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11/22/2017 10:05:29 PM
Posted: 10/26/2004 10:59:46 AM EST
[Last Edit: 10/26/2004 11:25:50 AM EST by -M60_Gunner-]
At what altitude does radar no longer able to track aircraft? Was the SR-71 and Mig-25 Foxbat/Mig-31 Foxhound able to fly above this limit?
Link Posted: 10/26/2004 11:01:23 AM EST
Well, given that we use radar to track satellites I don't think altitude is a problem.

CW
Link Posted: 10/26/2004 11:01:46 AM EST
No.

D(ThePhormerPhantomRADART­ech)Peacher
Link Posted: 10/26/2004 11:05:29 AM EST
Ok let me ask a more specific question then. At what altitude does radar for Commercial and civilian aircraft reach it's limit's; is the commercial/civilian radar system connected to the militarys radar systems?
Link Posted: 10/26/2004 11:09:16 AM EST
I think talking about the specifics of the US radar net, comericial and military, over the internet is a BAD idea. So let's just keep this stuff to ourselves shall we?
Link Posted: 10/26/2004 11:10:16 AM EST
Strangely enough saw this in the news this morning:
Navy Transfers Space Surveillance Mission to Air Force
Link Posted: 10/26/2004 11:11:25 AM EST
They use radar to map the surface of other planets and asteroids.

The MIG25 was/is not a stealth technology aircraft. They show up on radar like a christmas tree.

The SR-71 Blackbird/Habu was first generation stealth. The chine around the fuselage plus the use
or some primitive radar absorbant materials significantly reduced its radar signature. From head
on or the side it was virtually invisible since there are no right angle or flat surfaces to return signal
back to the transmitter.

I was in the tower at Kadena waiting for one of our birds to call in while an SR was on approach.
It didn't appear on the ground approach radar until it was about 10 miles away. The operator
pointed out several intermittent returns that he said were from the plane before that.
Link Posted: 10/26/2004 11:11:28 AM EST

Originally Posted By Cold_Warrior:
Well, given that we use radar to track satellites I don't think altitude is a problem.

CW



Hell, we use radar to track SPACE PROBES, let alone satellites!
Link Posted: 10/26/2004 11:12:38 AM EST
Are we talking about ceilings or floors? Why would you want to know unless you're looking to evade the net?
Link Posted: 10/26/2004 11:14:27 AM EST
From what I understand the Sr 71 Flew so high and so fast nothing could touch it. The Russians tried

to shoot it down and failed. The Mig 25 was designed to shoot it down but was never successful. No

radar reaches out past the atmosphere.
Link Posted: 10/26/2004 11:16:55 AM EST
The reason for the origional question was because of a previous discussion about "If you could ow any plane you wanted for a $1". One person had said the they would own the SR-71 but another poster responded that it would be pointless to own such an aircraft because you can't go super-sonic over the continental US and you'd have to stay within radar tracking capabilities.


The second question was "If were to own one of the aforementioned aircraft would it be ok to fly at say 60,000-70,000ft or would you need a special permit?"
Link Posted: 10/26/2004 11:18:26 AM EST

Originally Posted By jor-el:
Are we talking about ceilings or floors? Why would you want to know unless you're looking to evade the net?



On the contrary sir, I would be trying to stay within it based upon my theoretical question.
Link Posted: 10/26/2004 11:20:09 AM EST
The ASR9 (typical FAA terminal radar) tracks out to about 60nm. A plane should be able to be tracked at 100K ft as long as it is less than 60 miles away, and it is not in the RADAR's cone of silence (area above the radar sail).

Link Posted: 10/26/2004 11:20:18 AM EST

Originally Posted By Zaphod:

Originally Posted By Cold_Warrior:
Well, given that we use radar to track satellites I don't think altitude is a problem.

CW



Hell, we use radar to track SPACE PROBES, let alone satellites!


Just trying to keep it within the realm of understanding.

CW
Link Posted: 10/26/2004 11:20:40 AM EST
Link Posted: 10/26/2004 11:21:27 AM EST

Originally Posted By ar15bubba:
The ASR9 (typical FAA terminal radar) tracks out to about 60nm. A plane should be able to be tracked at 100K ft as long as it is less than 60 miles away, and it is not in the RADAR's cone of silence (area above the radar sail).




Cool,
thank's
Link Posted: 10/26/2004 11:24:53 AM EST
[Last Edit: 10/26/2004 11:25:15 AM EST by -M60_Gunner-]

Originally Posted By Cold_Warrior:

Originally Posted By Zaphod:

Originally Posted By Cold_Warrior:
Well, given that we use radar to track satellites I don't think altitude is a problem.

CW



Hell, we use radar to track SPACE PROBES, let alone satellites!


Just trying to keep it within the realm of understanding.

CW



Yeah but that's more the probes/satellites sending signals to the recievers on the ground right than it is radar stations sending radio waves intospace and bouncing them of the probes/satellites isnt it?.
Link Posted: 10/26/2004 11:38:07 AM EST
From what I recall of my IFR days, only ATC primary radar can track an aircraft without a transponder.

Also, if not transponder equipped, altitude is unavailable.

Link Posted: 10/26/2004 12:16:46 PM EST
[Last Edit: 10/26/2004 12:32:13 PM EST by 4get_No1]
It's a lot more complex than you might think but here's a summary:

Radar capability is expressed in several ways but a common way for overall sensitivity is called "loop gain". That is the "two-way" sum of;

1) signal gains (amplifiers to boost output strength and receiver sensitivity plus antenna gain - big antennas are better - to a great extent but there's more in a complex Radar)
and
2) signal losses (inefficiencies like heat, cable and waveguide losses, amplifier noise, and other simple losses such as atmospheric attenuation or background noise level).

Every Radar has different characteristics. The "two-way" part means it's not just the transmitter output power, it's also the receiver sensitivity. Make a big noise and listen for the echo sort of thing. A loud voice is good and hearing is even more important. The "loop gain" gets a bit more complicated in the details but as you can see, it's a constant and depends upon the Radar, not the target.

Now for the hard part - the target. Big target or small? Flat or round? Aluminum or fabric (a hot-air balloon doesn't reflect Radar very well). How far a given Radar can track depends upon the target too, not just the Radar.

In other words, not enough info to answer the question. However, there is no airplane including the Space Shuttle that can fly so high that altitude alone would make it hard to track with a good Radar. For reference, Google "AN/FPQ-14". They're about 30 year old technology and info in the public domain may surprise you.

<ETA - Well, I just picked "AN/FPQ-14" and THEN I Googled - not a lot to see. There should be quite a bit of info also available by looking at "AN/FPQ-6", "AN/TPQ-18", "AN/FPS-16" or "Eastern Range" or "Western Range".
Link Posted: 10/26/2004 2:39:45 PM EST
The two main Long Range Radars used today are the ARSR-4 (FAA) and the AN/FPS 117 (USAF).

General range goes out to about 250 miles depending on Altitude, Target size and Radar Cross Section (RCS).

Both radars are integrated into the Joint Surveillance System and are co-use by the FAA/Military.

Back to the original question. I've observed both the SR-71 and also the Shuttle landing at Edwards.

When the SR-71 flew, you've got to remember how fast it was going. it generally took about 3 large western states to execute a turn, and that would happen in a matter of minutes.

Also, both radars are considerd 3D. They provide Bearing, Range, and Altitude. No transponder is needed to detect altitude.

Cheers,
Landog
Link Posted: 10/26/2004 5:46:02 PM EST

Originally Posted By knightsar:
From what I understand the Sr 71 Flew so high and so fast nothing could touch it. The Russians tried

to shoot it down and failed. The Mig 25 was designed to shoot it down but was never successful. No

radar reaches out past the atmosphere.



Actually - the Mig 25 was designed to get with in 10miles of our Mach 3 Valkrie nuclear bomber and deliver its missle to it. But we scrapped the Valkrie before any where really made - as the ICBM delivered nukes even better.

The Russians didnt stop thier development of the Mig25 though and producted it.

And yes, the U2 and SR71 flew so high that nothing could touch it (other than that one U2 that got hit by a missle). If you are an SR71 pilot you get your astronaut wings for flying so high. And you wear a pressure suit.
Link Posted: 10/26/2004 6:35:09 PM EST
Having spent 25 years with various radars, I'll add my two cents worth.

From a National AirSpace Plan (NASP) point of view the civilain/military ATC radar coverage tops out around 60,000 feet but his varies with the aircraft's distance from the radar, as the antenna gain varies with altitude. It will be lower in places. IFF coverage is significatnly higher than that. Height finding radars can track you even higher. Also, the Earth is a globle and an aircraft's height above sea level may remain constant but the height above the radar does not. I have personally witnessed manned aircraft flying above 100,000 feet being tracked by radar and IFF.

There are special purpose military radars with performance that will greatly exceed these parameters. The CONUS has virtually 95% IFF coverage and about 85-90% radar coverage. Then there are holes in covergae because of physical inpediments such as mountains and weather effects.

I hope this helps,

Geno
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