星敏感器是一种通过观测恒星，直接提供运载体在惯性空间中三轴绝对姿态的光电仪器。它是目前精度最高的姿态敏感器。如果同时借助时钟系统提供的时间和GPS提供的运载体地理位置，可以精确确定运载体的水平姿态和航向。根据星敏感器测量过程中涉及到的各坐标系，从它们之间的转换关系入手，推导了水平姿态和航向解算模型，并在星敏感器上实现。最后，构建了实验装置，进行实际测星定姿试验。实验结果表明，星敏感器输出的水平姿态和航向可以正确反映实际载体水平姿态和航向，从而验证了此模型和计算方法的正确性和有效性。

A star sensor is an electro-optical instrument used to provide the absolute 3-axis attitude of a craft in the celestial sphere utilizing star observations. If the latitude and longitude of the craft and time are obtained, the horizontal attitude and heading of the craft can be obtained. The transformation among the reference frames involved by the star sensor work are analyzed in the paper. The model of the craft horizontal attitude and heading based on star sensor is set up. An experiment on horizontal attitude and heading determination based on star sensor is carried out. The validity of the model is confirmed.