Near Infrared Distance Sensing Method for Chang’E-3 Alpha Particle X-Ray Spectrometer
LIANG Xiao-hua, WU Ming-ye, WANG Huan-yu*, PENG Wen-xi, ZHANG Cheng-mo, CUI Xing-zhu, WANG Jin-zhou, ZHANG Jia-yu, YANG Jia-wei, FAN Rui-rui, GAO Min, LIU Ya-qing, ZHANG Fei, DONG Yi-fan, GUO Dong-ya
Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
Abstract：Alpha particle X-ray spectrometer (APXS) is one of the payloads of Chang’E-3 lunar rover，the scientific objective of which is in-situ observation and off-line analysis of lunar regolith and rock. Distance measurement is one of the important functions for APXS to perform effective detection on the moon. The present paper will first give a brief introduction to APXS, and then analyze the specific requirements and constraints to realize distance measurement, at last present a new near infrared distance sensing algorithm by using the inflection point of response curve. The theoretical analysis and the experiment results verify the feasibility of this algorithm. Although the theoretical analysis shows that this method is not sensitive to the operating temperature and reflectance of the lunar surface，the solar infrared radiant intensity may make photosensor saturation. The solutions are reducing the gain of device and avoiding direct exposure to sun light.
Key words：Alpha particle X-ray spectrometer;Near infrared;Distance sensing;Inflection point
[1] FU Xin-xin, GONG Chun-hua, LIU Meng-jun(富鑫鑫，龚春花，刘孟君). Journal of Shanghai University of Electric Power(上海电力学院学报), 2010, 26(4): 395. [2] http://rredc.nrel.gov/solar/spectra/am1.5/. [3] Gueymard C. Solar Energy, 2004, 76(4): 423.
