The so called indirect integral operation means that Eular angles can be gotten from the direction cosine matrix which is received by the integral operation of quaternions or direction cosine.

• 飞行器导航中,姿态角的获取可以通过直接或间接的积分运算求得的,所谓间接获取即是指通过四元数或方向余弦的积分运算求得姿态矩阵,再从姿态矩阵中提取姿态角。