AGM-114L: LOBL vs. LOAL

[Flagrum]

The radar Hellfire will use LOBL if the range is less than 2.5 km OR if it is a moving target. But how does the missile know if it is a moving target?

If the target is closer than 2.5 km, it will lock right on anyways and should not really have to worry if the target is moving or not. But what if the target is further away? It will default to LOAL - until it knows the target is moving and then enter LOBL mode. But how does this "knowing" actually work? I assume, the helo has to tell the missile, right?

Do I have to use MTT or LMC? Just manually following the target will probably not do the trick?

 

[Hobel]

vor 2 Stunden schrieb Flagrum:

The radar Hellfire will use LOBL if the range is less than 2.5 km OR if it is a moving target. But how does the missile know if it is a moving target?

If the target is closer than 2.5 km, it will lock right on anyways and should not really have to worry if the target is moving or not. But what if the target is further away? It will default to LOAL - until it knows the target is moving and then enter LOBL mode. But how does this "knowing" actually work? I assume, the helo has to tell the missile, right?

Do I have to use MTT or LMC? Just manually following the target will probably not do the trick?

 

My current assumption would be that the TADS only transmits a specific coordinate as the missile flies to the last Data Target point and does not fly an intercept course.
I would assume that the FCR, when it comes later, has the ability to transmit a specific intercept point based on the speed and direction of the target

wild guess on my part

Edited May 27, 2023 by Hobel

[pii]

3 hours ago, Flagrum said:

until it knows the target is moving and then enter LOBL mode

That is not likely since LOBL stands for lock On BEFORE launch.

[Flagrum]

1 hour ago, pii said:

That is not likely since LOBL stands for lock On BEFORE launch.

Yes, before launch. If my target is beyond 2.5 km, the default mode is LOAL. But if the target is moving, the missile will use LOBL. So, how does the missile know that it is supposed to lock on before the launch if the target is farther away than 2.5 km? How does it know that the target is moving?

[admiki]

8 minutes ago, Flagrum said:

Yes, before launch. If my target is beyond 2.5 km, the default mode is LOAL. But if the target is moving, the missile will use LOBL. So, how does the missile know that it is supposed to lock on before the launch if the target is farther away than 2.5 km? How does it know that the target is moving?

Helicopter is telling missile that target is moving by the motion of TADS ( I'm guessing FCR will be able to give same information).

[NeedzWD40]

The seeker can see moving targets out to 8km. When you use TADS, if the TADS is showing variances in angular momentum (varying laser range, significant varying slew rate), it commands the missile seeker into one of the submodes that looks for a moving target. If it finds one where the TADS is looking, it shifts to LOBL. Think of it like the close in radar modes in fighters like PAL and PLM. It's the same doppler processing as done with any other radar system.

[Hobel]

vor 34 Minuten schrieb NeedzWD40:

The seeker can see moving targets out to 8km. When you use TADS, if the TADS is showing variances in angular momentum (varying laser range, significant varying slew rate), it commands the missile seeker into one of the submodes that looks for a moving target. If it finds one where the TADS is looking, it shifts to LOBL. Think of it like the close in radar modes in fighters like PAL and PLM. It's the same doppler processing as done with any other radar system.

hm interesting, but the missile still flies to the last marked point and does not intercept where the target would be expected.
in DCS the moving target should still be in the field of view of the Hellfire, the missile performs an Sudden unsightly turn to the target.

[NeedzWD40]

10 minutes ago, Hobel said:

hm interesting, but the missile still flies to the last marked point and does not intercept where the target would be expected.

Are you getting a solid large box with a LOBL indication? Bear in mind the seeker needs to have a good view of the target, ie if you're looking slightly to the right and your missile is coming from the left wing, it likely won't be able to see.

[NeedzWD40]

I need to do some more testing, because it seems that LOBL can still result in a DBS trajectory on a moving target when it shouldn't. However, I had no misses in testing despite this.

 

 

[Poptart]

4 hours ago, Hobel said:

My current assumption would be that the TADS only transmits a specific coordinate as the missile flies to the last Data Target point and does not fly an intercept course.

In game, I think it does when you have a human CPG using LMC. George seems not to pass the computer an intercept course for moving targets.

[Hobel]

vor einer Stunde schrieb NeedzWD40:

Are you getting a solid large box with a LOBL indication? Bear in mind the seeker needs to have a good view of the target, ie if you're looking slightly to the right and your missile is coming from the left wing, it likely won't be able to see.

Okay, you're right, LOBL works perfectly for moving vehicles and Planes!

 

Even flies a good intercept course as you wish:

 

Edited May 27, 2023 by Hobel

[NeedzWD40]

A couple other findings: If the target is going less than 14 knots, the missile will go LOBL and give a big box, but sometimes it will shift to DBS. I suspect this is some oddity with a notch or some such. Further, trying to track a target like George does with no LMC or IAT results in no big box and no hits, which goes in tune with what I'd anticipate, with improper angular data being fed into the seeker, so this is likely why George doesn't do quite so well with them. I never got the big box and MSL TRACK indication when using him.

[admiki]

1 hour ago, NeedzWD40 said:

Are you getting a solid large box with a LOBL indication? Bear in mind the seeker needs to have a good view of the target, ie if you're looking slightly to the right and your missile is coming from the left wing, it likely won't be able to see.

I never get big box. Only LOBL NORMAL on HAD.

[NeedzWD40]

1 hour ago, admiki said:

I never get big box. Only LOBL NORMAL on HAD.

Do you have a short clip of how you're doing it? My procedure has been to get good LMC, IAT, then solid laser and hold the laser until I get the large box and MSL TRACK message. Sometimes I need to yaw slightly left or right to give the seeker a good view, but LOBL also takes a couple seconds longer to go full acquisition.

[GrEaSeLiTeNiN]

9 hours ago, Flagrum said:

Yes, before launch. If my target is beyond 2.5 km, the default mode is LOAL. But if the target is moving, the missile will use LOBL. So, how does the missile know that it is supposed to lock on before the launch if the target is farther away than 2.5 km? How does it know that the target is moving?

When beyond 2.5km, if you move your TADS cursor manually even when the crosshairs are just pointed at the ground (no target, let alone IAT or LMC), it transitions from LOAL to LOBL after lasing for target data is completed. Not sure how it is IRL though.

[AvroLanc]

9 hours ago, admiki said:

I never get big box. Only LOBL NORMAL on HAD.

I believe the missile does 3 LOBL attempts of 3 seconds each. So after a max of 9 seconds you’ll get either a LOBL BOX and RF MSL TRACK or a NO AQUIRE if the seeker can’t find the LOBL target.