In GPS survey procedure, which of the following is the most important measurement?

In GPS survey procedures, the measurement of antenna height is crucial because it directly impacts the accuracy of the positioning data obtained from the GPS receivers. Antenna height is important because it determines the elevation at which the GPS signals are received, which affects the correction calculations for both the receiver's position and the signal's travel time. If the antenna height is not accurately measured or accounted for, it can result in significant errors in the final positioning data, leading to unreliable survey results.

Accurate knowledge of antenna height allows surveyors to adjust for the height of the GPS antenna relative to the ground, ensuring that the data reflects the true ground locations. This is particularly vital when dealing with points on uneven terrain or when precise elevation measurements are required. These considerations make antenna height a fundamental aspect of GPS surveying techniques.