On Mar 19, 10:46*am, macpacheco wrote:
www.gpsworld.cominforms that PRN135 is now back to full healthy,
available for aviation and other safety of life applications.
But there's no word to that end onhttp://www.nstb.tc.faa.gov/as well
ashttp://www.faa.gov/about/office_org/headquarters_offices/ato/service_....
yet.
At the same time WAAS nstb SV status page shows PRN135 UDRE now at 50
meters. At this point PRN135 begins to really useful as a ranging
source for non precision approaches. This suggests that PRN135 has MT0
really removed. And this should mean absent any signal quality issues
in less than a day or two ranging UDRE improves to 7.5 meters (the
best possible for WAAS GEOs). UDRE 7.5 meters is useful for precision
approaches.

Marcelo Pacheco

The VPL realtime charts show coverage to NW Alaska fully restored.
This confirms without doubt that PRN135 is fully healthy for WAAS
integrity/corrections.
PRN 135 still has 12 degrees west to go until it reaches its normal/
backup orbital slot.
Also its currently operating on a 50 meter UDRE for ranging, which is
useful for non-precision approaches, but is useless for LPVs. This is
probably due to PRN 135 still being repositioned. Ranging allows WAAS
GEOs to be used like a regular GPS satellite, except that they are
always less accurate than a regular GPS satellite (GPS satellites
reach 3 meter UDRE after they come in view of a lot of WAAS reference
stations, while WAAS GEOs are limited to 7.5 meter UDRE, even though
they are monitored by most reference stations 24x7).

Marcelo Pacheco