Ground height detection sensor for control of harvesting equipment

The design and testing of a novel microwave sensor developed to detect ground level through sugarcane is described. The purpose of this sensor is to automate the height adjustment of the base-cutter on mechanical sugarcane harvesters. The new sensor measures the amplitude of an electromagnetic wave propagating from one side of the row of cane to the other. A multi-element receiver array is employed to measure the amplitude versus height profile. The shape of the response is then analysed to estimate the ground location relative to the receiver array. The sensor operates at a frequency of 2.4GHz and uses rectangular patch antennas to enable mounting inside the harvester row dividers. Tests on board a cane harvester show the viability of this approach.