Acoustic position-determination system
First Claim
Patent Images
1. A method of determining the position of a mobile unit within a detection zone comprising:
- emitting an acoustic signal from the mobile unit;
receiving said acoustic signal along a first path from the mobile unit at a first transducer;
receiving an echo of said acoustic signal after reflection from a surface within said detection zone at a second transducer;
determining the time of arrival at the first transducer of the acoustic signal along said first path;
determining the time of arrival of the echo at the second transducer; and
determining the position of the mobile unit within the detection zone from said times of arrival,wherein the first transducer is optimised for the reception of the signal along the first path, and the second transducer is optimised for the reception of the echo, the second transducer being configured to have greater directional sensitivity than the first transducer, and being directed towards said surface.
1 Assignment
0 Petitions
Accused Products
Abstract
The position of a mobile unit (12) within a detection zone is determined. An acoustic signal is emitted from the mobile unit and received along a first path (54). An echo of the signal is received after reflection from a surface (46) within said detection zone. The position of the mobile unit (12) within the detection zone is determined from the times of arrival of the signal and echo.
-
Citations
31 Claims
-
1. A method of determining the position of a mobile unit within a detection zone comprising:
-
emitting an acoustic signal from the mobile unit; receiving said acoustic signal along a first path from the mobile unit at a first transducer; receiving an echo of said acoustic signal after reflection from a surface within said detection zone at a second transducer; determining the time of arrival at the first transducer of the acoustic signal along said first path; determining the time of arrival of the echo at the second transducer; and determining the position of the mobile unit within the detection zone from said times of arrival, wherein the first transducer is optimised for the reception of the signal along the first path, and the second transducer is optimised for the reception of the echo, the second transducer being configured to have greater directional sensitivity than the first transducer, and being directed towards said surface. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
-
-
12. A position-determining system comprising a mobile unit, a receiver comprising a plurality of transducers, and a processor, the mobile unit being located within a detection zone, wherein:
-
the mobile unit is arranged to emit an acoustic signal; the receiver is arranged to receive said acoustic signal at a first one of said transducers along a first path from the mobile unit, and to receive, at a second one of said transducers, an echo of said acoustic signal after reflection from a surface within said detection zone, wherein the first transducer is optimised for the reception of the signal along the first path, and the second transducer is optimised for the reception of the echo, the second transducer being configured to have greater directional sensitivity than the first transducer, and to be directed towards said surface; and the processor is arranged to determine the time of arrival of the acoustic signal along said first path at the first transducer, to determine the time of arrival of the echo at the second transducer, and to determine the position of the mobile unit within the detection zone from said times of arrival. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
-
-
29. A receiver for use in a system for determining the position of a mobile unit within a detection zone, the receiver comprising:
-
a plurality of transducers and a processing system; wherein the receiver is arranged to receive an acoustic signal at a first one of said transducers along a first path from a mobile unit, and to receive, at a second one of the transducers, an echo of said acoustic signal after reflection from a surface within a detection zone, wherein the first transducer is optimized for the reception of the signal along the first path, and the second transducer is optimised for the reception of the echo, the second transducer being configured to have greater directional sensitivity than the first transducer, and to be directed towards the surface; and wherein the processing system is arranged to (i) determine the time of arrival of the acoustic signal along said first path at the first transducer, (ii) determine the time of arrival of the echo at the second transducer, and (iii) determine the position of the mobile unit within the detection zone from said times of arrival. - View Dependent Claims (30, 31)
-
Specification