What they are
Cargo trackers are battery-powered devices attached to containers or pallets that report location, and frequently environmental condition, throughout a journey.
Connectivity options
They use cellular networks (4G/LTE, NB-IoT, LTE-M) for cost and coverage near land, and satellite for the open ocean and remote routes.
Trade-offs
Designers balance battery life against reporting frequency, cache positions while offline, and update devices over the air to keep them current.