Garmin GPS 155XL TSO - Manual (Page 39)

29
SECTION
1
Enter the location, time and date for RAIM pre-
diction.
NAV KEY
RAIM Prediction
RAIM available for the entered time, date and
waypoint location.
The RAIM Prediction function allows you to confirm that GPS coverage is
available for your current location or at a specified waypoint any day of the year.
Receiver Autonomous Integrity Monitoring performs checks to ensure that the GPS
155XL will have adequate satellite geometry to work with during your flight. RAIM
availability will be near 100% in Oceanic, En route and Terminal phases of flight.
Because the FAA’s TSO requirements for non-precision approaches specify significant-
ly better satellite coverage than other flight phases, RAIM may not be available when
flying some approaches. The GPS 155XL will automatically monitor RAIM during
approach operations and warn you if RAIM is not available. RAIM prediction will
help you plan for a pending flight to confirm GPS operation during an approach.
To predict RAIM availability:
1. Press
N
and rotate
O
until NAV Menu 2 is displayed.
2. Press
C
and rotate
O
to highlight ‘RAIM Prd?’. Press
E
.
3. Rotate
O
to highlight the field which you would like to change.
4. Use K and O to enter the waypoint name, or leave it blank to use your current
position. Press
E
to accept.
5. Use
K
and
O
to enter the ETA in hours and minutes (in local or UTC time, whichever
you have selected from the clock display), and the day, month and year. The current date
will be displayed automatically. Press
E
to accept.
6. Rotate
O
to highlight ‘Compute RAIM?’.
7. Press
E
to compute information.
When the computations are complete, the GPS 155XL will display whether or not
RAIM is available for the specified waypoint at the specified date and time, +/- 15
minutes of your ETA. Refer to the table on page 99 for specific RAIM protection
limits as they relate to CDI scale figures.
155xlb manual 1/12/99 4:05 PM Page 29