Performance of "Low-Cost" GPS Receivers for Yield Mapping

Abstract

For the study, two low-cost handheld GPS receivers were compared to a DGPS receiver.A combine equipped with a yield monitoring system was configured so that yield data could becollected simultaneously using a low-cost handheld GPS receiver and a DGPS receiver. Results in2000 showed average relative positioning differences of 1.78 meters and that similar yield mapscould be created. Due to the limited hectares harvested in 2000 further analysis was desired.During the 2001 fall harvest, 212.2 hectares of corn and 283.7 hectares of soybeans were harvestedusing the above mentioned yield monitor configuration. In 2001, average relative positioningdifferences of 2.97 meters was obtained between GPS receivers. Yield maps were produced fromthe same field using standard yield mapping techniques. Comparisons were made between themaps of how similar they were at showing variability and yield in Mg/ha. Visually one coulddistinguish yield data collected between the two low-cost GPS receivers. Using regression analysisfor map comparison, R-squared values ranged from 0.3 to 0.9 with a mean of 0.73.