Grain truck fill detection

A method for controlling a grain cart relative to a grain truck, wherein the grain cart includes a grain tank and an unload auger configured to transfer crop material out of the grain tank, wherein the grain truck includes a truck box extending from a first end to a second end, wherein the truck box includes a top edge extending around the top of the truck box, the method comprising the steps of:

• identifying a distance to the top edge of the truck box;
• identifying a distance to an area in the truck box;
• determining a position of the grain cart relative to the grain truck;
• determining whether the grain cart is positioned near the first end of the truck box;
• and
• if it is determined that the grain cart is positioned near the first end of the truck box:
• determining a fill level in the area based on the distance to the top edge of the truck box and the distance to the area in the truck box;
• determining whether the fill level exceeds a threshold;
• and
• if it is determined that the fill level does not exceed the threshold, starting the unload auger.