3 ms·

The SR-71 had an automated celestial navigation system that could get a lock in daylight: http://en.wikipedia.org/wiki/Lockheed_SR-71_Blackbird#Astro-Inertial_N

by ceequof 11y ago

The SR-71 had an automated celestial navigation system that could get a lock in daylight: http://en.wikipedia.org/wiki/Lockheed_SR-71_Blackbird#Astro-Inertial_Navigation_System http://en.wikipedia.org/wiki/Lockheed_SR-71_Blackbird#Astro-... (The big disadvantage is that it can't see through clouds, of course)

tyho 11y ago
Didn't it fly above the clouds?
- ceequof 11y ago
  It was a surveillance aircraft, so it would need line of sight with the ground as well, which might require flying under cloud cover. Also, having a gyroscope component, I'm guessing that it would need to calibrate while stationary, on the runway.
  - PhantomGremlin 11y ago
    It didn't fly under cloud cover. It flew Mach 3.3, which it couldn't do in dense air. Also, flying at 80,000 feet makes it much more difficult to shoot down.