INDOOR ALTITUDE MEASURMENT BY GNSS RECEIVER

• US 20130099962A1
• Filed: 10/19/2011
• Published: 04/25/2013
• Est. Priority Date: 10/19/2011
• Status: Active Grant

• Current Assignee: Daniel A. Katz
• Original Assignee: Daniel A. Katz
• Inventors: Katz, Daniel A.
• Granted Patent: US 9,000,977 B2
• Time in Patent Office: Days
• US Class Current: 342/357.28
• CPC Class Codes: G01S 19/46 the supplementary measurement being of a radio-wave signal type

Abstract

Global Navigation Satellite Systems (GNSS), such as the US GPS, the European GALILEO and the Russian GLONASS are very limited indoors, due to very low power levels and significant multipath. So, though hundreds of millions of people around the world use GPS receivers, particularly embedded in mobile devices, they cannot use these devices indoors, where they stay most of the time. Present art methods for augmenting or assisting GPS indoors, are mainly based on cellular or WLAN networks, and embedded sensors such as accelerometers and compasses, yet no integrated solution was launched. The present invention discloses a method that may contribute to GNSS indoors navigation, enabling a GNSS receiver to measure its elevation above sea level, indoors, to a floor resolution. The disclosed method is based on terrestrial infrastructure, yet possibly only one beacon per building.

Claims

1. A method for determining the elevation of a receiver from a reference plane, configuring a beacon to broadcast signals, each of said signals specifying its transmission time instant and a reference point, said point and said beacon on a line perpendicular to said plane, said transmission time instant accounting for the distance between said point and said beacon, and configuring said receiver to detect said signals, measure the receiving time instant of the signal and determine its elevation from said plane.

2. A method according to claim 1, said line substantially crossing the center of the earth and configuring said receiver to determine its altitude above mean sea level.

3. A method according to claim 1, wherein said receiver is a Global Navigation Satellite System (GNSS) receiver, and said signals emulating signals broadcast by a satellite not in view in the area where said beacon is deployed.

4. A method according to claim 1, configuring said signals to propagate through cable, at least part of the way between said beacon and said receiver, configuring said transmission time instant accounting also for the propagation time of said signals through said cable, and for the propagation time of said signals on paths not perpendicular to said plane towards said receiver.

5. A method according to claim 4, configuring said cable with antennas or leaky antennas.

6. A method according to claim 4, configuring part of said cable for vertical deployment, with at least two Tee junctions, configuring each junction for connection to an antenna via a horizontal stem, and configuring these stems for substantially the same propagation time of said signals, and configuring the transmission time instant of each of said signals accounting also for propagation time on said stem.

7. A system for determining the elevation of a receiver from a reference plane, comprising a beacon and said receiver, said beacon configured to broadcast signals, each of said signals configured to specify its transmission time instant and a reference point, said point and said beacon on a line perpendicular to said plane, said transmission time instant accounting for the distance between said point and said beacon, and said receiver configured to detect said signals and measure the receiving time instant of the signal, and determine its elevation from said plane.

8. A system according to claim 7, said line substantially crossing the center of the earth and said receiver configured to determine its altitude above mean sea level.

9. A system according to claim 7, wherein said receiver is a Global Navigation Satellite System (GNSS) receiver, and said signals emulating signals broadcast by a satellite not in view in the area where said beacon is deployed.

10. A system according to claim 7, said signals configured to propagate through cable, at least part of the way between said beacon and said receiver, said transmission time instant configured accounting also for the propagation time of said signals through said cable, and for the propagation time of said signals on paths not perpendicular to said plane towards said receiver.

11. A system according to claim 10, said cable configured with antennas or leaky antennas.

12. A system according to claim 10, part of said cable configured for vertical deployment, with at least two Tee junctions, each junction configured for connection to an antenna via a horizontal stem, these stems configured for substantially the same propagation time of said signals, and the transmission time instant of each of said signals configured accounting also for propagation time on said stem.

13. A system according to claim 7, said beacon configured to broadcast signals in elevator shaft of a multi floor building.

14. A beacon for determining the elevation of a receiver from a reference plane, said beacon configured to broadcast signals detectable by said receiver, each of said signals configured to specify its transmission time instant and a reference point, said point and said beacon on a line perpendicular to said plane, said transmission time instant accounting for the distance between said point and said beacon, wherein said receiver configured to measure the receiving time instant of the signal and to determine its elevation from said plane.

15. A beacon according to claim 14, said line substantially crossing the center of the earth and said signals configured enabling said receiver to determine its elevation above mean sea level.

16. A beacon according to claim 14, wherein said receiver is a Global Navigation Satellite System (GNSS) receiver, and said signals emulating signals broadcast by a satellite not in view in the area where said beacon is deployed.

17. A beacon according to claim 14, said signals configured to propagate through cable, at least part of the way between said beacon and said receiver, said transmission time instant configured accounting also for the propagation time of said signals through said cable, and for the propagation time of said signals on paths not perpendicular to said plane towards said receiver.

18. A beacon according to claim 17, said cable configured with antennas or leaky antennas.

19. A beacon according to claim 17, part of said cable configured for vertical deployment, with at least two Tee junctions, each junction configured for connection to an antenna via a horizontal stem, these stems configured for substantially the same propagation time of said signals, and the transmission time instant of each of said signals configured accounting also for propagation time on said stem.

20. A beacon according to claim 14, coupled to a source providing accurate timing signals, at least one of:

a GNSS receiver, a cellular or mobile network or base station, a Local Area Network (LAN) or Access Point (AP), a wireless LAN or AP.