DSM 132/132RS Receiver User Guide 23
Overview 2
During darkness, when the beacon tower is more than
240–480 kilometers (150–300 miles) from the receiver, the sky
wave beacon signal may be reflected off the ionosphere. This
causes interference with the ground wave beacon signal. Self-
jamming at night may be a problem with stronger beacon
stations.
• Geographic de-correlation
This phenomenon causes radiobeacon signal accuracy to
decrease as the distance between the beacon tower and the base
station increases. Ionospheric conditions can affect accuracy by
as much as 1 meter (3 feet) for every 100 km (60 miles).
23.5 Receiving satellite DGPS
The DSM 132 receiver supports subscription-based OmniSTAR, and
Thales, satellite differential technology. Contact the service provider
for service activation or an encrypted activation passcode.
Note – For the DSM 132 to operate with these corrections, you must
subscribe to one of these services. The service provider may set
geographic limits on the use of its service.
In addition, the WAAS/EGNOS service is available free in North
America and Europe. For more information, see Configuring
Differential GPS, page 62, or go to the following websites:
• OmniSTAR (www.omnistar.com)
•Thales (www.landstar-dgps.com)
•WAAS (http://gps.faa.gov/Programs/WAAS/waas.htm)
• EGNOS (www.esa.int/export/esaSA/)