Mick F wrote:Having spent much of my professional career in ships, we used Nautical Miles and Cables (ten cables to the NM) we also used Data Miles and Radar Miles.
One of my jobs was maintaining the weapons radars which were made by Selinia ...... and Italian company, so the readouts on the display were in Kilometres. Good job the weapons system was computer driven, and everything was converted so all the equipments could talk to each other.
I maintained the computer suit too.
There are different nautical miles. The international one is exactly 1852m. The uk and US had longer ones that were different from each other.
One of the problems a mixing metric and imperial measurements, even if it is carried out by computer is it depends on the inputted data and how it's been programmed. NASA have had a couple of incidents where they have had a probe slam into a planet and a satellite collide with rather than dock with another due to using mixtures in units systems. It's cost hundreds of millions of dollars in losses.
I've calibrated ship's gyro-compass and verified ship's gps systems as well as providing positional reports and services for off shore facilities.