Magellan GPS PROMARK X, User Manual

Page: 67 / 188

Auxiliary Functions
ProMARK X
4-13
Press ENTER. If the unit already has an
almanac, a warning is displayed. Press
ENTER again to delete the current al-
manac and collect a new one.
ALMANAC WILL BE
CLEARED ! Press
ENTER to cont.
NOTE
The unit must remain on for about 15 minutes once Almanac
Collect is started to be sure the unit will have a complete alma-
nac. An incomplete almanac may have an adverse effect on unit
operation.
AUX 10 — Memory Stats. Memory Stats displays the percentage of
memory used and of memory remaining for file storage.
Access AUX 10. The unit displays how
much buffer memory is in use and how
much is available.
If none of the satellites in the system can be found, or if the unit cannot find
enough satellites for a 2D position fix (three satellites), the unit will restart the
search. This should occur only if the antenna does not have a clear view of
the sky.
Once a satellite is located, the unit acquires clock and ephemeris information
from it, then almanac information. (Ephemeris data is precise positioning
data for the broadcasting satellite.) At the same time, the unit continues to
search on the remaining channels.
A position fix is calculated and displayed when the unit has acquired
ephemeris data from three satellites. This generally occurs while ALM
COLLECT or ALM VERIFY is displayed on the fourth line.
Since the unit does not have a complete almanac when this fix is calculated,
it is unable to select the satellite set with the best PDOP. The fix may therefore
not be as accurate as subsequent position fixes, which will be obtained with
the optimum satellite set.
MEMORY STATS
AVAILABLE: 53
USED: 47