Novatel SMART7, Инструкция по установке и эксплуатации

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Chapter 4 SMART7 with SPAN Operation
SMART7 Installation and Operation User Manual v6 79
parameter:
INSCALIBRATE RBV ADD
9. 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.
10. 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 a kinematic alignment and has a valid INS solution.
For information about the logs and commands used in this procedure, refer to the OEM7 Commands
and Logs Reference Manual .
4.6 Azimuth Sources on a SPAN System
The SPAN system use three different methods to calculate the azimuth.
l
Course Over Ground
l
Inertial Azimuth
l
ALIGN Azimuth
4.6.1 Course Over Ground
The course over ground azimuth is determined using the position delta between two position solutions computed
by the OEM7 receiver. This is the simplest way to compute an azimuth and is done using either the GNSS solu-
tion or the INS solution. This method does not work when the vehicle is stationary as any position difference is
due to position error and the computed azimuth is meaningless.
Course over ground azimuth is of greatest advantage in aerial or marine environments where the actual direction
of travel may not match the forward axis of the aircraft/boat due to winds or currents. This effect is known as the
crab angle. Course over ground azimuth is a great way to compute the offset if another means of computing the
vehicle azimuth is available.
Course over ground azimuths are available in several different velocity logs. See Table 14: Logs with Azimuth
Data on the next page.
4.6.2 Inertial Azimuth
The inertial azimuth computed by the SPAN inertial navigation filter. It uses the sensors in the IMU to compute
the azimuth of the IMU (this can be rotated to another reference if desired). For more information, see the
SETINSROTATION command in the Agriculture Commands and Logs Reference Manual .