Leica MX420 Operator's Manual page 207

Glossary
Glossary
Version 1.5
Operator's Manual
AIS - Automatic Identification System.
A shipboard broadcast transponder system in which ships
continually transmit their ID, position, course, speed and other
data to other nearby ships and shoreline authorities on a
common VHF radio channel.
ALARM
Message by which the navigator signals the occurrence ofan event.
The alarm is indicated by an audible tone and/or a message
(or
icon) on the display.
ALMANAC
Library of coarse satellite orbital characteristics used to calculate
satellite rise times, set times, angles ofelevation, etc. Almanac data
is valid for 18 I days.
ALTITUDE
The height of the antenna over mean sea level.
AMBIENT
Surrounding or encompassing environment.
ANTENNA HEIGHT
The height (over the waterIine) in which the antenna is installed.
This value is used in
2D
mode only.
ATMOSPHERIC
PRESSURE
See
BAROMETRIC
PRESSURE.
APPARENT WIND
ANGLE
(AWA)
The angle ofthe wind as measured on the moving vessel relative to
the heading of the vessel. An AWA of 0° indicates a wind from
straight ahead, whereas 180° indicates a wind from straight astern.
An AWA of 90° indicates a wind perpendicular to the vessel from .
its starboard side.
APPARENT
WIND SPEED (AWS)
The speed of the wind as measured on the moving vessel.
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