A wireless gateway architecture integrates support for a plurality of wireless standards and protocols. A portion of an input signal is delayed by delay elements prior to being received by the predistortion subsystem. It is judged whether or not the dump truck 11 has transferred to a transporting status, and if it has transferred to a transporting status, then the transported weight G1 at the end of loading and immediately before transition to the transporting status is calculated and stored. The positioning surface is continuously flush.