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[RESOLVED] B1825.15 Ballistic Missile Intercept Calculations Failing
Posted: Sun Apr 05, 2026 5:45 pm
by 4Emprah
The calculations for trying to intercept incoming ballistic missiles does not seem to work for the GBI batteries. As seen in the attached scenario, the launchers will not even attempt an intercept (Fort Greely) or attempt to lead the target so far ahead that the GBI missiles will guarantee a miss (Vandenburg SFB).
Re: B1825.15 Ballistic Missile Intercept Calculations Failing
Posted: Sun Apr 05, 2026 6:49 pm
by Nikel
I have tested in previous builds.
The interceptors from Vanderberg did this turn to impact the incoming RV in B1662.
I had to change the db to v512.

- w1662.gif (705.22 KiB) Viewed 378 times
Re: B1825.15 Ballistic Missile Intercept Calculations Failing
Posted: Sun Apr 05, 2026 11:06 pm
by 4Emprah
I'm thinking it might be an altitude issue, with how high the ICBM apogee is and what the interceptors say they can reach. The missile is up around 2,800 km at the area I imagine the Fort Greely interceptors would be used:

- Screenshot 2026-04-05 185250.png (15.94 KiB) Viewed 352 times
The GBI [CE-II Blk, GMD] has a listed engagement altitude of 2,000 km:

- Screenshot 2026-04-05 185448.png (3.54 KiB) Viewed 352 times
At a glance it seems like the ICBM is climbing too high, but I am not an expert on ballistic mechanics.
Re: B1825.15 Ballistic Missile Intercept Calculations Failing
Posted: Mon Apr 06, 2026 7:12 am
by blu3s
This is an issue with the GBI propulsion elements from the DB. IIRC, this is fixed for next DB update, DB516
Re: B1825.15 Ballistic Missile Intercept Calculations Failing
Posted: Sun Apr 26, 2026 2:17 pm
by Nikel
Tested in B1852 with db v516, the GBI interceptors will turn now to impact the incoming missile. So it is fixed.
Tested also in the new build, without updating the db of the scenario, and the turn may happen or not.

- v516.gif (2.51 MiB) Viewed 243 times
Re: B1825.15 Ballistic Missile Intercept Calculations Failing
Posted: Tue Apr 28, 2026 1:18 am
by Mark352
Nikel wrote: Sun Apr 26, 2026 2:17 pm
Tested in B1852 with db v516, the GBI interceptors will turn now to impact the incoming missile. So it is fixed.
Tested also in the new build, without updating the db of the scenario, and the turn may happen or not.
I don't think this is fixed. The site in Alaska should be engaging that ICBM. That appears to be a problem with something, I just know what. It's good see that GBI from the Vandenburg site can successfully intercept the ICBM but, I still feel like the Alaska site should be trying a first shot at it.
Re: B1825.15 Ballistic Missile Intercept Calculations Failing
Posted: Wed Apr 29, 2026 12:31 am
by Mark352
Mark352 wrote: Tue Apr 28, 2026 1:18 am
Nikel wrote: Sun Apr 26, 2026 2:17 pm
Tested in B1852 with db v516, the GBI interceptors will turn now to impact the incoming missile. So it is fixed.
Tested also in the new build, without updating the db of the scenario, and the turn may happen or not.
I don't think this is fixed. The site in Alaska should be engaging that ICBM. That appears to be a problem with something, I just know what. It's good see that GBI from the Vandenburg site can successfully intercept the ICBM but, I still feel like the Alaska site should be trying a first shot at it.
I apologize. Upon further review this is working in Build 1852 as per Nikel's previous post. My bad. The Alaska site does engage and LRDR is seeing the missiles. Thanks!
Re: B1825.15 Ballistic Missile Intercept Calculations Failing
Posted: Wed Apr 29, 2026 7:13 am
by Nikel
Mark352 wrote: Wed Apr 29, 2026 12:31 am
I apologize. Upon further review this is working in Build 1852 as per Nikel's previous post. My bad. The Alaska site does engage and LRDR is seeing the missiles. Thanks!
No need to apologize Mark
Edit: I forgot to update the database to v516.
In this scenario the Alaskan GBI will also fire if the second one is removed.
What makes sense, the GBI unit is the same for both scenarios in the db, number 3710.
What are different are the Californians.
ABM Test
Alaska 3710
California 3711
Nuclear War test
Alaska 3710
California 2467

- GBI 2.gif (1.69 MiB) Viewed 172 times