120 20130-101a
GeminiG3 – 700MHz User Manual
30
4.7.4 GPS
All GeminiG3 radiomodems shipped from the Dataradio factory starting in May 2004 are fitted with a 12-
channel high efficiency GPS receiver, equipped with WAAS feature for better location precision (<3 me-
ters).
Note:
Except GeminiG3 Lite models, which are not GPS-equipped.
Programmers who need to decode the compressed information for their applications may contact Datara-
dio System Engineering for further information.
4.7.4.1 GPS
►
Status
Figure 23 - GPS – Status
Item
Description
Condition
In normal operation, indicates DGPS/WAAS.
When no GPS signal is present, the location indicators display the word “Invalid” and the
# of Satellites indicates “0”.
Differential
Differential GPS corrects various inaccuracies in the GPS system to yield measurements
good to a couple of meters when mobile is moving and even better when stationary.
Number SVs
The field “number of satellites” indicates the number of satellite signals being received
and used to calculate position.
UTC (hhmmss)
Universal time - uses a 24-hour clock format.
Position
Global position in Longitude (East-West) and Latitude (North-South) displayed using in-
formation obtained from a GeminiG3 (except “Lite” model) decoding a valid GPS input
signal.
Position with “(Last known)” displayed underneath indicates that the GPS data is either
old or not enough satellites signals are present to achieve a valid location computation. If
no “Last known” position was obtained, display shows (Unknown).
E.g. : Longitude of 73 degrees, 39 minutes and 45 seconds West would appear as:
073 39.7500 W
Altitude (meters)
The field “Altitude” indicates height above the WGS-84* reference ellipsoid in meters.
*WGS- 84 = World Geodetic System
True Course
Shows the current GPS-generated true course in degrees.
Ground Speed (km/h)
Shows travel speed (in km/h) from GPS-equipped GeminiG3 mobiles.
Vertical Speed (m/Sec)
Shows vertical displacement (in m/Sec) from GPS-equipped GeminiG3 mobiles.
