Abstract: A system for controlling the course of a vessel. A digital computer 22 receives information signals from a geographic position locator 20, such as a Loran-C receiver, a depth sounder, or a water temperature sensor, and is also capable of interactive communcations with a remote terminal 24 which is accessible by an operator of the vessel. The digital computer 22 continuously monitors the information signals and develops therefrom a digital output signal representing the sign and magnitude of vessel cross-track error. To obtain information required to determine cross-track error, and to obtain certain other information relating to the identity and type of the geographic position locator 20, the digital computer 22 transmits questions to the remote terminal 24 for display therby and evaluates responses made by the operator through remote terminal 24. The digital computer 22 may be enabled or disabled in response to instructions from the operator using remote terminal 24.

Abstract: An improved marine compass employs a Hall-effect device which provides an output signal related to the relative rotation of the compass card therein. When the Hall-effect device is mounted on a course dial whose position with respect to the compass' lubber line indicates a desired course, the output signal may be used as an input to an autopilot system. The system includes a DC constant current supply for the Hall-effect device, and an integrated circuit operational amplifier for amplifying said output signal to provide an angle signal having a usable level. A differentiator including a second IC operational amplifier provides a rate signal from the angle signal. A rudder signal is provided by a rudder position sensor employing a second Hall-effect device and a third IC operational amplifier.