ABSTRACT
Electronically scanned arrays (ESA) have been used in spaceborne applications since 1978 when NASA began the SEASAT mission. SEASAT was the first synthetic aperture radar mission in space, and used a horizontally polarized, L-band ESA to map the earth’s surface. This chapter presents a set of tools for analyzing and visualizing spaceborne ESA applications. It focuses on the pertinent coordinate systems, and the transformations from one to another. The chapter illustrates a method for determining the ESA field of view as the intersection of the ESA scan volume the angles to which the ESA can electronically scan without grating lobes with the ESA perspective of the earth’s horizon. The two-body orbit described in the previous section assumed an inertial reference frame. When modeling satellite orbits around earth, it is convenient to define an inertial coordinate system with earth’s center at the origin.
