Systems and methods for locating subsurface objects
First Claim
1. Subsurface object location apparatus for determining the position of an object located below a surface, comprising:
- a subsurface unit having a transmitter and being arranged to be mounted on an object the location of which is to be monitored;
a plurality of surface units disposed at spaced locations at the surface and each having a receiver; and
a processing unit arranged for determining at least one of, the times of reception and relative times of reception at the plurality of receivers, of a signal transmitted from the transmitter and determining the location of the object on the basis of at least one of, the times and the relative times of reception, wherein the transmitter and receiver are arranged respectively to transmit and receive inductive signals and wherein said processing unit is arranged for performing a cyclic correlation to determine one of the times of reception and relative times of reception of the signal at each surface unit, said cyclic correlation being performed between the received signal and a synthesized signal.
2 Assignments
0 Petitions
Accused Products
Abstract
A subsurface object location apparatus for determining the position of an object 2 located below a surface S such as a land surface, the surface of the sea or a seabed. A subsurface unit 1 having transmitter means for transmitting inductive signals is mounted on the object 2. A plurality of surface units 3 are disposed at spaced locations at the surface S. Each surface unit 3 has receiver means arranged for receiving the inductive signals. Processing means 4 are provided for determining the location of the object 2 using time difference of arrival techniques in respect of the signals received at the surface units. Cyclic correlation is used in determining the times of reception of signals at the surface units.
22 Citations
16 Claims
-
1. Subsurface object location apparatus for determining the position of an object located below a surface, comprising:
-
a subsurface unit having a transmitter and being arranged to be mounted on an object the location of which is to be monitored;
a plurality of surface units disposed at spaced locations at the surface and each having a receiver; and
a processing unit arranged for determining at least one of, the times of reception and relative times of reception at the plurality of receivers, of a signal transmitted from the transmitter and determining the location of the object on the basis of at least one of, the times and the relative times of reception, wherein the transmitter and receiver are arranged respectively to transmit and receive inductive signals and wherein said processing unit is arranged for performing a cyclic correlation to determine one of the times of reception and relative times of reception of the signal at each surface unit, said cyclic correlation being performed between the received signal and a synthesized signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
-
9. A method for determining the position of an object located below a surface, comprising the steps of:
-
mounting a subsurface unit having a transmitter on the object;
disposing at spaced locations at the surface a plurality of surface units each having a receiver;
using the transmitter to transmit an inductive signal from the object;
determining at least one of the times and relative times at which the inductive signal is received at each of the receivers;
determining the location of the object on the basis of, at least one of the times and relative times of reception; and
performing a cyclic correlation to determine, at least one of the times of reception and relative times of reception of the signal at each surface unit, said cyclic correlation being performed between the received signal and a synthesized signal. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
-
Specification