Space intersection is performed by the trigonometric intersection assuming a parallel projection of IKONOS imagery due to its small FOV and frame size.

• 影像匹配是采用多重解析度区域影像匹配技术来完成共轭点之搜寻，接著再利用三角几何关系进行前方交会得到地面点三维空间座标，也就是数值地表模型。