Systems and methods for locating remote terminals in radiocommunication systems
First Claim
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1. A method for determining a position of a remote unit communicating with a radiocommunication system comprising the steps of:
- receiving, at a plurality of measurement stations, a signal transmitted by said remote unit;
forwarding, by each of said plurality of measurement stations, said received signal to a central processing center;
selecting, by said central processing center, one of a time-of-arrival (TOA) and time-difference-of-arrival (TDOA) technique for processing said received signals, wherein the TOA and the TDOA technique is selected based on a predetermined threshold; and
determining said position of said remote unit using said selected technique.
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Abstract
Emergency call handling may, in the near future, require terminal unit location information to be provided to emergency service centers. Exemplary embodiments of the present invention provide improved techniques for using a system of monitoring or adjunct stations to provide this location information to the emergency service centers. For example, either time of arrival (TOA) or time difference of arrival (TDOA) techniques can be selectively used to process received signals and provide location information. Techniques for improving timing estimates are also disclosed.
53 Citations
12 Claims
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1. A method for determining a position of a remote unit communicating with a radiocommunication system comprising the steps of:
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receiving, at a plurality of measurement stations, a signal transmitted by said remote unit; forwarding, by each of said plurality of measurement stations, said received signal to a central processing center; selecting, by said central processing center, one of a time-of-arrival (TOA) and time-difference-of-arrival (TDOA) technique for processing said received signals, wherein the TOA and the TDOA technique is selected based on a predetermined threshold; and determining said position of said remote unit using said selected technique. - View Dependent Claims (2, 3, 4, 5)
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6. A method for determining a position of a remote unit communicating with a radiocommunication system comprising the steps of:
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receiving, at a plurality of measurement stations, a signal transmitted by said remote unit; forwarding, by each of said plurality of measurement stations, said received signal to a central processing center; selecting, by said central processing center, one of a time-of-arrival (TOA and time-difference-of-arrival (TDOA) technique for processing said received signals, wherein said step of selecting further comprises the steps of using said TOA technique as a default technique and using said TDOA technique only if said TOA technique fails; and determining said position of said remote unit using said selected technique.
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7. An adjunct system for determining a position of a remote unit communicating with a radiocommunication system comprising:
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a plurality of measurement stations each for receiving a signal transmitted by said remote unit; a central processing center which receives a copy of said received signal from each of said plurality of measurement stations, said central processing center including; means for selecting one of a time-of-arrival (TOA) and time-difference-of-arrival (TDOA) technique for processing said received signals, wherein the TOA and the TDOA technique is selected based upon a predetermined threshold; and means for determining said position of said remote unit using said selected technique. - View Dependent Claims (8, 9, 10, 11)
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12. An adjunct system for determining a position of a remote unit communicating with a radiocommunication system comprising:
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a plurality of measurement stations each for receiving a signal transmitted by said remote unit; a central processing center which receive s a copy of said received signal from each of said plurality of measurement stations, said central processing center including; means for selecting one of a time-of-arrival (TOA) and time-difference-of-arrival (TDOA) technique for processing said received signals, wherein said means for selecting further comprises means for using said TOA technique as a default technique and using said TDOA technique only if said TOA technique fails; and means for determining said position of said remote unit using said selected technique.
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Specification