User Guide

4 GPS
TH-D72A/E CONTENTS 27
For APRS, always configure the WGS-84 Geodetic Survey System for your GPS receiver.
The GPS unit is mounted on the upper surface of the body. The GPS unit incorporates SiRFstar III™
chipset that is highly accepted in the market.
Figure 4-4 Internal GPS Unit
During the GPS positioning, you can check the current status on the GPS satellite information
display.
The GPS satellite information display provides real-time data of the sky view, satellites’ signal
strength and status of the positioning. The display also helps you to get better reception by changing
the direction of the GPS antenna or making any other adjustments.
1 Sky View
The positions of the satellites indicated by the satellite numbers are plotted on the satellite location
chart. The satellite location chart shows the azimuth and elevation of the satellites. The outer
circle expresses the 360° of the azimuth. The sign of “N” at the top indicates North, the right
corresponds to East, the bottom to South and the left to West accordingly. The elevation is
represented by the proximity to the center; the outer circle shows 0° (horizontal position) and the
center indicates 90° (zenith). Observing the satellites’ positions, you can see they move little by
little over time.
2 Signal strength of the satellite
The signal strength is indicated by the bars appearing on the top of each satellite number. The bar
is based on a 15-point scale. The solid bar indicates the satellite is used for GPS positioning and
only the frame of the bar means the signal of the satellite is received but not used for positioning.
3 Status of positioning
• “2D” indicates the unit receives signals from three GPS satellites to perform two-dimensional
positioning with latitude and longitude.
• “3D” means the unit receives signals from more than four GPS satellites to perform three-
dimensional positioning with latitude, longitude and altitude.
4.2.4 Settings for Geodetic Survey System
4.3 Internal GPS
4.3.1 GPS Satellite Information Display