SPX SPIDAR NIC-500s Operation Manual page 53

It is important to aim for a reasonable step size to resolve subsurface targets. A step
size that is too coarse may result in missed subsurface targets. A step size that is too
fine may result in large data volumes, skipped traces and slow survey productivity.
In the case of a single NIC-500, the same step size must be used for all GPR
transducers/antennas connected to that NIC-500. For a multi-frequency application, you
will want to use the recommend step size for the highest frequency system.
Recommended step sizes for different frequencies are shown below:
Manual
This is typically used when surveying in difficult terrain where antennas cannot be moved easily.
The screen display is shown in Figure 4-28 for a single NIC-500 and in Figure 4-29 for multiple
NIC-500s.
The user specifies a step size, which is the distance between measurement points. For the
position of each measurement point, the system assumes the operator has moved the antennas
one step size along the survey line. A trace is collected every time the user presses a button in
the line scan screen
Step Size = Travel Speed x Trace Interval
Frequency (MHz)
12.5
25
50
100
200
250
500
1000
(Section 4.2)
Recommended Step
Size (m)
2
1
0.5
0.25
0.1
0.05
0.02
0.01
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SPIDAR Software