Garmin Apollo GX 50 User Manual page 311

Problem
No GPS signal
reception
MSG light stays on
after power-on.
Displayed message
is: IN USE SENSOR
CANNOT
COMPUTE Lat/Lon
No User waypoints
show up on the
Map display or the
Nearest waypoint
list
Waypoint
sequencing is
erratic
Possible Cause
Obstructed signal
path
Incorrect seed
position, time, or
UTC differential
entered
If using a wrong
antenna: faulty
external antenna,
wiring, or
connections
Interference
The In-Use position
sensor is not able to
calculate a position
Runway Limits are
set for a value that
is too large
Direct-To entry
option setting may
not be correct
Troubleshooting
Action
Move aircraft out of
hangar or away
from buildings to
provide an
unobstructed view
of the sky for the
antenna
Check these
settings, if necessary
in the System
Functions
Contact your dealer
to check the
antenna and other
wiring
Check for GPS L1
interference
sources. Contact
your dealer or II
Morrow tech
support.
Check for
obstructions and
connections to the
antenna.
The GPS engine may
need to be reset.
Reset the Runway
Limits value, see
page 3-12
If you are flying
Direct-To, the
option should be set
to "May Clear", see
page 7-9
13-3