AGM-114L Guidance

[Mad Dog 762]

I know we won't get the AGM-114L (Radar) for a while, but I am curious how this missile works.  Obviously it works with the fire control radar, which gives it rough directions, then does it have an onboard seeker that kicks on?  Or does it get continuous guidance from the aircraft radar?  I am under the impression you can do a radar sweep, then go back under cover and ripple off the Hellfires, right?  

On a related note, I was very surprised to see that the Hellfire is apparently in its last year of manufacture, to be replaced by the JAGM (Joint Air Ground Missile), which will apparently incorporate all the functions of all the Hellfire versions into one missile?  

[Ignition]

I'm also curious about this missile since it will be the first A/G radar guided weapon in the game.

I guess this weapon should be best employed for isolated targets and I don't think it's very good for moving targets since it could track an unwanted vehicle.

[FalcoGer]

It probably has both LOAL and LOBL capabilities. In the former case it shouldn't be too big of an issue to shoot a moving target. Even so if the information on wikipedia is to be believed the missile does mach 1.3. Even at max range the missile reaches the target in 1 second. I don't think you can go very far in an armored vehicle in one second. CA max speed is 40 mph, at that speed you can go about 17 meters in one second. I don't think that's a problem, really.

[drPhibes]

1 hour ago, FalcoGer said:

Even so if the information on wikipedia is to be believed the missile does mach 1.3. Even at max range the missile reaches the target in 1 second.

How did you come up with that number? If the data on wikipedia is accurate (which it probably isn't, but let's just say it is for the sake of simplicity), the maximum range of the 114L is 8000m. Mach 1,3 = 450m/s. If the missile flew at a constant velocity (which it doesn't, but these are ballpark figures), the time of flight at max range would be around 18 seconds. Then add a few seconds for the acceleration phase, and you're looking at ~20 seconds.

[RodBorza]

3 hours ago, Mad Dog 762 said:

I know we won't get the AGM-114L (Radar) for a while, but I am curious how this missile works.  Obviously it works with the fire control radar, which gives it rough directions, then does it have an onboard seeker that kicks on?  Or does it get continuous guidance from the aircraft radar?  I am under the impression you can do a radar sweep, then go back under cover and ripple off the Hellfires, right?  

On a related note, I was very surprised to see that the Hellfire is apparently in its last year of manufacture, to be replaced by the JAGM (Joint Air Ground Missile), which will apparently incorporate all the functions of all the Hellfire versions into one missile?  

It has both LOAL and LOBL capacity.

LOBL is the easy one. You keep target lock all the way, since detection, launch, and terminal guidance. Similar to launching a Sparrow missile. You need guidance all the way.

In LOAL, you can pop-up, sweep the targets, go back in to hiding, ripple the missiles. But the missile does not guide itself on the terminal phase. At least, as far as I know. 

You need to pop-up again, lock the target, and give it terminal guidance. The pilots receive a counter when releasing weapons, so when it is 10 seconds to impact, the pilot must pop-up, and illuminate the target. The missile seeker sees this radar return and locks into it. 

Of course, the missile is not dumb. When released, the Fire Computer gives the missile the general area where the target is located, so the missile knows what kind of loft trajectory it must make in order to hit the target. It is said that if the helicopter radar lock is lost, the missile switches to its own internal radar and guides to the target. I really don't know about this, as far as I knew about Hellfire missiles, they needed the terminal guidance illumination in order to fine tune the target location (i.e., in case the target has moved) and to activate the fuse. 

The Longbow system is a very advanced system that most people take for granted. It is very complex, lots of heavy mathematics involved (the kind you go through school thinking it is boring and unimportant until you discover that most military systems make a heavy use of them).

And that millimeter wave radar is a thing of beauty. Autonomous cars use millimeters wave radars for obstacle avoidance, since this kind of radar has great resolution. But they don't have much range, since atmospheric attenuation of signal is heavy at these radar bands. How do they implement a high resolution radar over great distances and bad weather must be a very well kept secret.    

 

[NeedzWD40]

6 minutes ago, RodBorza said:

It has both LOAL and LOBL capacity.

LOBL is the easy one. You keep target lock all the way, since detection, launch, and terminal guidance. Similar to launching a Sparrow missile. You need guidance all the way.

In LOAL, you can pop-up, sweep the targets, go back in to hiding, ripple the missiles. But the missile does not guide itself on the terminal phase. At least, as far as I know. 

This is only for the SAL missiles. RF missiles are autonomous once launched and require no further input once launched. LOBL vs LOAL modes for RF missiles are primarily dependent on target distance, motion, and acquisition source. Dumbed down, it can basically be said stationary = LOAL or LOBL; moving = LOBL only.

4 hours ago, Mad Dog 762 said:

On a related note, I was very surprised to see that the Hellfire is apparently in its last year of manufacture, to be replaced by the JAGM (Joint Air Ground Missile), which will apparently incorporate all the functions of all the Hellfire versions into one missile?

Yes, this is the plan. The old JCM program was originally going to be a tri-seeker, but this was complex and expensive. JAGM is MMW and SAL, while the JCM had MMW, SAL, and IIR.

[Raptor9]

The intracacies of the 114L guidance is sensitive in nature. But there is most likely plenty of open source info out there that talks about it in some form or fashion.

Edited November 2, 2021 by Raptor9
Spelling is hard sometimes

[Mad Dog 762]

There is some info in the -10.  Pretty light overview, but I found out a few interesting things.  The missile does have its own active seeker, and can be locked on before firing.  It does receive updates from the Apache radar as well.  Radar missiles are loaded on the outer rails as much as possible, and staggered side to side to prevent their radars from interfering with each other.  

I also found some interesting restrictions on the rockets subsystem, according to manual I have, they cannot be fired from the inner stations, or fired more than 2 at a time (1 per side) due to engine ingestion problems.  Looking through some Apache pics, I note that with a mixed loadout it is more common to have the rockets on the outer pylon, but there certainly are a lot cases where they are on the inner.  Plus, if they are restricted from the inner pylons, it would not be possible to have 76 rocket loadout.  Interesting.  We will see how DCS does it.   

[NeedzWD40]

3 hours ago, Mad Dog 762 said:

I also found some interesting restrictions on the rockets subsystem, according to manual I have, they cannot be fired from the inner stations, or fired more than 2 at a time (1 per side) due to engine ingestion problems.

It isn't that they can't, just that it generally isn't advisable to do so unless in exceptional circumstances. The reason is more due to the introduction of the Mk66 Hydra rocket motor, which has a hell of a lot more impulse and resulting exhaust gasses compared to the old Mk40 (note the AH-64 has software to shoot both motor types... or did). This is also why you see some AH-1Fs with the shroud on the underside if the engine intakes: they had similar engine surging problems when the Mk66 motors were introduced. So as long as your firing schedule isn't too rapid or you're in forward flight (similar to the Russian S-8 series of rockets), there's really no issues.

[MoarDakka]

On 11/2/2021 at 12:04 AM, NeedzWD40 said:

This is only for the SAL missiles. RF missiles are autonomous once launched and require no further input once launched. LOBL vs LOAL modes for RF missiles are primarily dependent on target distance, motion, and acquisition source. Dumbed down, it can basically be said stationary = LOAL or LOBL; moving = LOBL only.

Yes, this is the plan. The old JCM program was originally going to be a tri-seeker, but this was complex and expensive. JAGM is MMW and SAL, while the JCM had MMW, SAL, and IIR.

As far as I know JAGM is pretty much now just an AGM-114R with the new dual mode seeker. It's not that impressive compared to earlier plans. Brimstone 2 looks more capable due to the better rocket motor it has (greater range).

Edited November 5, 2021 by MoarDakka

[FalcoGer]

On 11/2/2021 at 3:01 AM, drPhibes said:

How did you come up with that number? If the data on wikipedia is accurate (which it probably isn't, but let's just say it is for the sake of simplicity), the maximum range of the 114L is 8000m. Mach 1,3 = 450m/s. If the missile flew at a constant velocity (which it doesn't, but these are ballpark figures), the time of flight at max range would be around 18 seconds. Then add a few seconds for the acceleration phase, and you're looking at ~20 seconds.

I don't know where I went wrong. A bit embarrassing really.

I blame the imperial system. Makes everything needlessly complicated.

[DaemonPhobos]

En 1/11/2021 a las 21:09, FalcoGer dijo:

It probably has both LOAL and LOBL capabilities. In the former case it shouldn't be too big of an issue to shoot a moving target. Even so if the information on wikipedia is to be believed the missile does mach 1.3. Even at max range the missile reaches the target in 1 second. I don't think you can go very far in an armored vehicle in one second. CA max speed is 40 mph, at that speed you can go about 17 meters in one second. I don't think that's a problem, really.

The missile leaves the rail at approximately mach 1.4, but it takes around 36 seconds to get to it's max range, depending on temperature.

Additionally, once the missile is fired, there is no connection between the aircraft and the missile.

The missile will either use it's own mmW radar when LOBL( always LOBL when it's a moving target), or use inertial data provided by the WP/MP for LOAL, then attempt to acquire the target in flight using its own radar.

[FalcoGer]

Is the missile smart enough that if you fire it say on an air defense target LOAL that it will distinguish it from a tank that's standing next to it or is it more like a harpoon that you fire in a general direction and it goes for whatever it deems a target mostly at random?

[DaemonPhobos]

hace 16 horas, FalcoGer dijo:

Is the missile smart enough that if you fire it say on an air defense target LOAL that it will distinguish it from a tank that's standing next to it or is it more like a harpoon that you fire in a general direction and it goes for whatever it deems a target mostly at random?

The missile should be able to engage the correct target as long as it has an acceptable RCS and matches the target parameters loaded in the programmable signal processor/REU, in case it's not capable of finding the target once fired, it may go for a secondary target assigned by the WP.

The missile receives the following info from the Weapons professor:

Target status: "ID, target type (air/ground), and LOBL inhibit on or off" ,Target detection time ,Target update time ,Target NED (north east down) position, Updated NED position,Target NED velocity,
Crossrange,Height, Range,Range rate, Cross-range: and Aircraft time at request.

It uses all of this information to inertially guide itself to the target until it can lock it with its own mmW radar.

[bies]

On 11/5/2021 at 9:26 PM, FalcoGer said:

I don't know where I went wrong. A bit embarrassing really.

I blame the imperial system. Makes everything needlessly complicated.

Where you were wrong? You have written Hellfire missile is reaching the target at max range in 1 second (!) so the target is going to travel only 17 meters from the launch of the missile to the impact...

It's not about any imperial system measure or anything, it's the lack of the most basic understanding or at least some common sense, and i don't want to sound rude.

Without calculating anything the common sense should tell you crossing ~8km in 1 second at ~ground level is utterly impossible, it would require some extreme hypersonic flight ~Mach=24, close to Earth's escape velocity, in the most dense atmosphere. Let alone missile needs to accelerate and engine burn time is limited so the overall average speed on max distance is way smaller than missile's max speed.

[Mad Dog 762]

23 hours ago, DaemonPhobos said:

The missile receives the following info from the Weapons professor:

 

I am wondering where we carry the Weapons Professor?  Is there another seat in the back or is he strapped to one of the pylons? 

[DaemonPhobos]

hace 4 horas, Mad Dog 762 dijo:

I am wondering where we carry the Weapons Professor?  Is there another seat in the back or is he strapped to one of the pylons? 

Lol, autocorrect failure, I will leave it that way because lazy

Now seriously, weapons processor 1 is mounted on the left EFAB center door 5L160.

Weapons processor 2 is mounted on right forward EFAB door 5R86 (you can see this door opened often on FARPs since the Sideloader is there as well.)

This is completely abstract for DCS purposes and only informative.

WP1 top, WP 2 bottom picture.

Edited November 8, 2021 by DaemonPhobos