Wireless Network uses “Smart Dust” Technology

As they move unseen under a carpet of stars through ocotillo and pungent creosote shrubs, the terrorists have not completely escaped detection — a network of tiny wireless sensors is tracking the zealots. The sensors communicate with each other through a self-configuring network by sending information along in short "hops" from one node to the next until it reaches a gateway that reports the information to the authorities.

The above scenario could happen because of our independent research and development efforts integrating low-power, wireless systems for border protection, advanced perimeter security, and other surveillance applications.

Such systems consist of several types of sensor nodes — the size of a deck of playing cards — configured in a low-power, wireless, self-configuring and self-healing mesh network. While the enabling technology (called a "mote," which includes a radio, a microprocessor, an interface for sensors and power, and networking software) is from Dust Networks, SAIC provides everything else that makes the network functional. (In fact, SAIC is an early integrator of motes from Dust Networks. Our integration and testing has led to key improvements in their mote products.)

Our work includes selecting sensors (which can measure a selected physical parameter — vibration for instance), developing sensor processing capabilities, and integrating the sensors, our own sensor processing board, batteries, and an antenna with motes into a sensor node package that meets deployment and system lifetime requirements.

SAIC also is developing data processing and fusion algorithms for these types of sensor networks. The networks include many different kinds of sensors, so the information needs to be fused into actionable information for our end users.

For example, we have integrated sensor nodes with a device that measures magnetic fields — a magnetometer. When a metallic vehicle disrupts the Earth's magnetic field, a signature is created that can be used to detect the vehicle and estimate its speed and direction. Fusion with information from other sources, such as seismic sensors, can help to characterize the size and type of the vehicle. Our networks, designed to detect, locate, track and characterize personnel and vehicles, include seismic, magnetic, acoustic, and passive infrared sensors. Some sensor nodes are also equipped with miniature cameras, like the ones used in cell phones, which can be triggered by other information in the sensor network for visual target confirmation. Other sensor nodes also include an optional GPS receiver.

Effective exploitation of this rich new source of information from a dense spatial network of sensors will require a new approach to data fusion. According to SAIC scientists, smart dust networks will provide less detailed information from individual sensors than is available from the current generation of unattended ground sensors, but they will provide a dense spatial sampling that is impractical with the current technology. Fusion techniques based on spatial and temporal correlations, including imaging processing, will be key to successful exploitation of these new sensor networks.

SAIC scientists believe Smart Dust enables ubiquitous deployment of a dense network of small, inexpensive and long lifetime sensors. There are many potential commercial, industrial, defense and intelligence applications. For example, it has been speculated that these kinds of sensor networks might be deployed in remote areas (such as the U.S. — Mexico border or the mountains of Afghanistan) by hand or by UAV. The sensors would self-configure into a network to collect information to support U.S. efforts in counterterrorism.

Not surprisingly, our emphasis for this technology has been on security needs of government customers. For example, the U.S. Border Patrol is one of the nation's largest consumers of unattended ground sensors — and it is looking to upgrade. Currently, its sensors are wired to each other and each one is connected to a hub that has a very large battery source. In contrast, our wireless sensor nodes have the equivalent of AA batteries and an expected lifetime of a year. As battery size decreases, the size of the sensor nodes will decrease — perhaps to the size of an aspirin tablet.