Raytheon Company

Michael E Lawrence

Charles T Hansen

Michael Y Jin

A synthetic aperture image of a scene is acquired using a radar system. The scene has one or more radar scatterers located on a horizontal flat {circumflex over (x)},&#x177; plane. The radar system is mounted on a moving platform moving at an angle &#x3b8;with respect to the {circumflex over (x)},&#x177; plane, with a component of motion in a perpendicular {circumflex over (z)} direction. The synthetic aperture image acquisition requires digitizing radar returns having a phase returned from scatterers in the scene, adjusting the phase of the radar returns in response to &#x3b8;to generate phase adjusted returns, then computing the synthetic aperture image from said phase adjusted returns. The phase adjustment takes into account &#x3b8;platform motion with respect to the scene.

Motion compensation for convolutional SAR algorithms

Motion compensation for coherent combination of pulses facilitates a SAR image of a scene on earth's surface. A great circle () is centered with respect to the earth's center, The great circle () has an axis () perpendicular to a first plane. Axis () passes through the earth's center. The first plane contains great circle () and includes the earth's center. Great circle () has a first center defined by an intersection of the first plane and axis (). The scene has one or more radar scatterers and is located on a surface (). The radar system is mounted on a moving platform () moving with a component of motion in a direction along great circle (). The radar comprises a radar receiver for digitizing the radar returns having a phase from scatterers on surface (), and a computer for focusing the phase of said radar returns from the scatterers on surface (). The surface () is located on a local scene centerline circle (), the local scene centerline circle () defining a second plane. This second plane is parallel to the first plane. The local scene centerline circle () is centered on the axis at a second center, where the second center is displaced with respect to the first center along the axis by a distance (). The phase of the radar returns received from the scene is compensated for the motion of the moving platform () using a cylindrical coordinate system referenced with respect to the second center to yield a SAR image.

Conformal range migration algorithm (CRMA) 'KARMA'

A method for processing squint-mapped synthetic aperture radar data of the present invention. The inventive method includes the steps of effecting range compression of the data; deskewing the data; performing a Fourier transform with respect to the deskewed data; providing a range migration interpolation of the transformed data; effecting a frequency remapping of the range interpolated data; and performing an inverse Fourier transform with respect to the deskewed data.

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San Pedro, CA, United States of America

Michael E Lawrence