User's Manual

Table Of Contents
RADARPILOT / CHARTRADAR
ED 3038 G 232 / 01 (2002-06)
Operating Instructions
5 Heading, Speed, Position
5.3 Position Sensor
b_r1_e23.fm / 21.06.02
62
Check of the Accuracy of the Position Data
In the PPI, any inaccuracy in the position data causes displacement between
- the own ship symbol and the radar video on the one hand, and
- the tracks and the maps on the other hand.
The position used by the radar is normally accurate enough if the symbols of a map that may have been
generated for this purpose coincide with the videos of the radar targets when the display range is set to
a small value.
Correction of a Constant Position-Error (Position Offset)
If the displayed position is incorrect, the videos of fixed point-targets (e.g. buoys) do not coincide with the
symbols of these targets that are entered at the correct positions in a map. The position error is corrected
manually by making the video of a fixed target coincide with its map symbol:
1. Switch on a sufficiently small radar range.
2. Click on the ADJUST button. By flashing, the button indi-
cates that the cursor in the PPI now has a special func-
tion.
3. Click on a map symbol whose radar echo is clearly recog-
nisable and identifiable.
If the cursor is now moved, the distances of the cursor
position from the clicked symbol in the north/south and
east/west directions are displayed behind the ADJUST
button.
4. Click on the radar echo of the map symbol on which you have clicked. As a result, the correction
values displayed behind the ADJUST button (= position offset) take effect and is added to the posi-
tion of the sensor.
The entire track and map synthetics move by an amount equal to the position offset. The posi-
tion offset that is entered continues to be displayed behind ADJUST.
1)
In this way, each direction can be corrected by up to 999 m.
1)
5. Check that the other symbols of the map too now coincide as well as possible with their radar
echoes. If necessary, processes 2 to 4 can be repeated on the basis of the position offset that exists
at that time.
If the entire video has a rotational displacement relative to the map, this indicates that there is
probably a compass error. Either the synchronisation with the compass system is inadequate
(this must then be corrected – see page 57) or the compass system itself has a static or
dynamic course error. This should, if possible, be corrected in the compass system.
Deleting the Position Offset
The position offset is deleted automatically as soon as a
different position-sensor is selected.
The position offset is deleted manually by clicking on the
ADJUST button by means of the MORE key and by then
clicking RESET ADJUST by means of the DO key.
1)
If the EP position is being used, the position data are modified by an amount equal to the position offset. No limitation takes place.
DO
POS
LAT
LON
COG
SOG
55:35. 285 N
008:36.437 W
51.6 °
18.3 NM
GPS1
ADJUST
–– ––
–– ––
REF
RADAR
ADJUST
135 N
368 E
1.MORE
RESET ADJUST
2.DO
ADJUST
– – –
– – –
m
m