Positioning and time transfer using television synchronization signals
First Claim
1. An apparatus comprising:
- a first receiver adapted to receive television signals and a message, wherein the television signals include an NTSC television signal and an ATSC television signal, wherein the message represents a first arrival time and a second arrival time, wherein the first arrival time represents an absolute time of arrival at the apparatus of a first wavefront of the NTSC television signal, and wherein the second arrival time represents an absolute time of arrival at the apparatus of a first wavefront of the ATSC television signal;
a local clock;
a first arrival time module adapted to measure a third arrival time and a fourth arrival time, based on the local clock, after the first receiver receives the message, wherein the third arrival time represents a time of arrival at the apparatus of a second wavefront of the NTSC television signal, and wherein the fourth arrival time represents a time of arrival at the apparatus of a second wavefront of the ATSC television signal; and
a clock correction unit adapted to provide a clock correction signal for the local clock based on the first arrival time, the second arrival time, the third arrival time, and the fourth arrival time.
4 Assignments
0 Petitions
Accused Products
Abstract
Methods having corresponding apparatus and computer-readable media comprise: receiving television signals and a message at an apparatus, wherein the television signals include an NTSC television signal and an ATSC television signal, wherein the message represents first and second arrival times representing absolute times of arrival at the apparatus of a first wavefront of the NTSC and ATSC television signals, respectively; measuring third and fourth arrival times, based on a local clock, after receiving the message, wherein the third and fourth arrival times represent times of arrival at the apparatus of a second wavefront of the NTSC and ATSC television signals, respectively; and providing a clock correction signal for the local clock based on the first arrival time, the second arrival time, the third arrival time, and the fourth arrival time.
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Citations
39 Claims
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1. An apparatus comprising:
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a first receiver adapted to receive television signals and a message, wherein the television signals include an NTSC television signal and an ATSC television signal, wherein the message represents a first arrival time and a second arrival time, wherein the first arrival time represents an absolute time of arrival at the apparatus of a first wavefront of the NTSC television signal, and wherein the second arrival time represents an absolute time of arrival at the apparatus of a first wavefront of the ATSC television signal; a local clock; a first arrival time module adapted to measure a third arrival time and a fourth arrival time, based on the local clock, after the first receiver receives the message, wherein the third arrival time represents a time of arrival at the apparatus of a second wavefront of the NTSC television signal, and wherein the fourth arrival time represents a time of arrival at the apparatus of a second wavefront of the ATSC television signal; and a clock correction unit adapted to provide a clock correction signal for the local clock based on the first arrival time, the second arrival time, the third arrival time, and the fourth arrival time. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. An apparatus comprising:
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first receiver means for receiving television signals and a message, wherein the television signals include an NTSC television signal and an ATSC television signal, wherein the message represents a first arrival time and a second arrival time, wherein the first arrival time represents an absolute time of arrival at the apparatus of a first wavefront of the NTSC television signal, and wherein the second arrival time represents an absolute time of arrival at the apparatus of a first wavefront of the ATSC television signal; first arrival time means for measuring a third arrival time and a fourth arrival time, based on a local clock, after the first receiver means receives the message, wherein the third arrival time represents a time of arrival at the apparatus of a second wavefront of the NTSC television signal, and wherein the fourth arrival time represents a time of arrival at the apparatus of a second wavefront of the ATSC television signal; and clock correction means for providing a clock correction signal for the local clock based on the first arrival time, the second arrival time, the third arrival time, and the fourth arrival time. - View Dependent Claims (19, 20, 21, 22)
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23. A method comprising:
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receiving television signals and a message at an apparatus, wherein the television signals include an NTSC television signal and an ATSC television signal, wherein the message represents a first arrival time and a second arrival time, wherein the first arrival time represents an absolute time of arrival at the apparatus of a first wavefront of the NTSC television signal, and wherein the second arrival time represents an absolute time of arrival at the apparatus of a first wavefront of the ATSC television signal; measuring a third arrival time and a fourth arrival time, based on a local clock, after receiving the message, wherein the third arrival time represents a time of arrival at the apparatus of a second wavefront of the NTSC television signal, and wherein the fourth arrival time represents a time of arrival at the apparatus of a second wavefront of the ATSC television signal; and providing a clock correction signal for the local clock based on the first arrival time, the second arrival time, the third arrival time, and the fourth arrival time. - View Dependent Claims (24, 25, 26, 27)
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28. Tangible, non-transitory computer-readable media embodying instructions executable by a computer to perform a method comprising:
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receiving television signals and a message at an apparatus, wherein the television signals include an NTSC television signal and an ATSC television signal, wherein the message represents a first arrival time and a second arrival time, wherein the first arrival time represents an absolute time of arrival at the apparatus of a first wavefront of the NTSC television signal, and wherein the second arrival time represents an absolute time of arrival at the apparatus of a first wavefront of the ATSC television signal; measuring a third arrival time and a fourth arrival time, based on a local clock, after receiving the message, wherein the third arrival time represents a time of arrival at the apparatus of a second wavefront of the NTSC television signal, and wherein the fourth arrival time represents a time of arrival at the apparatus of a second wavefront of the ATSC television signal; and providing a clock correction signal for the local clock based on the first arrival time, the second arrival time, the third arrival time, and the fourth arrival time. - View Dependent Claims (29, 30, 31, 32)
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33. A system, comprising:
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a monitor unit adapted to provide a message; and a user terminal, comprising; a first receiver adapted to receive television signals and to receive the message provided by the monitor unit, wherein the television signals include an NTSC television signal and an ATSC television signal, wherein the message represents a first arrival time and a second arrival time, wherein the first arrival time represents an absolute time of arrival at the monitor unit of a first wavefront of the NTSC television signal, and wherein the second arrival time represents an absolute time of arrival at the monitor unit of a first wavefront of the ATSC television signal; a local clock; a first arrival time module adapted to measure a third arrival time and a fourth arrival time, based on the local clock, after the first receiver receives the message, wherein the third arrival time represents a time of arrival at the user terminal of a second wavefront of the NTSC television signal, and wherein the fourth arrival time represents a time of arrival at the user terminal of a second wavefront of the ATSC television signal; a clock correction unit adapted to provide a clock correction signal for the local clock based on the first arrival time, the second arrival time, the third arrival time, and the fourth arrival time; and a processing module adapted to determine, based on the first arrival time, the second arrival time, the third arrival time, and the fourth arrival time, at least one of an absolute time of arrival at the user terminal of the second wavefront of the NTSC television signal, and an absolute time of arrival at the user terminal of the second wavefront of the ATSC television signal, and to determine a position of the user terminal based on the clock correction signal and at least one of the NTSC television signal and the ATSC television signal. - View Dependent Claims (34)
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35. A method comprising:
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receiving at an apparatus a first television signal, a second television signal, and a message, wherein the message represents a first time of transmittal and a second time of transmittal, wherein the first time of transmittal represents the time the first television signal was transmitted, and wherein the second time of transmittal represents the time the second television signal was transmitted; estimating a first time of arrival and a second time of arrival based on a local clock, wherein the first time of arrival represents the time the first television signal was received, and wherein the second time of arrival represents the time the second television signal was received; and providing a clock correction signal for the local clock based on the first time of arrival, the second time of arrival, the first time of transmittal, and the second time of transmittal. - View Dependent Claims (36, 37, 38, 39)
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Specification