Salute!
Yeah, Astur, prolly a nm per hour or less. Of course, it only had to get the missile within x yards after 30 seconds, and it was being used for a cluster bomb guidance system on a new system.
The reason I mentioned it was the technology advancements since the first large scale use of inertials and then the development of strapdown systems. The alignment times decreased by an order of magnitude. So way I see it is tonight I could lay my iPhone down next to me at the campsite and it would look at the stars and compare with my Starmap program and then compute.
I just have bad waves about a major conflict where the other side could disable or degrade the existing GPS system enough to cause big problems.
Gums sends...