The BRDF is the theoretical basic of multi-angle remote sensing quantitative interpretation. And the viewing angle is the important parameter, including viewing zenith and direction angle. Using a mechanical disk and draw a circle in the surface is the traditional measuring method. However, this method has the disadvantages of heavy equipment, lower accuracy and efficiency, and it isn' t fit for measuring waters. Consequently, a new method based on electronic technology is developed. The accelerometer is used with the purpose of measuring gravitational acceleration vector, and the magnetoresistive sensor is used to sense the geomagnetic field. Then the viewing angle of BRDF can be got by coordinate projection theory. It has the advantage of low cost and consumption, meanwhile it' s easy to operate. The viewing zenith angle is in the range of -90°~90° and the viewing direction angle is in the range of 0°~360°, accuracy is up to 1°. It meets the measurement requirements for BRDF viewing angle.%BRDF(双向反射分布函数)模型是多角度遥感定量解译的理论基础,观测角是模型中的重要参数,其中包括观测天顶角和观测方向角.传统的测量观测角的方法是采用机械圆盘以及在地表画圆,但这种测量方法设备笨重、精度低、效率低,不适合水域的测量.提出了一种新的电子测量方法,利用加速度计测量重力加速度的三维分量,利用磁阻传感器测量地磁场的三维分量,通过坐标投影原理得到BRDF模型中的观测角.这种测量方法设备便携、成本低、效率高.观测天顶角的测量范围为-90°～90°,观测方位角的测量范围为0°～ 360°,在测量范围内的测量精度为±1°,满足BRDF观测角的测量要求.
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