of the downlink signals received at the subscriber terminal at the geographical location is made and the mapping of the subscribers terminals is updated responsively to the first and second measurements. The geographical locations of the subscriber terminals is updated using the updated mapping.
16 Citations
20 Claims
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1. A method for location tracking, comprising:
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in a communication network, which includes base stations that transmit downlink signals to a plurality of subscriber terminals, defining a mapping between geographical locations and respective sets of signal strengths of the downlink signals received from one or more of the base stations at the geographical locations, the communication network further comprising a location system that calibrates the mapping of signal strengths to locations in order to account for changes in the signal environment that may occur over time; selecting a subset of the subscriber terminals; for each subscriber terminal in the subset, obtaining first measurements of a geographical location of the subscriber terminal using Uplink Time Difference of Arrival (U-TDOA), and obtaining second measurements of the downlink signals received at the subscriber terminal at the geographical location, wherein any change that affects signal propagation, such as addition or reconfiguration of base stations or a new building or obstacle is used in calibrating the mapping of signal strength; updating the mapping responsively to the first and second measurements obtained for the subscriber terminals in the subset; and measuring the geographical locations of at least one of the subscriber terminals in the plurality using the updated mapping. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. Apparatus for location tracking, comprising:
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an interface, which is configured to communicate with a communication network that includes base stations that transmit downlink signals to a plurality of subscriber terminals; a storage device, which is configured to store a mapping between geographical locations and respective sets of signal strengths of the downlink signals received from one or more of the base stations at the geographical locations, wherein the storage device further comprises a location system that calibrates the mapping of signal strengths to locations in order to account for changes in the signal environment that may occur over time; and a processor, which is configured to select a subset of the subscriber terminals, to obtain for each subscriber terminal in the subset, first measurements of a geographical location of the subscriber terminal using Uplink Time Difference of Arrival (U-TDOA), to obtain for each subscriber terminal in the subset second measurements of the downlink signals received at the subscriber terminal at the geographical location, to update the mapping responsively to the first and second measurements obtained for the subscriber terminals in the subset, and to measure the geographical locations of at least one of the subscriber terminals in the plurality using the updated mapping, wherein any change that affects signal propagation, such as addition or reconfiguration of base stations or a new building or obstacle is used in calibrating the mapping of signal strength. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification