United States Patent
US Patent 5838279: Navigation and tracking system for shielded spaces
US 5838279 · granted 1998-11-17
Abstract
A navigation and/or tracking system has a base station B and a roving receiver R both of which are capable of receiving signals from a plurality of transmission sources T.times.1,T.times.2. A link signal W,W' is passed between the base station and the roving receiver to enable the relative location of the roving receiver to be determined. The apparatus enables the determination of the position of the roving receiver within a space (such as a tunnel T) shielded from receipt of signals from the transmission sources and has equipment P,Q for producing substitute signals, each signal being locked in phase with a signal from a respective one of the transmission sources. A curvilinear transmission element or elements F,F',F", extend within the shielded space T for generating fields in the shielded space. The equipment P,Q propagates at least two of the substitute signals in opposite directions along the curvilinear transmission element or elements for receipt by the roving receiver R. Additional equipment S passes the link signal W' between the roving receiver and the base station B within the shielded space.
| Patent Number | 5838279 |
|---|---|
| Title | Navigation and tracking system for shielded spaces |
| Filed | 1995-11-20 |
| Granted | 1998-11-17 |
| Inventor(s) | Smith; Peter James, Woan; Graham |
| Assignee | Cambridge Positioning Systems Limited |
| Number of Claims | 24 |
Abstract
A navigation and/or tracking system has a base station B and a roving receiver R both of which are capable of receiving signals from a plurality of transmission sources T.times.1,T.times.2. A link signal W,W' is passed between the base station and the roving receiver to enable the relative location of the roving receiver to be determined. The apparatus enables the determination of the position of the roving receiver within a space (such as a tunnel T) shielded from receipt of signals from the transmission sources and has equipment P,Q for producing substitute signals, each signal being locked in phase with a signal from a respective one of the transmission sources. A curvilinear transmission element or elements F,F',F", extend within the shielded space T for generating fields in the shielded space. The equipment P,Q propagates at least two of the substitute signals in opposite directions along the curvilinear transmission element or elements for receipt by the roving receiver R. Additional equipment S passes the link signal W' between the roving receiver and the base station B within the shielded space.
Claim 1
Apparatus for use with a navigation and/or tracking system having a base station and a roving receiver both of which are capable of receiving signals from a plurality of transmissionsources, and between which a link signal is passed to enable the relative location of the roving receiver to be determined, the apparatus enabling the determination of the position of the roving receiver within a space shielded from direct receipt ofsignals from the transmission sources and comprising means for producing substitute signals, each signal being either locked in phase with a signal from a respective one of the transmission sources or a replica of it; a curvilinear transmission elementor elements extending within the shielded space for generating fields in the shielded space; means for propagating at least two of the substitute signals in opposite directions along the curvilinear transmission element or elements for receipt by theroving receiver; and means for passing the link signal between the roving receiver and the base station.
Claims
24 totalApparatus for use with a navigation and/or tracking system having a base station and a roving receiver both of which are capable of receiving signals from a plurality of transmissionsources, and between which a link signal is passed to enable the relative location of the roving receiver to be determined, the apparatus enabling the determination of the position of the roving receiver within a space shielded from direct receipt ofsignals from the transmission sources and comprising means for producing substitute signals, each signal being either locked in phase with a signal from a respective one of the transmission sources or a replica of it; a curvilinear transmission elementor elements extending within the shielded space for generating fields in the shielded space; means for propagating at least two of the substitute signals in opposite directions along the curvilinear transmission element or elements for receipt by theroving receiver; and means for passing the link signal between the roving receiver and the base station.