Container tracking is another area of application. Container tracking usually relies on RFID
tags which are attached to the containers, boxes and pallets included in the shipment and then
read at a number of points along the way. The limitation of using RFID only for container
tracking is that data can only be captured where appropriate infrastructures such as RFID
readers are in place. Recently a new breed of container tracking devices has been developed.
They feature several sensors that can operate simultaneously, and offer a range of tracking,
security and monitoring functionality (Smith and Hale, 2010). These devices are equipped
with onboard photoelectric sensors to monitor changes in the light level within a container
(indicating that a container has been opened or breached), accelerometers that detect impact
and GPS modules for location tracking. They are also able to access GSM networks and SMS
channels to send text or email alerts when waypoints are reached or anomalies occur, i.e. a
container can be tracked in real time in any part of the world. All the sensor data is available
to shippers, consignees, third party logistics providers and/or customs as well as terminal and
port authorities, via proprietary web and mobile interfaces. A typical example is the container
tracking system developed by Maersk and IBM (Maersk and IBM 2005; BDP1 2005) known
as tamper-resistant embedded controllers, or Trecs, for large shipping containers. The Trecs
are supported by back-end software and a wireless network, and a sensor system gives
shippers a remote view of the state of their cargo in transit. The data can be sent via antennas
on a container roof over short-range wireless networks such as Zigbee or Bluetooth, and over
longer-range mobile and satellite networks. Such systems give multimodal transport users the
opportunity to manage their supply chain more easily and to make changes in advance of
cargo arriving at its destination.