JDAM progress

Will it be possible to load coordinates through TGP container ?

They've already said that it's not going to work this way for the Harrier. Must not have been a normal thing. JDAMS are used on stationary targets and LGB's are used on moving targets and stationary targets.

They've already said that it's not going to work this way for the Harrier. Must not have been a normal thing. JDAMS are used on stationary targets and LGB's are used on moving targets and stationary targets.

But what prevents finding a stationary target through a TGP container and loading coordinates into JDAM. As now on the A-10C and F-18C.

But what prevents finding a stationary target through a TGP container and loading coordinates into JDAM. As now on the A-10C and F-18C.

Quote!

The TGP isn't fully integrated into the harrier IRL from what I have read.

Husker, perhaps the real harrier's avionics were simply not modified to work like the A10C or FA18 when using JDAMs.

This could possibly be because the United States Marine Corps only had enough funding to implement certain features deemed more critical than self-designation of JDAM targets. As an example: In a conventional war, the harrier is generally employed far more often in Close Air Support of friendly troops (who are designating which targets to hit, possibly via the CAS page), whereas the Hornet may go deeper into enemy territory where it must find it's own targets for JDAM via radar or target pod. The different missions drive the priority of system development.

The basic interface we currently see for JDAM employment in the harrier (compared to the more comprehensive Hornet) suggests that JDAM use was developed in each aircraft separately despite both aircraft sharing common avionic lineages.

I am quietly hopeful that once a markpoint is added, it can be moved like a waypoint in the EHSD data page. In this way you could dynamically designate JDAM targets.

I know I saw some where that there's a security concern preventing direct JADAM coordinate entry. Of course, now I can't find it anywhere.

I know I saw some where that there's a security concern preventing direct JADAM coordinate entry. Of course, now I can't find it anywhere.

Probably more of a fat finger problem... Cite the bombing of the Chinese embassy in Yugoslavia... "But it only happened twice"

But what prevents finding a stationary target through a TGP container and loading coordinates into JDAM. As now on the A-10C and F-18C.

My understanding on all this is the following.

You are basically talking about TOO mode, which didn't work on early harriers because they couldn't set the relative BIT on the bomb due to software integration issues. I presume this must have been fixed at some later date (don't know specifically). There were workarounds mentioned, specifically punching in the coordinates, and another PITA way of doing it. The issue with using the TGP is that it cannot generate high quality targeting data in "absolute mode" beyond about 6nm due to a variety of errors detailed in "a paper". Of course this isn't modeled at all in DCS Harrier since we don't have an actual INS simulation, so all coordinates are perfect.

My understanding on all this is the following.

 

You are basically talking about TOO mode, which didn't work on early harriers because they couldn't set the relative BIT on the bomb due to software integration issues. I presume this must have been fixed at some later date (don't know specifically). There were workarounds mentioned, specifically punching in the coordinates, and another PITA way of doing it. The issue with using the TGP is that it cannot generate high quality targeting data in "absolute mode" beyond about 6nm due to a variety of errors detailed in "a paper". Of course this isn't modeled at all in DCS Harrier since we don't have an actual INS simulation, so all coordinates are perfect.

I remember reading in Air Forces Monthly in 2015 (and I later found some over publication online) that the Super Hornet was newly cleared to self generate target coordinates for JDAM.

It was something new in 2015. In the online publication they also tester the Super Hornet generating coordinates and passing it to Legacy Hornet.

So it seems that generating targets coordinates from the plane doesn’t seem as easy to do as in the game.

If someone works on Hornet or Super Hornet you’re welcome to correct if I’m wrong :smilewink:

But what prevents finding a stationary target through a TGP container and loading coordinates into JDAM. As now on the A-10C and F-18C.

AFAIK, Nothing other than lack of info as the Tac Manuals available on the internet pre-date JDAM use.

‘Avengers’ unleash wrath with historic JDAM strike

===============================

By Sgt. Anthony Guas, November 9, 2006

 

AL ASAD, Iraq -- Since Nov. 10, 1775, Marines have carved their place in the history books and the “Wake Island Avengers” of Marine Attack Squadron 211 recently wrote a another page of their own.

 

The Avengers successfully conducted the first all AV-8B Harrier strike using Joint Direct Attack Munition bombs, Nov. 9, 2006.

...

“We are using Block 4 JDAM, which is able to use relative targeting,” explained Anderson. “The plane has new software which enables relative targeting. In simple terms, this means being able to put the targeting pod cursor on the target and then the software transfers those coordinates to the JDAM.”

...

https://www.2ndmaw.marines.mil/News/Article-View/Article/522816/avengers-unleash-wrath-with-historic-jdam-strike/

The TGP isn't fully integrated into the harrier IRL from what I have read.

Even before the software upgrade, when the Harrier was using H2.0 and couldn't use relative targeting, the TPOD refined a target's position with sufficient accuracy (+/-13m) once within 6 NM slant range and most JDAMS are dropped at closer distances.

An Analysis of Target Location Error Generated by the Litening Pod as Integrated on the AV-8B Harrier II, 2005

https://pdfs.semanticscholar.org/2915/792e3b6b0e3772bb61c35e3a336311e7887a.pdf

AFAIK Razbam are modelling elements of software H4.0

Relative mode is a different JDAM mode altogether. As long as the target's position relative to the aircraft is accurate, a resulting bomb drop is accurate, despite any errors ownship has in it's own positioning. This is the data a JDAM COULD use. JDAM doesn't JUST use absolute coordinates. It is capable of using translational data to cover a known slant range and bearing from ownship to the target without knowing the absolute coordinates of the destination.

The problem with the Harrier is a programming error in TPOD integration means some versions of the Harrier do not generate relative data, rather uses the TPOD to infer a set of coordinates and uses absolute targeting, meaning ownship errors are carried through to the targeting solution, and JDAMS are used in an absolute manner.

All aircraft when generating realtive targeting info suffer this inaccuracy, not just the Harrier. Corrective measures now allow TOO type (relative) operation of JDAMS. Since we do not really have a specific variant of the Harrier modeled (it's a "FrankenHarrier" we have modeled), it's difficult to predict whether this feature will be implemented.

Here's a great paper I found on the subject if you're ok with some academic reading.

https://pdfs.semanticscholar.org/2915/792e3b6b0e3772bb61c35e3a336311e7887a.pdf

EDIT: Jeese I just read the post before mine and saw the same two links shared. Consider my post supplemental and I apologize for the redundancy

Thanks for the clarifications guys, this is very interesting, especially the "relative mode" :thumbup:

Hello folks.

Some points on the JDAMs on the AV-8B (all versions).

1. No, It is not possible to input target coordinates directly using the UFC/ODU.

2. SOP is for the aircraft to fly with the JDAM targets loaded along with the flight plan when the aircraft starts.

3. Yes, you can attack TOOs with JDAMs. The process is a bit lengthy and do require overflying the target at least once. It also requires the TPOD.

4. JDAMs are always used in AUTO mode. There is no manual release mode.

5. JDAMs release cannot be configured by the pilot. All he can do is select fuzing method.

6. The AV-8B only releases on bomb per target. If a target needs multiple strikes, then several targetpoints will have the same position.

7. You release as many bombs as selected targets.

8. We used the CAS page because it is the only one that is documented. There are other ways to input JDAM targets on the aircraft but those are classified.

JDAM HUD Symbology

Here is a sample of the HUD symbology that is used when JDAMs are selected:

1. The targets:

Seven targets selected at an enemy airbase.

2. Target Selection

Now we have selected four of them for JDAM strike.

3. HUD JDAM page

The HUD symbology is based on real aircraft symbology.

Selected targets are displayed below the range circle. The target list is always being sorted based on range, with the nearest ones being first.

The center dot represents the position of the targets centroid.

A centroid is the center of a geometric figure. In this case it is the center of the geometric figure formed by the selected targets.

The center dot will provide steering cues for flying towards the centroid.

JDAMs use a concept called Launch Acceptability Region, which is the area where the bombs can be released and expected to hit the target. LAR calculation depends on several parameters.

The circle represents the Maximum LAR value.

The small triangle represents the Minimum LAR value. Its position is relative to the maximum.

The N indicates if terminal parameters (strike angle, heading and velocity) are not being used. If terminal parameters are being used then a T will be shown.

Terminal parameters affect LAR values calculation.

When there are several targets, the LAR values used in the HUD are for the first target in the list.

3. In range

When the aircraft is inside the LAR the following happens:

1. Those targets that are inside the LAR are shown in a larger font.

2. An inner circle, indicating range to target appears. Its edge indicates how far inside the LAR the aircraft is

Since ALL bombs will be released when pressing the circle it is best to wait until ALL targets are in range.

SOP is to release the bombs when in the middle of the LAR. That is when the range cricle edge is exactly a the half position between the top of the circle and the small triangle.

2. SOP is for the aircraft to fly with the JDAM targets loaded along with the flight plan when the aircraft starts.

That means that the function to load the coordinates from the F10-map into the aircraft is only available on ground? I ask because in the short video Decoy posted 1-2 days ago, he did that in the air, iirc. I assume, that was due to the WIP nature of the feature?

That means that the function to load the coordinates from the F10-map into the aircraft is only available on ground? I ask because in the short video Decoy posted 1-2 days ago, he did that in the air, iirc. I assume, that was due to the WIP nature of the feature?

No. It is availble both in the ground and in the air. But when in the ground it will automatically assign the first four to the aircraft's targetpoints

Hello there,

In the future, will it be possible to enter JDAMs target coordinates with UFC/ODU when it will be possible to create/edit targetpoints and when UTM coordinates will be available for the Harrier ?

Hello there,

 

In the future, will it be possible to enter JDAMs target coordinates with UFC/ODU when it will be possible to create/edit targetpoints and when UTM coordinates will be available for the Harrier ?

Already been said repeatedly. Read before you post.

Hello there,

 

In the future, will it be possible to enter JDAMs target coordinates with UFC/ODU when it will be possible to create/edit targetpoints and when UTM coordinates will be available for the Harrier ?

Sounds like a NO. On that. It may seem a bit weird for dcs, but i assume those coordinates are being provided a data link IRL, and thats maybe what the f10 map coords are supposed to simulate?

Hello folks.

Some points on the JDAMs on the AV-8B (all versions).

1. No, It is not possible to input target coordinates directly using the UFC/ODU.

2. SOP is for the aircraft to fly with the JDAM targets loaded along with the flight plan when the aircraft starts.

3. Yes, you can attack TOOs with JDAMs. The process is a bit lengthy and do require overflying the target at least once. It also requires the TPOD.

4. JDAMs are always used in AUTO mode. There is no manual release mode.

5. JDAMs release cannot be configured by the pilot. All he can do is select fuzing method.

6. The AV-8B only releases on bomb per target. If a target needs multiple strikes, then several targetpoints will have the same position.

7. You release as many bombs as selected targets.

8. We used the CAS page because it is the only one that is documented. There are other ways to input JDAM targets on the aircraft but those are classified.

@Zeus

On point #1, is there any IRL rationale for that?

@zeus, this looks really well researched, and your aircraft is the only one with simultaneous drop modeled. Kudos to you and your team for this. It's much more than I expected when you said you were going to implement JDAMS.

My question is on terminal attack parameters. You said the pilot is only able to select fuzing. Is it possible to set the attack parameters in the mission editor, or will this feature not be modeled?