the reason why gps leveling cant be used for height transfer across obstacle is that the height datum of both sides of obstacle is not consistent.
gps水準无法直接应用于跨障碍高程传递,其关键原因在于障碍物两侧的高程基準不一致。
the key of gps leveling across sea is that the height datum on each side of channel is not consistent, so the general geometrical fitting method can not be used directly.
gps跨海水準的关键问题是海峡两侧的高程基準不一致,因此无法采用常规的数值拟合方法。
the higher requirement of the former coordinate datum, height datum and gravity datum was in dire need of improvement and update in modernization.