Centre county Pennsylvania, USA | Mark, all of the green combines we have, or had, sense wheel speed and use that to compute acres in yield equation (yield = bushels divided by acres). Load and terrain induced wheel slippage (and wheel diameter changing as bin load changes) causes error in acres used to compute yield. Wheel slippage error can be post process corrected if GPS is logged but less than half of combines with yield monitors have GPS. Also, terrain compensated GPS speed is horizontal ground speed only but non-terrain compensated GPS speed is true ground speed so that needs to be accounted for in computing acres from GPS data.
Terrain also effects bushels part of yield equation. Bushels are computed from mass flow sensor data and impact plate type mass flow sensors are not terrain compensated. That means "throw" angle of grain hitting impact plate changes with terrain. That and earth gravity causes change in velocity of grain hitting impact plate which changes "calibration curve" of mass flow sensor.
Us folks in HEL country don't expect high accuracy in yield monitors, so far those expectations have been met.
My apology to Ted for "butting in", and to all others that have read this far......... |
Productivity Map on Ripper = Soil Density Map?
