Garmin G1000 NXi Pilot's Manual page 32

SYSTEM OVERVIEW
This box provides information regarding signal status. The accuracy of the aircraft' s GPS fix is calculated
using Estimated Position Uncertainty (EPU), Dilution of Precision (DOP), and horizontal and vertical figures
of merit (HFOM and VFOM). EPU is the radius of a circle centered on an estimated horizontal position in
which actual position has 95% probability of laying. EPU is a statistical error indication and not an actual
error measurement.
DOP measures satellite geometry quality (i.e., number of satellites received and where they are relative to
each other) on a range from 0.0 to 9.9, with lower numbers denoting better accuracy. HFOM and VFOM,
measures of horizontal and vertical position uncertainty, are the current 95% confidence horizontal and
vertical accuracy values reported by the GPS receiver.
The current calculated GPS position, time, altitude, ground speed, and track for the aircraft are displayed
below the satellite signal accuracy measurements.
• GPS Status
The GPS solution type (ACQUIRING, 2D NAV, 2D DIFF NAV, 3D NAV, 3D DIFF NAV) for the active GPS
receiver (GPS1 or GPS2) is shown in the upper right of the GPS Status Page. When the receiver is in the
process of acquiring enough satellite signals for navigation, the receiver uses satellite orbital data (collected
continuously from the satellites) and last known position to determine the satellites that should be in view.
'Acquiring' is indicated as the solution until a sufficient number of satellites have been acquired for computing
a solution.
When the receiver is in the process of acquiring a 3D differential GPS solution, 3D NAV is indicated as the
solution until the 3D differential fix has finished acquisition. SBAS (Satellite-Based Augmentation System)
indicates 'Inactive'. When acquisition is complete, the solution status indicates 3D DIFF NAV and SBAS
indicates 'Active'.
Viewing GPS receiver status information:
1) Use the large FMS Knob to select the Auxiliary Page Group (see Section 1.4 for information on navigating MFD
page groups).
2) Use the small FMS Knob to select GPS Status Page.
Selecting the GPS receiver for which data may be reviewed:
1) Use the FMS Knob to select the Aux - GPS Status Page.
2) To change the selected GPS receiver:
Press the desired GPS Softkey.
Or :
a) Press the MENU Key.
b) Use the FMS Knob to highlight the receiver which is not selected and press the ENT Key.
• RAIM (Receiver Autonomous Integrity Monitoring) Prediction (RAIM Softkey is selected)
In most cases performing a RAIM prediction is not necessary. However, in some cases, the selected approach
may be outside the SBAS coverage area and it may be necessary to perform a RAIM prediction for the intended
approach.
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Garmin G1000 NXi Pilot's Guide for Cessna Nav III
190-02177-00 Rev. A