With its high accuracy,autonomity and all-weather characteristics,astronomical navigation has become another important navigation means besides satellite navigation,inertial navigation and radio navigation. Due to the influence of weather conditions or environmental factors,the real sky visibility could not be guaranteed,and research and development tests of navigation products are severely constrained,therefore it is necessary to carry out relevant research with a high precision star simulator. A collimator based infrared star simulator was established,and a high precision measurement method for angular position of the simulated stars was proposed with Leica TM6100A theodolite as a main tool,the measurement method has a good repeatability of less than 5″.