Simrad GN70, Руководство оператора и инструкция по установке

Страница: 45 / 100

| 45
Navigating with the GN70/MX61x | GN70/MX610/MX612 Operator and Installation Manual
Navigation Method
Different methods are available for calculating the distance and bearing between any two
points on a chart.
The Great Circle (GC) route is the shortest path between two points. However, if you are to travel
along such a route, it would be difficult to steer manually as the heading would constantly be
changing (except in the case of due north, south, or along the equator).
Rhumb lines (RL) are tracks of constant bearing. It is possible to travel between two locations
using Rhumb line computation, but the distance would usually be greater than if Great Circle
is used.
Steering Alarm Limits
Arrival Radius
Sets an invisible circle around the destination waypoint.
The vessel is considered to have arrived at the waypoint when it is within
this radius.
Off Course (XTE) Limit
This parameter defines the vessel’s accepted offset distance from the leg.
If the vessel goes beyond this limit an alarm will be activated.
Arrival Alarm
When the arrival alarm is enabled, an alarm will be activated as the vessel
reaches the waypoint or when it is within the specified arrival radius.
Magnetic Variation
Magnetic variation is the difference between true bearings and magnetic bearings, caused by
different location of the Geographic and the Magnetic north poles. Any local anomalies such
as iron deposits might also affect the magnetic bearings.
Magnetic variation is applied in order to navigate with heading in “True” mode when a magnetic
compass is used as source.
When set to Auto, the system automatically converts magnetic north to true north. Select
manual mode if you need to enter your own local magnetic variation.
Datum
Most paper charts are made in the WGS84 format, which also is used by the GN70/MX61x
system.
If your paper charts are in a different format, you can change the datum setting accordingly to
match your paper chart.
Coordinate System
Several coordinate systems can be used to control the format for Lat/Long coordinates
displayed on the POS and PLOT panels.