求翻译：将光纤捷联罗经牢固的固定在水平和静止的基座上，稳定后求出稳定点艏向。关闭罗经 12小时至 7天，第二次启动罗经，稳定后求出稳定点首向。再关闭罗经12小时至 7天，第三次启动罗经，稳定后求出稳定点艏向。这样获得的三个稳定点艏向中，测取其中任意二个稳定点艏向之差。数据记录表格见附表4。是什么意思？

Fiber-optic strapdown compass firmly fixed on the base level and still find the stable points, stable heading. Close Luo 12-7 hours, the second start the compass, find the stable point of the first to stable. Then turn off the compass 12-7 hours, the third start compass, the stable to find the stabl