Methods of and apparatus for measuring time of arrival of remote Loran-C and related signals and effective time of transmission of local signals at transmitter sites
First Claim
1. A method of measuring time of arrival (TOA) of Loran-C and similar signals from a remote transmitter at a local transmitter located at the same site at which the remote signal is to be received in a receiving antenna disposed within a short distance of the antenna field of the local transmitter, that comprises, receiving at the receiving antenna the remote signal from the said remote transmitter;
- generating at said site a simulated Loran signal in a fixed, known time relationship to the signal locally transmitted by the local transmitter;
coupling the simulated signal into the receiving antenna;
measuring the time of arrival of the remote signal received in the receiving antenna from the same remote transmitter and comparing the same with the simulated signal; and
clocking the simulated signal to occur in a time slot not occupied by the signal from the local transmitter.
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Accused Products
Abstract
A method of and apparatus for measuring time of arrival of remote Loran-C and related signals and effective time of transmission of local signals at Loran transmitter sites through use of a simulated Loran signal locally generated and coupled into the receiving antenna system that receives the remote signals in a time slot not occupied by the local transmitted signal.
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Citations
9 Claims
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1. A method of measuring time of arrival (TOA) of Loran-C and similar signals from a remote transmitter at a local transmitter located at the same site at which the remote signal is to be received in a receiving antenna disposed within a short distance of the antenna field of the local transmitter, that comprises, receiving at the receiving antenna the remote signal from the said remote transmitter;
- generating at said site a simulated Loran signal in a fixed, known time relationship to the signal locally transmitted by the local transmitter;
coupling the simulated signal into the receiving antenna;
measuring the time of arrival of the remote signal received in the receiving antenna from the same remote transmitter and comparing the same with the simulated signal; and
clocking the simulated signal to occur in a time slot not occupied by the signal from the local transmitter. - View Dependent Claims (2, 4)
- generating at said site a simulated Loran signal in a fixed, known time relationship to the signal locally transmitted by the local transmitter;
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3. A method of measuring time of arrival of radio signals from a remote transmitter with respect to a local clock system located at the same site at which the remote signal is to be received in a receiving antenna that comprises, receiving at the receiving antenna the remote radio signal from the said remote transmitter;
- generating from the clock system at said site a simulated similar radio signal in a fixed, known time relationship to the local clock system;
coupling the simulated radio signal into the receiving antenna; and
measuring the time of arrival of the remote radio signal received in the receiving antenna from the said remote transmitter and comparing the same with the simulated radio signal.
- generating from the clock system at said site a simulated similar radio signal in a fixed, known time relationship to the local clock system;
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5. In the measuring of time of arrival of Loran C and similar signals from a remote transmitter at a local transmitter site at which the remote signal is to be received within a short distance of the antenna field of the local transmitter, the method that comprises, receiving the remote signal in a receiving antenna system on said site;
- generating on said site a local simulated Loran-C signal in a coding delay time relationship to the signal to be transmitted at said site by the local transmitter;
closely coupling the simulated signal into said receiving antenna system;
the time delay between the said time of arrival of the remote signal and the time of the simulated signal minus the coding delay at the local transmitter to determine the time of signal transmission by the local transmitter.
- generating on said site a local simulated Loran-C signal in a coding delay time relationship to the signal to be transmitted at said site by the local transmitter;
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6. A method of measuring time of arrival of Loran-C and similar signals from a remote transmitter at a local transmitter located at the same site at which the remote signal is to be received, that comprises receiving the remote signal from the remote transmitter in a loop antenna located at said site in the vicinity of the local transmitter antenna and other reflecting objects that also introduce scattered components of the said remote signal into the loop antenna;
- measuring the time of arrival of said remote signal as received in the loop antenna; and
orienting the loop in a plane substantially disposed at rights angles to the direction between the transmitters to obviate phase shifts in the received signals that could result from such scatter of the remote signal in order to obviate errors in the time of arrival measurement.
- measuring the time of arrival of said remote signal as received in the loop antenna; and
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7. Apparatus for measuring time of arrival of radio signals from a remote transmitter with respect to a local clock system located at the same site at which the remote signal is to be received in a receiving antenna, that comprises, means for receiving at the receiving antenna the remote radio signal from the said remote transmitter;
- means for generating from the clock system at said site a simulated similar radio signal in a fixed, known time relationship to the local clock;
means for coupling the simulated radio signal into the receiving antenna; and
means for measuring the time of arrival of the remote radio signal received in the receiving antenna from the said remote transmitter and comparing the same with the simulated radio signal. - View Dependent Claims (8, 9)
- means for generating from the clock system at said site a simulated similar radio signal in a fixed, known time relationship to the local clock;
Specification