radar detection and practical stealth application

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by tank-top » 30 Oct 2018, 06:55

I don’t want to ask about any specific stealth aircraft or about any specific radar ability. Rather what is the practical ability of any given radar bandwidth to detect an object of any given size and at what distance? For instance the F22 has an RCS of 0.0001, obviously this is dependent upon many factors but what is the theoretical ability of a tracking radar to detect an object this size? I guess my real question is at what point has stealth defeated radars theoretical ability to track and lock a target, and theoretically how close are we based upon published data? There are lots of armchair warriors who want to say this system can beat that system, my question is what are the limits of physics behind the ability of any given system to actually perform its job and at what point do we practically negate that ability?


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by hornetfinn » 30 Oct 2018, 10:07

There are so many factors that it's impossible to say. Most important things are:

- Radar wavelength
- Radar output power (especially average power)
- Radar antenna gain
- Radar waveforms
- Radar receiver sensitivity
- Radar system losses and internal interferences
- Signal processing system (both hardware and software)
- External interference (clutter, jamming, atmospheric attenuation)
- Target RCS at any given moment (it varies a lot depending on orientation, external carriage etc)

Basic radar equation can give the best case detection range in optimal conditions against certain RCS target. If we go by that only, then any radar should detect stealth aircraft like F-22 or F-35 at some distance. That doesn't seem to be the case as there are statements that pretty advanced radars have been unable to detect them at all even if seen by naked eye. I think this is because the radar returns are so small that they get lost in the background clutter and other internal and external interferences.

Another thing is that the radar might've detected the stealth aircraft, but the operator would not know that. That's because the radar needs to actually track the target and that requires multiple detections before a track file is created. It might also be that track file needs further confirmation before a track is displayed. That's because otherwise the radar display would be littered with false targets and would make the system pretty useless. Because of this, tracking range is usually somewhat shorter than detection range, depending on what detection criteria is used and how advanced the system is.


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by Gums » 31 Oct 2018, 03:18

Salute!

Thanks, Hornet. You coverd a lot there.

i may also add that just the ground radar physical design is a player as your last point states.

If the antenna is rotating and not in a "stare" mode, then the operator might get a glimpse on one sweep and nothing on the next. Even with good sfwe, a decent "track" might not develop.

Many things about the VLO platforms besides raw RCS.

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by hornetfinn » 31 Oct 2018, 11:52

Thank you Gums, that's a good point about rotating antennas.

One thing about practical application of stealth vs. radar is that stealth interferes with all parts of engagement using radars as sensors.

1. It makes detection much more difficult in the first place
2. If detection is made, it makes track initiation more difficult
3. If tracking is initiated, it makes maintaining tracks more difficult
4. If track is maintained by the enemy radar system, it still makes missile engagement more difficult as radar guided missile will also go through the previous points 1 to 3
5. Then we have to remember that stealth makes countermeasures (EW, chaff) more effective as it's much easier to hide very low signature. This will affect all parts of engagement.

I see too often that when talking about theoretical detection ranges that F-35 or F-22 will be dead as soon as they reach the theoretical maximum detection range. That could not be further from the truth. In real life single detection is basically meaningless and just a starting point of any engagement.



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