IRS Alignment

[gums]

Salute!

No doubt that starting the process with a good idea of "which way is up" helps to reduce "alignment" time, Mr Optimistic. And you are spot on about 30 years ago as you said.

OTOH, if I know where I am starting the "alignment" process, I can look up what my velocity in inertial space is supposed to be real easy. In milliseconds. So I tell my "platform" what all the velocities and rates should be for its frame of reference and go from there. Remember, the new systems are not using clumsy space-stabilzed" gyro platforms and are bolted to your plane's frame. Back in those golden days 40 years ago, we typed in our coordinates and the system compared sensed values with predicted values for that geo-referenced position in space. Airborne we did the same thing and tried to stay st-and-level for a bit. Airborne alignment wasn't as good as in the late 90's using GPS to provide actual position for the Kalman doofers to do their trick, but way better than 1970.

For those wondering where my education about these things advanced beyond what I taught in the 80's, it was during the JDAM operational concept demonstrations about 10 years later. I got to see all the goodies that various companies had for sale and had their engineers explain stuff so we could provide USAF with a good basis for further development or actual production. The JDAM was "aligned" in about one or two seconds from the carrier platform. The biggie then and now is present position, and rough body rates can be transmitted in a few milliseconds. The thing will get its own position from the satellites on its own very quickly after you drop it. If it knows where it was, then the calculations are able to get it squared away in seconds versus a half a minute. Over 20 years ago the B-2 could drop 16 of the suckers from it bays in a very short time, and the things could not get a GPS signal until a few seconds after release because they were in giant Faraday cage. Ditto for the Bone's bays and now the F-35.

Gums sends...