Heat seaking radar !

Really? I remember the warm engines of the Iraqi tanks showing up in the videos of Desert Storm. I thought they went well into the body-heat threshold. Hell, even IR gates do that (and get stubborn when it gets to

95F).

--
  Keith

Almost but not quite tautology. An interesting derivative.

My current pet peeve is (dis) orientated. Check the dictionary. I actually heard someone on TV use the word correctly tonight !

Graham

< chuckle > . Like it. ;-)

Graham

Optical stuff Jim. Not radio frequency. Incidentally ISTR that germanium makes good IR lenses.

Graham

Andy replies:

I did the same search as Richard Henry. I did not find any "reputable" source that even used the term. I thought perhaps that I might have missed something over the several decades that I was involved with this. It happens. But not this time.....

As a RADAR designer for many years for Texas Instruments and Raytheon, I have more than a passing familiarity with the subject, since most of my work was with the DOD. I also have extensive experience with infrared imaging systems for tanks, jet aircraft, and sniper rifles........

RADAR stands for Radio Distance And Ranging. It sends out energy and uses signal processing to determine both RANGE and DISTANCE. It can be pulses, a continuous illumination, or special modulations on a carrier.... Just depends on what you're trying to do, and how much you're willing to pay.

Remember, radio waves are EXACTLY the same as "heat" or "infrared"waves, except for the frequency. A heat radar would be essentially a LIDAR, since it sends out pulsed energy in a frequency range that is often refered to as heat, but LIDAR is not "heat seeking radar"....... it's plain old RADAR in the frequency range that Lasers put out....(I never designed a LIDAR , tho)

Many of our missles, and the F-16 terrain following radar, have both 1)thermal imaging capability, which can be used as a seeker, and 2) radar capability, which also can be used as a seeker. SEEKER means that it searches for something that is electronically determined to be a target, and then does stuff, like, home in on it before exploding or expending ordinance. I've spent many boring hours examining data tapes of the RADAR return and the thermal imager display, trying to determine why the autopilot was jerking around the F-16........ (ahh, the good old days)

A heat seeker is typically used in a missle to find a hot target..... However a heat seeker does not use an illuminator. It is essentially a TV camera that is sensitive to electromagnetic energy that is lower than frequency than the electromagnetic energy that our eyes are sensitive to. It works just like our eye, or a TV camera. The idea is that a lot of energy in a certain frequency range is generated by rocket motors, or human beings, or tank exhausts, etc etc , and the thingamabob looks for it, and tries to blow it up.. It does NOT rely on reflected energy, which is the main source of interference for this technique......In fact , it would be really great if there were no heat at all except for the target heat .... ....... Missles work better at night.....

Well, I'm off my rant. It seems that so many people were dancing around this subject , and I'm retired and got nothing to do anymore, so I just felt like sticking in my two cents worth...

When you want to hear the real skinny on some of our fantastic weapons, one shouldn't rely much on science writers. .... and you can't ask the engineers who built them, cause we can't talk about them.... much (grin).....

Have fun, Andy

keith wrote in news: snipped-for-privacy@att.bizzzz:

But were they showing you thermal imaging or night-vision displays? I suspect they were thermal imagers.They even make handheld,uncooled thermal imagers now,for firemen to use inside burning buildings,to see through smoke.(using microbolometer arrays)

--
Jim Yanik
jyanik
at
kua.net

[snip]

Google on "heat seeking radar", spelling "seeking" correctly), and you get 85 English hits.

But I guess those aren't "reputable" ?:-)

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.

"High speed of rate" actually seems correct.

--

Reply in group, but if emailing add
2 more zeros and remove the obvious.

The content ismore important than the count.

The first page I got are from a European press agency, the American Medical Directors Association, a political flack-house, defense-update.com (which is a false hit - the quote is "...various tupes of heat-seeking, radar guided and command to line of sight guided missiles...", slate magazine, an off-hand remark in an article titled "The Lack of Fiscal Management in Existing Salmon Recovery Programs", soulfulliving.com, etc, etc, etc.

Either non-reputable, or not germane.

Someone might become confused with the quoted sentence above. A heat seeking, radar guided , and command missle would be a missle that has three modes of operation:

1) an infrared heat seeker 2) a standard radar seeker 3) a remote command guidance system, probably TV camera linked.

but I am not aware of any single model, at least in the US arsenal, that has all three modes of operation......... however, I could be wrong..... Usually the more sophisticated types have two of the three, like Maverick. Sidewinder is heat only. HARM uses a radar seeker and has a passive mode that is NOT infrared.....TOMAHAWK has a radar seeker and GPS guidance.......depending on the model.

As I have said, there is no "heat seeking radar".

I guess some people should know when to go into the "knowledge seeking" mode rather than to automatically go into the "knowledge illumination" mode. Perhaps they don't have enough homework in their high school......

Andy

Regarding the difference between Thermal Imagers and Night Vision equipment ---

Remember, each object gives off radiation from two sources.

1) The temperature of the object gives off radiation at frequencies dependent on it's own temperature. (Example: Glowing coals in a fire, on a pitch black night , appear red to our eyes) 2) It also reflects energy at the frequencies of other objects around it that bounce off it's surface. ( Example- light from the sun bounces off a tree into our eyes and we detect the reflected light.)

A Thermal Imager and a Night Vision system are basically the same but work at different frequencies, just like different frequencies on the TV set.

Thermal Imagers are optimized at the band of frequencies given off by the object itself, as a function of temperature. This is usually in the infrared region.

Night Vision viewers are optimized for reflected radiation, as from the moon, or stars, or some sort of illuminator that can be used. This is usually in the visible light (to our eyes) region.

There is a lot of information on the net about remote temperature measurements . These things sell for about 50 bucks or so, and tell you an object's temperature at a distance, based on the radiation. The tutorials on their operation will explain the inaccuracies that are encountered when the surface of the objects being measured have different reflectivities, which combines the radiated and reflected radiation to give an inaccurate temperature measurement.

If you point either night vision goggles or thermal imagers at the sun, you will get a LOT of signal. If you point a directional antenna at the AM broadcast band at the sun, you will get a LOT of signal ( not practical to test since the size would be too big).

EM radiation is EM radiation ---- only the frequencies are different.

Andy

Andy replies to Jim:

I did as you did and used the same spelling and can confirm that there is a large number of hits. The "sources" seemed like "sophisticated" entities.

But then I went to a couple of them and read what they had to say. I suspect these sensational articles were written by journalism interns who started writing stories for a living after they flunked out of engineering school......

Lots of medical articles exist in the New York Times, but the editor probably doesn't have a medical degree, and I would use them ONLY to get an idea of where to find a doctor..

Engineers are USUALLY terrible writers. Writers are USUALLY terrible engineers and tend to intermingle technologies.....

So, in reply to your "guess" above.... I haven't yet looked at all

85, and probably won't, but the dozen I did look at have not impressed me as "technically accurate"....but rather as "fluff articles" written to impress the public.

Perhaps you can give an example of maybe , ONE SINGLE MANUFACTURER who advertises the sale of a heat seeking RADAR.......???? I'd certainly like to read over their technical data......

Andy

In that case, I will try to do my cringing in private in the future. ;-)

--Mac

Perhaps we're getting into definitions now, but it was video from the "nigh-vision" goggles (hmm) of the helicopter crews. In the latest invastion the embedded news people had similar video.

--
  Keith

What's wrong about passive sonar ?

Towed passive sonar arrays are frequently used by yours and ours nuclear subs.

Graham

I'm sorry, but this is incorrect. It's "Radio Detection and Ranging."

Now, you've completely gone and lost it:

a couple of excerpts: - in radar meteorology, the straight-line distance from the radar k12.ocs.ou.edu/teachers/glossary/r.html - Distance from the radar antenna. The WSR-88D radar has a range for velocity products out to 124 nm and reflectivity products out to 248 nm.

In other words, 'RANGE' _IS_ 'DISTANCE'.

Sorry, Andy, but you've blown this one.

Thanks, Rich

Andy replies:

You're absolutely correct , Rich. But it was not an "error", rather a "flag".

I was interested in seeing whether anyone who "critiqued" my post bothered to read it . Believe me, anyone who has any knowledge of radar KNOWS what R A D A R stands for. If you re-read that couple of lines, you will find glaring misstatements, that actually have nothing to do with the point I was making. Not an accident or a missprint....

Actually, the idea that you had to give a website for the term RADAR means that you aren't a radar man, either. No apologies necessary , few working radar engineers have the time to waste on a newsgroup discussion like this. Like I said before, I am retired... (grin)

The signal processing determines both DETECTION, DISTANCE, VELOCITY and ACCELERATION of a target return .. (DISTANCE AND RANGE are essentially the same terms, duhhh!)

It can also 'IMAGE' a target from the returns, effectively creating a photograph of the target based on processing the returns. ( SAR Synthetic Aperture Radar, Radar imaging, etc)

If you are familiar with "Probablility of Detection"vs"Probability of False Alarm" and "M out of N", you will understand how processing provides enhanced detection.

VELOCITY is determined by processing the frequency bins (caused by doppler) of the returns, and can only be done well with a high PRF transmission. In olden days, we looked at the returns from the range bins and did simple division D/T to determine velocity, but you don't get a lot of information from low prf.....

I haven't done ACCELERATION processing myself, but know bearded guys with sandals who have....They don't shower much and their breath reeks of Hostess Twinkies and Sechuan food , but otherwise they are a real hoot to work with...

So, while you have shown that you actually bothered to read my post before starting your criticism, you actually missed the point. I was only giving a little basic background for my explanation of why there is no "heat seeking radar".

Of course, I could be wrong. Have you, in your effort to critique every detail in my post, located any manufacturer of "heat seeking radar" ???? I'd really like to see something more useful here than technical sniping. It's easy to prove me wrong --- just show a website that has a description of heat seeking radar and I'll have learned something....

Heck, we all may have learned something.....

Andy

Misprint? ;-D ...

Well, I did do a google on "heat-seeking radar", and a lot of people use the term, but I did get an impression that it's used mainly as marketing hype or to make some kind of point, by people who have no idea what they're talking about. It _does_ sound like a logical thing to your typical layman. :-)

Like others have said, it gets used in the press release for some new military airplane once or twice, but they're written by market droids, so really doesn't mean anything.

Apologies if I came on a little too ham-fisted. :-)

Now I'm on a crusade to inform people that ionization doesn't necessarily automagically cause ozone! :-)

Thanks! Rich

Andy replies :

RE: Missprint Since I compose on the fly, I occasionally type a word that belongs later on, and I may not catch it when I proof it. .... and sometimes I don't proof it. So THAT'S what I mean by missprint. " DISTANCE and RANGE" was not a missprint, since I meant to state it that way, as I have said before. It was amusing to me that out of a fairly large and comprehensive post, someone took the time to reply to the post on an insignificant word or two in the first couple of lines, that had essentially NOTHING to do with the point of the post, .....which was to disavow the accuracy of the term "heat seeking radar".....

Perhaps you are retired also.??? If so, we should be able to spend many happy hours swapping posts. :>)))) However, I am not good at spotting missplaced commas and typos, so my critique will probably deal with other aspects that you might present.... :>))))))

RE: Crusade

"Now I'm on a crusade to inform people that ionization doesn't necessarily automagically cause ozone! :-) "

Well, I am curious about this. Assuming that the ionization occurs in the presence of oxygen, howcum you don't get ozone every time ??????? (Perhaps a new thread would be in order ) :>)))

Que te vaya bien. Andy