Steering of phased.constantgamma clutter

Hello sir....My question is regarding steer angle of constant gamma clutter mode. The 'platform direction' defines the angle between array normal and velocity vector in azimuth and elevation. The angle with respect to azimuth is also called crab angle in literature.

Q1: What is the other angle, which is defined with as elevation angle? Can u show/help with refernce geometry??

Q2: How can we steer the main beam of clutter towards any azimuth/elevation direction...There is no refernce available in this regard...