“…If we may assume that the mode-elevation angles remain constant, or nearly constant, over several frames, but that the relative amplitudes and phases of the modes vary from frame to frame, a very simple mathematical technique may be used to find the angles. Suppose that a linear combination of the aerial signals can be found, such that, for each frame, and a,S, cos </ >, • = 0 a,Sj sin <f>; = 0 (9) (10) Physically, the a, represent amplitude taper, and the linear combination of signals represents the output of an array network combining the six aerials with appropriate taper. Comparison of eqns.…”