工程测量学中前方交会的vb代码：已知A、B两点坐标，观测了角a、b，求P点坐标。用坐标反算AB方向的坐标方位角。-Engineering measurement science in front of the intersection of vb code: known A, B, two coordinates, the observation angle a, b, seeking a point P coordinates. Calculated by coordinates, the a