GNS430 on the Airway

Matt Barrow wrote:
wrote in message newsDbHf.33957$JT.26162@fed1read06...

ted wrote:



The only issue (or flaw) that has come to my attention is the risk of
radio interference on the GPS civilian frequency. The replacement GPS
satellites are being designed with a second civilian frequency to address
this problem.


How long will that take to populate the entire constellation?


If necessary to facilitate commercial avaition, not nearly as long as you
think.



I guess to make that work we'll need to know how long I think it will be
and then the percentage reduction you think will be applied to what I
think.

Matt Barrow wrote:

wrote in message news:Z_4Hf.33790$JT.747@fed1read06...

Matt Barrow wrote:

How so?




There isn't a newer version because the FAA does not like to admit when
they do incorrect planning.

If those old documents were valid some VORs would already be shutdown.


Though VORs have some use in the near term, I can't see them being viable
beyond a "few" years.



No matter how old or crummy VORs are compared to GPS, GPS still has a
continuity and integrity issue for sole-means en route navigation in a
non-radar domestic airspace environment. Until the FAA, with some
agreement from the other ICAO members, hammer that one out, VOR will
continue to be the primary en route nav aid for domestic airspace.

The FAA criteria worked out by an FAA/Industry rulemaking group for the
new performance-based RNAV (RNP) IAPs just went into effect last June
and has as one of its fundamental premises the failure of GPS during the
performance-based RNAV (RNP) IAP and requires conventional nav aids for
the missed approach or, where terrain requires continued RNP for the
missed approach, then the aircraft must have at least one IRU to sustain
acceptable RNP levels during the critical phase of the missed approach.

Note the new KPSP RNAV (RNP) IAPs do not require RNP for the missed
approach; they track to TRM VOR using Level 1 RNAV missed approach
criteria until reaching TRM (Level 1 is the same criteria used for
plain-old RNAV (GPS) IAPs). Note the KSUN RNAV (RNP) IAP requires RNP
because of terrain and the lack of VOR.

"ted" wrote:

The only issue (or flaw) that has come to my attention is the risk of radio
interference on the GPS civilian frequency. The replacement GPS satellites
are being designed with a second civilian frequency to address this problem.

http://www.dot.gov/affairs/1998/dot5598.htm

http://www.aero.org/news/newsitems/g...on-041398.html

http://geodesy.geology.ohio-state.ed...09/gpsfre.html

http://igscb.jpl.nasa.gov/mail/igsma.../msg00316.html

http://clinton6.nara.gov/1998/03/199...an-signal.html

Ted, the second civil frequency on the Block IIRM satellites (known as
L2C) is not operational. I have no idea when it will be operational.
Look at the phase-out date for VORs in the 1999 FRP. I don't recall
the date but I would guess that we are close to it now.

Plus L2C is not in an approved protected frequency band for aviation
(ARNS) so the FAA will not allow it for aviation.

Ron Lee

"Matt Barrow" wrote:


wrote in message newsDbHf.33957$JT.26162@fed1read06...
ted wrote:


The only issue (or flaw) that has come to my attention is the risk of
radio interference on the GPS civilian frequency. The replacement GPS
satellites are being designed with a second civilian frequency to address
this problem.

How long will that take to populate the entire constellation?

If necessary to facilitate commercial avaition, not nearly as long as you
think.

If you launch three satellites per year then about 24/3 = 8 years.

Ron Lee

"Matt Barrow" wrote:

Don't use outdated FRPs.

Do you have a newer version?

The 2005 version is he

http://www.navcen.uscg.gov/Default.htm

I have not read it yet.

Ron Lee

From the 2005 FRP

A reduction in the VOR population (only) is expected to begin in 2010.
The proposed reduction will transition from today’s VOR services to a
minimum operational network (MON). The MON will support IFR operations
at the busiest airports and serve as an independent civilian backup
navigation source to GPS and GPS/WAAS in the NAS. Section 3.2
discusses the transition in more detail.

The FAA plans to sustain existing DME service to support en route
navigation, and to install additional low-power DMEs to support
Instrument Landing System precision approaches as recommended by the
Commercial Aviation Safety Team. The FAA may also need to expand the
DME network to provide a redundant RNAV capability for terminal area
operations at major airports and to provide continuous coverage for
RNAV operations at en route altitudes."


Conclusion: The "phase OUT" is no longer the plan. Some undefined
and certainly changeable "phase DOWN" is the current plan.

Ron Lee

"Ron Lee" wrote in message
...
"ted" wrote:

The only issue (or flaw) that has come to my attention is the risk of
radio
interference on the GPS civilian frequency. The replacement GPS
satellites
are being designed with a second civilian frequency to address this
problem.

http://www.dot.gov/affairs/1998/dot5598.htm

http://www.aero.org/news/newsitems/g...on-041398.html

http://geodesy.geology.ohio-state.ed...09/gpsfre.html

http://igscb.jpl.nasa.gov/mail/igsma.../msg00316.html

http://clinton6.nara.gov/1998/03/199...an-signal.html

Ted, the second civil frequency on the Block IIRM satellites (known as
L2C) is not operational. I have no idea when it will be operational.
Look at the phase-out date for VORs in the 1999 FRP. I don't recall
the date but I would guess that we are close to it now.

I suggest there was never any doubt that VORs would NOT be totally
eliminated. That NDBs will completely disappear is fairly certain, but not
likewise for VORs. Already SatNav approaches are the majority (I suspect).

Perhaps the biggest factor to making GPS the primary navagation method is
how badly channeling all traffic over a VOR, along airways, in cluttered
space such as along the Atlantic coastal area (NY,Philly, DC...). The lack
of precision for VOR navigation is a another factor.

In the 1999 paper, the baseline for shutting down VORs was 2005, and now
it's 2010. In any case, VORs make a good backup, but only that
(comparatively speaking). I'd originally mentioned their being phased
out/dpwn over a "few" years. Depending on ones definition of "few", and mine
is 10-20, I suspect that being unable to perform WAAS grade approaches will
be akin to the inability to do much IFR nav NORDO.

In sum, it's not a matter of IF, but of WHEN. There are liekly going to be
more stumbles and pratfalls along the way, but eventually the technical
solutions will become "primary".

wrote in message news:%_hHf.33984$JT.6861@fed1read06...
Matt Barrow wrote:

wrote in message news:Z_4Hf.33790$JT.747@fed1read06...

Matt Barrow wrote:

How so?




There isn't a newer version because the FAA does not like to admit when
they do incorrect planning.

If those old documents were valid some VORs would already be shutdown.


Though VORs have some use in the near term, I can't see them being viable
beyond a "few" years.



No matter how old or crummy VORs are compared to GPS, GPS still has a
continuity and integrity issue for sole-means en route navigation in a
non-radar domestic airspace environment.

WAAS solves the integrity issue. I'm not sure what you mean by "continuity
issue"

ted wrote:
wrote in message news:%_hHf.33984$JT.6861@fed1read06...

Matt Barrow wrote:


wrote in message news:Z_4Hf.33790$JT.747@fed1read06...


Matt Barrow wrote:


How so?




There isn't a newer version because the FAA does not like to admit when
they do incorrect planning.

If those old documents were valid some VORs would already be shutdown.


Though VORs have some use in the near term, I can't see them being viable
beyond a "few" years.




No matter how old or crummy VORs are compared to GPS, GPS still has a
continuity and integrity issue for sole-means en route navigation in a
non-radar domestic airspace environment.


WAAS solves the integrity issue. I'm not sure what you mean by "continuity
issue"



Continuity means the reliability of the primary GPS sats themselves.
They can have a sat failure or, more likely, jamming.

-----Original Message-----
From: ]
Posted At: Sunday, February 12, 2006 5:53 AM
Posted To: rec.aviation.ifr
Conversation: GNS430 on the Airway
Subject: GNS430 on the Airway

ted wrote:
wrote in message
news:%_hHf.33984$JT.6861@fed1read06...
....clipped for brevity...
[Jim Carter]
Continuity means the reliability of the primary GPS sats themselves.
They can have a sat failure or, more likely, jamming.

[Jim Carter]
Unless control of the satellite management system can be achieved, and
the entire constellation interrupted, wouldn't jamming be a localized
event based on the radiation pattern and power of the jamming
transmitter? And to continue jamming wouldn't the transmitter have to
stay active, making it a pretty easy target for any of several modern
weapons systems that don't rely on GPS for navigation?