Patent ID: 6987479
Filing Date: 2006-01-17
Classification: G01S

Abstract:
1. A radar for acquiring a synthetic aperture image of a scene on earth, said earth having a great circle centered with respect to said earth's center, said great circle having an axis perpendicular to a first plane, said axis passing through said earth's center, said first plane containing said great circle including said earth's center, said great circle having a first center defined by an intersection of said first plane and said axis, said scene having one or more radar scatterers on a surface, said radar system mounted on a moving platform moving with a component of motion in a direction along said great circle, said radar comprising: a radar receiver for digitizing radar returns having a phase from scatterers on said surface, and a computer for focusing said phase of said radar returns from said scatterers on said surface, said surface located on a local scene centerline circle, said local scene centerline circle defining a second plane, said second plane parallel to said first plane, said local scene centerline circle centered on said axis at a second center, said second center displaced with respect to said first center along said axis by a distance; said phase of said radar returns received from said scene focused for the motion of said moving platform along said great circle using a cylindrical coordinate system referenced with respect to said second center.