"The equation (A) can be obtained as follows: A dot 11 on the north polar region Ns has polar coordinates [R,??(j),??(t)] where ?? is the angle between the radius at the dot 11 around the center O and Z-axis, ?? is the angle between the radius Rp at the dot 11 around Z-axis and Y-axis, and t is an integer from 0 to 6j-1." . . . .