Operator manual
Compass
STD 22
110--233
STD22 Compact and STD22
23
3646/110--233.DOC010102
Edition: May 20, 2005
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 courses than on easterly
and westerly courses.
Speed error is a physical deviation from the steering course indicated on the gyro
compass (compass course) from the true course (chart course). It depends on the speed
of the ship, the course 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 course 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) course.
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:
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.
The speed error correction function on the STD22 Gyro Compass
In this version, besides the automatic speed error correction function (with GPS and
Pulse 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 no.
3648 “Operator Unit 130-613”)
Add the correction value taken from the table to the uncorrected course (making sure
you note the leading sign).