Abstract: In order to solve the difficulty to measure the beam unparallelism of infrared scene simulator with transmission optical system,we propose the measurement and compensation method with the infrared pentaprism and infrared imaging detector in this paper.First,we analyze the mechanism of generation of the beam unparallelism of infrared scene simulator and propose an improved measurement method and a compensation method of the infrared beam unparallelism.By the movement of the infrared pentaprism on the one-dimensional translation stage,the direction of parallel beam from the infrared scene simulator is changed by 90 °.The infrared imaging detector can receive the beam and measure the distance changed by the process of cutting the beam.This distance in the infrared imaging detector reflects the angel of beam unparallelism.The results show that the method can be used for the 1′ beam unparallelism measurement requirement for the transmission optical system of infrared scene simulator in the application of infrared guidance hardware-in-the-loop simulation test.

Key words: Transmission optical system, Beam unparallelism, Infrared scene simulator