空间TDICCD相机动态信噪比计算方法研究

信噪比是空间光学相机系统的主要设计指标之一,可用于表征相机的辐射性能.文章通过建立遥感卫星轨道模型,分析计算一年中任意时刻用太阳高度角和卫星观测角描述太阳、卫星、地面目标点之间的相对位置关系,并将计算得到的卫星观测角和太阳高度角等参数导入大气传输软件MODTRAN,输出在相机入瞳处的地面目标光谱辐亮度,再根据信噪比的计算方法,最后完成TDICCD相机动态的信噪比计算值.通过该方法,可以计算任一时刻任一观测目标的信噪比,这将有利于判断在某一时刻的能量是否满足观测要求,以随时改变TDICCD的探测器级数,使得成像像质达到最佳.

Research on Calculation Method of Dynamic SNR of TDICCD Camera

The SNR is one of the primary parameters in optical sensor system, which can be used to reflect radiation performance of remote sensor. The orbit model of the remote sensing satellite was built, then the solar angle and observer angle, which were used to describe the relative position of the sun, the satellite and objects, were input into the air transmission software MODTRAN, the spectral radiance calibration was output by this model, and the real time SNR of TDICCD camera was completed. By the proposed method, dynamic SNR at any time and for any observation objects can be calculated, which will help to estimate whether the energy is enough for observation. The result is used to change the level of TDICCD to make the image quality best.