User Guide

5-105190-00649-00 Rev. A
Garmin G1000 Pilot’s Guide for the Diamond DA42
GPS NAVIGATION
The sky view display at the top left corner of the page shows the satellites currently in view as well as their
respective positions. The outer circle of the sky view represents the horizon with north at the top of the circle;
the inner circle represents 45° above the horizon, and the center point shows the position directly overhead.
Each satellite has a 30-second data transmission that must be collected (hollow signal strength bar) before the
satellite may be used for navigation (solid signal strength bar). Once the GPS receiver has determined position,
the G1000 indicates position, altitude, track, and ground speed. The GPS receiver status field also displays the
following messages under the appropriate conditions:
• Acquiring Sat - The GPS receiver is acquiring satellites for navigation. In this mode, the receiver uses satellite
orbital data (collected continuously from the satellites) and last known position to determine the satellites
that should be in view.
• 2D Navigation - The GPS receiver is in 2D navigation mode.
• 3D Navigation - The GPS receiver is in 3D navigation mode and computes altitude using satellite data.
The Satellite Status Page also indicates the accuracy of the position fix, using Estimated Position Error (EPE)
and Dilution of Precision (DOP) figures. 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. The lowest numbers denote
the best accuracy and the highest numbers denote the worst. EPE uses DOP and other factors to calculate a
horizontal position error in feet or meters.
OPERATIONS
RAIM PREDICTION
“RAIM” is an acronym for Receiver Autonomous Integrity Monitoring, a GPS receiver function
that performs a consistency check on all tracked satellites. RAIM ensures that the available satellite
geometry will allow the receiver to calculate a position within a specified protection limit (2.0 nautical
miles for oceanic and enroute, 1.0 NM for terminal, and 0.3 NM for non-precision approaches).
During oceanic, enroute, and terminal phases of flight, RAIM is available nearly 100% of the time.
Because of the tighter protection limit on approaches, there may be times when RAIM is not available.
The G1000 automatically monitors RAIM and warns with an alert message when it is not available. If RAIM
is not available when crossing the FAF, the missed approach procedure must be flown.
The RAIM prediction function also indicates whether RAIM will be available for a specified date and
time. If RAIM is not predicted to be available for the final approach course, the approach does not become
active — as indicated by an “Approach is not active” message, and a “RAIM not available from FAF to MAP”
message.