Radio positioning systems
First Claim
1. A method of estimating the time offsets between signals transmitted by plural transmitters of a communications network and received by a receiver attached to a terminal, the method comprising the steps of(a) creating a terminal section of a representation of the signals from the plural transmitters received by the receiver at the terminal;
- (b) creating a first section of a representation of the signal transmitted by a first of said transmitters, and creating a second section of a representation of the signal transmitted by a second of said transmitters, each of which sections overlaps in time with the terminal section;
(c) using the first section, the second section and a set of signal parameters, including initial estimates of the time offsets between the first section and the terminal section and between the second section and the terminal section, to create a model of a section of a representation of the composite signal received by the receiver from the first and second transmitters;
(d) comparing the model with the terminal section;
(e) refining the set of signal parameters including the time offset estimates to minimise the difference between said model and the terminal section; and
(f) adopting the time offsets in the refined parameter set used to minimise the difference between said model and the terminal section, as the estimated time offsets between the first section and the terminal section and between the second section and the terminal section.
1 Assignment
0 Petitions
Accused Products
Abstract
The invention provides a method of estimating the time offsets between signals transmitted by plural transmitters of a communications network and received by a receiver attached to a terminal. In the method a section of a representation of the signals from the plural transmitters received by the receiver at the terminal (a “terminal section”) is created as are a first section of a representation of the signal transmitted by a first of said transmitters and a second section of a representation of the signal transmitted by a second of said transmitters. Each of the first and second sections overlaps in time with the terminal section. Using the first section, the second section and a set of signal parameters, including initial estimates of the time offsets between the first section and the terminal section and between the second section and the terminal section, a model of a section of a representation of the composite signal received by the receiver from the first and second transmitters is created. Thereafter, the model is compared with the terminal section and the set of signal parameters including the time offset estimates is refined to minimize the difference between the model and the terminal section. The time offsets in the refined parameter set used to minimize the difference between said model and the terminal section, are adopted as the estimated time offsets between the first section and the terminal section and between the second section and the terminal section.
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Citations
21 Claims
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1. A method of estimating the time offsets between signals transmitted by plural transmitters of a communications network and received by a receiver attached to a terminal, the method comprising the steps of
(a) creating a terminal section of a representation of the signals from the plural transmitters received by the receiver at the terminal; -
(b) creating a first section of a representation of the signal transmitted by a first of said transmitters, and creating a second section of a representation of the signal transmitted by a second of said transmitters, each of which sections overlaps in time with the terminal section; (c) using the first section, the second section and a set of signal parameters, including initial estimates of the time offsets between the first section and the terminal section and between the second section and the terminal section, to create a model of a section of a representation of the composite signal received by the receiver from the first and second transmitters; (d) comparing the model with the terminal section; (e) refining the set of signal parameters including the time offset estimates to minimise the difference between said model and the terminal section; and (f) adopting the time offsets in the refined parameter set used to minimise the difference between said model and the terminal section, as the estimated time offsets between the first section and the terminal section and between the second section and the terminal section. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. Apparatus for estimating the time offsets between signals transmitted by plural transmitters of a communications network and received by a receiver attached to a terminal, the apparatus comprising
(a) processing means arranged to create a terminal section of a representation of the signals from the plural transmitters received by the receiver at the terminal; -
(b) processing means arranged to create a first section of a representation of the signal transmitted by a first of said transmitters, and to create a second section of a representation of the signal transmitted by a second of said transmitters, each of which sections overlaps in time with the terminal section; (c) processing means arranged to create a model of a section of a representation of the composite signal received by the receiver from the first and second transmitters using the first section, the second section and a set of signal parameters, including initial estimates of the time offsets between the first section and the terminal section and between the second section and the terminal section; (d) processing means arranged to compare the model with the terminal section; (e) processing means arranged to refine the set of signal parameters including the time offset estimates to minimise the difference between said model and the terminal section; and (f) processing means arranged to adopt the time offsets in the refined parameter set used to minimise the difference between said model and the terminal section, as the estimated time offsets between the first section and the terminal section and between the second section and the terminal section. - View Dependent Claims (16, 17)
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18. A telecommunications terminal including apparatus for finding the time offsets between signals transmitted by a plurality of transmitters of a communications network and received by a receiver attached to the terminal, the apparatus comprising
(a) processing means arranged to create a terminal section of a representation of the signals from plural transmitters received by the receiver at the terminal; -
(b) processing means for receiving a first section of a representation of the signal transmitted by a first of said transmitters and a second section of a representation of the signal transmitted by a second of said transmitters, each of which sections overlaps in time with the terminal section; (c) processing means arranged to create a model of a section of a representation of the composite signal received by the receiver from the first and second transmitters using the first section, the second section and a set of signal parameters, including initial estimates of the time offsets between the first section and the terminal section and between the second section and the terminal section; (d) processing means arranged to compare the model with the terminal section; (e) processing means arranged to refine the set of signal parameters including the time offset estimates to minimise the difference between said model and the terminal section; and (f) processing means arranged to adopt the time offsets in the refined parameter set used to minimise the difference between said model and the terminal section, as the estimated time offsets between the first section and the terminal section and between the second section and the terminal section. - View Dependent Claims (20)
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19. A communications network for finding the time offsets between signals transmitted by a plurality of transmitters of the communications network and received by a receiver attached to a terminal, the network comprising
(a) a computing device or devices; -
(b) a terminal having a receiver attached to the terminal, processing means arranged to create a terminal section of a representation of the signals from plural transmitters received by the receiver at the terminal, and means for sending the section to the computing device or devices; (c) sampling devices associated with respective first and second ones of said transmitters for creating respective first and second sections of representations of the signals transmitted by a first and a second of said transmitters, each of which sections overlaps in time with the terminal section, and for sending the sections of representations to the computing device or devices; the computing device or devices being adapted to create a model of a section of a representation of the composite signal received by the receiver from the first and second transmitters using the first section, the second section and a set of signal parameters, including initial estimates of the time offsets between the first section and the terminal section and between the second section and the terminal section; compare the model with the terminal section; refine the set of signal parameters including the time offset estimates to minimise the difference between said model and the terminal section; and adopt the time offsets in the refined parameter set, used to minimise the difference between said model and the terminal section, as the estimated time offsets between the first section and the terminal section and between the second section and the terminal section.
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21. A program code embodied on a computer-readable medium adapted to
create a terminal section of a representation of the signals from plural transmitters received by the receiver at the terminal; -
process a first section of a representation of the signal transmitted by a first of said transmitters and a second section of a representation of the signal transmitted by a second of said transmitters, each of which sections overlaps in time with the terminal section; create a model of a section of a representation of the composite signal received by the receiver from the first and second transmitters using the first section, the second section and a set of signal parameters, including initial estimates of the time offsets between the first section and the terminal section and between the second section and the terminal section; compare the model with the terminal section; refine the set of signal parameters including the time offset estimates to minimize the difference between said model and the terminal section; and adopt the time offsets in the refined parameter set, used to minimize the difference between said model and the terminal section, as the estimated time offsets between the first section and the terminal section and between the second section and the terminal section.
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Specification