Abstract: A frequency correction for frequency difference of arrival geolocation of transmitted target signals may be provided. A frequency of a target signal may be determined at a first collector based upon a first reference timebase source. A frequency of the target signal may be determined at a second collector based upon a second reference timebase source. An observed frequency of a reference carrier signal based upon the first reference timebase source may be determined at the second collector based upon the second reference timebase source. A relative timebase error between the first collector and the second collector may be calculated based upon a difference between the intended frequency of the reference carrier signal and the observed frequency of the reference carrier signal. A corrected frequency difference for the target signal may be calculated based upon the relative timebase error and a proportional scaling factor.

Abstract: A frequency correction for frequency difference of arrival geolocation of transmitted target signals may be provided. A frequency of a target signal may be determined at a first collector based upon a first reference timebase source. A frequency of the target signal may be determined at a second collector based upon a second reference timebase source. An observed frequency of a reference carrier signal based upon the first reference timebase source may be determined at the second collector based upon the second reference timebase source. A relative timebase error between the first collector and the second collector may be calculated based upon a difference between the intended frequency of the reference carrier signal and the observed frequency of the reference carrier signal. A corrected frequency difference for the target signal may be calculated based upon the relative timebase error and a proportional scaling factor.

Abstract: A look-ahead detection system (LADS) that actively controls the suspension of at least some of the seats in a watercraft to drastically reduce the shock and/or vibrations experienced by passengers within the seats caused by waves, other water conditions and/or the bending of the craft as it travels through the water. The look-ahead detection system utilizes downward-looking sensors to help the system predict when the craft will strike the water and how strong the impact will be. That is, the look-ahead detection system uses the sensors to look forward in time and down in space.

Abstract: A dynamic degaussing system includes a magnetic field sensor for generating a sensor signal in response to a sensed magnetic field. The magnetic sensor is coupled to a controller that produces an output signal based on the sensor signal. The controller may include feedforward and feedback control loops. The output signal of the controller controls a magnetic field generator which generates a magnetic field so as to attenuate the sensed magnetic field. According to one aspect of the invention, a vessel is provided with a reduced magnetic signature and a control system for controlling magnetic fields about a podded electric motor. The control system employs feed-forward and feedback control in tandem. The control system may be dynamically adapted to changing physical characteristics of the motor. Control signals are generated in response to sensed or predicted magnetic fields internal to, or external to, the motor.

Abstract: A multi-sensor, multi-actuator control system for controlling vibration in a mechanical structure. The system employs feedforward and feedback control strategies in tandem. Outputs from adaptive feedforward and modal feedback control loops are added to each other. The control system may be dynamically adapted to the changing physical characteristics of the controlled structure. For example, the plant transfer function estimates for the feedforward unit and the gain for the feedback unit may be calculated as functions of sensed physical parameters (location, mass, etc.), and the plant transfer function estimates may be dynamically modified to reflect time-varying feedback control gains. If desired, the control system may be used to cancel low frequency vibrations (<20 Hz) in industrial processes. The actuators may be formed of electromagnets, fixed armatures and interposed flux sensors. In a preferred embodiment of the invention, the robust actuators are sealed so as to be impervious to fluids and dust.

Abstract: A dynamic degaussing system includes a magnetic field sensor for generating a sensor signal in response to a sensed magnetic field. The magnetic sensor is coupled to a controller that produces an output signal based on the sensor signal. The controller may include feedforward and feedback control loops. The output signal of the controller controls a magnetic field generator which generates a magnetic field so as to attenuate the sensed magnetic field. According to one aspect of the invention, a vessel is provided with a reduced magnetic signature and a control system for controlling magnetic fields about a podded electric motor. The control system employs feed-forward and feedback control in tandem. The control system may be dynamically adapted to changing physical characteristics of the motor. Control signals are generated in response to sensed or predicted magnetic fields internal to, or external to, the motor.

Abstract: A multi-sensor, multi-actuator control system for controlling vibration in a mechanical structure. The system employs feedforward and feedback control strategies in tandem. Outputs from adaptive feedforward and modal feedback control loops are added to each other. The control system may be dynamically adapted to the changing physical characteristics of the controlled structure. For example, the plant transfer function estimates for the feedforward unit and the gain for the feedback unit may be calculated as functions of sensed physical parameters (location, mass, etc.), and the plant transfer function estimates may be dynamically modified to reflect time-varying feedback control gains. If desired, the control system may be used to cancel low frequency vibrations (<20 Hz) in industrial processes. The actuators may be formed of electromagnets, fixed armatures and interposed flux sensors. In a preferred embodiment of the invention, the robust actuators are sealed so as to be impervious to fluids and dust.

Abstract: An optical monitoring system maps high aspect ratio regions of space using an imaging or viewing device that has a field of view with a low aspect ratio and a plurality of mirrors positioned and arranged relative to the imaging device and the region of space such that the plurality of mirrors directs the image of the region of space to the imaging device in a plurality of segments. Each of the segments is smaller than the field of view of the imaging device and all segments fit together in the field of view of the imaging device such that all of the region of space is mapped and monitored by the single imaging device. The present invention eliminates the need for several imaging devices to monitor high aspect ratio regions of space.