Abstract：In this paper, to solve the seven-parameter model of the three-dimensional datum transformation, quaternion is introduced to construct rotation matrix. The spatial rotation axis, rotation direction and angle of quaternion are determined by using simple spatial geometric principles, resulting in more accurate initial rotation matrix. The matrix coupled with a more accurate approximation of the scale parameter and the translation parameters is substituted into the linearized observation equations, which can quickly and accurately determine the exact value of each parameter and then improve the reliability and stability of solution. Meanwhile Simulation results show that the algorithm is applicable to three-dimensional coordinate conversion about any angle.
