Sensors Mag

Too Close for Comfort

March 31, 2006 By: Tom Kevan

With international terrorism front-page news and cargo containers such a tempting target, we need wireless sensor-based security systems that provide early detection and notification.

With international terrorism front-page news and cargo containers such a tempting target, we need wireless sensor-based security systems that provide early detection and notification. So why are we waiting until the containers are sitting in U.S. ports to look for trouble?

More than 9 million cargo containers arrive in our ports each year. Since the September 11, 2001, terrorist attacks, the government, port facility managers, importers, and exporters have expressed growing concerns that container security represents one of the weakest links in our defense against international terrorism. Specifically, security experts fear that terrorists could use legitimate containers to deliver nuclear, biological, or chemical weapons of mass destruction to U.S. soil. While there are a number of sensor-based container security systems available, it would seem that most would warn us too late of the potentially dangerous cargo.

Short Notice

A recent Information Week article, reported that between Sept. 28 and Dec. 13, GE Security, part of General Electric's infrastructure division; Unisys; and China International Marine Containers tested new "tamper-evident secure container" technology. In both the embedded and standalone versions, the unit consists of a sensor, circuit board, and 2.4 GHz radio. The sensor device is said to have a lifespan of 10 years, which is the typical life for a container. A cell phone or a stationary reader with a 30-meter range can access the sensor's data. Interrogation of the security device would usually take place in the port facility.

GE's security system is not the only product that provides warnings in the ports. Other systems using sensor and RFID technology have been tested in port facilities in the northwest, with similar results.

Now, I don't dispute that the situation poses a real threat. The detonation of a weapon of mass destruction in Long Beach, CA, or Portland, OR, would cost the lives of millions of people. And the use of wireless sensor systems is the logical way to go. What bothers me is that the systems that I have mentioned so far all deliver the warnings too late. The weapon is already sitting in the middle of port facilities located in highly populated areas. If the reaction to the warning is not fast enough or something goes wrong, a lot of people would lose their lives, vast tracts of property would be destroyed, and international trade would grind to a halt.

A Better Alternative

It seems that the time to identify such a threat would be when the container was at sea. And the system used to make this assessment should be automated so that a warning would go out even if the ship's crew were compromised in some way.

I have heard about a sensor-based system that provides this automated advance warning. San Jose-based Rae Systems offers a multisensor wireless system called RaeWatch. The system uses a mesh network to link the sensors that monitor the cargo containers. The results are then passed on to a satellite uplink radio, which passes the data to databases used by customs and security personnel. In short, the warning is received while the ship is still at sea.


As an afterthought, it is kind of ironic that the same country that is building security-enhanced cargo containers—China—is the same country that agreed to provide Iran with missile technology. Maybe that is China's version of a win-win business model.

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