Precision artillery with Excalibur shells keeps missing target

[Apocal]

52 minutes ago, HerrTom said:

16 penetrations into the engine compartment (40mm RHAe) and 2 into the engine compartment.

Unintentional repeat? What was the other thing, besides the engine compartment?

46 minutes ago, c3k said:

GPS can be spoofed and jammed. 

Excalibur has INS as well and if it is anything like JDAM, the GPS set is effectively backup to the INS, not the other way around. In other words, if you spoof the GPS, the weapon just ignores it and goes pure INS. It's also technically tricky to spoof the later marks because they have built-in protection that basically amounts to the weapon making sure the GPS signal is coming from above and not below.

I don't think EWAR effects it in-game, other than taking a stupendously long time to arrive.

[c3k]

33 minutes ago, Apocal said:

Unintentional repeat? What was the other thing, besides the engine compartment?

Excalibur has INS as well and if it is anything like JDAM, the GPS set is effectively backup to the INS, not the other way around. In other words, if you spoof the GPS, the weapon just ignores it and goes pure INS. It's also technically tricky to spoof the later marks because they have built-in protection that basically amounts to the weapon making sure the GPS signal is coming from above and not below.

I don't think EWAR effects it in-game, other than taking a stupendously long time to arrive.

Agreed.

In-game, ECM doesn't affect GPS. IRL, GPS is hard to jam (militarized GPS, that is), and there are backups. (Some sources differ from your statement. They say that the round REQUIRES initial GPS acquisition which would then enable inertial nav. That begs the question of firing it without knowing the status of the GPS signal at the tube. Hard to fake that.) A big part of the gps anti-jam are the directional antennas.

The last bit of spoofing the Russians have are the fuze jammers which could cause bursts too high to be very effective. Not sure what the deal is with those these days.

[Michael Emrys]

3 hours ago, c3k said:

GPS can be spoofed and jammed.

It also occurs to me that a first-rate power might at the outset of a war begin shooting down GPS emitting satellites, thus nullifying anything reliant on that signal, which these days is nearly everything that moves.

Michael

[Michael Emrys]

3 hours ago, c3k said:

 

Edited September 4, 2017 by Michael Emrys
Repeat post

[Michael Emrys]

3 hours ago, c3k said:

 

Edited September 4, 2017 by Michael Emrys
Repeat post

[TheForwardObserver]

28 minutes ago, Michael Emrys said:

It also occurs to me that a first-rate power might at the outset of a war begin shooting down GPS emitting satellites, thus nullifying anything reliant on that signal, which these days is nearly everything that moves.

Michael

No worries.  Everything GPS can do can be done from ground stations as well.  It's how it was done before GPS.  See the Loran system

 

[Sgt.Squarehead]

As c3k point out, based on the Iranian RQ-170 incident, it appears that it is possible to spoof GPS coordinates too.

Edited September 4, 2017 by Sgt.Squarehead

[Rinaldi]

The really upsetting part is that people think precision artillery is pinpoint precise 

[Sgt.Squarehead]

I've not noticed the issue with Excalibur described here, but I was massively disappointed at the lack of firepower modelled into Russian PGMs.....Multiple direct hits being unable to score a mission kill on an IFV. 

As modelling in other threads has shown, large calibre artillery strikes are not at all kind to armoured vehicles:

This was done by mortars:

Pretty sure those two fellas were both a lot tougher than a Bradley. 

Edited September 4, 2017 by Sgt.Squarehead

[c3k]

1 minute ago, Sgt.Squarehead said:

I've not noticed the issue with Excalibur described here, but I was massively disappointed at the lack of firepower modelled into Russian PGMs, multiple hits unable to score a mission kill on an IFV.  As modelling in other threads has shown, large calibre artillery strikes are not at all kind to armoured vehicles:

This was done by mortars:

Pretty sure those two fellas were both a lot tougher than a Bradley. 

Based on the photographic evidence, the mortar shells probably entered into the opened hatches, hence the destruction. Brads stay buttoned in combat zones. Better air conditioning.

My point, though tangentially put, is that photographic evidence is not evidence of what hit and what destroyed the vehicles. I am NOT saying that BFC has it totally right: I think a bit more damage to vehicles would be appropriate, in-game. Herr Tom is doing some great work on this.

[Sgt.Squarehead]

Agreed. 

While I may have some criticisms, they are meant to be constructive.....I think the first tank might reasonably be described as 'bludgeoned to death', regardless of the hatches (which are not burned on the inner surfaces).  CM does not appear to model this and IMHO it should.

Edited September 4, 2017 by Sgt.Squarehead

[HerrTom]

11 hours ago, Apocal said:

Unintentional repeat? What was the other thing, besides the engine compartment?

Excalibur has INS as well and if it is anything like JDAM, the GPS set is effectively backup to the INS, not the other way around. In other words, if you spoof the GPS, the weapon just ignores it and goes pure INS.

2 hits to the CREW compartment! My bad!

INS isn't particularly accurate and if TFO is right about the 10m CEP with GPS guidance I'd be surprised if you could hit close to that purely inertially!

[Michael Emrys]

12 hours ago, TheForwardObserver said:

No worries.  Everything GPS can do can be done from ground stations as well.  It's how it was done before GPS.  See the Loran system

But, does LORAN provide global coverage the way that the satellite system does? And does it have the same pinpoint accuracy?

Michael

[c3k]

No, LORAN is nowhere near as quick or as accurate as GPS. That's why GPS was developed AFTER LORAN: it resolved a lot of shortcomings.

Here's something about differential/enhanced Loran: http://gpsworld.com/edloran-the-next-gen-loran/

Also, if you're fighting an adversary who is adept enough to jam GPS (and you can't unjam it or destroy their jammers), then they're probably good enough to do the same to LORAN, no? (Note that we're talking localized jamming of LORAN, not theater-wide, just enough to protect my forces. Or, the forces I care about at that moment. )

(That's why ICBMs use celestial nav. Or, they used to. Gotta dig that up. Kind of hard to spoof that.)

[HerrTom]

Set off ultra high altitude nuclear explosions to fool the sensor that the stars aren't really where they are! And nuke the moon while you're at it. Just to show those Soviets we own it!

As far as I know they use inertial navigation corrected by celestial readings. They also have the advantage that their inertial sensors don't have to survive (and read) thousands of G's when they're shot out of a howitzer. 

[TheForwardObserver]

5 hours ago, c3k said:

No, LORAN is nowhere near as quick or as accurate as GPS. That's why GPS was developed AFTER LORAN: it resolved a lot of shortcomings.

Here's something about differential/enhanced Loran: http://gpsworld.com/edloran-the-next-gen-loran/

Also, if you're fighting an adversary who is adept enough to jam GPS (and you can't unjam it or destroy their jammers), then they're probably good enough to do the same to LORAN, no? (Note that we're talking localized jamming of LORAN, not theater-wide, just enough to protect my forces. Or, the forces I care about at that moment. )

(That's why ICBMs use celestial nav. Or, they used to. Gotta dig that up. Kind of hard to spoof that.)

Okay but Michael said 'shooting down satellites' not jamming them.  If they're shooting down our sats, than terrestrially based navigation solutions will be our best bet.  It's feasible and the concept pre-dates GPS, that was my point.  

[TheForwardObserver]

14 hours ago, HerrTom said:

INS isn't particularly accurate and if TFO is right about the 10m CEP with GPS guidance I'd be surprised if you could hit close to that purely inertially!

10 CEP is where the line is drawn for a munition to be considered precision and 6 is what I would plan for; so while the EXCAL may very well be [is] capable of achieving a more precise CEP, for fire support planning you would start with 10 as a planning value and if needed, weigh the risks of assuming or attempting fire with an expectation of a lower CEP if you know you're able to deliver.  Using the cutoff values can help mitigate the impact that poorer than expected TLE will have on achieving actual effects.  A static artillery battery on a FOB, experiencing little disruption and no displacement in Iraq/Afghanistan are pretty good conditions for achieving optimal expectations, whereas chaotic on the move support of a rolling mechanized thrust through eastern Europe with forests, rain, fog, and, mud probably less so.  The cutoff for near precision munitions is 50 CEP, but for example, the precision guidance kit [PGK] which is a cheaper alternative to EXCAL that attaches to unguided shells [and would be a sweet addition to the game] can achieve a much better performance than 50 CEP [10-20] but will still be planned for with an expectation of a 50 CEP by default.  If you've got a good reason to modify your expectations you do so at your own risk.  I don't know what CEPs the game uses but Vanir gave some good insight and I don't see any problem with the way the game does it either.