The aim of the present work was to determine the characteristics of a tracking scintillation detector by measuring cosmic muons above- and underground at the Gran Sasso National Laboratory (LNGS). The detector has been designed for demonstrational purposes and had never been involved in scientific research before. It is a compact, layered detector using plastic scintillator bars and silicon photomultipliers (SiPM). In the present setup no energy information is used. In the underground laboratory we had to deal with a very low rate of muons (6 orders of magnitude less than on the surface). For this reason we optimized the trigger configuration. During the evaluation process we designed and optimized a maximum likelihood line fitting method which is able to deal with the high dark count rate and the non optimized detection efficiency of the detector. We also carried out simulations to calculate the actual flux and intensity from the measured ones. Finally, we compared our results with the literature and they were found to be in agreement.