Radar Systems Prism2, Руководство пользователя

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Fig. 2.2. Shape of radiated electromagnetic wave.
These electromagnetic waves are propagating in sounded medium, thus reflecting from
various inhomogeneities (metals, cavities, various objects, layer boundaries with different
parameters, etc.). Reflected sounded waves which carry information on the medium being
sounded are received by the receiver using a receiving antenna. Receiving signal however, in
addition to reflected wave also contain a direct wave that is going by the shortest distance
directly from the transmitting to the receiving antenna. Therefore, the receiver's output signal is
combination of transmitter's pulse (as shown in Fig. 2.2) followed by reflected pulses. This
transmitter's pulse should be used as a starting point for estimating a delay of reflected signals
for the purpose of determining the target's depth of occurrence in the medium.
Fig. 2.3. Example of received signal.
Transmitter pulse is clearly visible to the left.
Passing process shown in Fig. 2.3 is very fast, and takes tens to hundreds of nanoseconds
which in technical terms makes him very difficult to process. Therefore stroboscopic converter is
used to "expand" this process in time. Synchronizer is used for controlling all Georadar
assemblies operation, while in its turn synchronizer, is controlled by the “
Prism2
” software
from your computer, and its description you are holding in your hands right now. Computer
running “
Prism2
” is the one that receives radiolocation sounding data delivered from GPR.
When analyzing received data, it is important to keep in mind that the propagation speed of
electromagnetic waves in sounded medium (other than air) is not equal to the velocity of light, in
fact – its velocity is
less due to the square root of the sounded medium dielectric permittivity.
Consideration of this factor in the software is made automatically, and you will see it soon by
yourself.