Question

Why can we not use sky waves for navigation?

(a) Low power

(b) More noise

(c) Unpredictable path

(d) Not economical

I had been asked this question during an internship interview.

This key question is from Radio Propagation and Noise Characteristics topic in section Terrestrial Radio Navigation System of Avionics

Answer 1

Right answer is (c) Unpredictable path

The best I can explain: The sky waves makes some types of long range communication possible, but is of less value to navigation system because it’s transmission path is unpredictable. A rough location where the sky waves might get reflected can be determined by Snell’s law.