Development of topographic maps and rear steering control for an agricultural vehicle through incorporation of posture and attitude measurements

Abstract

A self-propelled agricultural sprayer was equipped with four RTK DGPS receivers and an inertial measurement unit (IMU) to measure vehicle attitude and field elevation as the vehicle was driven across a field. Data was collected in astop-and-go fashion at 3.05 m (10 ft) intervals, as well as in a continuous fashion at three different speed levels on a 2.3 ha field area with varying topography. Pitch and roll bias angles were estimated to within 95% confidence intervals that ranged from 0.01 ° to 0.10°. Using ordinary kriging, digital elevation models (OEMs) were interpolated using only elevation measurements, as well as a combination of elevation and vehicle attitude measurements. The resulting OEMs were compared to each other to evaluate the effect of including attitude measurement on DEM accuracy. At the widest measurement swath width, the OEMs generated with attitude measurements had substantially lower error measures than those OEMs generated without attitude measurements. Vehicle speed affected DEM error, but no discernable trends were detected. These results provide evidence that support the feasibility of using vehicle-based measurements collected during typical field operations for accurate DEM development.