Raymarine A65 - Manual (Page 37)

Chapter 2: General Operation and System Setup 37
The sky view graphic shows the position of these satellites. Positional accuracy is
dependent upon these parameters. In particular, the azimuth and elevation
angles are used in a triangulation process to calculate your position.
HDOP
Horizontal Dilution of Position (HDOP) more precisely estimates the accuracy of
horizontal (latitude/longitude) position fixes by adjusting the error estimates
according to the geometry of the satellites used. A higher figure signifies a greater
positional error. In ideal circumstances, the figure should be in the region of 1.0.
Fix Status
The fix status can indicate:
• NO FIX: no satellite fix can be acquired
• FIX OK: a normal GPS fix has been acquired
• D-FIX: a differential fix has been acquired
• SD-FIX: a satellite differential fix has been acquired
Mode/Datum
The Mode parameter describes the type of fix obtained:
• 1: no satellite fix can be acquired
• 2: the receiver has acquired the signal of at least 3 satellites and has calcu-
lated a two dimensional (2-D) or horizontal position fix (latitude and longi-
tude)
• 3: the receiver has acquired the signal of at least 4 satellites and has calcu-
lated a three dimensional (3-D) position fix (latitude, longitude and altitude)
The Datum field displays which mathematical model of the Earth's shape was
used to determine your position. The datum used by the A65 is WGS 84 (World
Geodetic System 1984).