星载探测器的信噪比(Signal-to-Noise Ratio, SNR)决定预警卫星检测并识别弹道目标的能力, 因此分析各因素对 SNR的影响极具现实意义。首先分析了目标和背景辐射、探测器内部各种噪声产生的电子数, 引出了基于电子数法的 SNR计算模型; 其次利用某些具体的性能参数、导弹尾焰辐射强度以及 MODTRAN仿真的大气透过率和背景辐射亮度计算了不同类型探测器的 SNR值, 为后续 SNR灵敏度分析奠定了基础; 最后从目标与环境、焦平面和光学组件三个方面对 SNR进行了较为全面的灵敏度分析, 给出了 SNR对模型因子的响应曲面, 得到了 SNR灵敏度分析的定量和定性结果。

Signal-to-Noise Ratio (SNR) of infrared warning satellite-based detector contributes greatly to detecting and recognizing the ballistic missile, so analyzing various effects on SNR is of great practical importance. Given the electrons generated by radiance from target, background and noise source in detector, the SNR model was proposed firstly. Then SNR results for various working detectors were simulated by some performance parameters, plume radiance and atmosphere transmittance and background radiance calculations from MODTRAN. Furthermore, sensitivity analysis was made fairly comprehensively for SNR model in terms of target and environment, focal plane and optical module. Response surfaces about SNR versus model factors were given and some qualitative and quantitative significant conclusions had been drawn. The research in this paper can support the design of infrared detector in space-based warning satellite and the operation of missile defense.