Calls attention to some common sources of GPS position error. Relates GPS position error, expressed as a distance, to errors in latitude and longitude . Illustrates in very general terms the effect of differential correction .
Helps identify situations that call for differentially corrected position coordinates.
Every location has its own coordinate address. Due to environmental influences on the satellite signals that these receivers use, small position errors are always present in GPS computed coordinates. As long as a receiver is used on jobs that do not exceed its design limitations, position error will not be a problem, and it may not even be noticed. Although the HAE coordinate can be very important for land surveys, construction and land leveling jobs, there are a lot of mapping and other GPS uses where HAE is not critical. Since in Arkansas a one-second latitude difference is equivalent to 101.1 feet of horizontal distance, the true gate position is a little more than 200 feet north of the position indicated on the receiver's coordinate display.