WAAS Broadcasting Satellite Having Problems

WAAS Broadcasting Satellite Having Problems
http://www.gpsworld.com/gps/news/waas-broadcasting-satellite-having-problems-9810?print=1
April 12, 2010
By: Eric Gakstatter

Intelsat S.A. announced they lost control of their Galaxy 15 (G-15)
satellite. G-15 (PRN 135 to GPS users) is one of the two Wide Area
Augmentation System (WAAS) broadcasting satellites (GEOs) that broadcast
GPS corrections for aviation and ground users all over North America.
Despite the Intelsat announcement, the WAAS payload on G-15 is still
broadcasting corrections.

WAAS GEOs are a critical part of the WAAS infrastructure that provides
GPS corrections to aviation and ground users all over North America.
Although the system can operate with one WAAS GEO in service, the second
provides dual coverage and increased visibility to the WAAS service
area. After data is compiled and optimized from 38 GPS reference
stations throughout North America, the two WAAS GEOs are used to
broadcast the GPS corrections to all users in North America.

It's being speculated that the FAA might utilize another Inmarsat
satellite in place of Galaxy 15, but no announcement has been made.
Furthermore, the FAA has not issued any NOTAMs (Notice to Airmen)
regarding a change in WAAS.

Aside from this event, the Federal Aviation Administration (FAA) has
already begun testing a new WAAS geo satellite (Inmarsat 4 at 98°W)
scheduled to be brought into service late this year or early next.

According to the Intelsat announcement, there has been no immediate
service interruption to customers, and based on current technical
information, no service interruption is expected for the media customers
on this satellite. All media traffic on this satellite is planned to be
transitioned to Intelsat’s Galaxy 12 satellite, which is the designated
in-orbit spare for the North American region. Galaxy 12 is currently
relocating to the 133° W orbital location. Intelsat’s global fleet, the
largest of any commercial satellite operator, includes 12 other
satellites that serve the continental U.S. region. Galaxy 12 does not
have the payload (L-band) necessary to broadcast WAAS corrections.

Intesat stated that G-15 was launched in 2005 and is an Orbital Star
satellite. Intelsat and Orbital Sciences Corporation, the manufacturer
of G-15, are conducting a technical investigation with respect to the
anomaly, which has had no impact on the communications services
delivered by the spacecraft. Galaxy 15 has 24 C-band transponders and
was designed to be operational through 2022.

More:
http://www.gpsworld.com/gps/news/waas-broadcasting-satellite-having-problems-9810?print=1