Sperry Marine Inc.

Clifford B Cantrell

Lawrence H Gilligan

Paul E Hollandsworth

The line of sight of an airborne radar antenna is stabilized from the pitch and roll motions of the aircraft by mounting the antenna on a three degree of freedom gimbal system. The gimbal system is comprised of a first gimbal mounted for rotation about the aircraft Z axis (azimuth) for pointing the antenna along the intended line of sight, a second gimbal mounted on the first gimbal for rotating up and down with respect to the azimuth gimbal and a third gimbal mounted on the second gimbal to which the antenna is connected for providing rotation to align antenna polarization relative to inertial ground. A two degree of freedom stabilization gyro provides stabilizing signals representative of aircraft pitch and roll motions with respect to inertial reference axes. The stabilization signals, together with a line of sight pointing signal, are applied to coordinate transformation equations to generate drive signals for the respective gimbals so as to maintain the antenna pointing in the intended direction with correct polarization.

Orientation stabilization by software simulated stabilized platform

A video camera system has a modulation transfer function (MTF). Video image data are stored in frame grabbers and converted in a digital signal processor from the image domain to the spatial domain by a two-dimensional digital Fourier transform. The spatial data are filtered by a two-dimensional aperture correction filter that has an MTF inverse to the uncorrected system MTF. The filtered spatical data are converted back into the image domain by a two-dimensional inverse digital Fourier transform. The two-dimensional digital aperture correction filter is stored in the form of software in the digital signal processor.

Video image enhancement utilizing a two-dimensional digital aperture

The gating circuit includes a low voltage section and a high voltage section with a fast and a slow switch in the high voltage section for providing the gating pulses to the photocathode (PC) of the image intensifier. A high voltage isolated DC/DC power supply referenced to the MCPin terminal of the integral wrap around power supply of the image intensifier provides, to the fast and slow switches, positive and negative potentials referenced to MCPin. The negative potential is sufficient to turn the PC on and the positive potential is sufficient to turn the PC off and to clear burned in PC images. The high voltage isolated power supply provides high voltage isolation between the low voltage section and the reference input and outputs thereof in the high voltage section. A driver included in the high voltage section for driving the fast switch receives operating potentials from a low voltage isolated DC/DC power supply referenced to the high voltage supply. The elements of the driver therefore only experience low voltages thereacross. High speed gating pulses and low speed gating pulses are conveyed between the low voltage section and the high voltage section across respective high and low speed isolation barriers to drive the fast and slow switches, respectively. The high speed barrier comprises a high voltage capacitor and the low speed barrier comprises an opto-isolator. The high speed pulses include narrow, low repetition rate pulses for clearing burned in images from the PC.

Growing community of inventors

North Garden, VA, United States of America

Clifford B Cantrell