运动补偿下成像光谱仪的辐射能量采集特性(英文)

Characteristics of Spectral Radiance Measured by Imaging Spectrometer with Motion Compensation

为研究运动补偿下成像光谱仪的辐射能量采集特性,首先推导出系统探测器像元采集到的光谱辐射能量与瞬时视场光轴摆角的关系式。据此,在可见近红外(0.4～1.0μm)光谱范围内,计算不同摆角下系统采集到的光谱辐射能量与观测星下点(对应光轴摆角为0o)时系统采集到的光谱辐射能量的比值。结果表明:与观测星下点相比,运动补偿过程中系统采集到的总光谱辐射能量随光轴摆角的增大而减小,并且其中地面目标辐射所占的比例也随之减小。系统信噪比有类似的特性。要使整个观测过程辐射能量提高的倍率保持或接近预期的补偿倍率,光轴摆角尽量小于30o。

In order to study the characteristics of spectral radiance measured by imaging spectrometer with motion compensation, the relationship between measured radiance and the tilt angle of the axis of Instantaneous Field of View （IFOV） was derived. In the Visible-near Infrared （VNIR） （0.4-1.0 μm）, the ratio of the spectral radiance measured by imaging spectrometer with a certain tilt angle a to that with tilt angle α=0° （corresponding to observing nadir point） was calculated. Compared with observing nadir point （tilt angle α=0°）, the measured total radiance decreases with the tilt angle a increasing in the process of motion compensation. And the proportion of measured target radiance in measured total radiance also becomes small. In order to make the increment of measured radiance keep or approach the gain by design in the process of motion compensation, the tilt angle of axis of a should be less than 30°.