By applying the formula, which transforms a terrestrial vector to its local (station) coordinate system, the orientations of the marginal displacement vector detectable by GPS can be determined.

• 将边际位移向量视为空间二点间的向量，依三维大地测量学坐标转换理论，可迳求出边际位移向量的方位角及其天顶距，进而算出其东、西二方向的分量。