水平方向上的大气透过率和热辐射计算模型研究

大气透过率和大气热辐射是影响目标本征辐射特性测量精度的重要因素。传统的空间目标辐射特性测量方法就是利用大气观测设备配合MODTRAN等软件或者利用红外恒星计算大气热辐射。然而,水平方向上的空气对流和复杂的地面状况会导致模式计算大气热辐射不确度增大,而火箭、导弹等目标发射起始段的红外特性测量有助于实现目标识别。因此,研究水平大气透过率和热辐射对于目标红外辐射特性测量具有十分重要的意义。针对以上问题,首先借鉴垂直廓线理论建立了同层大气“水平温度廓线”模型。然后推导了水平方向上的大气透过率和热辐射计算公式,并对其进行了实验验证。最后将大气热辐射的MODTRAN软件计算结果和实验测量结果进行了比较。结果表明,基于传统软件的热辐射计算精度为8.65% ,而本文方法的计算精度为4.91%。该实验说明这种算法在水平方向上是正确的。通过公式推导和实验验证说明了本文方法的合理性,为目标辐射特性测量过程中的水平大气透过率和热辐射计算提供了一种新的思路。

A Model of Calculating Atmospheric Transmittance and Thermal in Horizontal Direction

Atmospheric transmittance and thermal radiation is an important factor which affects the measurement accuracy of target radial characteristics. The traditional method of measuring spatial targets radial characteristics is calculating atmospheric thermal radiation by using atmospheric observation equipment and software (e.g. MODTRAN) or infrared star. The air convection in horizontal direction and complex ground conditions lead to increased uncertainty in the calculation of atmospheric thermal radiation, however, infrared characteristics of target launching initial stage are of great significance to recognition. Therefore, it is very important to study the calculation method of atmospheric thermal radiation in horizontal direction to improve the accuracy of infrared radiation measurement. Based on the above problems, we first established the "horizontal temperature profile" model of the same layer atmosphere. Then we deduced the formula for calculating atmospheric thermal radiation in horizontal direction, and carried out experimental verification. Finally, we compared the results of MODTRAN software calculation and experimental measurement of atmospheric thermal radiation. The experiment shows that the accuracy of traditional software is 8.65% and that of the proposed calculation method is 4.91%. The experiment fully proves that the calculation method is correct in horizontal direction. In this paper, the validity of the calculation method is demonstrated by formula derivation and experimental verification. And this paper provides a new idea for the calculation of thermal radiation at low elevation in the measurement of target radiation characteristics