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Old January 18th 11, 08:02 PM posted to sci.geo.satellite-nav,rec.aviation.ifr
HIPAR
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Posts: 6
Default I have a dream. A GPS/SBAS/QZSS dream ! In honour of MLK day.

I haven't seen proposals for a QZS type operation over the western
hemisphere, Many years of preparation will be required to convince
the technical community and political decision makers of a requirement
that leads to appropriations for that project. Currently funded GPS
projects operating along with forthcoming GNSS constellations remains
the best option for civilian PNT enhancements and US government policy
allows that.

I'm still skeptical about the technical quality of the IIFsatellites.
GPS IIF-1 might be experiencing thermal problems with respect to long
term clock stability. There are measurable distortions in the L5
signal. A recent report suggests IIF-1 didn't gracefully enter its
eclipse season. Now I'm suspicious if some last minute rework is in
progress prior to the next launch this summer.

The Air Force contends technical problems aren't an issue anymore ..
maybe one launch per year if the satellites are delivered and funding
is available to launch them.

Consequently, those IIA satellites will be with us for several years.
If the recent trend continues, one per year will be retired and
replaced. That really doesn't matter because modernized satellites
cannot be fully operated owing to limitations of the master control
station. So, I'm thinking L5 and L2C will not be certified until
about 2015 when OCX master control begins to come on-line. Meanwhile,
the legacy portion of the GPS constellation performs as advertised.

GPS III is pragmatically on schedule having achieved important
milestones. Now comes the hard part .. making the actual hardware
perform in accordance with modernized standards. I'm agreeing with
the GAO expecting several years slippage to 2016-2017 before the first
GPS IIIA is launched. Hopefully, with OCX, the 32 satellite limit
will be lifted and the modernized signals can finally be set usable.

That's my analysis.

--- CHAS