NE South Dakota Clark, SD | AGPS uses control points. They are a fixed reference point that does not move. I usually use an approach that has a culvert through it. You put your receiver in the center of the culvert and center of the approach and capture a control point. You could come back 10 years later with a different brand of GPS and a different base loacation. You return to the same spot and park in the same place. These control points need to be something that is easy to get back to. When you recall the control point, it readjusts every thing from that fixed reference point. I have seen some RTK Bases in quick survey base mode move quite a bit from one start up to the next without moving the tripod. |