User's Manual

IDS Ingegneria Dei Sistemi S.p.A. N doc: MN/2009/028 - Rev. 1.1

DETECTOR DUO SYSTEM – User manual

As the propagation speed in the medium increases (

), the ratio

between the flight time of the outwards and return signal

twt

relative to echoes originating from lateral points and the

twt

relating to the top surface of the target decreases. Therefore the

hyperbola widens with higher propagation speed,

With increasing depth of the target, the ration between the

twt

relating to the echoes from the side points and the

twt

relating to

the top surface of the target decreases. Again, the hyperbola

widens with increasing target depth.

For equal propagation speed, depth and type of target, the

hyperbola will be wider for geometrically larger targets (for

examples for wider diameter pipes).

When interpreting the maps, it is therefore a good idea to remember

that the width of a hyperbola does not just depend on the geometrical

size and shape of the target. Fig. 7.2 shows two maps featuring echoes

of an irregular interface between two layers with different dielectric

properties (asphalt) and six pipes situated perpendicularly to the

direction of investigation.

Fig. 7.2 – Maps showing traces of an interface and pipes perpendicular to the direction of

investigation

interface

Top

surface

of the

pipes