Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
61 words
.1. A method for locating buried objects, which method includes the steps of transmitting into the ground polarisable radiation, receiving reflected signals, indicative of said object, incident upon at least two co-located angularly disposed transducers and comparing the signals thus received, said radiation being transmitted from a transducer source which is co-located but angularly disposed with respect to each receiver transducer.
Claim 2
Dependent Claim
13 words
A method as claimed in claim 1 wherein the transmitted radiation is polarised.
Claim 3
Dependent Claim
16 words
A method as claimed in claim 2 wherein said transmitted radiation is circularly or eliptically polarised.
Claim 4
Independent Claim
144 words
A method as claimed in any one of claims 1 to 3 wherein said comparison includes the steps of : (i) measuring the time taken for said signals to be received from said buried object. (ii) determining the time taken for signals to be received when transmitted at a known depth, distance and angular orientation from a known reference target. (iii) from the data relating to the reference target, constructing a three-dimensional wave form which constitutes a three-dimensional matched filter, corresponding to the known orientation angle and which can be changed to correspond to any arbitary orientation angle. (iv) constructing a three dimensional waveform from the measurements made with respect to said buried object, (v) passing the three-dimensional wave-form (iv) through said matched filter and, (vi) determining, by varying the orientation angle, the combination of time and angle which leads to maximum filter output.
Claim 5
Dependent Claim
63 words
An antenna assembly suitable for use in locating buried objects, said assembly comprising an arrangement of at least three, co-located, two terminal antennas wherein the antennas are angularly disposed with respect to each other around a common point and each antenna is adapted to be capable of selectively transmitting polarisable radiation into the ground and receiving reflected radiation from out of the ground.
Claim 6
Dependent Claim
13 words
An assembly as claimed in claim 5 wherein the antennas are substantially planar.
Claim 7
Dependent Claim
18 words
An assembly as claimed in claim 5 or claim 6 wherein the assembly comprises at least six antennas.
Claim 8
Dependent Claim
24 words
An assembly as claimed in any of claims 5 to 7 wherein the antennas are spirally arranged in single plane around a common cnetre.
Claim 9
Dependent Claim
25 words
An assembly according to any one of claims 5 to 8 wherein the surface to be located nearest the ground is clad with a dielectric.
Claim 10
Dependent Claim
12 words
An assembly according to claim 9 wherein the dielectric is substantially lossless.
Claim 11
Dependent Claim
29 words
An assembly according to claim 9 or claim 10 wherein the coating thickness is at least λd/20 where λd is the wavelength of the lowest frequency to be transmitted.
Claim 12
Dependent Claim
21 words
An assembly according to any of claims 9 to 11 wherein the relative permittivity of the dielectric is at least 3.5.
Claim 13
Dependent Claim
21 words
An assembly according to any of claims 4 to 11 and substantially as hereinbefore described with reference to the accompanying drawings.