Speed of agricultural machinery on cultivated soil. Accuracy of measurements of a microwave Doppler radar.

Travelling speed and distance measurements of agricultural machines are very important both for research and machine applications on farm. On asphalt or concrete a double beam Doppler radars gives accurate measurements of these two physical dimensions. Accuracy in distance and speed measures of the same instrument mounted on an agricultural tractor has been tested on some rough ground: harrowed soil, grassland stubble and corn stubble for speeds up to 20 kmh-1. Results confirm the goodness of distance and travelling speed measurements done on these surface. In all conditions we used in the trials the double beam microwave speed gauge gives speed measurements very near to the corresponding expected theoretical value. The error is in most of the cases les than 1%, and 2% at maximum. Distance has been evaluated with an error in near all trial not grater than 1%. Only in same cases error rise to 2% maximum. Tested speed gauge based on a double beam microwave radar reflection permits more appropriate estimation of speed of agriculture machinery on rough terrain than other similar devices employed in the same conditions