Method for determining 0 position of U-shaped mobile rotation platform of large-aperture optical system

The invention discloses a method for determining the 0 position of a U-shaped mobile rotation platform of a large-aperture optical system. The method comprises the following steps: starting a positioning and orientating instrument by using an axis for determining the large-aperture optical system of an auxiliary optical system; measuring an included angle between a connection line of two measurement antenna phase centers and the true north, wherein the included angle serves as an included angle between an auxiliary optical system observing and aiming optical axis which is a main optical axis of the large-aperture optical system and the true north; inputting the angle value into a rotation platform operation system to determine the 0 position of the rotation platform. The method has the benefits that the method can be used without the limit of the meteorological condition, the test site support is not required, the positioning and orientating instrument is used for quickly determining the 0 position of the U-shaped mobile rotation platform, and the test preparation time is greatly shortened.