Speed Error - Raytheon Standard 22 Compact Operator's Manual

2.2.2

Speed error

A speed error occurs while the ship is travelling. This becomes greater as the speed
increases and is more pronounced on northerly and southerly headings than on easterly
and westerly headings.
Speed error is a physical deviation from the steering heading indicated on the gyro
compass (compass heading) from the true heading (chart heading). It depends on the
speed of the ship, the heading it is steering and the latitude.
The speed error is typically within the range of 0--2, and with fast ships, it can even
reach 5or more.
With automatic speed error correction the compass heading is continually corrected
using the values shown in the speed error table (see section 2.2.2.1). The digital display
on the compass and the connected repeater displays will always indicate the true
(corrected) heading.
For automatic speed error correction the ship's speed and the latitude are read into the
gyro compass.
The speed error correction function on the STD22 Compact Gyro Compass
Only the automatic speed error correction function applies; in order for it to operate
GPS or Pulse Log and GPS data (speed and degree of latitude) must be supplied to the
compass.
CAUTION:
The speed error correction function on the STD22 Gyro Compass
In this version, besides the automatic speed error correction function (with GPS and Log
data) the speed error correction function can also be carried out (with manual speed and
latitude values input) manually. The speed error can be corrected manually on the
Operator unit by entering the speed and latitude manually (see also Manual of Operator
Unit 130-626)
Add the correction value taken from the table to the uncorrected heading (making sure
you note the leading sign).
4201.DOC010102
Operator Manual
Compass Standard 22
and
Standard 22 Compact
If the speed and latitude are not available for automatic speed error
correction (Pulse Log or GPS failure), no automatic correction can
take place. The gyro compass will be showing the uncorrected
value.
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Edition: February 2015