GPS antennas should be mounted on the center line of a combine, tractor or truck and above any part of the machinery that might obstruct a line of sight to a satellite. If the cab is centered and the top of the cab is above other portions of the machine, a cabtop mounting may be the best location. However, on a steep side slope, a high mounting point will result in an error in position calculation due to the offset in horizontal position.
GPS and DGPS receivers may have separate antennas but usually there will be a combination antenna so that both are centered at the same location. A delay of several seconds often occurs in agri- cultural applications such as yield monitoring, spraying and fertilizer application.