Tracking military aircraft?

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screamin72

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So if they can't be tracked with SSR does civilian use primary radar I guess to coordinate aircraft from running into one another? Like when the Blue Angels come out here how do civial operators know where they are? Since they don't use ADS-B how would an F-18 show up on TCAS?
All aircraft seem to be transmitting a ICAO24 identifier in which military larger aircraft do transmit but sometimes they transmit position sometimes no. Sometimes they transmit a cal sign and sometimes no. Using software decoders on your ADS-B receiver you look up ICAO24 displayed and find out what it is. Positional data is voluntary for the military. As far as civil, I am not sure about the choice.

ACF54F is a ICAO24 which comes back to a Airbus A319 owned by Jet Blue.

Right now I don't see any military ICAO24 on RTL1090 to give a military example. They could be flying just not with MODE-S. They do turn it off. That's how they can be invisible. This makes sense to me because when they are doing practice missions in the air they want to simulate being invisible on radar flying low altitudes hence <3,000 ft above see level. I watched a K35R flying around at 2.900 ft while it's Mode-s was transmitting positional data. then I saw it just disappear mid-flight. I am only a few miles away from the flight pattern so I know they do turn it off completely.
 
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poltergeisty

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So an ATC radar site will have an IFF interrogator that constantly transmits to integrate military aircraft? Is IFF on 1030 MHz as well?

How does the F-22 Raptor or anly other jet for that matter use this IFF? I know the signal is encrypted but couldn't the mere fact that there is a RF signal be sent would indicate where the jet is at to the enemy?

Edit- I think I just figured it out. The ping is so fast that by the time the enemy sees a blip of RF energy the friendly is far away from that position. But that still gives away an approximate position, doesn't it?
 
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Token

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So an ATC radar site will have an IFF interrogator that constantly transmits to integrate military aircraft? Is IFF on 1030 MHz as well?

How does the F-22 Raptor or anly other jet for that matter use this IFF? I know the signal is encrypted but couldn't the mere fact that there is a RF signal be sent would indicate where the jet is at to the enemy?

Edit- I think I just figured it out. The ping is so fast that by the time the enemy sees a blip of RF energy the friendly is far away from that position. But that still gives away an approximate position, doesn't it?
You don't suppose a military aircraft, or civilian for that matter, would have the ability to shut off an IFF system? Or the system might have a selective ability to respond?

However, yes, IFF emissions have been exploited in the past to help target / find aircraft. For example, the SA-7/14 IR guided MANPAD operator had the ability to fit a supplemental passive RF antenna and headphones setup to his helmet, tracking RF emissions, including IFF, from potential targets.




With IFF the interrogation pulse is on 1030 MHz, the reply from the target is on 1090 MHz. There are multiple modes of operation defined, Mode 1, 2, 3/A, 4, and 5. Modes 1, 2, 4, and 5 are military only. Mode 4 and 5 are encrypted and have the ability to respond ONLY when interrogated by friendly forces. Going a bit further some modes can respond to only interrogations that the user sets as authorized, so not even all friendly military have the ability to get a response. And there is an additional Mode 5 encrypted mode called "lethal interrogation" that can be used as the final step before a hard kill, to try and prevent blue on blue issues.

And then there is basic EMCON (EMissions CONtrol), only turning such give away signals on when you want them on. Combine Mode 4 and 5 with EMCON and you have a pretty good ability to control who might be able to detect an IFF signal.

And no, the pulse is not so fast that it is not usable to the enemy. At the simplest level, if a pulse can be used by friendly's it can be equally used by enemies. And IFF response pulses travel at the speed of light, the aircraft cannot move far before the pulse is received.

T!
 
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poltergeisty

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You will have to forgive my ignorance. I was basing the idea about moving so fast that the pulse wouldn't be able to be received on a Yahoo answers question. They must be full of crap then. :lol:

I'm looking up EMCON right now. I want to understand what this is.

Edit- This is what I got. http://en.wikipedia.org/wiki/Radio_silence Seems simple enough. :lol: Kinda like what has been going on in the TNT show The Last Ship.

COOL! http://www.emcon.com/ Now I know the NSA won't see what I'm doing? HA!
 

Token

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EMCON (EMissions CONtrol), is the act or policy of controlling the emissions (primarily RF) of your platform to deny the use of those emissions by others.

For example, a warship (or aircraft) might have radars A, B, C and D on board, and might be the only single platform with that combination of radars. If an enemy sees (on their ESM or ELINT equipment) that combination of radars being radiated they know exactly what type of threat they face, even if they are not close enough to see the ship. But if radar B is also used by 100's of other radars and the ship only radiates that radar it can hide its identity.

Also, you can track a target by its emissions, the signals it transmits. You can plot its motions by tracking the RF emissions. Complete EMCON denies that ability, limiting you to active tracking methods (like your own radar, and giving away your location) or by direct site to track a target.


T!
 

poltergeisty

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It can still be tracked, as it is still a transmission.

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Don't you need a near field receiver to be able to even get a signal? After all the squawk code would be spread over several frequencies in a second. I read something on Wikipedia about NATO wanting to use FHSS, but the plan fell through I guess.I can't find where I read that.

After reading this perhaps DSSS is the way to go.

Also, for military apps, DSSS appears as 'noise' on a spectrum. Narrow band interferers, and signals can clearly be seen on a scope, as a 'spike'. DSSS simply increases the noise level by a small amount, meaning the 'enemy' does not even know someone is transmitting.
 
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Token

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Don't you need a near field receiver to be able to even get a signal? After all the squawk code would be spread over several frequencies in a second. I read something on Wikipedia about NATO wanting to use FHSS, but the plan fell through I guess.I can't find where I read that.

After reading this perhaps DSSS is the way to go.
Be careful with the term “near field”, it has a very specific meaning in the world of RF and no, you do not have to be anywhere near the near field to receive FHSS, or DSSS for that matter.

The immunity to detection (LPI, Low Probability of Intercept, when talking about radar and similar signals, like IFF) of FHSS and DSSS is often overstated. While both can be harder to find when talking about casual monitoring neither are particularly hard to find when that is the job at hand. With the right tools they are detectable at any usable level. Duty cycle and bandwidth leverage, power management, high receiver sensitivities, angle manipulation (bistatic), coherent detection, high gains and enhanced processing gain, optimal modulation techniques, all of these factors can be used in combinations to reduce probability of intercept. But anything that results in a usable signal for you, the source, also results in a usable signal for someone else, as soon as they understand the techniques you are using.

What does ESM stand for? Wikipedia doesn't seem to have it.
ESM = Electronic Support Measures.


T!
 
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