[Milsurplus] [ARC5] AN-Ranges

[Mike Morrow]

Bruce wrote:

> Another technology that fascinates me is inertial navigation.
> It is completely self contained and does not require any sort
> of beacons or satellites. 

Inertial navigation for long duration transits does require periodic position updates (fixes) from other sources.

Ballistic missile submarines in my era had two independent ship inertial navigation systems (SINS) on board in continuous operation...the best systems of that type available in the world.  Still, the ship had to came to periscope depth frequently to get a fix from the TRANSIT doppler navigation satellite array that operated on 150 MHz and 400 MHz.  The principls motivation for developing and operating the TRANSIT SATNAV system was specifically to provide those mid-sea position updates for SSBN SINS.  Our Poseidon missile system could drop its MIRVs no more accurately than position at launch time was known, so a monumental amount of money and effort was spent to know that position.

The missile's INS didn"t get post-launch position updates, but the ship's INS often did.

Mike / KK5F