GP1670F_1870F Operator's Manual - Furuno USA

11. CUSTOMIZING YOUR UNITsetting if the GPS fix changes greatly.[SPEED FILTER]: During position fixing, ship's velocity (speed) is directly measuredfrom the GPS satellite. The raw velocity data may change randomly depending on receivingconditions and other factors. You can reduce this random variation by increasingthe filter setting. Like with the latitude and longitude filter, the higher the speed filtersetting the more smoothed the raw data. If the setting is too high, however, the responseto speed and course change slows. For no smoothing, choose Off.[FIX DATUM]: Select the datum used to prepare your chart.[NAVIGATION SETUP]: Navigate provides for customizing of the map display.[COORDINATE SYSTEM]: Select the coordinate display method, amongddd mm.mmm, ddd mm.mmmm, or ddd mm ss.[MAP DATUM]: Select the datum.[ROTATION OF THRESHOLD]: Sets the amount of course (in degrees) that initiatesredrawing of the course in the Auto course-up mode.[COMPASS SETUP]: Select the type of compass used and set magnetic variation.[BEARINGS]: Select True for gyrocompass, Magnetic for magnetic compass.[VARIATION]: The location of the magnetic north pole is different from the geographicalnorth pole. This causes a difference between the true and magnetic north location.This difference is called magnetic variation, and varies with respect to the observationpoint on earth. Your unit is preprogrammed with all the earth's magnetic variations.However, you may wish to enter variation manually, referring to a nautical chart, to refineaccuracy. Set to [AUTO] to get correct variation when there is no position data.[INTERNAL GPS SETUP]: Set up the internal GPS receiver.11-4