the fallacy of HARM missiles

[bwanaaa]

So often we read or hear about the air force's use of harm missiles in the neutralization of enemy radar sites. The missile uses the radar as a homing beacon. But I do not understand why the emitter has to be so geographically close to the sensor (same truck in the case of mobile SAMs). Scatter a dozen emitters on the ground and the sensor with the launch vehicle simply has to listen. Since the location of the emitter is known and the emitter can be triggerred remotely, the SAM operator can figure distance of the bogey by time it takes for the signal to reach him. The doppler signature of the reflected waves gives velocity of the incoming bogey.

So a million dollar harm missile will accurately target a radar emitter the size and cost of a microwave oven. if the emitters are airborne and switched on and off in a pattern, we're screwed. So why do we keep using harm missiles? I would much rather trust the photographs of something like a kh-11 looking for the infrared signature of a big missile carrying truck in a forest or a desert . How did we neutralize SAM sites on our way into IRAQ?

I cant believe some smart Iraqi didnt figure this out already?

 

[Gibsons]

Harm missiles are pretty sophistocated from what I understand and can distinguish between a microwave oven and a sophisticated air search radar. There's also a human in the loop deciding which way and what target to point the missile at. We keep using them because they keep working.

If you put a bunch of microwave emitters "in the air," how long are they going to stay there? Not indefinitely.

How did we neutralize SAM sites on our way into IRAQ?

in GW I, some apaches snuck in on the deck and hosed some crucial initial sites with 30mm and/or hellfires. HARMs took out a few after that.

I cant believe some smart Iraqi didnt figure this out already?

Of course they did. But Americans are presumably just as smart, and in this case, likely had a large budget and a lot of time to plan ahead.

On a side note, there are a few reports out there of attempts at jamming GPS signals as well, but apparently none have been successful. GPS jamming is potentially really bad news for a lot of U.S. systems, but obviously it was made pretty robust in anticipation of this.

 

[bwanaaa]

i really dont know about gps but it would seem pretty easy to make a jam proof system-use spread spectrum transmission and i MEAN SPREAD spectrum - bursting little packets at different frequencies. Then you can selectively go to those frequencies where the checkbits of the packets are least often wrong. the only way to jam that would be to blanket the whole spectrum with noise and that would disable all the theaters comms - no combattant would have any comm. just shot yourself in the foot.

my analogy to microwave ovens was hyperbole. I was just trying to illustrate the fact that distributing a bunch of radar emitters would make a sam site vastly more survivable-harm missiles would be rendered harmless.as fo staying in the air indefinitely, that concept has already been demonstrated. I forget who fielded the aircraft - a flying wing with 12 solar powered props and onboard computer with gps all solar powered. It circled the globe at altitudes >70000 feet. All carbon fiber and virtually no radar signature. put 3 of those in a theater of war. pulse the radar for a second, detect the reflection from the bogey using your ground site, launch when desired. your ground launcher becomes lighter, anonnymous, and can launch from almost anywhere. The airborne radar emitter doesnt need a ton of juice because the radar is pulsed for brief intervals. by the time a harm gets a lock on the signal, the signal is gone and the emitter has already flown away.

but in reality, the use of such weapons is becoming obsolete. the real threat is the anonymous terrorist who strikes randomly. the only way to prevent that is to have assets on the ground-basically spies who are part of the opposing society who can give intel on the flow of explosives/perceived targets.

 

[Gibsons]

Originally posted by: bwanaaa
i really dont know about gps but it would seem pretty easy to make a jam proof system-use spread spectrum transmission and i MEAN SPREAD spectrum - bursting little packets at different frequencies. Then you can selectively go to those frequencies where the checkbits of the packets are least often wrong. the only way to jam that would be to blanket the whole spectrum with noise and that would disable all the theaters comms - no combattant would have any comm. just shot yourself in the foot.

my analogy to microwave ovens was hyperbole. I was just trying to illustrate the fact that distributing a bunch of radar emitters would make a sam site vastly more survivable-harm missiles would be rendered harmless.as fo staying in the air indefinitely, that concept has already been demonstrated. I forget who fielded the aircraft - a flying wing with 12 solar powered props and onboard computer with gps all solar powered. It circled the globe at altitudes >70000 feet. All carbon fiber and virtually no radar signature. put 3 of those in a theater of war. pulse the radar for a second, detect the reflection from the bogey using your ground site, launch when desired. your ground launcher becomes lighter, anonnymous, and can launch from almost anywhere. The airborne radar emitter doesnt need a ton of juice because the radar is pulsed for brief intervals. by the time a harm gets a lock on the signal, the signal is gone and the emitter has already flown away.

but in reality, the use of such weapons is becoming obsolete. the real threat is the anonymous terrorist who strikes randomly. the only way to prevent that is to have assets on the ground-basically spies who are part of the opposing society who can give intel on the flow of explosives/perceived targets.

You're proposing an umannned AWACS, basically. It'll be very expensive and a very high priority target. A decoy should be cheap and disposable. A solar powered flying wing with an autopilot and power source for an emitter is probably going to cost you as must as the radar you're trying to save, quite alot more if it's also going to have the abillity to light up targets for you. Also, I have serious doubts about the stealthiness of anything with solar panels and propellors. It can probably be done, but that's going to cost you even more money and quite a bit of R&D time. It's certainly a long ways from cheap and disposable.

For a decoy to work in this scenario, you're gong to need a lot of them, at least several for each radar dish you're trying to protect. I imagine it's tough to build something cheap that can fool a HARM with a competent pilot on the trigger. Air search radars have some very particular signals (chirping, etc) that are easy to detect and might cost you some money to replicate (I can't say for sure, but I know there are some EE types that read this forum.... ).

You can try baloons, but they'll blow away...

As for GPS, the sattelites are in the air. There's no changing how they work now. Here's a discussion on the issue
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[nweaver]

as an FYI, the Apaches may have waxed the installations, but it was the Kiowa Warrior's that painted them red for the Apaches...

My bro flys Kiowa's for the 3rd ACR, just got back from round 2 a couple of days ago, I'm itching to go listen to the stories you never hear on the news!

 

[CycloWizard]

The reason people don't throw airborne radars up to do what you proposed is that no one is willing to fly against us. There's a reason Iraq buried their planes in the sand rather than fly against us, and that's because we're about four decades ahead of any other country in air technology (according to most estimates). Our planes that are now being retired would be the best thing in pretty much any other nation's arsenal, and we can afford to scrap them because our new stuff is THAT much better.

 

[GhostDoggy]

Its war. And if someone wishes to microwave in the middle of a warzone then BAM!

 

[bwanaaa]

Originally posted by: Gibsons
You're proposing an umannned AWACS, basically. It'll be very expensive and a very high priority target. A decoy should be cheap and disposable. A solar powered flying wing with an autopilot and power source for an emitter is probably going to cost you as must as the radar you're trying to save, quite alot more if it's also going to have the abillity to light up targets for you.

can anything touch it at 90000 feet?

Also, I have serious doubts about the stealthiness of anything with solar panels and propellors. It can probably be done, but that's going to cost you even more money and quite a bit of R&D time. It's certainly a long ways from cheap and disposable.

who cares if you can ping it. you cant hit it. And it's just a transmitter. how much can that cost? no receiver/signal proc.

For a decoy to work in this scenario, you're gong to need a lot of them, at least several for each radar dish you're trying to protect. I imagine it's tough to build something cheap that can fool a HARM with a competent pilot on the trigger. Air search radars have some very particular signals (chirping, etc) that are easy to detect and might cost you some money to replicate (I can't say for sure, but I know there are some EE types that read this forum.... ).

I am not suggesting decoys. These are the real thing-the transmitter part of the radar. maybe extra transmitters on the ground would be cheaper - in hyundai pickup trucks driven around by captured terrorists

 

[Smilin]

If you are going to go through all the trouble of building and deploying multiple emmiters why not just deploy multiple sites altogether?

If our enemy wants to waste resources on this all the better for us. It's sure cheaper to build an anti-radar missle than it is to build a radar site.

 

[Gibsons]

can anything touch it at 90000 feet?

Yeah. The F-4's ceiling is given at 60 to 70k, I imagine the F-15 is higher, and then there's the F-22. I'd bet an F-14 with a phoenix could do it easily, if they were still around. Don't forget this target is very large, very slow and very fragile.

Also, I think you'll have lot of trouble getting your emitter and an appropriate power supply for it to fly at 90,000 for an extended period. This is a very very expensive project, probably beyond most countries capabilities.

who cares if you can ping it. you cant hit it. And it's just a transmitter. how much can that cost? no receiver/signal proc.

The plane you're basing it on was something like 15 million and the result of some pretty fancy engineering. Your mini awacs is going to cost a bit more and probably require some even better engineering, which not every country has.

Anyways, I think if I were in the business of trying to fool HARMs on the cheap, I'd look into modifying microwave ovens into something that looked as close to my radars as possible (not sure how reasonable that really is, though), and send out teams into the desert/hills/whatever, with a generator or two, dozens of modified ovens and some very long extension cords. Then set up *hundreds* of them. This might pose a problem for the HARM signal processing (who knows). Might also cause problems for your own radar, but it's better than being blown up.

edit: grammar are hard

 

[0roo0roo]

How did we neutralize SAM sites on our way into IRAQ?

i think we've been hammering them on and off since the end of gw1. even clinton went in to hammer saddam.
http://www.washingtonpost.com/wp-srv/inatl/longterm/iraq/after/afterfox.htm
http://en.wikipedia.org/wiki/Operation_Desert_Fox
http://www.globalsecurity.org/military/ops/desert_thunder.htm

 

[dkozloski]

I was in the anti-radiation missile racket many years ago and even then the missile was very intelligent and was able to separate the wheat from the chaff. The SAM missile radar signal requires distinct encoding to allow it to be useful to guide the SAM. If the SAM can sort the decoys out, so can the HARM. Also you are not neccessarily trying to destroy the site, you are trying to protect attacking aircraft. If you can get the guys on the ground to shut down their system and run like hell you've won the battle.

 

[Spike]

One thing to remember is the HARMS backup system. I am not sure if it was originally there but HARM's now have memory for where they detected a radar site before. If their target Radar decides to turn off their signal rather than get destroyed when the detect the incoming HARM it uses it's memory of where the Radar was and goes for it. Works very well against a stationary ground radar, not so well against an aircraft.

As for spoofing it with lots of emitters I figure that is the problem of the person launching the missle. They decide what to launch at and where it goes.

-spike

 

[bwanaaa]

dkozloski

I am not suggesting decoys, rather i am suggesting multiple REAL emiiters geographically remote from the detector/launch vehicle. If all you really care about is the reflected signal, who cares where it originates from. To be extreme, you might even consider a maser lighting up a piece of the ground your interested in (say the japanese or chinese just put up a nuclear powered satellite that can do it). you just want the target lit.

 

[dkozloski]

The illuminating Radar is encoded so the missile can determine if it is valid and not be lead astray by a decoy also. The target must still be tracked somehow so the illuminators can be properly directed. The tracker becomes the target. Mutiple illuminators are easily attacked by cluster bombs. The HARM has position memory to counteract intermittant illumination and tracking. Believe me when I say that there are some very clever people working on all aspects of air defense weaponry. In a wartime environment a new tactic may only be effective for a matter of hours or days before it is counteracted. When an attacking force encounters air defense situations they are using every weapon at their idsposal simultaneously which may be HARM missiles, ECM jammers, stealth, decoys, terrain masking, cruise missiles, and spit balls. All the attacker has to do to be successful is to disrupt the defense long enough for the attacking force to hit the target and depart. Our guys are really, really good at this. Wait and see how they deal with the Iranian atomic program. For a preview do a Google search on conventional ICBM warheads.

 

[bwanaaa]

dkozloski,

I am sorry if i upset you but you seem to be skipping some thoughts in your paragraph. Some of your sentences are nonsequiturs to my primitive and naive view. I am not doubting that this scenario (multiple illuminators) has been considered and possibly solved by our brilliant engineers at Caltech as well as their Taiwanese post-docs. I am simply trying to understand how it would be solved. An interesting solution might be for The HARM itself to record the painting pulse and then to emit an exact echo through an on board maser directed at the ground . The resulting reflections would confuse the detector at the SAM. In this case, the harm would never find and destroy the SAM site, but just confuse it into uselessness. This may be stoopid thinking but I cant seem to find how this problem was solved - for obvious reasons. The thing about Iranian nukes is beyond me...

 

[dkozloski]

Multiple illuminators can be handled by multiple harm missiles. In addition the multiple illuminators would result in gross phasing errors, multipath, and noncoherence in the signals received by the SAM both directly and reflected. It would be like jamming your own system. Even if you had a switching system to power each illuminator, independently and momentarily, the Harms would still get them because of their ability to "coast". The Iran comment was to alert you to the fun to come when the Iranian Nuclear sites are taken out. The remark about conventional ICBM warheads was to alert you to the prospect of the Iranians looking up and seeing 8000lbs of New Hampshire granite approaching their buried sites at 17,500 mph which ought to be an interesting prospect for SAM missile operators. That ought to put a whole new meaning to HARM. In fact it ought to put the HURT to them.

 

[TerryMathews]

Originally posted by: bwanaaa
dkozloski,

I am sorry if i upset you but you seem to be skipping some thoughts in your paragraph. Some of your sentences are nonsequiturs to my primitive and naive view. I am not doubting that this scenario (multiple illuminators) has been considered and possibly solved by our brilliant engineers at Caltech as well as their Taiwanese post-docs. I am simply trying to understand how it would be solved. An interesting solution might be for The HARM itself to record the painting pulse and then to emit an exact echo through an on board maser directed at the ground . The resulting reflections would confuse the detector at the SAM. In this case, the harm would never find and destroy the SAM site, but just confuse it into uselessness. This may be stoopid thinking but I cant seem to find how this problem was solved - for obvious reasons. The thing about Iranian nukes is beyond me...

The best parts of how HARM works are still classified - up to its flight speed. You're asking questions that cannot be answered by the people who are truly qualified to give you a straight answer, and with good reason.

I can tell you that there are several AA systems, mostly Soviet in design, that have multiple emitters. It's not so true now, but go back far enough and you get to a point where you need one emitter per target. No one does multiple emitters as decoys because the emitters are the most expensive part of the AA system.

You can tell a difference between a tracking radar and simply emitting microwave radiation - so just throwing up some microwaves is out as a decoy measure.

But the most important thing to remember is that HARM is a deterrent weapon - it works best when you never have to fire it. It's completely passive, so the enemy can't tell if you've fired it, or even if you're carrying it at all. Since a lot of especially older AA systems have the controller sitting in close proximity to the emitter, a controller flipping on that AA system can be like flipping the switch to his own death.

 

[dkozloski]

TerryMathews, you're right on the mark. It has been a long time since I was in this racket but I am still reluctant to get into details because of security questions and it's hard to be candid about clasified equipment, even at this late date. It's interesting to me that the Navy adapted a SAM missile, the Standard Surface to Air Missile, to make the Standard ARM Anti-Radiation Missile. It's almost like incest.

 

[bwanaaa]

Originally posted by: dkozloski
... It's interesting to me that the Navy adapted a SAM missile, the Standard Surface to Air Missile, to make the Standard ARM Anti-Radiation Missile. It's almost like incest.

I'd say it was Oedipal...the son killing the father. That Harm is the son of SAM also harks back to another episode in the history of american psychocriminals...if you are old enough to remember the 'son of sam'...

But back to the point...I didnt recognize that emitters were more expensive than detectors. I guess at this point If I were building this kind of a system (e.g. patriot,scud,etc.) I would make the parts as geographically separate as possible to protect them from HARM. Of course if I were the opposition, I would create cheap remotely piloted drones that have the radar signature of HARMs- just to DETER. After all, why waste your expensive HARMs. send the drones in with the stealthy overflight of F117 or F22 concurrent.

 

[bwanaaa]

Originally posted by: 0roo0roo

How did we neutralize SAM sites on our way into IRAQ?

i think we've been hammering them on and off since the end of gw1. even clinton went in to hammer saddam.
http://www.washingtonpost.com/wp-srv/inatl/longterm/iraq/after/afterfox.htm
http://en.wikipedia.org/wiki/Operation_Desert_Fox
http://www.globalsecurity.org/military/ops/desert_thunder.htm

thanks for these interesting links.

 

[Coraanu]

HARM's are only $284k according to http://en.wikipedia.org/wiki/AGM-88.

I'd much rather spend $284k than lose pilots and aircraft. Not sure how much the SAM or AA emitters cost, though.

 

[gsellis]

BTW, 90000 ft is in range of any interception mission. AA Missles are solid fuel rockets. The only thing they would be poor at is last second course corrections because of the thin air. The Soviets had late generation SAMs to hit something at 90000 ft and they would be more effective against a slow ship than what they were trying to design to hit, the SR71.

And for altitude, remember that the US was testing an anti-satellite weapon launched from a F-15 at the top of its ceiling. Those rockets could go up to 100 miles (528000 ft) to hit spy sats IIRC.

 

[Yeormom]

Originally posted by: Coraanu
HARM's are only $284k according to http://en.wikipedia.org/wiki/AGM-88.

284k seems kinda low for the cost of a HARM considering a SRAW runs 200k according to "contractors" so that makes me question whether 284k is what we pay for the box they ship it in...

 

[Gibsons]

Originally posted by: Yeormom

Originally posted by: Coraanu
HARM's are only $284k according to http://en.wikipedia.org/wiki/AGM-88.

284k seems kinda low for the cost of a HARM considering a SRAW runs 200k according to "contractors" so that makes me question whether 284k is what we pay for the box they ship it in...

That's the production cost, if you included development cost, it's a little more.

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