The soiling of heliostats is a highly detrimental process that affects the energy conversion efficiency of solar tower power plants as soiled heliostats suffer significant drops of reflectance. Tools that allow reliable soiling measurements and predictions are needed to accurately assess the induced power losses and to develop strategies that mitigate the related detrimental effects. The results of an experimental campaign conducted at the Fraunhofer ISE laboratories are presented and discussed in this paper. Four different techniques were used to measure the reflectance of artificially soiled mirrors: (i) measurements obtained with a portable specular reflectometer 15R-RGB (D&S), (ii) spectral analysis of the outcomes of a spectrophotometer, (iii) post-processing analysis of the measurements obtained with the device VLABS (very low angular beam spread), and (iv) microscope-captured image processing. A detailed comparison between the measurements obtained with each device is performed to evaluate the agreement among them and the motivations of slightly different trends in the results. Finally, the outcomes of the analyses are proved to give further strength to the validation of a previously developed solar reflectors soiling model.

定日镜的污染是一个非常有害的过程，会影响太阳能塔式发电厂的能量转换效率，因为污染的定日镜反射率会显着下降。需要允许可靠的污染测量和预测的工具来准确评估感应功率损耗并制定减轻相关不利影响的策略。本文介绍并讨论了在弗劳恩霍夫 ISE 实验室进行的实验活动的结果。四种不同的技术被用于测量人工弄脏的镜子的反射率：(i) 使用便携式镜面反射仪 15R-RGB (D&S) 获得的测量值，(ii) 分光光度计结果的光谱分析，(iii) 对使用 VLABS 设备获得的测量结果进行后处理分析（非常低的角光束扩展），以及 (iv) 显微镜捕获的图像处理。对每个设备获得的测量结果进行详细比较，以评估它们之间的一致性以及结果中略有不同趋势的动机。最后，分析结果证明进一步加强了先前开发的太阳能反射器污染模型的验证。