Enhanced position calculation
First Claim
1. A method for determining a location from which an unknown position radio signal is transmitted, comprising the steps of:
- transmitting from first and second known locations respective first and second radio signals;
receiving said first radio signal at plural receivers located at different known locations;
receiving said second radio signal at plural receivers located at different known locations;
determining a reference time of reception when each radio signal transmitted from said first and second known locations is received by the plural receivers;
communicating to a central processing device (CPD) the first and second radio signals received by plural receivers and the respective times of reception when the first and second signals were received by the plural receivers;
training a network in the CPD using the received first and second radio signals and using the known locations from which the received first and second radio signals were transmitted in relation to the respective reference times of reception at the plural receivers of the received first and second radio signals;
receiving at plural receivers an unknown position radio signal from an unknown location;
communicating to the CPD the radio signals received by the plural receivers and the respective reference times of reception of the unknown position radio signal at the plural receivers;
using the communicated unknown position radio signals at the plural receivers in relation to the respective reference times of reception of the unknown position radio signals as inputs to the trained network in the CPD; and
outputting from the CPD an estimate of the actual location from which the unknown position radio signal was transmitted.
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Accused Products
Abstract
The invention discloses several computation and control techniques which use historic information as well as other cues in order to enhance the accuracy of a radio position fix. These computational techniques include neural networks, mapped grid coefficients as input to a set of simultaneous or differential equations, and table lookup of correction coefficients for known low accuracy positions. The invention further discloses techniques for receiver array synchronization so that all system elements in a particular coverage area obtain a time reference appropriate for time of flight radio location measurements. The invention further teaches techniques to enhance the accuracy of a position fix by use of both fixed references, which are located in a coverage area, as well as a mobile reference carried by a search team. The invention also discloses techniques to provide information appropriate to guide a search team to an unknown positioned transmitter that is located within a building or structure. The invention discloses techniques to train a central computing unit, by using actuarial data, so that multi-path errors resulting from fixed or mobile obstacles may be reduced.
239 Citations
47 Claims
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1. A method for determining a location from which an unknown position radio signal is transmitted, comprising the steps of:
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transmitting from first and second known locations respective first and second radio signals; receiving said first radio signal at plural receivers located at different known locations; receiving said second radio signal at plural receivers located at different known locations; determining a reference time of reception when each radio signal transmitted from said first and second known locations is received by the plural receivers; communicating to a central processing device (CPD) the first and second radio signals received by plural receivers and the respective times of reception when the first and second signals were received by the plural receivers; training a network in the CPD using the received first and second radio signals and using the known locations from which the received first and second radio signals were transmitted in relation to the respective reference times of reception at the plural receivers of the received first and second radio signals; receiving at plural receivers an unknown position radio signal from an unknown location; communicating to the CPD the radio signals received by the plural receivers and the respective reference times of reception of the unknown position radio signal at the plural receivers; using the communicated unknown position radio signals at the plural receivers in relation to the respective reference times of reception of the unknown position radio signals as inputs to the trained network in the CPD; and outputting from the CPD an estimate of the actual location from which the unknown position radio signal was transmitted. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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30. A method, tolerant of fixed obstacles, for determining a location from which an unknown position radio signal is transmitted, comprising the steps of:
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transmitting from first and second known locations respective first and second radio signals; receiving said first radio signal at plural receivers located at different known locations; receiving said second radio signal at plural receivers located at different known locations; determining a reference time of reception when each radio signal transmitted from said first and second known locations is received by the respective plural receivers; communicating to a central processing device (CPD) the first and second radio signals received by the respective plural receivers and the respective times of reception when the first and second signals were received by the respective plural receivers; training a network in the CPD using the received first and second radio signals and the known locations from which the received first and second radio signals were transmitted in relation to the respective reference times of reception at the plural receivers of the received first and second radio signals, wherein a correction factor is obtained after each training iteration, said training factor correcting for differences between said known locations and locations estimated by said network; storing the correction factors; receiving at plural receivers an unknown position radio signal from an unknown location; communicating to the CPD the radio signals received by the plural receivers and the respective reference times of reception of the unknown position radio signal at the plural radio receivers; using the communicated unknown position radio signals at said plural receivers in relation to the respective reference times of reception of the unknown position radio signals as inputs to the trained network in the CPD; outputting from the CPD an initial estimate of the actual location from which the unknown position radio signal was transmitted; and correcting said initial estimate using one of said stored correction factors. - View Dependent Claims (31, 32, 40)
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33. A method for determining a location inside a building from which an unknown position radio signal is transmitted, comprising the steps of:
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transmitting from plural known indoor locations respective indoor radio signals; receiving said indoor radio signals at plural receivers located at different known locations, said indoor radio signals having at least one of leading edge peak and leading edge valley delay spread profile cues; determining plural reference times of reception when each indoor radio signal transmitted from said known indoor locations is received by the plural receivers which received each respective radio signal; communicating to a central processing device (CPD) the indoor radio signals received by the plural receivers and the plural respective times of reception when each of the indoor radio signals were received by the respective plural receivers; training a network in the CPD using the received indoor radio signals and the known locations from which each of the received indoor radio signals were transmitted in relation to the respective plural reference times of reception at the respective plural receivers of the received indoor radio signals; receiving at plural receivers an unknown position radio signal from an unknown location; communicating to the CPD the radio signals received by the plural receivers receiving the unknown position radio signal and the respective reference times of reception of the unknown position radio signal at the respective plural receivers; using the communicated unknown position radio signals in relation to the respective reference times of reception of the unknown position radio signals as inputs to the trained network in the CPD; and outputting from the CPD an estimate of the actual location from which the unknown position radio signal was transmitted. - View Dependent Claims (34, 35, 36, 37, 38, 39, 41, 42)
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43. A method for training a neural network, comprising the steps of:
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transmitting from plural known mobile locations respective mobile radio signals; receiving said mobile radio signals at plural receivers located at different known locations, said mobile radio signals having at least one of leading edge peak and leading edge valley delay spread profile cues; determining a reference time of reception for respective mobile radio signals from said at least one of said leading edge peak and said leading edge valley delay spread profile cues when each mobile radio signal transmitted from said mobile known locations is received by respective plural receivers; communicating to a neural network the mobile radio signals received by the plural receivers and the plural respective times of reception when each of the mobile radio signals were received by the plural receivers; and training the neural network using the received mobile radio signals and the known locations from which each of the received mobile radio signals were transmitted in relation to the plural respective reference times of reception at the plural receivers of the received mobile radio signals.
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44. A method for enhancing an estimate of a location from an unknown transmitter transmitted by using a neural network, comprising the steps of:
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receiving at plural receivers an unknown position radio signal from an unknown location, said unknown position radio signal having at least one of leading edge peak and leading edge valley delay spread profile cues; determining a reference time of reception for said unknown position radio signal from said at least one of said leading edge peak and said leading edge valley delay spread profile cues when said unknown position radio signal transmitted from said unknown location is received by said plural receivers; communicating to a trained neural network the radio signals having said at least one of leading edge peak and leading edge valley delay spread profile cues received by the plural receivers and the respective reference times of reception of the unknown position radio signal at the plural receivers; using the communicated radio signals and the respective reference times of reception of the unknown position radio signal as inputs to the trained neural network; and outputting from the trained neural network an estimate of an actual location from which the unknown position radio signal was transmitted.
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45. A method for enhancing an estimate of a location from an unknown transmitter transmitted by using a neural network, comprising the steps of:
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transmitting from plural known mobile locations respective mobile radio signals; receiving said mobile radio signals at plural receivers located at different known locations, said mobile radio signals having at least one of leading edge peak and leading edge valley delay spread profile cues; determining a reference time of reception when each mobile radio signal transmitted from said mobile known locations is received by the plural receivers; communicating to a neural network the mobile radio signals having said at least one of leading edge peak and leading edge valley delay spread profile cues received by the plural receivers and the respective times of reception when each of the mobile radio signals were received by the plural receivers; receiving at plural receivers an unknown position radio signal from an unknown location, said unknown position radio signal having at least one of leading edge peak and leading edge valley delay spread profile cues; determining a reference time of reception for said unknown position radio signal from said at least one of said leading edge peak and said leading edge valley delay spread profile cues when said unknown position radio signal transmitted from said unknown locations is received by said plural receivers; communicating to the trained neural network the radio signals having said at least one of leading edge peak and leading edge valley delay spread profile cues received by the plural receivers and the respective reference times of reception of the unknown position radio signal at the plural receivers; using the mobile radio signals in relation to the respective reference times of reception of the mobile position radio signals and the unknown radio signals in relation to the respective reference times of reception of the unknown position radio signals as inputs to the trained neural network; and outputting from the neural network an estimate of an actual location from which the unknown position radio signal was transmitted.
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46. A system for determining a location from which an unknown position radio signal is transmitted, comprising:
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means for transmitting from first and second known locations respective first and second radio signals; means for receiving said first radio signal at plural receivers located at different known locations; means for receiving said second radio signal at plural receivers located at different known locations; means for determining a reference time of reception when each radio signal transmitted from said first and second known locations is received by the plural receivers; means for communicating to a central processing device (CPD) the first and second radio signals received by plural receivers and the respective times of reception when the first and second signals were received by the plural receivers; means for training a network in the CPD using the received first and second radio signals and using the known locations from which the received first and second radio signals were transmitted in relation to the respective reference times of reception at the plural receivers of the received first and second radio signals; means for receiving at plural receivers an unknown position radio signal from an unknown location; means for communicating to the CPD the radio signals received by the plural receivers and the respective reference times of reception of the unknown position radio signal at the plural receivers; means for using the communicated unknown position radio signals at the plural receivers in relation to the respective reference times of reception of the unknown position radio signals as inputs to the trained network in the CPD; and means for outputting from the CPD an estimate of the actual location from which the unknown position radio signal was transmitted.
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47. A system for determining a location inside a building from which an unknown position radio signal is transmitted, comprising:
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means for transmitting from plural known indoor locations respective indoor radio signals; means for receiving said indoor radio signals at plural receivers located at different known locations, said indoor radio signals having at least one of leading edge peak and leading edge valley delay spread profile cues; means for determining plural reference times of reception when each indoor radio signal transmitted from said known indoor locations is received by the plural receivers which received each respective radio signal; means for communicating to a central processing device (CPD) the indoor radio signals received by the plural receivers and the plural respective times of reception when each of the indoor radio signals were received by the respective plural receivers; and means for training a network in the CPD using the received indoor radio signals and the known locations from which each of the received indoor radio signals were transmitted in relation to the respective plural reference times of reception at the respective plural receivers of the received indoor radio signals.
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Specification