Ensuring vigilance in cargo tracking and security

A number of issues affect the security of shipping containers, the cargo they hold and the associated air, sea, and road terminals that handle them. The current methods of providing protection by the implementation of technology are described below, along with the necessity for investment in future innovative technologies.

Approximately 90% of world cargo moves in containers. More than 200 million cargo containers move between the major sea ports each year. US ocean-borne trade in 2003 amounted to more than US$700 billion. The US has 25 major seaports, receiving about 140 seagoing ships a day. These ships are laden with more than 16 million containers annually. Rail freight carriers have over 150,000 miles of track and more than 20,000 locomotives. In support of these, there are dispatching centres, yards, bridges, and tunnels to defend against terrorism.

There are over 1.6 billion air containers, known as Unit Load Devices (ULDs) in circulation. At any one time, 5% of ULDs are on loan to airlines. Losses from air containers in storage or transit are estimated at US$30 million to US$50 million per year. Globally, the total value of cargo theft is estimated at US$40 billion per year.

There are approximately 800,000 domestic hazardous materials shipments in the US each day, using all modes of transportation. About 90% of hazardous materials are transported on highways. The majority of these shipments are petroleum products and flammable gases but others include explosives; poisons; corrosives; flammable materials; infectious substances; and radioactive materials.

There is an ever-increasing threat of containers carrying a so-called ‘dirty bomb’. In the shadow of the risk to public health from such a device, there is the economic cost relating to the closure of a port and the resultant loss of trade. Customs officials are currently only able to inspect about 2-4% of containers annually. The use of radiation detection devices is not widespread, due to budget restraints and the low threat perception of an undetected device entering a port.

A large problem exists with containers that are transported with unknown contents. The illegal importation of drugs and illegal immigrants has been a constant issue with the US Coast Guard and customs officials. Migrant smuggling activity is valued at US$10 billion a year and the import value of drugs such as cocaine is approaching US$5 billion a year.

In addition to the threat of terrorism, there are other operational benefits of knowing where a particular container is located within a port, terminal or at sea and what the contents are. Piracy is an increasing problem, especially in southeast Asia where there are between 200-300 attacks each year at sea.

Tracking technologies

It is recognised that technology can be adopted to enhance, regulate and improve safety and efficiency within the industries concerned with the transportation of cargo containers.

The requirements and level of investment will depend on the need to comply with directives and improve supply chain management. An important factor that has also emerged is the need to combat acts of terrorism in the industry using locking and tracking devices monitored via software that can easily be installed and configured on a PC platform.

The use of tracking technologies ranges from identifying staff and their movements to providing containers with locks that can be monitored and traced in ports, terminals or anywhere across the globe. The contents of containers may be secured from source to destination with event histories tracked throughout. Within the terminals themselves there is a need to locate palettes, track vehicles and monitor portals such as exit/entry gates, dock doors and checkpoints. It is vital that the movement of dangerous cargo (including radioactive materials) is monitored throughout its transportation stages and that high-risk containers can be identified and treated accordingly by both operators and customs officials.

Seaport and air terminal authorities need to identify their requirements as to whether cargo is to be tracked within boundaries, located to specific co-ordinates or be monitored at all points in the transportation phase. How this information is treated will affect business operations and efficiency. Simple alarm and alerts may be all that is required locally, or detailed mapping and display of the whereabouts of containers throughout the world may be an option with information available via the Internet.

Using wireless technologies

There is a clear need to adopt wireless technologies to satisfy individual requirements. The most suitable ones currently available include low, high, and ultra-high Radio Frequency Identification (RFID); active tagging; electronic seals (e-seals); Real Time Locating Systems (RTLS); Global Positioning Systems (GPS); and the mobile telephone network that encompasses Mobile Communication Terminals (MCT) and Short Message Services (SMS). These technologies can all be integrated into internet

monitoring services using the standard Transfer Control Protocol and Internet Protocol (TCP/IP) for data transfer.

RFID can be broken down into passive and active technology. Passive transponders or tags use the electromagnetic radio frequency field generated by antennas to power the onboard silicon memory chips. Data can then be read from or written to the tag using interrogators or readers.

The restriction of this type of tag is that there is a limitation to the usable range (<3m) and number of tags (anti-collision factor) that can be read in the field at any one time. This is due to the amount of energy available to power, interrogate and communicate with each tag, especially if many are moving through the field at speed. Active RFID technology improves the read distance (100m) and memory size, but tags must have their own battery powered supply and consequently have a limited lifespan. The cost per tag is also greater for this type.

Active tags are normally proprietary devices developed for a particular purpose. They typically transmit information over longer distances (500m) at regular intervals to receivers that may monitor the tag’s status, general location or exact position. Status information may include a tamper check in the case of an electronic lock (e-seal) or information gathered by sensors controlled by the active tag. Sensors can be used to monitor temperature, light, humidity, noise, liquid levels, the presence of dangerous materials and other useful data.

To achieve the required coverage in a port or terminal, use may be made of strategically placed RFID or active tag readers communicating with access points (802.11b) to monitor zones. It may only be necessary to determine when a container enters or leaves a zone, giving its general location within a site. To more accurately determine the location of containers, the principle of triangulation can be used. This normally uses three readers strategically positioned to cover an area, whereby the distance to an active tag is measured by each reader and a software algorithm used to locate the position.

E-seals can be used in combination with a mechanical lock on a container door to ensure that the contents remain intact or untampered with throughout the container’s journey. Monitoring of these seals is predominantly required at the exporting company’s shipping yard and the container’s final destination, but hand-held or gate readers may be used at other stages to verify the lock status.

In response to a Request for Information (RFI) for smart and secure containers from US Customs and Border Protection, the World Shipping Council’s Security Advisory Committee suggests that e-seals have a unique seal number that can be electronically and visually read; that the date and time can be recorded when the seal was activated, sealed, opened or breached; and that e-seals have read but not write capabilities. In addition, they should meet the high security manual seal standards in ISO PAS 17712.

The proposal is that an e-seal cannot be re-used. To allow supply chain management to be addressed, a combination of RFID and e-seal technologies may be used alongside each other. A passive read-only RFID tag could be permanently affixed for the lifetime of the container with information such as container number and owner code. An active read/write non-reusable RFID cargo shipment tag can be affixed for that particular shipment upon stuffing. The standards for this type of tag could be formulated by the shipping community.

RTLS can be used to track assets or vehicles using GPS technology and the mobile telephone network. Vehicles and their contents can be monitored and tracked with communication available directly with the drivers. Remote disabling of transport is possible in case of security breaches and all data can be recorded and archived to assist fleet management. The principle of Geofencing can be employed, which only allows access of certain vehicles to restricted areas.

GPS equipment tracks assets using satellite tags that receive data from the 24 satellites orbiting the earth. In conjunction with the 5 monitor stations around the globe, encrypted data is received by the tag from a minimum of 3 satellites. The time each signal takes to reach the receiver is measured to determine the longitude and latitude of the device. This process is known as ‘trilateration’.

Satellites operate on two carrier frequencies giving normal and military precision code. Increased accuracy is also obtained if a fourth satellite’s data is used to eliminate clock synchronisation inaccuracies. Differential GPS (DGPS) gives even better accuracy, especially for moving objects. This system uses a surveyed land-based monitor station to determine atmospheric factors that can be used to provide correction offsets to calculate timings more accurately. Inverted DGPS uses standard receivers but tracking offices supply the correction factors.

A system that combines a GPS receiver with a Subscriber Identifier Module (SIM) card has the capability to convert coordinates to an SMS message to be sent over the Global System for Mobiles network. Such a device is known as a MCT. Data in this form is easily converted to the TCP/IP data format that can be used to display clear graphical information on a standard personal desktop or laptop computer.

Other issues raised by the World Shipping Council as a response to US Customs' request for information on secure container technology include the suggestion that any technology used should have a non-proprietary, open architecture allowing competitive sourcing of the product and its supporting infrastructure. It should be noted that hundreds of thousands of containers are opened each year during transit for legitimate reasons, often by foreign customs officials.

The design, use and application of security devices must address this reality. Leased containers comprise roughly half of the global container fleet: therefore technologies attached to any one container must account for this. The recommendation is that unless a device is permanently affixed to the container it should be designed for single usage. With wireless technologies it is important to recognise that some RFID frequencies and bandwidths are not commercially available in some major trading nations.

Although many of the issues of securing and tracking containers can be addressed by existing technologies, the cost of devices and the implementation of systems remains high.

There is still great scope for developing and improving monitoring and locating systems that use wireless communication. This ultimately requires investment in companies that understand the cargo transportation industry needs and can provide reliable, cost effective solutions that can be adopted on a global basis.

The level of protection now required for handling cargo containers is greater than ever. New rules and regulations have to be adopted quickly and correctly with technology undoubtedly employed to satisfy these requirements and additionally enhance supply chain management. Intelligent planning of security and tracking systems will not only protect personnel and assets, but over time increase efficiency and reduce the vulnerability of ports and terminals to terrorist attacks.

Existing specific technologies can satisfy certain safety requirements, but the combination of tracking and communication systems can provide total solutions that comply and assist authorities with the benefit of controlling and monitoring cargo throughout the world. There is a continued need for investment, the development of new technologies and solutions in order to cope with the evolving demands of the container transportation industry.

Ian Courtney is head of technology at Ozonelink Limited, a high-technology homeland security solutions provider


US Bureau of Transportation Statistics Annual Report 2001.

Article 1(a) of the 1958 IMO Convention.

The International Management Code for the Safe Operation of Ships and for Pollution Prevention.

International Ship and Port Facility Security Code.

Intersec Journal March 2004.

Oceanborne trade statistics 2003 supplied by The World Shipping Council.

Cost of Security for Sea Cargo Transport - The Logistics Institute Asia Pacific.

Explore our related content