9. OTHER FUNCTIONS
9-16
the setting, the more smoothed the raw data, however too high a setting slows re-
sponse time to change in latitude and longitude. This is especially noticeable at high
ship’s speeds. 000 is the normal setting; increase the setting if the GPS fix changes.
[SPEED SMOOTHING]: During position fixing, ship’s velocity (speed) is directly mea-
sured by receiving GPS satellite signals. The raw velocity data may change randomly
depending on receiving conditions and other factors. You can reduce this random vari-
ation by increasing the smoothing. Like with latitude and longitude smoothing, the
higher the speed smoothing the more smoothed the raw data. If the setting is too high,
however, the response to speed and course change slows. For no smoothing, enter
all zeroes.
[SPEED AVERAGING]: Calculation of ETA and TTG is based on average ship’s
speed over a given period. If the period is too long or too short, calculation error will
result. Change the setting accordingly if calculation error occurs.
[NMEA SPEED AVERAGING]: Speed averaging for the ship’s speed data received
from external equipment in NMEA format.
[LATITUDE OFFSET], [LONGITUDE OFFSET]: GPS-generated position may be off
by some seconds because of various factors. In this case, you can apply an offset to
GPS position to refine position accuracy. Calculate the error on a nautical chart. The
L/L offset icon (
) appears at the bottom right of the plotter display.
[DISABLE SATELLITE(GPS)]: Every GPS satellite is broadcasting abnormal satellite
number(s) in its Almanac, which contains general orbital data about all GPS satellites,
including those which are malfunctioning. Using this information, the GPS receiver au-
tomatically eliminates any malfunctioning satellite from the GPS satellite schedule.
However, the Almanac sometimes may not contain this information. If you hear about
a malfunctioning satellite from another source, you can disable it manually. Enter sat-
ellite number (max. 3 satellites) in two digits.
[ANTENNA HEIGHT]: Enter the height of the antenna unit above sea surface.
[GPS FIX MODE]: Selects the position-fixing mode from 2D or 2D/3D. When selecting
2D/3D, 2D or 3D is automatically selected depending on the number of available sat-
ellites. (3D requires four or more satellites.)
[DGPS/SBAS]: Selects the position-fixing method from [DGPS], [SBAS] or [AUTO-
MATIC]. (For SBAS, see "WHAT IS SBAS?" on page AP-12.) The GP-3700 requires
the optional DGPS beacon receiver to fix position by DGPS. [AUTOMATIC] fixes po-
sition by SBAS when DGPS correction data is not available. For normal GPS position-
ing, select [NO].
[DGPS/SBAS ALARM]: This alarm alerts you when the DGPS or SBAS signal is lost.
[ON]: Alarm sounds when the position fixing method is switched from DGPS (or
SBAS) to GPS. Alarm sounds until the position fixing method is restored to DGPS (or
SBAS), or silencing the buzzer.
[OFF]: Alarm does not sound when the DGPS or SBAS signal is lost.
