GPS - instrumentation Standard Stand-alone receiver relying on satellite GPS data. Suitable for broad-scale surveying (not precision viticulture).

Differential GPS (DGPS) Stand-alone receiver using satellite GPS data plus regional correction signal. Sub-meter accuracy (suitable for PV, longitude / latitude position). Suitable for broad-scale elevation mapping (not suitable for PV if accurate elevation surveying required).

Real Time Kinematic GPS (RTK GPS) Uses roving receiver that corrects satellite positions from local base station. Centimeter accuracy. Required for accurate surveying (horizontal & vertical positioning).