Of all long-range positioning technologies, the Global Navigation Satellite System (GNSS), which includes the original GPS constellation as well as the GLONASS, GALILEO, and BEIDOU systems, provides the most ubiquitous global coverage. A GNSS tracker communicates with the satellite network using a process known as trilateration, where at least three satellites are used to determine the latitude, longitude, elevation, and time of the trackable asset. Regional and local positioning can also be achieved using cellular and LPWAN networks, where base stations act as beacons. While not as precise as GNSS positioning, cellular tracking leverages the ubiquity, standards, and service availability of commercial networks. Solutions using cellular positioning consume less battery power than those based on GNSS. Cellular tracking is often used for fleet management applications and can be used in combination with GNSS tracking or on a standalone basis.
Long-range tracking systems require a wide area network for internet connectivity, and multiple wireless technologies may be needed, depending on the container's location. Satellite networks, such as Iridium or Inmarsat, would be essential at sea, while less expensive cellular or LP-WAN networks could be used when closer to shore or on the road between the warehouse and port.
Short-range tracking or Real-Time Location Systems (RTLS) solutions, figure 2, are typically deployed to address indoor use cases, such as the tracking of people and equipment. Short-range solutions are common in large buildings like hospitals or factories, although they can also be used outdoors, in yards, and so on.
GNSS positioning is not viable in indoor locations, so alternative wireless ranging techniques must be used. Internet connectivity in these environments can be achieved using existing infrastructure, such as Wi-Fi.
