Navigation General · GPS & GNSS
GPS determines a receiver's position by measuring:
- AThe signal strength from the nearest satellite
- BThe precise time of arrival of signals from multiple satellites to compute ranges✓ Correct
- CThe Doppler shift of satellite signals to determine bearing and speed
- DThe phase difference between an AM carrier and its sub-carrier frequency
Explanation
GPS operates on pseudo-range measurement: each satellite broadcasts a timing signal, and the receiver measures the travel time from each satellite to compute its distance (range) from that satellite. With ranges from at least four satellites (to solve for latitude, longitude, altitude, and clock error), the receiver calculates its three-dimensional position.
Authority: Bowditch (Pub. 9), Ch. 13
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