Question

GPS requires at least ___ satellites in view of the receiver.

(a) three

(b) two

(c) five

(d) four

The question was asked during an interview.

The doubt is from Available Technologies for Cognitive Radio in section Cognitive Radio Basics of Cognitive Radio

Answer 1

Correct answer is (d) four

The best explanation: GPS receiver monitors several satellites to precisely compute the location and clock deviation. It requires at least four satellites to be present in its field of view. Three position coordinates and clock deviation from satellite time are the unknown entities to be computed.