| This section is based on an
article written by a member of the Darling Downs Soaring
Club and is reproduced here with the kind permission of DDSC.
About GPS
The Global Positioning System utilises a
"constellation" of low earth orbiting satellites to provide position information
to a display unit (GPS receiver). Nominal GPS accuracy is to within 30 metres of
horizontal and altitude information is about 3 times less accurate. Positions are found by
a complex process of triangulation of the signals from each satellite.
GPS units can provide uses with many
functions above pure position information. Speed over the ground, track, time and
distance/bearing/time to known locations (waypoints) can be displayed.
GPS and Gliding
GPS has obvious benefits to the soaring
pilot. Navigation can be improved by the use of waypoints and the "GoTo"
function of the waypoints. Tasks can be easily set and monitored. The 'Track' will show
the bearing over the ground and 'Estimated time of Arrival' can be shown. Ground speed can
help with calculating glides along with 'Distance to Waypoint'.
GPS tracks can be used as a debriefing tool.
These tracks when overlaid on a map display the pilots flight. This can be the subject of
long discussions over choice of track, visible features, thermalling techniques, thermal
strength and many other details.
Software and Uses 
The CGC Nimbus-2C (VH-GAW) is fitted a Cambridge Lnav with GPS coupling to a Cambridge
GPS Data Logger.
The following software can be used in
conjunction with Garmin GPS units (Cambridge Aero
Instruments use the Gamin GPS) to manage waypoints and display maps with overlaid
information.
Waypoint+
is a freeware tool for managing files between your Garmin GPS and computer. Waypoints,
tracks, routes can be moved in both directions to enable sharing of information and ease
of editing.
OziExplorer is a GPS mapping tool
for overlaying GPS information on maps. It is an excellent 'low end ' GIS system. Maps can
be imported from Geo referenced map files (generally expensive) or by scanning ANY map
into the computer and then calibrating it to known points.
Connectors for a Garmin GPS can be
purchased though a hardware / shareware system. You pledge an amount for some connectors,
they mail them to you and then you send the money. Darling Downs Soaring Club Members
report that this system works well. Alternatively the Australian GPS Information Site has
a range of ready made GPS cables, antennas and other related products.
Darling Downs Soaring Club Waypoint File
If you are looking to add waypoints to your
GPS unit, visit the Worldwide
Soaring Point Exchange and select the file format you require. The file includes a
list of approximately 450 waypoints within 1000km of the club. A hard copy of the list is
available in the clubhouse.
Due to the method used to obtain waypoint
details in the Darling Downs Soaring Club Waypoint List, the accuracy of each waypoint can
not be confirmed. If you intend to use the information located in this file it is your
responsibility to confirm these details. |
