Abstract: The invention comprises a sensor unit, and method and system for cargo and personnel detection and tracking. The method comprising the following steps: detecting, or creating for new CCUs, a unique CCU signature, wherein the unique CCU signature is constructed by analyzing images of the CCU capture by a sensor device, and analyzing the images according to one or more of predefined detection methods, and the analysis providing a combination of one or more descriptors defined by CCU feature points, contours, dimensions, weight, colour, movement pattern, neighbour CCU feature point, planned travel route or last known location.