LAAS (Local Area Augmentation System) was to provide CAT 2 and 3 ILS
capability at major airports by fine tuning GPS and up loading
correction signals to aircraft. FAA has canceled the program. Looks like
the ground based ILS systems once slated for removal by 2010 are here to
stay.

"JJ" > wrote in message
...
> LAAS (Local Area Augmentation System) was to provide CAT 2 and 3 ILS
> capability at major airports by fine tuning GPS and up loading
> correction signals to aircraft. FAA has canceled the program. Looks like
> the ground based ILS systems once slated for removal by 2010 are here to
> stay.

It is only the VOR bandwidth that will be freed up.

ILS is a good system.

JJ wrote:

> LAAS (Local Area Augmentation System) was to provide CAT 2 and 3 ILS
> capability at major airports by fine tuning GPS and up loading
> correction signals to aircraft. FAA has canceled the program. Looks like
> the ground based ILS systems once slated for removal by 2010 are here to
> stay.

They finally figured out the airlines are married to ILS, both domestically
and internationally.

Tarver Engineering wrote:

> "JJ" > wrote in message
> ...
> > LAAS (Local Area Augmentation System) was to provide CAT 2 and 3 ILS
> > capability at major airports by fine tuning GPS and up loading
> > correction signals to aircraft. FAA has canceled the program. Looks like
> > the ground based ILS systems once slated for removal by 2010 are here to
> > stay.
>
> It is only the VOR bandwidth that will be freed up.
>
> ILS is a good system.

High-end MLS would have been better.

> wrote in message ...
>
>
> Tarver Engineering wrote:
>
> > "JJ" > wrote in message
> > ...
> > > LAAS (Local Area Augmentation System) was to provide CAT 2 and 3 ILS
> > > capability at major airports by fine tuning GPS and up loading
> > > correction signals to aircraft. FAA has canceled the program. Looks
like
> > > the ground based ILS systems once slated for removal by 2010 are here
to
> > > stay.
> >
> > It is only the VOR bandwidth that will be freed up.
> >
> > ILS is a good system.
>
> High-end MLS would have been better.

The MLS systems with GPS substituted for DME work well, but I don't see how
to justify the expense of the change.

In article >, wrote:

> JJ wrote:
>
> > LAAS (Local Area Augmentation System) was to provide CAT 2 and 3 ILS
> > capability at major airports by fine tuning GPS and up loading
> > correction signals to aircraft. FAA has canceled the program. Looks
> > like
> > the ground based ILS systems once slated for removal by 2010 are here
> > to
> > stay.
>
> They finally figured out the airlines are married to ILS, both
> domestically
> and internationally.

except in for the problems with ILS in Europe...

--
Bob Noel

I don't have that kind of money to put the equipment in my plane.

ILS system seems to be fine for me.


> wrote in message ...
>
>
> Tarver Engineering wrote:
>
> > "JJ" > wrote in message
> > ...
> > > LAAS (Local Area Augmentation System) was to provide CAT 2 and 3 ILS
> > > capability at major airports by fine tuning GPS and up loading
> > > correction signals to aircraft. FAA has canceled the program. Looks
like
> > > the ground based ILS systems once slated for removal by 2010 are here
to
> > > stay.
> >
> > It is only the VOR bandwidth that will be freed up.
> >
> > ILS is a good system.
>
> High-end MLS would have been better.
>
>

Bob Noel > writes:

> except in for the problems with ILS in Europe...

What's the problem with ILS approaches in Europe? Frequency congestion?

-jav

In article >, Javier Henderson
> wrote:

> > except in for the problems with ILS in Europe...
>
> What's the problem with ILS approaches in Europe? Frequency congestion?

yes. and interference from FM radio stations.

--
Bob Noel

"Richard Hertz" > wrote in message
t...
> I don't have that kind of money to put the equipment in my plane.
>
> ILS system seems to be fine for me.

And in probably 95% of cases it's fine for everyone.
>
>
> > wrote in message ...
> >
> >
> > Tarver Engineering wrote:
> >
> > > "JJ" > wrote in message

> > > It is only the VOR bandwidth that will be freed up.
> > >
> > > ILS is a good system.
> >
> > High-end MLS would have been better.

And terribly expensive with little gain in functionality in the overwhelming
majority of implementations.

Richard Hertz wrote:

> I don't have that kind of money to put the equipment in my plane.
>
> ILS system seems to be fine for me.

ILS is a fine system, and has served us well for many years as a robust
precision approach and landing system. Category III facilites are particularly
awesome, representing bleeding edge refinements in a system that has been
around for a long time. In the early 1970s they replaced most of the "WW II"
components with much more stable localizers, at least at the major airports.

JJ wrote:

> LAAS (Local Area Augmentation System) was to provide CAT 2 and 3 ILS
> capability at major airports by fine tuning GPS and up loading
> correction signals to aircraft. FAA has canceled the program. Looks like
> the ground based ILS systems once slated for removal by 2010 are here to
> stay.

There is a variation on this theme, however. Boeing has spent no small
amount of money developing and testing its own LAAS system at Mose Lake,
Washington. It does awesome things with appropriate equipment Boeings,
which is mainly a few 737-900s at the present time. The aircraft can fly RF
legs (radius to fix legs) so even the turns are positive course guidance
along a precisely defined arc segment. I suspect the Boeing model could
become a future private system for advanced RNP instrument approaches at
difficult airports,

In article >,
says...
>
>In article >, Javier Henderson
> wrote:
>
>> > except in for the problems with ILS in Europe...
>>
>> What's the problem with ILS approaches in Europe? Frequency congestion?
>
>yes. and interference from FM radio stations.
>

And what do you base this on?
CAT IIIc approaches are in effect at major airports, and small reliever
airports everywhere are using ILS CATI. What "problems" do you refer to?

G Faris

In article >, (G Faris)
wrote:

> >> What's the problem with ILS approaches in Europe? Frequency congestion?
> >
> >yes. and interference from FM radio stations.
>
> And what do you base this on?

On the revisions to the ICAO and JAA standards for ILS and VOR FM
immunity. These revisions were made as a result of the decreased
protection from high power FM radio broadcasts.

Do a search for ICAO, FM immunity, ILS

Look at:

ICAO Annex 10, Volume I Radio Navigation Aids,
Fifth Edition dated July 1996, Chapter 3, Paragraphs 3.1.4, 3.3.8

EUROCAE ED-46B

RTCA DO-195

(unfortunately, all of those documents are probably not available
on the web for free).

--
Bob Noel

The LAAS correction uplink is in the 150MHZ area. It would have been
more susceptible to FM interference than a Localizer. Just another
little tidbit of info.

Bob Noel wrote:
> In article >, Javier Henderson
> > wrote:
>
>
>>>except in for the problems with ILS in Europe...
>>
>>What's the problem with ILS approaches in Europe? Frequency congestion?
>
>
> yes. and interference from FM radio stations.
>

"JJ" > wrote in message
...
> LAAS (Local Area Augmentation System) was to provide CAT 2 and 3 ILS
> capability at major airports by fine tuning GPS and up loading
> correction signals to aircraft. FAA has canceled the program. Looks like
> the ground based ILS systems once slated for removal by 2010 are here to
> stay.
>

I have not seen a news report of that anywhere. Do you have a link with more
details?

"Bob Noel" > wrote in message
...
> In article >, JJ >
> wrote:
>
> > The LAAS correction uplink is in the 150MHZ area. It would have been
> > more susceptible to FM interference than a Localizer. Just another
> > little tidbit of info.
>
> eh? a (presumably) digital signal in the 150 MHz area would
> have more susceptible to FM interference than a localizer
> around 108 MHz?

The vhf digital link is adjacent to the VHF com.

Big link but under www.aviationnow.com

http://www.aviationnow.com/avnow/search/autosuggest.jsp?docid=44783&url=http%3A%2F%2Fwww.aviationnow.com%2Favnow%2Fnew s%2Fchannel_aviationdaily_story.jsp%3Fview%3Dstory %26id%3Dnews%2Fcut02034.xml

C J Campbell wrote:
> "JJ" > wrote in message
> ...
>
>>LAAS (Local Area Augmentation System) was to provide CAT 2 and 3 ILS
>>capability at major airports by fine tuning GPS and up loading
>>correction signals to aircraft. FAA has canceled the program. Looks like
>>the ground based ILS systems once slated for removal by 2010 are here to
>>stay.
>>
>
>
> I have not seen a news report of that anywhere. Do you have a link with more
> details?
>
>

Bob Noel > wrote in news:ihatessppaamm-
:

> In article >, JJ >
> wrote:
>
>> The LAAS correction uplink is in the 150MHZ area. It would have been
>> more susceptible to FM interference than a Localizer. Just another
>> little tidbit of info.
>
> eh? a (presumably) digital signal in the 150 MHz area would
> have more susceptible to FM interference than a localizer
> around 108 MHz?
>

Very possibly. Harmonics can do as much damage as the fundamental
frequency. But it appears to me, from reading both on and between the
lines, that money was the driver here, as it always is. The contractor led
the agency down the primrose path, claiming 80% completion when it was
actually only 20%, or similar figures. The new administrator was not
amused. Rather than simply rap some knuckles, the entire program was
cancelled, thus punishing all aviation interests.

--
Regards,

Stan

"Stan Gosnell" > wrote in message
...

>
> Very possibly. Harmonics can do as much damage as the fundamental
> frequency. But it appears to me, from reading both on and between the
> lines, that money was the driver here, as it always is. The contractor
led
> the agency down the primrose path, claiming 80% completion when it was
> actually only 20%, or similar figures. The new administrator was not
> amused. Rather than simply rap some knuckles, the entire program was
> cancelled, thus punishing all aviation interests.

The whole WAAS/LAAS mess has been circling the drain since Kenneth Mead
found Garvey in violation of the Inspector General's Act; for exceeding her
Authority signing WAAS contracts. There are better ways for FAA to spend
the aviation trust fund.

"JJ" > wrote in message
...
> The LAAS correction uplink is in the 150MHZ area. It would have been
> more susceptible to FM interference than a Localizer. Just another
> little tidbit of info.

Wrong. The LAAS VHF Data Broadcast (VDB) is capable of existing on 108.00
MHz to 117.75 MHz (LOC and VOR freqs). The plan is to use VOR freqs (114.00
and up) until ILS freqs become available thru decommissioning (if it ever
goes that far.) Since the VDB is a D8PSK digital signal it is not
significantly affected by the interference from the FM band.


> Bob Noel wrote:
> > In article >, Javier Henderson
> > > wrote:
> >
> >
> >>>except in for the problems with ILS in Europe...
> >>
> >>What's the problem with ILS approaches in Europe? Frequency congestion?
> >
> >
> > yes. and interference from FM radio stations.
> >
And multipath. Terrain and new high-rise construction around airports
creates multipath that puts "bends" and "noise" in the ILS path (it's an AM
system). Too much of either and you can't use it for CAT III.

MLS mitigates all three of those problems. There are 200 channels vs. 20
for ILS. It operates in the 5.1 GHz band so there's no high power
transmitters operating near it avoiding the FM broadcast interference. And
the use of a scanning beam instead of an AM differential signal greatly
improves multipath rejection.

Heathrow put in two new MLS ground stations and there are others scheduled
to be installed on the continent.

Gerry

Stan Gosnell wrote:
> Very possibly. Harmonics can do as much damage as the fundamental
> frequency.

Harmonics, from FM broadcast radio? The FM broadcast band is 88-108MHz.
The second harmonic of the lowest of those frequencies is 176MHz (the
highest second harmonic is 216MHz), well above 150 MHz. The third
harmonic is higher, the fourth higher yet, etc. At 108MHz, the most
likely sources of interference from FM broadcast radio are spurious
signals (lousy filtering at the transmitter), or front-end overload
(very strong signals overloading the ability of the receiver to reject
nearby frequencies). I'd be inclined to think the latter, given the
transmission purity standards.

--Dave

--
Dave Buckles

http://www.flight-instruction.com

"Dave Buckles" > wrote in message =
news:vpw0c.5983$fD2.3759@lakeread02...
> Stan Gosnell wrote:
> > Very possibly. Harmonics can do as much damage as the fundamental=20
> > frequency.
>=20
> Harmonics, from FM broadcast radio? The FM broadcast band is =
88-108MHz.=20
> The second harmonic of the lowest of those frequencies is 176MHz =
(the=20
> highest second harmonic is 216MHz), well above 150 MHz. The third=20
> harmonic is higher, the fourth higher yet, etc. At 108MHz, the most=20
> likely sources of interference from FM broadcast radio are spurious=20
> signals (lousy filtering at the transmitter), or front-end overload=20
> (very strong signals overloading the ability of the receiver to reject =

> nearby frequencies). I'd be inclined to think the latter, given the=20
> transmission purity standards.
>=20
> --Dave
>=20
Exactly, Dave.
But if someone in the airplane is playing an FM broadcast receiver,
it's local oscillator will likely be 10.7 MHz above the tuned frequency,
i.e. 98.8, 99.0, 99.2, etc., up to 118.6 MHz.
That's unrelated to FM stations interfering with a data channel, though.
---JRC---

Dave Buckles > writes:
> Stan Gosnell wrote:
> > Very possibly. Harmonics can do as much damage as the fundamental
> > frequency.
>
> Harmonics, from FM broadcast radio? The FM broadcast band is 88-108MHz.
> The second harmonic of the lowest of those frequencies is 176MHz (the
> highest second harmonic is 216MHz), well above 150 MHz. The third
> harmonic is higher, the fourth higher yet, etc. At 108MHz, the most
> likely sources of interference from FM broadcast radio are spurious
> signals (lousy filtering at the transmitter), or front-end overload
> (very strong signals overloading the ability of the receiver to reject
> nearby frequencies). I'd be inclined to think the latter, given the
> transmission purity standards.

"Harmonics" from FM broadcast is a little more complicated
than you describe. The transmitted signal is spread over
the center frequency +/- the modulation frequency. The
"purity" of the transmitted signal isn't that pure even
when in compliance with FCC requirements. At close range,
all sorts of signals can be detected.

However, as several people noted, a signal with digitially-
encode information /probably/ isn't going to be bothered
much. But "probably" doesn't necessarily get you reliable
operation.

Not quite. I had lunch with one of the FAA guys, and he told me there were
some significant technical hurdles that were not adequately addressed. They
were much further from fielding than anyone was led to believe.

I also heard that WAAS will never get close to Cat I cert...

Then again, he stated that legacy systems can't even meet the new
performance specs to begin with. Looks like the bar was set too high...


> wrote in message ...
>
>
> JJ wrote:
>
> > LAAS (Local Area Augmentation System) was to provide CAT 2 and 3 ILS
> > capability at major airports by fine tuning GPS and up loading
> > correction signals to aircraft. FAA has canceled the program. Looks like
> > the ground based ILS systems once slated for removal by 2010 are here to
> > stay.
>
> They finally figured out the airlines are married to ILS, both
domestically
> and internationally.
>