On July 31, 2007, the FAA will decommission WAAS satellites 122 and 134,
leaving satellites 135 and 138 for WAAS differential corrections in North
America. In order to continue receiving WAAS differential corrections
after the July 31, 2007cutoff date, receivers must have updated WAAS
firmware loaded onto their systems or have satellites 135 and 138
manually selected through a terminal communication program. Customers
should check with their GPS manufacturer to see if firmware updates are
required for their particular GPS receiver brand and model.
Currently there are three WAAS satellites broadcasting correction signals
for North America(PRNs 122, 134, and 135). An additional WAAS satellite
(PRN-138) is available for non-aviation use. PRN-138 has not been fully
commissioned and is still undergoing testing. Its planned release date is
in July 2007. Also in July 2007, PRN- 122 and PRN-134 will be
decommissioned. This means that PRN-135 and PRN-138 will be the only
active WAAS signal satellites for North America. Receivers that are not
in a scan mode or are locked on to PRN-122 or PRN-134 will need to be
adjusted or programmed to receive either PRN-135 or PRN-138. This dual
redundancy coverage means there would have to be an outage of both
correction satellites for service to be lost. PRN 122 and 134 will be
decommissioned on Tuesday, July 31, 2007. PRN 138 will be placed into
service (commissioned) on Wednesday,July 11, 2007. More details are
available at GPS World: here
** Out thanks to Kurt Donaldson, President of the WVAGP for passing on
this valuable information
WVAGP Meeting
The next GIS Association meeting will be held on September
15th. The site has not been announced but we will keep you
posted.