[WAD] LRASM detection problems(?)

[erick33]

I'm not sure if this was intended, but I'm reporting it because I think it's questionable

LRASM has detected a problem that is detected at a greater distance than expected.
It is mainly detected by the IRST sensor of an aircraft or ship, and the distance is thought to be quite far. LRASM's IR detection distance is 0.7nm on the DB. However, the experiment showed that the aircraft could be detected at a distance of about 6 to 7nm at 36,000 ft, and the ship could be detected at a distance of more than 15nm.

I'm not sure if this is intended, but I'm reporting it in doubt.

[thewood1]

Just a quick data point:

1) 3rd gen IRST on the J-15s initial detection range 3.9nm at 36k ft
2) 2nd gen IRST on a J-11 initial detection range 0.1nm at 36k ft
3) 1st gen IRST on a Mig-25P no detection at 36k ft

So the detection of even low visibility units/weapons seems very dependent on the technology level of the detection IR sensor. It looks like there are some other dependencies as well.

[erick33]

Just a quick data point:

1) 3rd gen IRST on the J-15s initial detection range 3.9nm at 36k ft
2) 2nd gen IRST on a J-11 initial detection range 0.1nm at 36k ft
3) 1st gen IRST on a Mig-25P no detection at 36k ft

So the detection of even low visibility units/weapons seems very dependent on the technology level of the detection IR sensor. It looks like there are some other dependencies as well.

Yes, I understand, but as you can see in the picture, the Type 517H radar also succeeds in detecting LRASM at a distance of 16nm. Soon after this, the trap sensors also detect LRASM. It is true that some questions are raised about LRASM's stealth capabilities, so I hope the developers take a look

[thewood1]

"It is mainly detected by the IRST sensor of an aircraft"

OK...so now you are talking about radar, not IRST? Is there another sensor you are going to bring up?

[Dimitris]

This looks to be WAD.

LRASM's IR detection distance is 0.7nm on the DB.

The "reference" IR sensor used for the nominal IR detection range is the original LANTIRN, a pretty obsolete FLIR by today's standards. The IRST making detection here is a far more modern set (3rd generation IRST, 2000/2010s tech gen) and when it does pick up the missile it is observing it beam-on (side-on IR signature is much higher), so it's not a surprise that the detection happens at a much longer range.

and the ship could be detected at a distance of more than 15nm.

The LRASMs were picked up by the OFC-3 TV camera on the Fujian (Type 003) at ~15nm because they knew where to look. The contacts had already been detected by airborne assets, so the IR & visual sensors could do a cued narrow-sector search, which is more effective (and thus longer-ranged) than an uncued volume search.

So, not seeing anything unexpected.

[Dimitris]

Just a quick data point:

1) 3rd gen IRST on the J-15s initial detection range 3.9nm at 36k ft
2) 2nd gen IRST on a J-11 initial detection range 0.1nm at 36k ft
3) 1st gen IRST on a Mig-25P no detection at 36k ft

So the detection of even low visibility units/weapons seems very dependent on the technology level of the detection IR sensor. It looks like there are some other dependencies as well.

Yes, I understand, but as you can see in the picture, the Type 517H radar also succeeds in detecting LRASM at a distance of 16nm. Soon after this, the trap sensors also detect LRASM. It is true that some questions are raised about LRASM's stealth capabilities, so I hope the developers take a look

The Type 517H radar (a.k.a. P-10 "Knife Rest") is a low-frequency set explicitly selected for its counter-VLO properties. LRASM has a frontal RCS of -36.1 dbsm in the A-D spectrum (-46.1 dbsm in the E-M segment), so it can be detected at much longer range at low frequencies.

You never wondered why an otherwise thoroughly modern missile destroyer is fitted with a radar that originally entered service in the early 1950s? That's why.