Lockheed Martin Corporation

Carl V Jannetti

John B Stetson, Jr

Edward M Brennan

Alan M Rosenwinkel

A method for geoposition determination from a platform involves using star observations to determine the orientation of the platform relative to an Earth-Centered Earth-Fixed (ECEF) frame. Observations are also made from the platform of azimuth, elevation, and possibly range of an orbiting Earth satellite. Platform orientation in an inertial frame fixed in time (IFFIT) is determined, and the satellite azimuth and elevation are transformed to the IFFIT. The satellite orbital ellipse is determined. Vectors extending from the platform frame to the foci of the ellipse are defined and converted into ECEF. The vector extending to the gravitational center of the Earth is identified and defines the location of the platform.

Geoposition determination from star and satellite observations

A method is disclosed for determining relative motion between equipment systems positioned on a structure that is subject to deformation due to vibrations, using accelerometers. Relative motion between equipment systems can introduce error into the targeting information provided to a system such as a weapons system, and thus the method facilitates compensation for such relative motion. A method is disclosed in which the raw accelerometer signals are filtered, then combined with attitude signals in a displacement calculation module (DCM). Within the DCM, the signals are manipulated to calculate, for each equipment system, the translational and rotational displacements due to hull modal vibration and the translational and rotational displacements due to force vibration. The sum of these values represent the movement of each of the affected equipment systems. Relative motion between systems is calculated as the difference between the calculated movement values.

Method for determining relative motion using accelerometer data

A system and method are disclosed for determining relative motion between ship-based combat system elements using accelerometers. Relative motion between combat system elements can introduce error into the targeting information provided to the weapons system, and thus the system facilitates compensation for such relative motion. The system includes accelerometers mounted on radar systems, inertial navigation system (INS) sensors, and weapons systems. An algorithm is disclosed in which the raw accelerometer signals are filtered, then combined with ship INS attitude signals in a displacement calculation module (DCM). Within the DCM, the signals are manipulated to calculate, for each combat system element, the translational and rotational displacements due to hull modal vibration and the translational and rotational displacements due to force vibration. The sum of these values represent the movement of each of the affected combat system elements. Relative motion between elements is calculated simply as the difference between the calculated movement values for each element.

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Huntingdon Valley, PA, United States of America

Carl V Jannetti