Initial heading and magnetic declination in M2KC for INS alignment.

[DmitriKozlowsky]

I am curious why there is no need in M2KC to enter magnetic declination and initial heading , prior to alignment. Like we do in AV-8B.

I suppose the other part of that question, why we do not provide initial height to Harrier's INS?

 

I imagine that INS is INS. Whether French, American, or Russian.

[QuiGon]

Awesome question! :thumbup:

I was wondering about this myself recently, but was too lazy to ask. I'm really curious about the answer, because I have no idea that would be the way it is?

[DmitriKozlowsky]

Internet has yet to yield forth the answer. But I was thinking, that Mirage's INS just takes current magnetic heading, adjusts it for MagDec (set by maintenance), and that is good enough. At least good enough for Mirage. As it is a strike aircraft.

With AV-8B, Marines want more precision thus Harrier's EGI needs initial azimuth. Close air support requires higher precision for delivery, thus higher precision of Nav system. That and the airfield that Marine Harriers take off and recover on , is a small 800 ft LHA, that is moving.

 

Perhaps both compensate with TACAN triangulation, to sweeten dynamic position fix of a fast jet.

[QuiGon]

Well, as long as GPS is available (which is part of the EGI), it can be used for initial status, as well as fixes during flight, but usally the INS should function entirely without GPS, even if integrated in an EGI, because GPS can get jammed/spoofed/destroyed.

[Shimmergloom667]

At least good enough for Mirage. As it is a strike aircraft.

 

It is not, the -C is an interceptor. (but probably still good enough)

[myHelljumper]

Precision is not the goal of the 2000C INS, remember that, at best, the INS will have 1nm of drift per hour, so magnetic heading + magnetic deviation sounds like enough.

 

In a air defense mission, 1nm drift per hour is not that much of a problem.

[Frederf]

If either airplane blocks alignment until variation value is supplied, it wouldn't be due to a fundamental incompatibility with INS principles but instead some design-based rule enforcement. From all of my reading on the subject entry of variation is not strictly required in real AV-8B.

 

The Earth could have no magnetic field at all and INS will function all the same. Earth is a ball that spins and has gravity. This is all that is needed to discover orientation and velocity provided position. The INS does not take magnetic heading to arrive at true heading by altering it by some variation value. It's the other way around, magnetic heading is INS heading fudged by the variation value.

 

One answer is that M2000 module doesn't require it is because it's simplified. The variation value is hard-supplied from the simulation and while the value can be changed in the real airplane cockpit, in sim it can't.

[Harlikwin]

If either airplane blocks alignment until variation value is supplied, it wouldn't be due to a fundamental incompatibility with INS principles but instead some design-based rule enforcement. From all of my reading on the subject entry of variation is not strictly required in real AV-8B.

 

The Earth could have no magnetic field at all and INS will function all the same. Earth is a ball that spins and has gravity. This is all that is needed to discover orientation and velocity provided position. The INS does not take magnetic heading to arrive at true heading by altering it by some variation value. It's the other way around, magnetic heading is INS heading fudged by the variation value.

 

One answer is that M2000 module doesn't require it is because it's simplified. The variation value is hard-supplied from the simulation and while the value can be changed in the real airplane cockpit, in sim it can't.

 

Yup, if anyone wants a detailed understanding of how the INS works in the harrier, and "in theory" the mirage you can look in the harrier NATOops and Tacman (I forget which one has it, but its an entire chapter of how it all works, both theory and practical). Its also worth noting that the earlier harrier II's didn't have a GPS system. And one of the things that made the earlier harriers really great at CAS was the fact that the ARBS didn't need any sort of coordinates to be highly accurate.

[Harlikwin]

 

I imagine that INS is INS. Whether French, American, or Russian.

 

In theory at least :), in practice I would expect rather different solutions and workarounds to various problems. I wouldn't expect laser ring gyros on the vast majority of soviet era aircraft and therefore much higher drift rates.

[DmitriKozlowsky]

It is not, the -C is an interceptor. (but probably still good enough)

 

Point taken. Still there is awful lot of AG munitions available DCS: M2KC. With plenty of stations to mount AG munitions. Beluga kind of sort of, works on armor and thin skin vehicles. Not as good as MK-20.

Its a bit of a bummer that inner wing pylons cannot take Air-Air missiles. If they could , then we would be able to carry 4 X MagicII on outer and mid wing pylons, and 530 on inner.

[jojo]

Point taken. Still there is awful lot of AG munitions available DCS: M2KC. With plenty of stations to mount AG munitions. Beluga kind of sort of, works on armor and thin skin vehicles. Not as good as MK-20.

Its a bit of a bummer that inner wing pylons cannot take Air-Air missiles. If they could , then we would be able to carry 4 X MagicII on outer and mid wing pylons, and 530 on inner.

 

What you call “inner wing pylons” are generally called “fuselage pylons”.

 

Super 530D are too big to fit there.

 

But Mica are small enough. Meet Mirage 2000-5. But this isn’t what we have in DCS right now.

New weapon system (radar & cockpit).