Furuno GP-3300, GD-3300 manual GPS Smoothing, Speed and course GPS smoothing, 10-6

2.Enter satellite number using two digits.

3.Press the [] key to display desired option. Each press of the key deletes item in parentheses (namely, enables the satellite) or displays DESELECT or FORCED.

4.Press the [ENT] key.

10.4GPS Smoothing

Latitude and longitude GPS smoothing

When the DOP or receiving condition is unfavorable, the GPS fix may change greatly, even if the vessel is dead in water. This change can be reduced by smoothing the raw GPS fixes. A setting between 0 and 9 is available. The higher the setting the more smoothed the raw data. Note however that too high a setting slows response time to change in latitude and longitude. This phenomenon is especially no- ticeable at high ship’s speeds. “0” is the normal setting; increase the setting if the GPS fix changes greatly.

LATITUDE

RAW POSITION FIX

AFTER SMOOTHING

LONG-

ITUDE

Figure 10-4 Latitude and longitude GPS smoothing

Speed and course GPS smoothing

During position fixing, ship’s velocity (speed and course) is directly measured by receiving GPS satellite signals. The raw velocity data may change randomly depending on receiving conditions and other factors. You can reduce this random variation by increasing the smoothing. Like with latitude and longitude smoothing, the higher the speed and course smoothing setting the more smoothed the raw data. If the setting is too high, however, the response to speed and course changes slows. For no smoothing, enter “0”. “5” is suitable for most conditions.

SPEED (KNOT) COURSE (DEGREE)

RAW POSITION FIX	RAW POSITION FIX
AFTER SMOOTHING	AFTER SMOOTHING
TIME	TIME

Figure 10-5 Speed and course GPS smoothing

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