function eul_vect = dcm2eulr(DCMbn)
  if nargin<1,error('insufficient number of input arguments'),end
%歐拉角和方向余弦陣之間的轉換關系；DCMnb陣是載體系和導航系間的方向余弦陣；
  phi = atan(DCMbn(3,2)/DCMbn(3,3));
  theta =asin(-DCMbn(3,1));
  psi = atan2(DCMbn(2,1),DCMbn(1,1));

  eul_vect = [phi theta psi]';