Positioning system for digital telephone networks
First Claim
1. A positioning system comprising at least two receivers of a digital telephone network having a plurality of transmission sources, the first of which receivers is at a known location and the second of which is a mobile receiver whose position is to be determined, said system utilising transmission signals having a format at least a portion of which has predetermined values or a portion which is repeated, each receiver includinga reference clock;
- means for generating in each receiver a reference signal locked to the reference clock, the reference signal having a similar format to the transmission signals and thus a portion identical to the portion of the received signal which has predetermined values or which is repeated; and
means, in each receiver, for comparing the received transmission signal and the reference signal to determine their relative time offset to enable thereby the position of the second receiver so be determined by determining the time delay between the respective signals received at both receivers.
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Accused Products
Abstract
The invention relates to a determining the position of a mobile receiver 4 in a digital telephone network positioning system. A first receiver 3 is at a known location and others are mobile. The method involves transmitting signals from a plurality of sources 1, the transmission signals having a format at least a portion of which has predetermined values or a portion of which is repeated. The time offset of the transmission signals received at each receiver 4,5 from a transmission source 1 relative to a reference clock of each receiver is determined by generating a reference signal locked to the reference clock. The reference signal has a similar format to the transmission signals and includes a portion identical to the predetermined values or repeated portion of the received signal and compares the received transmission signal and the reference signal. The time delay between the respective signals received at the receivers 4,5 is determined from their relative time offset, to thereby determine the position of the other receivers 4.
61 Citations
100 Claims
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1. A positioning system comprising at least two receivers of a digital telephone network having a plurality of transmission sources, the first of which receivers is at a known location and the second of which is a mobile receiver whose position is to be determined, said system utilising transmission signals having a format at least a portion of which has predetermined values or a portion which is repeated, each receiver including
a reference clock; -
means for generating in each receiver a reference signal locked to the reference clock, the reference signal having a similar format to the transmission signals and thus a portion identical to the portion of the received signal which has predetermined values or which is repeated; and means, in each receiver, for comparing the received transmission signal and the reference signal to determine their relative time offset to enable thereby the position of the second receiver so be determined by determining the time delay between the respective signals received at both receivers. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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- 22. A positioning system comprising at least two receivers of a digital telephone network having a plurality of transmission sources, the first of which receivers is at a known location and the second of which is a mobile receiver whose position is to be determined, said system utilising transmission signals having a format at least a portion of which has predetermined values, and the relative time offsets of the transmission signals received at each receiver from said transmission sources being measured relative to each other in said receivers by means for comparing the received transmission signals from the different transmission sources with one another to determine their relative time offsets and thereby determine the position of the second receiver by determining the time delay between the respective signals received at both receivers.
- 41. A positioning system comprising at least two receivers of a digital telephone network having a plurality of transmission sources, the first of which receivers is at a known location and the second of which is a mobile receiver whose position is to be determined, said system utilising transmission signals having a format at least a portion of which is sequentially repeated, in which the relative time offsets of the transmission signals received at each receiver from said transmission sources are measured relative to each other in said receivers by means for comparing the sequentially received transmission signals from the different transmission sources with one another to determine their relative time offsets and thereby determine the position of the second receiver by determining the time delay between the respective signals received at both receivers.
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60. A method of determining the position of a mobile receiver in a digital telephone network positioning system having at least two receivers, the first of which is at a known location and the second of which is mobile, the method comprising
transmitting signals from a plurality of sources, the transmission signals having a format at least a portion of which has predetermined values or a portion of which is repeated; -
determining the time offset, of the transmission signals received at each receiver from a transmission source relative to a reference clock of each receiver, by generating a reference signal locked to the reference clock, the reference signal having a similar format to the transmission signals and including a portion identical to the predetermined values or repeated portion of the received signal and comparing the received transmission signal and the reference signal; and determining the time delay between the respective signals received at both receivers by determining their relative time offset, to thereby determine the position of the second receiver. - View Dependent Claims (61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74)
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75. A method of determining the position of a mobile receiver in a digital telephone network positioning system having at least two receivers, the first of which is at a known location and the second of which is mobile, the method comprising
transmitting signals from a plurality of sources, the transmission signals having a format at least a portion of which has predetermined values; -
measuring the relative time offsets, of the transmission signals received at each receiver from the plurality of transmission sources, relative to each other by comparing with one another the received transmission signals from the different transmission sources; and determining the time delay between the respective signals received at both receivers to determine the position of the mobile receiver. - View Dependent Claims (76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87)
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88. A method of determining the position of a mobile receiver in a digital telephone network positioning system having at least two receivers, the first of which is at a known location and the second of which is mobile, the method comprising
transmitting signals from a plurality of sources, the transmission signals having a format at least a portion of which is repeated sequential; -
measuring the relative time offsets, Of the transmission signals received at each receiver from the plurality of transmission sources, relative to each other by comparing with one another the sequentially received transmission signals from the different transmission sources; and determining the time delay between the respective signals received at both receivers to determine the position of the mobile receiver. - View Dependent Claims (89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100)
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Specification