A cargo detection unit that detect the status of cargo and loading activity within a container. The device transmits microwave radio frequency energy pulses and detects reflections from cargo. Similar to the operation of a radar, the reflected pulses are then analyzed to determine (a) the presence of cargo, such as by comparing the reflected pulses against stored empty containers signature signals and/or (b) detecting a Doppler effect, as caused by loading and/or unloading cargo from the container. The device may use standard radar signal processing techniques, i.e., a digital signal processor, to generate and analyze the reflected pulses cargo status. Activity reports can be forwarded to a cargo tracking unit such as one that uses a wireless mobile telephone communication network to report cargo status to a central location.