SPX SPIDAR NIC-500s, Operation Manual

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SPIDAR Software
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Figure 4-20: GPR1 & GPR2 must have the same points per trace
4.3.4 GPS
The user has the following options for configuring the GPS parameters (Figure 4-21):
•
GPS Device
– Use this dropdown to select the External GPS or turn GPS off. If the user
selects External, they can attach an optional GPS to the system via the serial cable.
•
Baud rate
– This option only appears if External GPS is selected. The baud rate is the
speed that data is sent from the GPS receiver to the serial port of the NIC-500, specific
to the GPS manufacturer. Using the dropdown box, it can be set to one of the following
values: 4800, 9600, 19200, 57600 or 115200.
•
External Power - This option only appears if External GPS is selected. The serial port
on NIC-500 can also output power, thereby enabling a single cable to be used for the
GPS (for power and data). This is specific to the GPS that is sold by Sensors &
Software.
•
Positions
– input the coordinate of the GPS relative to the origin of your configuration as
set in Section 4.3.2
. The ‘Z’ position will be the height of your GPS receiver from the
ground.
•
Latency -
The GPS latency time is the time difference between when the GPS receiver
obtains its position and when it is logged by the NIC-500. If GPS latency time is not
corrected for, the GPS position of targets and features of interest in the GPR line is less
accurate. GPS latency is not a large problem when GPR data are collected on slow-
moving platforms such as the SmartCart or SmartTow; it has the largest effect when
trying to determine the true position of a fast-moving platform such as the SmartChariot.