激光四象限定位光学系统具有体积小、精度高的优点。针对传统激光四象限定位光学系统结构复杂、质量大、成本高的缺点，提出采用菲涅尔透镜代替普通透镜。根据激光四象限定位光学系统定位原理，分析了光斑照度分布对四象限探测器输出偏差信号与目标方位角之间线性关系的影响，认为只有中心光照度低于边缘光照度的光斑才能产生这一理想线性关系。给出理想激光四象限定位光学系统的设计方法，利用此方法设计了实例，验证了分析结果的准确性。模拟结果中输出偏差信号与目标方位角的比值接近常数。

The laser four-quadrant location system has the advantage of small-size and high-precision. Aiming at the disadvantages of structure-complicated, large weight and high-cost of traditional laser four quadrant location optical system, the Fresnel lens is used to take the place of the ordinary lens. Based on the principle of laser four-quadrant location optical system, effect of spot illumination distribution on ratio between four-quadrant’s deviation signal and the azimuth angle is analyzed, conclusion that only the spot whose centre illumination is lower than edge illumination could meet the ideal liner relation is obtained. The design method of ideal laser four-quadrant location optical system is given, a four-quadrant location optical system which can testify the analysis result is designed using this method. The ratio between deviation signal and azimuth angle of simulation result could approach a constant value.