David.Smith@cmu-cs-ius.arpa (04/10/84)
Why are the distances, speeds, etc. measured in terms of nautical miles? Why not statute miles? For that matter, why not kilometers? It is time-honored navigational practice. Given the coordinates of origin and destination, spherical trigonometry can be used to produce the arc length between them, expressed in angular measure (vertex of angle at center of earth). This arc is historically measured in degrees, minutes, and seconds. The nautical mile is defined to be one arc-minute over the surface of the earth. I will tiptoe quietly away from the question of how the earth's oblateness is handled. David Smith
LShilkoff.es@Xerox.ARPA (04/10/84)
"Why are the distances, speeds, etc. measured in terms of nautical
miles? Why not statute miles? For that matter, why not kilometers?
Nautical miles is the standard unit of distance used by pilots
worldwide. More than likely, it was chosen by NASA (or whatever it was
called way back when) because of the close relationship with the Air
Force and other flight branches of the armed forces. Seems to be even
more appropriate today with our latest space vehicle resembling an
airplane rather than an inverted kitchen funnel.
LShilkoff.es@xerox.ARPA
Larry