One embodiment is directed towards a physics package of an atomic sensor. The BS is configure to generate a DL-R-MAP for the BS and a first frame according to a resource usage status of the multi-hop network, and transmit the first frame in a DL relay zone according to the DL-R-MAP for the BS, wherein the first frame comprises a plurality of DL-R-MAPs for RSs, and each of the DL-R-MAPs for RSs. The antenna structure comprises a radiating mechanism configured to transmit or receive electromagnetic radiation. The processor is configured to compare the sensed capacitance at the first capacitor with a reference capacitance to determine the composition of the fluid in the fluid line at the first capacitor. The sensor device is configured such that on detection of the second marking within the image within a predetermined time period of detection of the first marking, the sensor device communicates with the speed controller to set the maximum speed limit to that associated with the second marking and on detection of no marking within the image, the maximum vehicle speed remains unchanged.