Abstract:Based on the requirements of good image quality, miniaturized dimension and high-temperature adapatability on infrared optical system applied in the battle field environment, and in order to realize real-time detecting and tracking on tank targets by joint transform correlator, an athermalized infrared telephoto objective with the features of compact structure, light weight, good image quality and environmental adaptability was designed. According to the biggest battle distance of tanks for 3km, the parameters of the optical system were defined as: f=200mm,F=3,2ω=3.056°, and its working wavelength was set as 8~12μm. Based on the comparison of current three athermal technologies, passive optical athermalization design was applied for the infrared optical system. It is proved that the modulation transfer function can approach the diffraction limit in the temperature range of -40~70℃. The telephoto objective can be used for tank sight, and it meets practical application requirements of tracking and recognition for tank targets.