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

In message , Kevin Brooks
writes
"Paul J. Adam" wrote in message
...
"In service" or "in development and undergoing testing"?

JDAM did not begin being delivered for testing purposes until 1997, from
what I have read in a couple of sources; the program was not started until
1992.

It absorbed various Navy and USAF projects like GAM and IAM, however
(GAM was flying captive-carry in 1989, IIRC)

--
When you have to kill a man, it costs nothing to be polite.
W S Churchill

Paul J. Adam MainBoxatjrwlynch[dot]demon{dot}co(.)uk

"Paul J. Adam" wrote in message
...
In message , Kevin Brooks
writes
"Paul J. Adam" wrote in message
...
"In service" or "in development and undergoing testing"?

JDAM did not begin being delivered for testing purposes until 1997, from
what I have read in a couple of sources; the program was not started
until
1992.

It absorbed various Navy and USAF projects like GAM and IAM, however
(GAM was flying captive-carry in 1989, IIRC)

Odd--nothing I have found via Google indicates GAM being around (in any
form) before about 1996 at the earliest, and IIRC 1998 was when it was
introduced to the B-2 force.

Brooks

In message , Kevin Brooks
writes
"Paul J. Adam" wrote in message
...
I've only *done* weapon system acceptance and integration, so what do I
know?

Not as much as the USAF, I'd wager. At least about the F/A-22 and its
capabilities.

"The USAF who will fly and fight the aircraft", or "the USAF press
releases and contractual acceptance schedules"? Big difference.

I know this for su all "capable" means is "has not been proved
impossible".

I don't think so. Must be Brit-speak, huh?

British and several other nations, including the US.

I don't tell you combat engineering, you don't tell me how to integrate
weapons onto airframes.

Why don't you not tell the USAF how to define what the initial capabilities
of the F/A-22 are/will be when it enters into operational service?

I have. Release certification and clearance to carry and drop the live
weapon.

So far all that's been published is some wind-tunnel model work. Nowhere
near actual operational utility.


That's "capable" according to some contracts: but for actual real-world
utility, unless you can persuade the enemy to occupy the relevant
wind-tunnel right under the model aircraft it's not much use.

"Software in place" is relatively straightforward when the weapon's in
use elsewhere and the software is developmental: "dummy tests conducted"
can be as simple as "flew with a blivet" or "conducted one safe jettison
from safe, slow and level" and certainly does not imply "cleared for
operational use".

Argue it with the USAF-

Where would you suggest?

-they appear quite confident that the "A" in the
title will be justified when it starts flying with the 1st TFW sometime
during the next year or two.

Been there, done that, seen the pencil-whipping. Give me a single F/A-22
JDAM warshot drop. There must be _some_ news article _somewhere_ to
report an event like that.

Or is it "fully operational" except that the first actual live-fire test
will be in combat? Yeah, *that* has worked really well in the past.

That you are not is not going to cause me any
loss of sleep, OK Paul?

I'm not paying for the 'A' designator and it's not my military trusting
that 'capability' will mean 'can actually put warheads on target'.

Pause and think, Kevin. The F-22 is, airframe versus airframe, the best
fighter in the world. But that tells you nothing about its air-to-ground
capability, and the notional ability to fit munitions into internal bays
means very little if you have not thoroughly tested the ability to get
the munitions _out_ of those bays (a thousand-pound blivet that doesn't
fully separate can thoroughly wreck a modern fighter) even before you
worry about presetting and arming.

You think it's easy and already handled? Then you're not paying
attention.

--
When you have to kill a man, it costs nothing to be polite.
W S Churchill

Paul J. Adam MainBoxatjrwlynch[dot]demon{dot}co(.)uk

In message , Kevin Brooks
writes
"Paul J. Adam" wrote in message
...
It absorbed various Navy and USAF projects like GAM and IAM, however
(GAM was flying captive-carry in 1989, IIRC)

Odd--nothing I have found via Google indicates GAM being around (in any
form) before about 1996 at the earliest, and IIRC 1998 was when it was
introduced to the B-2 force.

AIWS kicked off in March 1987: IAM went public in 1988 and in 1991
Friedman was speculating about how its accuracy could be improved if GPS
were used as a complement to inertial guidance. (IAM, not GAM, was
flying before 1991 - my mistake)

IAM definitely wants a good targeting sensor, though: GPS will fly to a
gridref, IAM didn't care where 'here' or 'there' is but started from
launch and went where it was told. Less dependence on satellite
navigation, but much more need for the launch aircraft to tell the
weapon "you are now HERE, and your target is HERE+INCREMENT, go kill!".

--
When you have to kill a man, it costs nothing to be polite.
W S Churchill

Paul J. Adam MainBoxatjrwlynch[dot]demon{dot}co(.)uk

In article , "Kevin Brooks"
wrote:


It's ridiculous that anyone would think SAR is required. That has been
discussed
here over and over. BTW, DTM is not required either.
All that's required is GPS, INS, and for better accuracy, SAR.

Which is why I argued that SAR is NOT required; maybe you were addressing
your "that's ridiculous" elsewhere and mistakenly appended it after my
response? As to DTM, I guess it would not be required if the coordinates of
the target or the IP (or whatver point is chosen as an update location) are
known and input into the equation; the system takes the known point and then
compares the chosen point on the SAR output to further refine the "where am
I at release" info. OK, that makes sense.


Sorry if I was not more clear. My statement was meant to cast aspersion
on the statement that SAR is somehow needed, so I was actually agreeing
with you.


SAR updates to pre-programmed INS settings have been used since the
early 90's to improve the accuracy of GPS aided munitions.

Uhmmm...Harry, what GPS guided munitions were in service during the
"early
90's"? JDAMS was not; perhaps the ALCM or SLCM used GPS updates in
conjunction with their stored DTM (but there you go again, that pesky
DTM...); I can't think of any others that used GPS during that
timeframe.

SAR updated GPS aided munitions were used by the B-2's in Bosnia with
eye-opening effect. You don't think that happened overnight?

Actually, B-2's were not used in the first (Bosnia) episode--they came later
during the Kosovo operation. So unless you are thinking that 1999 was "early
90's".... :-) Another poster has noted that GPS was used earlier, in the
case of SLAM, but not IAW any SAR usage that I am aware of--it instead,
along with an INS, got the missile to the general target area, where an
optical system took over, the signal being datalinked back to the launch
aircraft.

Say, rather the mid 90's. I know that work was being done earlier, but the
engineering world usually predates the operational world by quite a lot.
Sometimes it's hard to keep straight.

You don't need the SAR update to launch a JDAM, but it dramatically
improves the CEP of the weapon and essentially means that you can use
a smaller weapon to take out a target.

Well, it improves it, but not sure how "dramatically"; dramatic
improvement
of JDAMS appears to be dependent upon use of a secondary IR imaging
system

not IR. SAR. And the amount depends on the performance of the radar.
Numbers will not be mentioned here.

DAMASK is not IR? According to the following (amongst other sites), it does
indeed use an imaging infrared seeker:

My statement is intended to counter your statement that
"dramatic improvement of JDAMS appears to be dependent upon use of a
secondary IR imaging"
Dramatic improvement does not depend upon IR imaging if you have
a high accuracy SAR aboard.


(DAMASK) or ISAR input after the drop, as was tested in the joint F-16
dropped, and E-8 updated AMSTE (Affordable Moving Surface Target
Engagement) JDAM.

Hmmm. DAMASK at least has a future.
Can't imagine flying an E-8 close enough to a potential target to
get useful data without becoming a target yourself.
Well, maybe in the future if they port it to a UAV.

That is one possibility. But also recall that the E-8 can look pretty deep
into a battlefield; one orbiting fifty miles behind the FLOT can see, under
optimal conditions, some 100 miles beyond the FLOT, if you use the FAS
numbers (actual range being classified, no doubt). Being able to kill mobile
targets of opportunity with JDAM to that depth would seem to be a rather
valuable capability.

Remember that the further away you are, the more range error you accumulate.
If you want a high accuracy solution, you need either a very high powered
SAR system (more than an E-8) or need to be closer. Closer brings it's
own jepardy.

--
Harry Andreas
Engineering raconteur

"Harry Andreas" wrote
"Tarver Engineering" wrote:


The usual process since the early 90's.

You are way behind the power curve Harry. Have a look at the fleet
numbers
for reliabilty for the F/A-18E vs the F-14s. Think about how the F-22's
target number compares.

Ummm, let me check....yep, one of my radars is on the F/A-18E/F, and it
uses COTS parts. Oh, and the new AESA radar is on the F/A-18E/F, and it
uses COTS parts, too.
Digging a little deeper; yep, I worked on the F-14D's APG-71 and that
one uses Mil-spec parts.
And, of course, I worked on ATF and F-22 back in the day.
And JSF currently.

You're trying to teach me what exactly?

Been there, done that, doing it presently, with COTS and high reliability.
BTW, the current system I'm working has a reliability number higher
than the airframe life.

I doubt we could build AESA and associated
systems_without_commercial-heritage parts. The USG just doesn't have that
kind of money. My company builds fiber-optic and other high speed serial
networks for avionics and space and there is no way to build them without
commercial heritage Serializer-Deserializers and switch chips as an example.
The die are repackaged and screened to meet military quality requirements
but we live with the temperature limits. The reality of the relative size of
the commercial semiconductor industry and the military electronics
business-guarantees-that most die used in military systems will be built on
fab lines whose primary business is the commercial market.

"Paul F Austin" wrote in message
...

"Harry Andreas" wrote
"Tarver Engineering" wrote:


Been there, done that, doing it presently, with COTS and high
reliability.
BTW, the current system I'm working has a reliability number higher
than the airframe life.

I doubt we could build AESA and associated
systems_without_commercial-heritage parts. The USG just doesn't have that
kind of money. My company builds fiber-optic and other high speed serial
networks for avionics and space and there is no way to build them without
commercial heritage Serializer-Deserializers and switch chips as an
example.
The die are repackaged and screened to meet military quality requirements
but we live with the temperature limits. The reality of the relative size
of
the commercial semiconductor industry and the military electronics
business-guarantees-that most die used in military systems will be built
on
fab lines whose primary business is the commercial market.

Mil-spec 883 does it all these days.

"Harry Andreas" wrote in message
...
In article , "Kevin Brooks"
wrote:


It's ridiculous that anyone would think SAR is required. That has been
discussed
here over and over. BTW, DTM is not required either.
All that's required is GPS, INS, and for better accuracy, SAR.

Which is why I argued that SAR is NOT required; maybe you were
addressing
your "that's ridiculous" elsewhere and mistakenly appended it after my
response? As to DTM, I guess it would not be required if the coordinates
of
the target or the IP (or whatver point is chosen as an update location)
are
known and input into the equation; the system takes the known point and
then
compares the chosen point on the SAR output to further refine the "where
am
I at release" info. OK, that makes sense.


Sorry if I was not more clear. My statement was meant to cast aspersion
on the statement that SAR is somehow needed, so I was actually agreeing
with you.


SAR updates to pre-programmed INS settings have been used since
the
early 90's to improve the accuracy of GPS aided munitions.

Uhmmm...Harry, what GPS guided munitions were in service during the
"early
90's"? JDAMS was not; perhaps the ALCM or SLCM used GPS updates in
conjunction with their stored DTM (but there you go again, that
pesky
DTM...); I can't think of any others that used GPS during that
timeframe.

SAR updated GPS aided munitions were used by the B-2's in Bosnia with
eye-opening effect. You don't think that happened overnight?

Actually, B-2's were not used in the first (Bosnia) episode--they came
later
during the Kosovo operation. So unless you are thinking that 1999 was
"early
90's".... :-) Another poster has noted that GPS was used earlier, in the
case of SLAM, but not IAW any SAR usage that I am aware of--it instead,
along with an INS, got the missile to the general target area, where an
optical system took over, the signal being datalinked back to the launch
aircraft.

Say, rather the mid 90's. I know that work was being done earlier, but the
engineering world usually predates the operational world by quite a lot.
Sometimes it's hard to keep straight.

You don't need the SAR update to launch a JDAM, but it
dramatically
improves the CEP of the weapon and essentially means that you can
use
a smaller weapon to take out a target.

Well, it improves it, but not sure how "dramatically"; dramatic
improvement
of JDAMS appears to be dependent upon use of a secondary IR imaging
system

not IR. SAR. And the amount depends on the performance of the radar.
Numbers will not be mentioned here.

DAMASK is not IR? According to the following (amongst other sites), it
does
indeed use an imaging infrared seeker:

My statement is intended to counter your statement that
"dramatic improvement of JDAMS appears to be dependent upon use of a
secondary IR imaging"
Dramatic improvement does not depend upon IR imaging if you have
a high accuracy SAR aboard.

Which is why I had the *or* in the original statement, mentioning AMSTE,
which does indeed use radar. DAMASK and AMSTE appear to offer "dramatically
improved" accuracy, IMO (to the point that the latter can engage a mobile
target). Use of SAR with "vanilla" JDAMS does improve the accuracy, but I am
not sure if that level of improvment merits the moniker "dramatic"--the
JDAMS without SAR but with a decent INS/GPS update prior to release
apparently offers pretty good accuracy as is.



(DAMASK) or ISAR input after the drop, as was tested in the joint
F-16
dropped, and E-8 updated AMSTE (Affordable Moving Surface Target
Engagement) JDAM.

Hmmm. DAMASK at least has a future.
Can't imagine flying an E-8 close enough to a potential target to
get useful data without becoming a target yourself.
Well, maybe in the future if they port it to a UAV.

That is one possibility. But also recall that the E-8 can look pretty
deep
into a battlefield; one orbiting fifty miles behind the FLOT can see,
under
optimal conditions, some 100 miles beyond the FLOT, if you use the FAS
numbers (actual range being classified, no doubt). Being able to kill
mobile
targets of opportunity with JDAM to that depth would seem to be a rather
valuable capability.

Remember that the further away you are, the more range error you
accumulate.
If you want a high accuracy solution, you need either a very high powered
SAR system (more than an E-8) or need to be closer. Closer brings it's
own jepardy.

Eh? The E-8 is operating at that range--you think that the range error of
the E-8's ISAR itself increases significantly through the depth of its
coverage? The platform doing the weapons release would have to be about on
top of the target. This configuration, using AMSTE, was credited with a
successful strike in its first test drop, from what I have read. Of interest
would be how much the E-8 "sees"--can it also pick up the aircraft dropping
the munition (regular JDAM in this case)(as I believe the follow-on E-10
will be able to do)? If so, then it would appear to offer the dropping
aircraft the same accuracy enhancement that its own SAR would afford--the
E-8 would have the target and the delivery platform in the same frame of
reference, so any ranging error would be largely negated?

Brooks


--
Harry Andreas
Engineering raconteur

"Paul J. Adam" wrote in message
...
In message , Kevin Brooks
writes
"Paul J. Adam" wrote in message
...
I've only *done* weapon system acceptance and integration, so what do I
know?

Not as much as the USAF, I'd wager. At least about the F/A-22 and its
capabilities.

"The USAF who will fly and fight the aircraft", or "the USAF press
releases and contractual acceptance schedules"? Big difference.

In your mind.


I know this for su all "capable" means is "has not been proved
impossible".

I don't think so. Must be Brit-speak, huh?

British and several other nations, including the US.

I don't think so.


I don't tell you combat engineering, you don't tell me how to integrate
weapons onto airframes.

Why don't you not tell the USAF how to define what the initial
capabilities
of the F/A-22 are/will be when it enters into operational service?

I have. Release certification and clearance to carry and drop the live
weapon.

Good on you--you go keep those USAF types in line, Paul; God only knows how
we have managed to muddle through thus far without your editorial input to
the folks who fly these things and fight in them.


So far all that's been published is some wind-tunnel model work. Nowhere
near actual operational utility.

Tell it to the USAF. Go ahead--tell them they just HAVE to delete any
reference to the F/A-22 being JDAM capable when it enters front-line service
'cause you say so...



That's "capable" according to some contracts: but for actual real-world
utility, unless you can persuade the enemy to occupy the relevant
wind-tunnel right under the model aircraft it's not much use.

"Software in place" is relatively straightforward when the weapon's in
use elsewhere and the software is developmental: "dummy tests
conducted"
can be as simple as "flew with a blivet" or "conducted one safe
jettison
from safe, slow and level" and certainly does not imply "cleared for
operational use".

Argue it with the USAF-

Where would you suggest?

Do a google.


-they appear quite confident that the "A" in the
title will be justified when it starts flying with the 1st TFW sometime
during the next year or two.

Been there, done that, seen the pencil-whipping. Give me a single F/A-22
JDAM warshot drop. There must be _some_ news article _somewhere_ to
report an event like that.

Or is it "fully operational" except that the first actual live-fire test
will be in combat? Yeah, *that* has worked really well in the past.

Note that it has yet to enter into front-line combat unit service; those
fielded thus far are either at Edwards or joining the conversion/opeval unit
at Tyndall.


That you are not is not going to cause me any
loss of sleep, OK Paul?

I'm not paying for the 'A' designator and it's not my military trusting
that 'capability' will mean 'can actually put warheads on target'.

Who really cares at this point. USAF says it will be JDAM capable when it
enters operational service--you say it won't be. Most folks will accept the
USAF version unless you can prove they are lying. Kind of hard for you to do
at this point.

Brooks


Pause and think, Kevin. The F-22 is, airframe versus airframe, the best
fighter in the world. But that tells you nothing about its air-to-ground
capability, and the notional ability to fit munitions into internal bays
means very little if you have not thoroughly tested the ability to get
the munitions _out_ of those bays (a thousand-pound blivet that doesn't
fully separate can thoroughly wreck a modern fighter) even before you
worry about presetting and arming.

You think it's easy and already handled? Then you're not paying
attention.

--
When you have to kill a man, it costs nothing to be polite.
W S Churchill

Paul J. Adam MainBoxatjrwlynch[dot]demon{dot}co(.)uk

"Paul J. Adam" wrote in message
...
In message , Kevin Brooks
writes
"Paul J. Adam" wrote in message
...
It absorbed various Navy and USAF projects like GAM and IAM, however
(GAM was flying captive-carry in 1989, IIRC)

Odd--nothing I have found via Google indicates GAM being around (in any
form) before about 1996 at the earliest, and IIRC 1998 was when it was
introduced to the B-2 force.

AIWS kicked off in March 1987: IAM went public in 1988 and in 1991
Friedman was speculating about how its accuracy could be improved if GPS
were used as a complement to inertial guidance. (IAM, not GAM, was
flying before 1991 - my mistake)

IAM definitely wants a good targeting sensor, though: GPS will fly to a
gridref, IAM didn't care where 'here' or 'there' is but started from
launch and went where it was told. Less dependence on satellite
navigation, but much more need for the launch aircraft to tell the
weapon "you are now HERE, and your target is HERE+INCREMENT, go kill!".

So we are back to the fact that we have not seen any GPS guided rounds
(minus that SLAM sort-of-GPS-guided-but-with-a-separate-terminal-seeker)
flying around until the latter part of the nineties.

Brooks


--
When you have to kill a man, it costs nothing to be polite.
W S Churchill

Paul J. Adam MainBoxatjrwlynch[dot]demon{dot}co(.)uk