设有A、B、P三点，A、B为已知坐标的点，P为未知点，用仪器测得∠PAB和∠PBA,根据A、B的坐标可求得P点的坐标，这种方法叫做前方交会-Features A, B, P three points, A, B point coordinates are known, P is an unknown point, as measured by the instrument ∠PAB and ∠PBA, the coordinates A, B coordinates of point P can