Are inertial navigating devices being improved ?

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Salute!

Ahem.....

1) Star tracking was used by the most accurate ICBM kniown as well as the submarine Trident INS. Worked on that one and was amazed. As long as initial position of launch was within a few miles (SECRETNOFORN). the INS rotated all the gimbal shells to align a hole on the star of interest. So that sucker could launch from a few thousand miles away and hit inside of a football stadium with a big bomb.

2) The advent of super clocks made the RLG INS and GPS possible, as well as optics that used the interference patterns of the laser beam for the RLG systems. Add in fairly cheap digital accelerometers for the short term and you have very good systems. The RLG's and similar are super, as virtually zero mechanical drift as we had in the 60's INS that used spinning gyro's. The strapdown INS systems for new missiles are super for short time-of-flight navigation if they have a good positional update at launch. For a minute or so, their posiitonal accuracy is scary. Body rates and attitude are easy peasy within a second of pressing the launch button..

3) Over dependence upon GPS, IMHO, is not very viable for the military due to somebody mesing around or actually destroying much of the system. Best bet for updates is using a star or landmark visible with optical sensors or radar. We did this in late 60's to great effect.

4) As far back as 1970, the A-7D could do airborne alignments of the INS and overall nav system by using the doppler system we had. Had to wait about 2 minutes or so to get "platform" level. Refinement and pointing north could be done after launch. A decent intial position helped, but you could take off and flyover a point that was on out projected map and get a decent position - say within 1000 feet or so.

Gums sends...