Final answer:
For accurate GPS navigation in aviation, at least four satellites must be simultaneously visible to the receiver. These satellites feature precise atomic clocks to calculate the position based on signal travel time, and must account for relativistic effects for precise location pinpointing.
Step-by-step explanation:
In aviation, the number of satellites required for accurate GPS navigation is at least four. GPS relies on a constellation of 24 satellites that orbit the Earth, of which a minimum of four must be visible to a receiver at any location to accurately determine position. These satellites are equipped with precise atomic clocks to measure the time it takes for their signals to reach the receiver. This time measurement is critical because even a 50-billionth of a second difference in timing can correspond to a positional error of about 50 feet. It is crucial to account for relativistic effects due to the high speeds at which the satellites travel and their distance from Earth, affecting the accuracy of GPS timing and location determination.