Jeppesen Marine Workboat Navigator 1.3 - Manual (Page 156)

148
Global Positioning System (GPS)
A worldwide radio-navigation system
developed by the US. Department of
Defense. In addition to military purposes
it is widely used in marine, terrestrial
navigation and location based services.
Uses stationary satellites or a surface
signal to locate the boat with a very high
degree of accuracy. The term GPS is
frequently used to refer to GPS receivers.
GPS
See Global Positioning System.
Heading
The direction the boat is oriented.
Knot
A speed unit of one international nautical
mile (18520.0 meters or 6,076.11549
international feet) per hour.
Latitude
The designation for angles measuring
how far North or how far South a
position is. Value range is from 90ºS
to 0º at the equator to 90ºN. Latitude
values are represented by the Greek
letter lambda (λ).
Lat/Lon
Any object’s position, expressed in
Latitude and Longitude.
Leg
The segment of a route between two
waypoints.
Local Notice to Mariner (LNM)
A means for disseminating information
concerning aids and hazards to
navigation and other marine information
of interest to mariners travelling in
the waters of the United States, US
territories, and US holdings. These
notices are essential to all navigators
for the purpose of keeping charts, light
lists, coast pilots and other nautical
publications up-to-date.
The USCG publishes LNM weekly.
Longitude
The designation for angles measuring
how far West or how far East a position
is. Value range is from 180ºE to 180ºW.
Values of longitude are represented with
the Greek letter phi (φ).
LORAN (Long Range Aid to
Navigation)
LORAN is a terrestrial-based navigation
system using the time interval between
radio signals to determine the position of
the receiver. LORAN was popular with
marine navigation prior to the existence
of GPS. The current version of LORAN
in use is LORAN-C.
Magnetic Variation
The degree to which the magnetic north
differs from the true north. This data is
available from the Compass Rose on a
chart.
Man Overboard (MOB)
Mark that can be placed on a digital
chart to indicate emergency location.
Jeppesen Workboat Navigator will track
that location and return the boat to the
MOB coordinates.
Mark
In general, any created object on a chart
(routes and boundaries are composed of
marks). Specifically, marks are objects
created using the Mark tool, and can be
displayed as a number of different icons.
A mark may have a name, annotative
information, and an icon.
MARPA (Mini Automatic Radar
Plotting Aid)
A feature of contemporary radars that
greatly enhances their ability to track
targets, lock on, estimate closest point
of approach, calculate the target’s true
speed and course, and output this
information to other devices.
MOB
See Man Overboard.
National Marine Electronics
Association (NMEA)
This organization has determined
a standard, 0183, to which all data
transmission to and from marine
peripherals must conform. The NMEA
issues standards for interfacing marine
electronics devices. Pronounced “nee-
ma”. Not to be confused with NEMA
(National Electrical Manufacturers
Association).
Computers directly connected to NMEA
producing devices (GPS, heading
sensor, etc.) receive raw NMEA data.
Glossary
Glossary