SVN63 almost in position, SVN35 clock/NAV status

According to WAAS Satellite status pictures, SVN63 (IIF-2/PRN1) is
very close to PRN11 (D2-F), and should arrive at D2-A slot in less
than 48 hrs. Since PRN24 is still working fine, I'm hoping they will
let SVN63 move further west, assuming a configuration similar to
PRN19/3/6 (with SVN63 having a good space west of PRN24).

SVN35 so far is showing clock/ephemeris performance worse than SVN27,
but SBAS and other augmentation systems can correct for that, while
SVN49 multipath error might not be so correctable by augmentations,
since the actual error is receiver dependent (a function of the
receiver's resistance to multipath). Lets just hope SVN35 can live at
least a couple of years.

Marcelo Pacheco

My satellite tracking software also shows GPS IIF-2 to be behind PRN11
with PRN24 approaching . The latest orbital data (Day 225) shows GPS
IIF-2 Mean Motion remains at 1.97479 revolutions/day.

So, running the simulation for GPS IIF-2 until it drifts behind PRN24,
I'd suspect it will reach its place sometime during 18 Aug. If the
intent is to directly replace PRN24, then GPS IIF-2 will be in
position sometime between Aug 16 -17.

I would expect to see a notice that PRN24 is to be UNUSUFN or
decommissioned if the intent is to directly replace it.

Over in Plane B, SVN35 sending PRN30 (unusable) is currently orbiting
close to GPS IIF-1 (PRN25). It completes 2.003568 revolutions per day
so It will be on station to replace decommissioned SVN30 late this
year but it should be set usable well before then.

Just a few 'semi-educated' guesses for fun about what's happening.

--- CHAS

Indications of final SVN63 positioning

SVN63 almanac values:

SQRT(A) (m 1/2) -- relates to height and period of orbit

Sat 13 Aug 5180.3
Sun 14 Aug 5180.3
Mon 15 Aug 5173.4
Tue 16 Aug 5166.4

Nominal value for GPS is 5153.7

--- CHAS

SVN63 is now clearly west of PRN24.
It looks like its going through a DeltaV event right now (2117Z
08/16/11) - WAAS showing its status DNU instead of the usual NM.
Please, let SVN63 continue its westward drift, for a wide pair like
PRN5/10. It does wonders for PDOP.
Anyhow, with SVN63 in position, and just over a month since it's
launch, it should be ripe for going healthy any day now.

Also SVN35 was just set healthy:
NOTICE ADVISORY TO NAVSTAR USERS (NANU) 2011062 NANU TYPE: GENERAL
*** GENERAL MESSAGE TO ALL GPS USERS ***
GPS SATELLITE SVN35 (PRN30) WAS USABLE AS OF JDAY 228 (16 AUG 2011)
BEGINNING AT 2045Z
*** GENERAL MESSAGE TO ALL GPS USERS ***

Marcelo

Fri 19 Aug

SQRT(A) (m 1/2): 5153.615723

It's on station.

--- CHAS