What is differential correction? Group of answer choices A method for improving the accuracy of GPS positioning by averaging many readings recorded at a single location. A method surveyors use to calculate elevation by comparing the difference between the height of a leveling instrument above one point with its relative height above another point. A method for improving the accuracy of positions recorded by a mobile GPS receiver by filtering out errors recorded by a second stationary receiver. Choosing the best time of day to minimize the uncertainty of GPS coordinates caused by unfavorable arrangements of the satellite constellation