详细论述了星光半物理实验平台用遮光罩抑制实验环境杂光的一种新的设计思想，用以最大程度地还原星光模拟器产生的模拟星光与周围暗背景的对比度，从而大大提高了实验检测精度。根据实验系统原理推导出一整套设计公式，并提出利用程序递推计算遮光罩内部挡光环位置和尺寸的新方法。在TracePro杂光分析软件中建立遮光罩实验模型，对遮光罩径向成1°～85°之间的18个偏角的平行光源进行杂光抑制情况模拟，通过计算得到不同偏角遮光罩杂光抑制能力曲线。仿真结果表明，杂光偏角为25°以上时，光通量抑制比下降到10-3量级。加工出实物在半物理仿真平台上进行检验，实际拍摄结果显示，以该方法设计的遮光罩能够有效抑制环境中的杂散光，还原星光模拟器的对比度，使CCD相机能够准确观测到6等以上的星，保证了实验系统的可靠性。

In order to restore the contrast of celestial simulator-generated starlight with the surrounding dark background, improve the recognition rate of the star map and navigation solution accuracy, a new design of the lens hood for celestial navigation simulation system to decrease environmental stray light is discussed detailedly. Design formula is derived in accordance with its principles, and a new method to calculate the position and size of the vane inside the hood with computer program is proposed. Using the baffle model established in TracePro, 18 different deviation angles between 1°~85° of parallel light source are simulated. The stray light suppression curves for different deviation angles are obtained. Results show that above 25°, suppression ratio of the luminous flux decreases to the order of magnitude of 10-3. A physical test is carried out on semi-physical simulation platform. The actual results show that this design of the lens hood can decrease the environmental stray light and effectively restore the contrast of starlight simulator.