Chapter 3 SPAN Operation
OEM7 SPAN Installation and Operation User Manual v14
105
come to a stop on the finishing point of the previous line.
9. Initiate the second pass of the calibration by issuing the
INSCALIBRATE
command with the
ADD
para-
meter:
INSCALIBRATE RBV ADD
10. Drive the vehicle back along the original course, until you reach the starting point for the first pass. Stop the
vehicle, and re-issue the
INSCALIBRATE
command, with the
STOP
parameter.
INSCALSTATUS
will
again indicate a source status of CALIBRATED.
At this point the multi-line calibration can be considered complete, but more iterations can be repeated until
the desired accuracy level is reached.
11. When the calibration is complete, the calibrated offset value can be viewed in either the
INSCALSTATUS
log or the
INSCONFIG
log.
To save a calibrated rotation for subsequent start ups, issue the
SAVECONFIG
command after calibration is
complete. Each time the IMU is re-mounted this calibration should be performed again.
After the
INSCALIBRATE RBV ENABLE
command is entered, there are no body-vehicle rotation para-
meters present and a kinematic alignment is NOT possible. Therefore this command should only be
entered after the system has performed either a static or kinematic alignment and has a valid INS solu-
tion.
For information about the logs and commands used in this procedure, refer to the
.
3.5 Synchronizing External Equipment
A SPAN system allows you to synchronize with external equipment.
All SPAN receivers accept input pulses (events). Each event signal can be configured for positive or negative
polarity. Time, or a solution (position, velocity, attitude), can be generated and output with each input pulse.
3.5.1 Configuring an Input Strobe
SPAN systems have several input strobes. The input strobes apply an accurate GNSS time to the rising, or fall-
ing, edge of an input pulse called an event. For each event, an accurate position, velocity or attitude solution is
also available. Each input strobe is usually associated with a separate device, therefore different solution output
lever arm offsets can be applied to each strobe.
Each input strobe can be configured using the
EVENTINCONTROL
command for the following parameters:
Polarity
:
When polarity is set to positive, events trigger on the rising edge. When polarity is set to negative, events
trigger on the falling edge.
Time Bias (t_bias)
:
A constant time bias in nanoseconds can be applied to each event pulse. Typically this is used to account
for a transmission delay.
Time Guard (t_guard)
:
The time guard specifies the minimum number of milliseconds between pulses. This is used to coarsely filter
the input pulses.
