Modern star sensors are powerful to measure attitude automatically which assure a perfect performance of spacecrafts.
They achieve very accurate attitudes by applying algorithms to process star maps obtained by the star camera mounted
on them. Therefore, star maps play an important role in designing star cameras and developing procession algorithms.
Furthermore, star maps supply significant supports to exam the performance of star sensors completely before their
launch. However, it is not always convenient to supply abundant star maps by taking pictures of the sky. Thus, star map
simulation with the aid of computer attracts a lot of interests by virtue of its low price and good convenience. A method
to simulate star maps by programming and extending the function of the optical design program ZEMAX is proposed.
The star map simulation system is established. Firstly, based on analyzing the working procedures of star sensors to
measure attitudes and the basic method to design optical system by ZEMAX, the principle of simulating star sensor
imaging is given out in detail. The theory about adding false stars and noises, and outputting maps is discussed and the
corresponding approaches are proposed. Then, by external programming, the star map simulation program is designed
and produced. Its user interference and operation are introduced. Applications of star map simulation method in
evaluating optical system, star image extraction algorithm and star identification algorithm, and calibrating system errors
are presented completely. It was proved that the proposed simulation method provides magnificent supports to the study
on star sensors, and improves the performance of star sensors efficiently.