1. A navigation and control system comprising: one or more position sensors configured to generate position signals indicative of the location and heading of a vehicle; one or more operation control mechanisms having inputs and producing outputs which control an operation of the vehicle; and a self-contained autonomous controller disposed remote from the operation control mechanisms, comprising, a processor configured to receive the position signals from the position sensors and to generate operation control signals defining an updated travel path for the vehicle, and a programmable interface providing communication among the position sensors, the operation control mechanisms, and the processor, and configured to normalize inputs to the processor from the position sensors and to generate compatible operation control signals applied as the inputs to the operation control mechanisms, whereby the self-contained autonomous controller is configurable for operation with a variety of different sensors and different operation control mechanisms.