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Question about the F-22 and it's radar.



 
 
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  #11  
Old April 3rd 04, 01:44 AM
John Cook
external usenet poster
 
Posts: n/a
Default


The whole avionics suite of the F-22 is now obsolete, and will cost
another $3.5 Billion to 'upgrade' thats the cut from the $11.7 Billion
thats been bandied about.

Do you have anything to support that contention? There is a bit of a
difference between wanting to improve the computers during the spiral
development process and claiming that the "whole avionics suite is
*obsolete*", isn't there?


I quote the GAO-04-597T report directly

"The basic mission of the F/A-22, initially focused on air-to-air
dominance,has changed to include a significantly greater emphasis on
attacking ground targets. To accomplish this expanded mission, the
Air Force will need additional investments to develop and expand
air-to-ground attack capabilities for the F/A-22. Moreover, the
efforts to expand its capability will also add risks to an already
challenged program. To accommodate planned changes will also require a
new computer architecture and processor to replace the current less
capable ones."


Now thats hardly ambiguous is it.....



Let's see, 155 out of a possible total buy of some 269 aircraft, or a more
likely buy of 200-220, would seem to indicate that the first few *years* of
production are covered. Nor has it been conclusively demonstrated that these
processors are incapable of handling the aircraft's air-to-ground strike
needs during it's initial gestation; more in the form of not being able to
handle the *ultimate* (post spiral) capability that is envisioned.


Conclusivly demonstrated!!!!, it can't demonstrate stability yet

The Glabal Strike Ehanced program is slated to start in 2011, thats
when the Raptors system architecture is officially obsolete, the
Global strike Basic is due (with current cpu architecture + systems)
in 2007(read end of development cycle for the old stuff), one might
well ask is 2007 too ambitious for a system that still a tiny bit
'buggy', Thats four years of use from your 'its not obsolete its
proccessor challenge' system. providing its reliable enough to pass
the review.....

I quote again the GAO-04-597T report directly


"The stability and performance of F/A-22 avionics has been a major
problem causing delays in the completion of developmental testing and
the start of IOT&E. Because the F/A-22 avionics encountered frequent
shutdowns over the last few years, many test flights were delayed. As
a result, the Air Force Operational Test and Evaluation Center wanted
assurances that the avionics would work before it was willing to start
the IOT&E program. It established a requirement for a 20-hour
performance metric that was to be demonstrated before IOT&E would
begin. This metric was subsequently changed to a 5-hour metric that
included additional types of failures, and it became the Defense
Acquisition Board’s criterion to start IOT&E. In turn, Congress
included the new metric, known as Mean Time Between Avionics Anomaly
or MTBAA, in the National Defense Authorization Act for Fiscal Year
2004.5 As of January 2004, the Air Force had not been able to
demonstrate that the avionics could meet either of these criteria.
Testing as of January 2004 showed the program had achieved 2.7 hours—
54 percent of the 5-hour stability requirement to begin IOT&E. While
the Air Force has not been able to meet the new criteria, major
failures, resulting in a complete shutdown of the avionics system,
have significantly diminished. These failures are occurring only about
once every 25 hours on average. This is the result of a substantial
effort on the part of the Air Force and the contractor to identify and
fix problems that led to the instability in the F/A-22 avionics
software. However, less serious failures are still occurring
frequently."



Now the Raptor can't run the software to do its air to ground mission
for the same reasons what would you call it?. "processor
challenged???"


"Can't run the software" to do the air-to-ground mission? Odd, as the USAF
claims that at present, "The F/A-22 also has an inherent air-to-surface
capability." It can already lug a couple of JDAM's. So how does that even
*require* an optimized ground mapping radar to allow it to strike ground
targets with significant precision?



Dropping a couple of JDAMS whohooooo!!!,
Cutting edge that... well worth the money of investing in a system
thats equivelent of a couple of cray supercomputers.

one wonders what there using that processing power for?. must be a
very nice graphical interface....


what the USAF have stated they want is, but cant have because of the
limitations of the system are :-

2011
Improved radar
capabilities to seek and destroy advanced surface-to-air missile
systems and integrate additional air-to-ground
weapons.

2013
Increased capability to suppress or
destroy the full range of air defenses and improve speed and
accuracy of targeting.

2015
Capability for full intelligence, surveillance, and reconnaissance
integration for increased target sets and lethality.


Out of curiousity, why do you have this visceral hatred of the F/A-22?

Does
it perhaps stem from the fact that you know your own nation can never

afford
it, or what?


I don't hate it, I just think its not worth the money, if it had been
half the price and worked as advertised I would be impressed.
As it is the price is $150M and development is not mature, production
has started, How would you describe the F-22 process?.


LOL! By your definition, no aircraft would ever enter service, as
"development is not mature". I guess you have kind of missed out on the
*continuing* development of the F-15, F-16, and F/A-18, huh? I'd describe it
as about par for the course, especially when viewed against contemporaries
like the Typhoon and Raptor,


Difference is they have demonstrated their requirements and have been
accepted, now they are in production.

compare the F-22 which is in production and hasn't demonstrated it

Do you see the difference?.

I'll ask you again How would you describe they F-22 process??

If 10 is a perfect development program, and 1 is an utter fiasco that
results in over priced, marginalised product thats ripe to be
cancelled, whats the Raptors score?

which are also entering service while
development continues. You really need to get your head out of the WWII era
in terms of fighter development--heck, even before that, as we saw with how
both the P-47 and P-51 gestated (recall the original P-51's were purchased
and produced with less-than-optimal engines, to boot).


Its not a model that every industry is adopting is it.


Looks an awful lot like the same model the Europeans are using, based upon
where they are with Rafale and Typhoon.


Yes the Typhoons processors are old, but they work as advertised now
and are in production - tranche 2 models are being negotiated with
the updated systems included, as per the original plans, with a
federated architecture its relatively simple in comparison.


I do not doubt that Australia can't afford it, however its looking
increasing likely that the US may join us in that.


I think you can probably count on seeing that "Silver Bullet" force enter
into service...


You might be right, it may go into service, and if reports are to be
beleived - despite the cost, despite the reliability problems, despite
the obsolete architecture, the only credable justification is avoiding
an embarrising procurement fiasco, 200 odd hanger queens.....
astounding...


Cheers

John Cook

Any spelling mistakes/grammatic errors are there purely to annoy. All
opinions are mine, not TAFE's however much they beg me for them.

Email Address :-
Spam trap - please remove (trousers) to email me
Eurofighter Website :-
http://www.eurofighter-typhoon.co.uk
  #12  
Old April 3rd 04, 02:24 AM
Brian
external usenet poster
 
Posts: n/a
Default


"John Cook" wrote in message
...
Just the official reports!!, Lockheed has only purchased enough
processors for 155 F-22's because there out of production, the demand
for Air to ground operations has increased the demand on processing
power, something the original processors are not quite upto hence the
_need_ for the 'upgrade'.


I kind of find that hard to believe. The system I worked on (and is still a
front line system) was based on Z-80's and a bunch of other 'exotic' chips.
If they can still find parts for that, the F-22's radar should be too
'obselete'.


  #13  
Old April 3rd 04, 02:43 AM
Tarver Engineering
external usenet poster
 
Posts: n/a
Default


"Felger Carbon" wrote in message
link.net...
"Harry Andreas" wrote in message
...
In article , John Cook
wrote:


Just the official reports!!, Lockheed has only purchased enough
processors for 155 F-22's because there out of production, the

demand
for Air to ground operations has increased the demand on

processing
power, something the original processors are not quite upto hence

the
_need_ for the 'upgrade'.

So the processors are obsolete, (too old)... the Avionic

architecture
needs to be replaced before the F-22 can become the F/A-22 because

the
present system is based on the old processors and rewriting the

code
is pointless on an obsolete system, that would only support half

of
the F-22 fleet


Methinks there's some confusion there between processors, avionics
architecture, and software.
While it's true that Intel tried to shut down i960 production

causing a
chinese fire drill, there are enough assets to get by until a new

processor is
ready.


Full disclosu I'm a retired electrical engineer. I specialized in
high-end embedded microprocessors, which the "i960" in the F-22 is. I
know nothing about designing aircraft. I do know a little about the
Intel processor at the heart of the F-22:

The i960MX was designed by Intel specifically and solely for the F-22.


Nope, the i960 is a processor designed to control printers. The i860, the
predicessor of the i960, was designed for the i432 MPP system. The i432
nearly bankrupted Intel and caused them to have to sell 16% of the company,
a controlling interest, to IBM. The Brits were the only ones to ever get
any software to run on the i432 MPP and Lochkeed is lucky to have them
writing the software.


  #14  
Old April 3rd 04, 03:06 AM
D. Strang
external usenet poster
 
Posts: n/a
Default

The F/A-22 also has an inherent air-to-surface
capability." It can already lug a couple of JDAM's. So how does that even
*require* an optimized ground mapping radar to allow it to strike ground
targets with significant precision?


I'm not a bombardier, but I think the SAR radar is necessary for the INS
inputs. The INS being only updated by the GPS, and only if the GPS
isn't being jammed (which will be unlikely down the road). I think I read
where GPS only doubles the accuracy of the INS (50 feet versus 100 feet).

Without SAR, and GPS being jammed, you'll need a good pair of TACAN's,
which some enemies don't seem to provide :-)


  #15  
Old April 3rd 04, 03:33 AM
Phil Miller
external usenet poster
 
Posts: n/a
Default

On Fri, 2 Apr 2004 17:43:06 -0800, "Tarver Engineering"
wrote:


"Felger Carbon" wrote in message
hlink.net...
"Harry Andreas" wrote in message
...
In article , John Cook
wrote:


Just the official reports!!, Lockheed has only purchased enough
processors for 155 F-22's because there out of production, the

demand
for Air to ground operations has increased the demand on

processing
power, something the original processors are not quite upto hence

the
_need_ for the 'upgrade'.

So the processors are obsolete, (too old)... the Avionic

architecture
needs to be replaced before the F-22 can become the F/A-22 because

the
present system is based on the old processors and rewriting the

code
is pointless on an obsolete system, that would only support half

of
the F-22 fleet

Methinks there's some confusion there between processors, avionics
architecture, and software.
While it's true that Intel tried to shut down i960 production

causing a
chinese fire drill, there are enough assets to get by until a new

processor is
ready.


Full disclosu I'm a retired electrical engineer. I specialized in
high-end embedded microprocessors, which the "i960" in the F-22 is. I
know nothing about designing aircraft. I do know a little about the
Intel processor at the heart of the F-22:

The i960MX was designed by Intel specifically and solely for the F-22.


Nope, the i960 is a processor designed to control printers.


http://www.gao.gov/cgi-bin/getrpt?GAO-04-391

"The F/A-22 is dependent on its onboard computers and software to
perform its mission. Unlike other fighter aircraft, it has a highly
advanced,integrated avionics system capable of detecting, identifying,
and engaging the enemy at ranges beyond a pilot’s vision. The key to the
F/A-22 avionics lies in its fully integrated core architecture and its
two central, networked computers called common integrated processors
(CIP).CIPs use very high-speed integrated circuits to collect, process,
and integrate data and signals from the aircraft’s sensors. CIP serves
as the “brains” for the F/A-22’s integrated avionics system and is
unique to this aircraft.

The primary processor in CIP is the Intel i960MX microprocessor,which is
used strictly for avionics processing. This microprocessor is based on
1990’s technology and has a 32-bit processor that operates at speeds of
25mhz." etc.

Caught bull****ting again Splappy?


Phil
--
Great Tarverisms #3

No, a flap makes the wing thicker and thereby
creates more bernoulli lift.

John P. Tarver, MS/PE

rec.aviation.military
09 January 2003
  #16  
Old April 3rd 04, 03:43 AM
Kevin Brooks
external usenet poster
 
Posts: n/a
Default


"John Cook" wrote in message
...

The whole avionics suite of the F-22 is now obsolete, and will cost
another $3.5 Billion to 'upgrade' thats the cut from the $11.7

Billion
thats been bandied about.

Do you have anything to support that contention? There is a bit of a
difference between wanting to improve the computers during the spiral
development process and claiming that the "whole avionics suite is
*obsolete*", isn't there?


I quote the GAO-04-597T report directly

"The basic mission of the F/A-22, initially focused on air-to-air
dominance,has changed to include a significantly greater emphasis on
attacking ground targets. To accomplish this expanded mission, the
Air Force will need additional investments to develop and expand
air-to-ground attack capabilities for the F/A-22. Moreover, the
efforts to expand its capability will also add risks to an already
challenged program. To accommodate planned changes will also require a
new computer architecture and processor to replace the current less
capable ones."


There is where you go wrong--accepting the GAO report at face value. Don't
you know they have a well known reputation for shading things in the
direction they want, or just plain ol' incompetency in some cases? What they
are describing is the spiral development program that the USAF has already
articulated--nothing new about it, and nothing shocking.



Now thats hardly ambiguous is it.....


Well, either it is being ambiguous, as the USAF has decidedly stated that
the F/A-22 is already capable of conducting ground attack missions, or you
are slanting it to your purposes. IIRC this is the same GAO report that ol'
Henry used when he began trumpeting the $11 billion claim--until it was
pointed out to him that the small print explained that cost was for a whole
range of spiral developments, from air-to-air, to ISR, to *improving*
(note--NOT *creating*) its ground attack capabilities, etc.




Let's see, 155 out of a possible total buy of some 269 aircraft, or a

more
likely buy of 200-220, would seem to indicate that the first few *years*

of
production are covered. Nor has it been conclusively demonstrated that

these
processors are incapable of handling the aircraft's air-to-ground strike
needs during it's initial gestation; more in the form of not being able

to
handle the *ultimate* (post spiral) capability that is envisioned.


Conclusivly demonstrated!!!!, it can't demonstrate stability yet


Uhmm..you missed the USAF statement that it can indeed carry and deliver
JDAM's? What, you think JDAM is some kind of air-to-air weapon?! And that is
with the current processors--I believe Harry Andreas has already addressed
that particular issue much better than I can...and oddly, you don't seem to
have replied to his comments...


The Glabal Strike Ehanced program is slated to start in 2011, thats
when the Raptors system architecture is officially obsolete,


Uh, what?! "Officially obsolete"? And where do you come up with *that*
little factoid? never heard of any US program going forward with an already
"officially" established date of obsolescence...

the
Global strike Basic is due (with current cpu architecture + systems)
in 2007(read end of development cycle for the old stuff), one might
well ask is 2007 too ambitious for a system that still a tiny bit
'buggy', Thats four years of use from your 'its not obsolete its
proccessor challenge' system. providing its reliable enough to pass
the review.....

I quote again the GAO-04-597T report directly


You just never learn, do you? GAO does not equal either competence or
accuracy in terms of military developments, organizations, etc.



"The stability and performance of F/A-22 avionics has been a major
problem causing delays in the completion of developmental testing and
the start of IOT&E. Because the F/A-22 avionics encountered frequent
shutdowns over the last few years, many test flights were delayed. As
a result, the Air Force Operational Test and Evaluation Center wanted
assurances that the avionics would work before it was willing to start
the IOT&E program. It established a requirement for a 20-hour
performance metric that was to be demonstrated before IOT&E would
begin. This metric was subsequently changed to a 5-hour metric that
included additional types of failures, and it became the Defense
Acquisition Board's criterion to start IOT&E. In turn, Congress
included the new metric, known as Mean Time Between Avionics Anomaly
or MTBAA, in the National Defense Authorization Act for Fiscal Year
2004.5 As of January 2004, the Air Force had not been able to
demonstrate that the avionics could meet either of these criteria.
Testing as of January 2004 showed the program had achieved 2.7 hours-
54 percent of the 5-hour stability requirement to begin IOT&E. While
the Air Force has not been able to meet the new criteria, major
failures, resulting in a complete shutdown of the avionics system,
have significantly diminished. These failures are occurring only about
once every 25 hours on average. This is the result of a substantial
effort on the part of the Air Force and the contractor to identify and
fix problems that led to the instability in the F/A-22 avionics
software. However, less serious failures are still occurring
frequently."


You know, this reminds me a bit of the early MBTF problems with the F-15, in
particular its radar IIRC. What all of this says is that we have a new
system with typical new system teething problems. Thank goodness neither you
nor the GAO were making the decisions at that time--we'd still be trying to
keep F-4E's in the air, no doubt, as y'all would have undoubtedly cancelled
that obviously deficient F-15 program...




Now the Raptor can't run the software to do its air to ground mission
for the same reasons what would you call it?. "processor
challenged???"


"Can't run the software" to do the air-to-ground mission? Odd, as the

USAF
claims that at present, "The F/A-22 also has an inherent air-to-surface
capability." It can already lug a couple of JDAM's. So how does that even
*require* an optimized ground mapping radar to allow it to strike ground
targets with significant precision?



Dropping a couple of JDAMS whohooooo!!!,
Cutting edge that... well worth the money of investing in a system
thats equivelent of a couple of cray supercomputers.


All of that computing power helps it get to the target area so it can drop
those "whohooo" JDAM's. And last i heard the JDAM was judged a particularly
accurate and lethal munition. Now, I do believe you were crowing that the
F/A-22 is incapable of performing the ground attack mission? How do you like
your crow, rare or well done?


one wonders what there using that processing power for?. must be a
very nice graphical interface....


what the USAF have stated they want is, but cant have because of the
limitations of the system are :-

2011
Improved radar
capabilities to seek and destroy advanced surface-to-air missile
systems and integrate additional air-to-ground
weapons.

2013
Increased capability to suppress or
destroy the full range of air defenses and improve speed and
accuracy of targeting.

2015
Capability for full intelligence, surveillance, and reconnaissance
integration for increased target sets and lethality.


Gee, can't have any of that, huh? And why not?



Out of curiousity, why do you have this visceral hatred of the F/A-22?

Does
it perhaps stem from the fact that you know your own nation can never

afford
it, or what?

I don't hate it, I just think its not worth the money, if it had been
half the price and worked as advertised I would be impressed.
As it is the price is $150M and development is not mature, production
has started, How would you describe the F-22 process?.


LOL! By your definition, no aircraft would ever enter service, as
"development is not mature". I guess you have kind of missed out on the
*continuing* development of the F-15, F-16, and F/A-18, huh? I'd describe

it
as about par for the course, especially when viewed against

contemporaries
like the Typhoon and Raptor,


Difference is they have demonstrated their requirements and have been
accepted, now they are in production.


Have they now? rafale was in production while its ground attack capability
was in the pure ghostware stage--which is why the French Navy went to sea
with them being capable *only* of performing air-to-air missions. The RAF
wants to retune the Typhoon to perform in the multi-role strike manner
before they had originally planned--meaing that their aircraft were not
optimized for that mission when Typhoon went into production. Sounds a bit
like the F/A-22, doesn't it?


compare the F-22 which is in production and hasn't demonstrated it


You don't think it has successfully dropped a JDAM?


Do you see the difference?.

I'll ask you again How would you describe they F-22 process??


Like most current advanced aircraft projects--that you still can't see that
is hardly surprising, given your obvious bias and reliance upon the *GAO* as
your primary source.


If 10 is a perfect development program, and 1 is an utter fiasco that
results in over priced, marginalised product thats ripe to be
cancelled, whats the Raptors score?

which are also entering service while
development continues. You really need to get your head out of the WWII

era
in terms of fighter development--heck, even before that, as we saw with

how
both the P-47 and P-51 gestated (recall the original P-51's were

purchased
and produced with less-than-optimal engines, to boot).


Its not a model that every industry is adopting is it.


Looks an awful lot like the same model the Europeans are using, based

upon
where they are with Rafale and Typhoon.


Yes the Typhoons processors are old, but they work as advertised now
and are in production - tranche 2 models are being negotiated with
the updated systems included, as per the original plans, with a
federated architecture its relatively simple in comparison.


I do not doubt that Australia can't afford it, however its looking
increasing likely that the US may join us in that.


I think you can probably count on seeing that "Silver Bullet" force enter
into service...


You might be right, it may go into service, and if reports are to be
beleived - despite the cost, despite the reliability problems, despite
the obsolete architecture, the only credable justification is avoiding
an embarrising procurement fiasco, 200 odd hanger queens.....
astounding...


Yes, it is amazing--you, Cobb, and Tarver are the only ones gifted enough to
realize what a true dog it is, huh? All of those blue-suited folks being too
darned dumb to figure it out, right?

Again, thank goodness you are not in the decisionmaking chain.

Brooks



Cheers

John Cook

Any spelling mistakes/grammatic errors are there purely to annoy. All
opinions are mine, not TAFE's however much they beg me for them.

Email Address :-
Spam trap - please remove (trousers) to email me
Eurofighter Website :-
http://www.eurofighter-typhoon.co.uk



  #17  
Old April 3rd 04, 03:47 AM
Kevin Brooks
external usenet poster
 
Posts: n/a
Default


"D. Strang" wrote in message
news:1%obc.4658$zc1.3787@okepread03...
The F/A-22 also has an inherent air-to-surface
capability." It can already lug a couple of JDAM's. So how does that

even
*require* an optimized ground mapping radar to allow it to strike ground
targets with significant precision?


I'm not a bombardier, but I think the SAR radar is necessary for the INS
inputs. The INS being only updated by the GPS, and only if the GPS
isn't being jammed (which will be unlikely down the road). I think I read
where GPS only doubles the accuracy of the INS (50 feet versus 100 feet).

Without SAR, and GPS being jammed, you'll need a good pair of TACAN's,
which some enemies don't seem to provide :-)


I have yet to hear that a SAR update is required. Doing so would require the
preloaded data for the terrain (so that the SAR would have something to
relate its picture to). From what i understand, the weapon gets its update
from the aircraft (through its own INS), then after release it uses GPS to
improve the accuracy of its own INS. If SAR was required, then I guess the
A-10 would never be certified to carry JDAM...?

Brooks







  #18  
Old April 3rd 04, 04:00 AM
D. Strang
external usenet poster
 
Posts: n/a
Default

"Kevin Brooks" wrote
"D. Strang" wrote
The F/A-22 also has an inherent air-to-surface
capability." It can already lug a couple of JDAM's. So how does that

even
*require* an optimized ground mapping radar to allow it to strike ground
targets with significant precision?


I'm not a bombardier, but I think the SAR radar is necessary for the INS
inputs. The INS being only updated by the GPS, and only if the GPS
isn't being jammed (which will be unlikely down the road). I think I read
where GPS only doubles the accuracy of the INS (50 feet versus 100 feet).

Without SAR, and GPS being jammed, you'll need a good pair of TACAN's,
which some enemies don't seem to provide :-)


I have yet to hear that a SAR update is required. Doing so would require the
preloaded data for the terrain (so that the SAR would have something to
relate its picture to). From what i understand, the weapon gets its update
from the aircraft (through its own INS), then after release it uses GPS to
improve the accuracy of its own INS. If SAR was required, then I guess the
A-10 would never be certified to carry JDAM...?


An A-10 at altitude? What a waste. They were designed to be down with the
tanks...

The way I picture it, and I admit I may be completely bogus on this, but I
picture the navigator finding a reference point (coordinates), and then using
the SAR to find the point in weather, and then updating the INS from this
point. You wouldn't need SAR if the point was available by other means,
or the target could tolerate greater than 100 foot error. For example, if
a 2k/lb jobber hit 500 foot from my house, I'd still be dead, and the house
would be destroyed :-)


  #19  
Old April 3rd 04, 04:14 AM
Kevin Brooks
external usenet poster
 
Posts: n/a
Default


"D. Strang" wrote in message
news:HNpbc.4808$zc1.3884@okepread03...
"Kevin Brooks" wrote
"D. Strang" wrote
The F/A-22 also has an inherent air-to-surface
capability." It can already lug a couple of JDAM's. So how does that

even
*require* an optimized ground mapping radar to allow it to strike

ground
targets with significant precision?

I'm not a bombardier, but I think the SAR radar is necessary for the

INS
inputs. The INS being only updated by the GPS, and only if the GPS
isn't being jammed (which will be unlikely down the road). I think I

read
where GPS only doubles the accuracy of the INS (50 feet versus 100

feet).

Without SAR, and GPS being jammed, you'll need a good pair of TACAN's,
which some enemies don't seem to provide :-)


I have yet to hear that a SAR update is required. Doing so would require

the
preloaded data for the terrain (so that the SAR would have something to
relate its picture to). From what i understand, the weapon gets its

update
from the aircraft (through its own INS), then after release it uses GPS

to
improve the accuracy of its own INS. If SAR was required, then I guess

the
A-10 would never be certified to carry JDAM...?


An A-10 at altitude? What a waste. They were designed to be down with

the
tanks...

The way I picture it, and I admit I may be completely bogus on this, but I
picture the navigator finding a reference point (coordinates), and then

using
the SAR to find the point in weather, and then updating the INS from this
point. You wouldn't need SAR if the point was available by other means,
or the target could tolerate greater than 100 foot error. For example, if
a 2k/lb jobber hit 500 foot from my house, I'd still be dead, and the

house
would be destroyed :-)


I am guessing that the primary means of updating the aircraft INS is via
GPS; maybe BUFFDRVR or one of the folks who has a clue can answer that
question. Otherwise you'd have a wee bit of a problem if your target was a
coastal one and your ingress was from over the water, or if you were
dropping it over a nice, relatively flat desert plain where you could not
get much in the line of significant terrain features from which to perform
your update, etc.

Brooks





  #20  
Old April 3rd 04, 04:43 AM
Paul F Austin
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"Felger Carbon" wrote
"Harry Andreas" wrote

Methinks there's some confusion there between processors, avionics
architecture, and software.
While it's true that Intel tried to shut down i960 production

causing a
chinese fire drill, there are enough assets to get by until a new

processor is
ready.


Full disclosu I'm a retired electrical engineer. I specialized in
high-end embedded microprocessors, which the "i960" in the F-22 is. I
know nothing about designing aircraft. I do know a little about the
Intel processor at the heart of the F-22:

The i960MX was designed by Intel specifically and solely for the F-22.
It was an extremely large chip (die) for its day, being octagonal in
shape so that the production 'mask' could be projected by the largest
then-available optics. The reason for the large size was the triple
redundancy built into the chip, which is what separates the i960MX
from all the other COTS i960s. The i960MX was _not_ a particularly
high-performance part, even when new.

It's likely that the reason Intel issued an end-of-life advisory on
the i960MX was that Intel was closing down the last 'fab' that was
capable of running that long-ago technology. A chip with a million
transistors on the die was pretty big back then, while 200 million
transistors per die is routine today.

Intel built the i960MX at the tail end of the period when electronics
companies would manufacture special "mil spec" parts for the military.
I suppose it was intended to be a public-relations gesture, as the
part was most certainly never going to make a profit, or anything
remotely close to that.

I don't think Intel realized that the F-22 project was going to drag
out so long that no significant production would occur before the
manufacturing technique and facilities for the i960MX would become so
obsolete (not merely obsolescent).

These problems exist WRT replacing the i960MX:

1. It unlikely that Intel would, these days, agree to build a special
triple-redundant microprocessor as a replacement. Charity for the
military is now a vanished concept, even (especially?) as a
public-relations effort.

2. You can't just replace a dozen-plus-year-old micro with a new one
and make no other changes. A complete new computer subsystem would
have to be designed. New parts are simply too fast to have any chance
of working in the old system.

3. Airplane controllers are necessarily real-time systems, and that
means a vastly-faster microprocessor, while a good thing at an
abstract level, requires a total re-write of the software (aside from
the new features to be designed in). If the system were _not_
real-time, this could be avoided. Alas.

I now return you to your regularly scheduled aircraft experts. ;-)


Thanks for the insight into the i960MX.

As it happens, GDIS in Mineapolis has developed a quad-redundant voting
PPC603E module for spacecraft applications. Voting schemes aren't new, years
ago Harris build a triple R3000 hybrid. You're right that you just can't
slip a new CPU into an existing system. You_can_build a new processor CCA
compliant with the existing ICD. F-22 uses a multicomputer architecture
based on FDDI which is of course stone slow by current standards. The FDDI
plant should be adequate until the next block change. Newer systems are
using FibreChannel signaling at 1GBaud while 10Gb Ethernet is the future.
That said,

You're quite right about the real-time code for flight control. The RADAR
data and signal processing and ICNIA functions should be fairly unperturbed
and quite portable.


 




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