Mounting Basics; Special Functions - NorthStar 941X Reference Manual

getting more
accuracy
Mounting
Special
Functions
loran TDs
Rev. D
If you need a higher level of accuracy than what basic GPS provides,
there are two choices available to you:
1. Use Differential GPS by installing a Northstar internal differential
beacon receiver (or use an externally-located Northstar differential
beacon receiver), or other source of differential corrections for your
941X. DGPS should provide better than 10-meter accuracy (repeat-
able and absolute) 95% of the time. See "Using GPS" on page 25 for
more information.
2. Interface your loran receiver to your 941X (provided the loran has
the appropriate NMEA 0183 format output capability). You will
then keep the "repeatable accuracy" of your loran, and add all of
the navigation features of the 941X, including the excellent world-
wide "absolute accuracy" of GPS. Refer to Table 2 on page 114 for
connector pin wiring guide.
The 941X is designed to be yoke- or flush-mounted on your boat. The
unit is waterproof and can be exposed directly to the weather. The GPS
antenna should be mounted fairly low on the vessel to minimize the ef-
fects of pitch and roll, and where it has a clear view of the entire sky. The
Beacon Receiver antenna (if installed) should be mounted fairly high,
like a loran antenna. Refer to "Mounting the 941X," on page 100, for de-
tails.
The following functions are unique to the 941X; you may want to read
about them in detail before using them.
The 941X automatically converts GPS coordinates to loran TDs for those
who have lists of fishing spots and other waypoints recorded as TDs. This
feature is called Phantom Loran™. You can display your position as TDs
or enter waypoints as TDs. The accuracy to be expected from this conver-
sion is generally better than 500 to 1500 feet. You can also interface your
existing loran receiver to the 941X and then display and navigate with
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