Unsolved JASSM is missing targets
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@CheckPoint said in JASSM is missing targets:
What type of target ?
Control Tower building at Haeju, NK. They may have missed by 20 ft but not by miles, like OP reporting.
I’m using TR#13 with altered loadout. No threats in area so I just fly in behind them, and watch them slam into the ground floor of the bldg.
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@CheckPoint said in JASSM is missing targets:
From 25 to 14 nm, 20 000 ft
what JASSM range and alti, I mean.
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Never said miles… 50m is 50 meters. Did you think it was miles. And that wasn’t in OP. Screenshot in OP shows example of miss clearly it is not miles.
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@Hubert3000 You said “Big miss” and I couldn’t see anything else around for … idk, hundreds of meters? could be miles? I dunno. I’m just trying to help repro.
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I think I maybe have an idea.
When I’m assigning precision steerpoint, I’m doing it (mostly out of habit) the old way, using this button on the Recon window
If I open the data cartridge, I can see that it has set target steerpoint #4 (or #99 or whatever) appropriately.
But if I use this newer Target List pane, which pops up along with Recon window … maybe I’m doing it wrong? – I’m clicking ‘Assign’ and it looks like it assigned the control-tower to WP#4 but then it doesn’t show up in Data Cartridge window … and indeed my missiles hit a few hundred yards away, landing at non-precision-waypoint #4
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@airtex2019
The settings in the target list are just there to assign targets to different aircraft. They don’t produce precision steerpoints. When you arrive on target, you can see this clearly in your TGP, which is not exactly aligned.You have to use DESIGNATE AS TGT STPT in recon window. These are settings solely for the player.
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No, JSSM doesn’t depend on wind. It simply can’t be because there is nothing in the missile’s guiding code that take wind into account.
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@I-Hawk said in JASSM is missing targets:
No, JSSM doesn’t depend on wind. It simply can’t be because there is nothing in the missile’s guiding code that take wind into account.
OK, so pb is coming from something else.
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Hi @CheckPoint,
I would understand the effect of the wind direction and strength with a free fall bomb but I don’t understand this effect with a GBU weapon. Why don’t we observe this effect with a LGB and with a GBU-31? These weapons are always reaching their targets. A GPS-assisted weapon should compensate its flight path for external factors like the wind and “land” where we expect him to be. Is it possible that the JASSM is missing the target because of the (lack of) accuracy of GPS coordinates of the ground target? -
Intrigued, I took the opportunity to try out JASSM myself and found that I could only hit the target when I preset the precision SP from within the recon window as @airtex2019 showed. I found that if I changed the coordinates of the target SP while in flight using the coordinates from the TGP, it did not update to the new location and still hit the original pre-planned location. Also, it wouldn’t hit a new location that I point tracked with the TGP (without any update of the SP coordinates). My understanding was that with GPS weapons, the established SPI from any sensor (TGP, Ground Radar lock, HUD etc.) would become the target as kindly pointed out by @I-Hawk, but it doesn’t seem so in this case from my observations. Everything I did pointed to JASSM only targeting the pre-planned location set in 2D and the coordinates couldn’t be altered in flight. Is this the correct behavior for JASSM?
There was wind and I didn’t notice a wind factor, but didn’t look for it.
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@Atze-0 said in JASSM is missing targets:
The settings in the target list are just there to assign targets to different aircraft. They don’t produce precision steerpoints.
It’s not for me to say that’s a bug or by-design … but I will say, it’s a very confusing design – I can easily see how it would be a point of confusion, for folks.
Overlaid with other sources of confusion, like strong crosswinds and SPI delta from steerpoint / cursor-zero, etc.
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@Magnum1964 said in JASSM is missing targets:
with a free fall bomb but I don’t understand this effect with a GBU weapon. Why don’t we observe this effect with a LGB and with a GBU-31?
I’ve noticed JSOW range is pretty strongly affected by headwind and even crosswind.
LGB and JDAM are very heavy and falling mostly straight down, at terminal velocity… I think it would take hurricane force wind to blow them off course… if dropped from mid/high altitude.
But JASSM is a little jet-powered cruise missile that flies at M 0.9 … should be ok even in a hurricane. unless it flies directly through a tornado
Not sure where I’ve seen but I think real jet SMS/CNTL page does have some parameters to input estimated wind speed/direction. Presumably it just adds or subtracts to the computation of effective range / JIZ envelope.
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In my experience, on the fly targeting is best done by setting up the coordinates in stpt 81-99. I believe that the INS steerpoints are not meant for changing once in 3D
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@jayb
Worth to give this hint a try, yeah.Thanks for sharing it and with best regards.
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@foxster said in JASSM is missing targets:
while in flight using the coordinates from the TGP, it did not update to the new location and still hit the original pre-planned location.
I just did a quick check, and it seems ok to me – there may be some further nuance we need to drill down on?
What I did:
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TR#13, change loadout to JASSM … move waypoint 4 to near (but not on) airbase
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in flight: at distance ~30nm, activate TGP … note it’s aligned a few hundreds yards away from airbase, as expected
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slew TGP to target control tower … use “area-track”
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launch 2x JASSM
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observed: both hit the control tower
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expected: both hit the control tower
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@airtex2019 said in JASSM is missing targets:
It’s not for me to say that’s a bug or by-design … but I will say, it’s a very confusing design – I can easily see how it would be a point of confusion, for folks.
Overlaid with other sources of confusion, like strong crosswinds and SPI delta from steerpoint / cursor-zero, etc.
For more confusion: the manual says, you can make your normal steerpoints to precision steerpoint using the recon window (Designate as TGT STPT).
Best is to use Steerpoints 99 downwards for your GPS munitions.That normal steerpoints are not absolutely on target is a feature: before JDAMs were introduced, you had to align your target pod for lasing exactly like in real life.
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@airtex2019 Thanks for the feedback - based on your observation I had to assume I did something wrong (not surprising as I’m definitely still learning). I flew the op several times and kept getting the same results until I stumbled across what appears to have been my problem - altitude. I was having difficulty locking up the target with the TGP due to the sporadic clouds, so I was dropping below them at around 4-5k. At that low altitude I had to be doing over 360 knots in order to fire the JASSM. Because it’s self propelled, I didn’t think much of it being low, but it would miss completely, or at best overshoot the target by several hundred yards.
I re-ran the engagement at 20k which allowed a somewhat lower launch speed and used ground radar to obtain a lock if I couldn’t get the TGP to do it. It worked flawlessly each time hitting the designated targets perfectly.
I didn’t really find any technical specs on the JASSM in the manuals to find out about its parameters and limitations…is this a newer addition to BMS or am I just really missing something?
Something I must say I love about BMS is this attention to fine detail which gives different results by taking all parameters into account. Nice job as always Devs - this is the stuff that keeps it interesting!
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@foxster Ah, another layer of potential confusion!
Yes they do fly a slightly descending glide path, as noted above in the thread … just 1-2 degrees downward, I think. But that could be enough to limit range, if dropped from low alt. (review acmi)
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@Hubert3000 said in JASSM is missing targets:
@I-Hawk said in JASSM is missing targets:
@Hubert3000 said in JASSM is missing targets:
@I-Hawk said in JASSM is missing targets:
Hi,
Are you guys launching the weapon always when it’s in “RDY alignment” state?
Yes. As stated in OP other GPS guided weapons working and JASSM was working in previous bms versions, that rules a few things out. Clearly a bug IMO but if no one else is seeing it then it’s a weird one.
And I tried stock CPU settings as I have OCed CPU as I suspected same result so it’s not that if that is next question lol. Ram, GPU on stock.
Anyway not a huge issue if no one else is seeing it just thought I’d mention it.I’ll try to test myself later thanx.
Some more questions - When you say other weapons are working, does that include other similar weapons - i.e GPS guided with motor? or maybe only gliding weapons like JSOW or SDB?
Yes everything working right except JASSM.
Edit: Tested non F-16 as pilot.
Typhoon with Stormshadow
EF-18 with Taurus
Rafale with Apache and Scalp
All missing going off target. Didn’t notice as I never fly these planes or use these weapons. Any other GPS guided powered munitions in game?These missiles are also dropping altitude slowly as they fly to target like JASSM.
For Taurus and Stprm Shadow I figured that the guidance selected was different. It used TV and not IR and was different from JASSM. The missiles were flying to the target area, but came down in the middle of nowhere. When I changed the guidance of the weapons they were working properly.
The TV guidance probably required datalink support (man in the loop).
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Balkans, same problem with AI launched missiles. Sead escort to b-2 loaded with jassms, all missed targets.