Applanix POS MV V5 Installation And Operation Manual page 189

IMU
If bad IMU frames do occur, their likely cause is one of the following:
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Loss of Calibration
If IMU performance falls below specification (as may happen if the
IMU experiences excessive shock or vibration), the IMU Status field
on the controller main window will indicate an IMU failure.
Refer to the Fault Detection and the Message log windows
(described in Fault Identification on page 9-3 and Message Log on
page 9-9) for a more detailed identification of the fault.
Note: If POS MV detects that the IMU performance is outside
specification, it will alert you and continue navigation.
If POS MV detects a hardware failure in the IMU, the controller main
window will display the warning message IMU Failure. Note any
indications on the Fault Detection or the Message Log windows, and
contact Applanix for advice.
GNSS
The GNSS subsystem can experience a permanent loss of satellites,
or a breakdown of communication between the GNSS receiver and
the PCS.
Permanent Loss of Satellites
POS MV provides continuous information on the status of the GNSS
receivers. The status of the GNSS receivers may be monitored on the
GNSS Data window; select V iew, GNSS D ata from the MV-POSView
menu bar. Additionally, the GNSS Data window includes detailed
information on the satellites that the receiver is tracking and on the
receiver mode (i.e. tracking, navigate, etc.).
The GNSS subsystem may experience periodic GNSS dropouts
caused, for example, by antenna obstruction. The controller program
indicates a GNSS dropout by displaying GNSS Not Available or
GNSS Data Gap in the GNSS Status field on the main window.
However, if a GNSS dropout occurs and persists without any
apparent antenna obstruction, then one of the following problems may
exist:
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Copyright © Applanix Corporation, 2017
POS MV V5 Installation and Operation Guide
Problems in the data cable that connects the IMU to the PCS
Problems with the IMU or the power supplied to the IMU
Problems within the PCS
A loss of GNSS receiver configuration
Fault
Identification
9-15