SPX SPIDAR NIC-500s Operation Manual page 48

For example, at 25 km/h, you are moving 6.94m per second. If the GPS has 1.00 second
latency, your data position would be off by 6.94m. Details on calculating GPS Latency
can be found in
EKKO_Project. It could also be adjusted at that time, if it's unknown at the time of
acquisition.
Note: In a daisy-chained configuration, GPS data is only recorded on the Master NIC-500.
For the subordinate NIC-500s, the user must copy the .GP2 files from the Master NIC-500
and rename them to match the subordinate NIC-500(s). Then the appropriate GPS offset
must be applied in the EKKO_Project software (see the EKKO_Project manual for details).
4.3.5 Triggers
A trigger is used to fire, or pulse, the GPR system to collect a trace of data. There are three
ways to trigger the GPR system: using an Odometer, Manually or Free Run mode. These are
set by selecting Trigger method and configuring the appropriate settings.
Note: If there are multiple NIC-500s, the same Trigger Method must be used for all of them.
Odometer
Used most often if the configuration has a wheel encoder. When the odometer wheel moves
one step size, it will cause the transmitter to fire. This is the easiest mode to operate in, as you
don't have to worry about collecting data at equally spaced intervals.
Appendix B. The latency will be saved in the data for use in
Figure 4-21: Setting options under the GPS tab
40
SPIDAR Software