December/January 2016 | Vol.13, No.1 INSIGHT & ANALYSIS FOR GOVERNMENT DECISION MAKERS

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From SBINet to IFT: +

A DHS Insider’s View

Jihadists at the DoorCountering terrorist infiltration at the SW borderEXCLUSIVE

Brides of ISIS: The Internet seduction of Western females into ISIS

IT Resolutions for Federal Agency Leaders in 2016

How Drones are Revolutionizing Campus Security

Invisibility Detection:Using tomographic sensor technology to see threats

BY G. I. “DUTCH” FORSTATER

Invisibility DetectionUsing tomographic sensor technology to see threats

Throughout human history we have championed the invisible. In trying to catch prey, we are silent - employing paint and cam-ouflage. Using natural cover - we sneak up on prey. Now, with a technological leap, we are able to see biological images within spaces not surveilled by cameras or other means. Invisibility de-tection and the creation of the methods to avoid being seen are both valuable security attributes.

From Watergate to gated estates, people have been entering properties with the intention of invisibility, but usually only a simple alarm is triggered and, perhaps, a possible capture of video documentation. Detecting a person as a three dimensional object entering a space is called volumetric detection.

What if a private property, warehouse or sensitive critical evi-dence storage location could be secured by not only detecting human presence, but tracking, following and recording for true verification of human entry? This is the new direction of sensor technology.

The biggest drawback to volumetric detection is that in some cases they cannot see what is visible. These devices usually have line of sight restrictions so that anything behind a wall will not be visible. Volumetric detection sensors are usually optical, ther-mal, acoustical, microwave or ultrasonic. Each has its inherent limitations. Not seeing through walls or obstacles makes humans non detectable both in magnitude and direction (which way did they go?).

Seeing what’s behind walls and doors without placing sensors in the space is a challenge. Reinvention and application of tech-nology helps with this challenge. Useable technology is based on evolution, adaptation and reinvention of existing technology.

New concepts often use unrecognized simple adaptations by in-genious thinkers who can recognize solutions with the reinven-tion of additional components for adoption into new uses. This is the basis for radio frequency tomographic sensor technology.

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What exactly is tomographic detection? Tomography is actu-ally a solution to the problem of super imposition of structures when taking slices in x-ray, radio frequency, or, in our discussion, using WiFi in the gigahertz range. Super imposition is when you get layer upon layer of things you really don’t want to see.

For instance, when taking a picture of a faraway object using a telephoto lens, you may not only pick up the individual you’re trying to track, but also the trees, branches, leaves, fog and blowing dirt. Tomography is the ability to get beyond these distractions by filtering them out by focusing in on the object in the distance; in this case - moving human beings behind walls and doors.

In security, WiFi has been a tempting tool for use in volumetric detection. It has been used in duress alarms, tracking and in sen-sors. The use of WiFi in a tomographic sense, that is to cut away all the stationery objects and to focus on the organic materials that enter the space, is worth investigating for security applications.

How is it done?Joey Wilson, PhD, earned his doctorate in 2010 from the Univer-sity of Utah by adapting and reinventing uses of high frequency WiFi communication and adopting it to possible security sce-narios. Along with his dissertation advisor, Neil Patwari, an investigation began into radio frequency technologies that are adaptable to use WiFi in the 2.4 gigahertz range to detect human beings as “obstructions” to radio frequency waves that would otherwise be “pattern-stationary.” That is, always in a constant pattern without variance. Those entering the space cause significant variance of the stationary electromagnetic radio frequency field.

Multiple integration platforms form the basis of the aggrega-tion of technologies (AoT) used by Wilson in his experiments into radio tomography. It uses a blend of ZigBee radio mesh networks, narrow band radio WiFi transmission, amplification, detection and AES 128 encryption.

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It uses 32-bit ARM microprocessor architecture and has em-bedded flash memory as well as RAM for program storage. It meets IEEE 802.15.4 - 2003 standards to integrate MAC address functions for each independent device to run embedded ap-plications. Output can either be simple contacts or utilize IPv6 Protocol - commonly referred to as an IP based wireless. It even uses four layers of the OSI model - physical, data link, network and transport.

This technology is blended into a streamline mass-produced, micro miniaturized, inexpensive product readily available from manufacturers such as Atmel, Silicon Labs and NXP Semicon-ductors. Wilson’s company, Xandem, uses these devices as nodes and a processing unit with custom software. The current design uses multiple nodes surrounding an area to be protected that are each independent and redundant using mesh network-ing technology. It is reported biological objects over about 40 pounds moving in the room are sensed, providing a detected output within 5,000 sq. ft. area or about 50,000 cubic ft. of vol-ume.

Each device is the size of a pack of gum and has a minimum amount of setup requirements with versatility of applications. Its small size can, in and of itself, be considered of intentionally covert design.

How is it used?In Xandem’s case, this motion detection system has a number of applications in the security world for volumetric detection in secure spaces. Through funding grants by the National Science Foundation, these devices were designed to be inconspicuous or remain totally hidden even inside walls or covertly inside fur-niture. They can be wired permanently, be plugged into electric outlets, or be battery operated and portable.

It can cover entire areas with a detection height exceeding 10 feet. It penetrates all interior spaces, so it’s not line-of-sight like a passive infrared detector. It even penetrates without using higher intensity frequency waves like in microwave detectors.

It’s immune to dirt, clutter, changes in the environment, tem-perature, humidity, sunlight, ventilation issues or darkness. Moving furniture, walls or contents has little effect.

Unlike walking slowly within an ultrasonic detected space, using temperature masking for passive infrared detectors, or painting over other detection systems, there is little in the way of mask-ing a biological, organic-based species from being detected in WiFi filled space - other than flooding with an easily recogniz-able jamming signal.

Of course the first application might be for residential or busi-nesses where there are no large pets and everything is stable during protected periods. But other future applications include

use by SWAT teams; placing devices with portable electronics in battery-powered plastic cases around the outside of a hos-tage situation or perhaps a school where the first responders can track individuals inside.

The importance of this use will become significant when the detailing of a weapon can be discriminated against those of per-haps a dozen other individuals in the same area. SWAT teams are more efficient and threats less of a guessing game upon quick entry with the ability to tomographically witness through a laptop the tracking of individuals without the risk of placing internal sensors.

Applications in seeing the invisibleSome applications are simple, while others may be more auto-mated and high tech. One application outside of security may be home automation and monitoring. One example could be using the system to monitor for elder care without having cam-eras throughout the property while even providing an alarm for lack of movement over a certain period of time. A house could be wired with these devices to automatically turn on lights, heat, or to even re secure zones after leaving.

The “sterile zone” concept of homeland security using this technology could be useful in many smaller airports for sterility compliance. Airport checkpoints can be closed entirely - with volumetric detection of anyone trespassing into the sterile zone. Likewise, the US Secret Service could use instant deploy-ment sensors after sweeps and clearance for absolute positive verification of no intrusion into the cleared space. The same would be true for verification that no electronic eavesdropping devices were placed prior to an event after RF, audio, and junc-tion (cellphone parts) detectors were used.

Other security uses of WiFi include the transportation and lo-gistics market which experiences significant losses. Lawrence Livermore National Labs developed a system using WiFi for se-curing cargo containers using WiFi technology.

Two final application examples include one that may well prove useful now, and another that may seem futuristic. First, with its potentially lower nuisance alarm rates, built in mesh networking, small current required for power and small de-vice size with easily replaceable elements, a perfectly confined “line type” volumetric detection system may be obtainable for high-security fenced perimeters where two existing fences of at least 10 feet high exist and where the center is designated “no man’s land.” This one type of sensor may overstep the lackluster performance of buried cables, the expense of fiber optics, the awkward appearance of microwaves and infrared detectors and overcome obstacles and discriminating effects of optical and thermal cameras.

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Bridging over older high security detection barriers may pre-vent detection and still requires verification usually by cameras. Not so with a WiFi based tomographic system. The verification is built in, and viewable. Cameras are needed only for identifica-tion.

In our second example, AoT certainly may go to this radio tomo-graphic imaging security system. Melding three inch sized gyro drones each with its own transmitter, and the deployment of 20 swarming “smart drones” can provide an instant mesh network to detect movement inside hostage or target sites that may be penetrated with RF signals but invisible to the perpetrators. These “flying ZigBees” could be pre positioned, virtually silent, and provide actionable data within the target premises that would otherwise be unobtainable. Being able to successfully locate the hostage(s) or targets with real time accuracy allows neutralization of threats while reducing risk.

AnalysisFeatures of future systems will include better location and vec-tor discrimination, better detection, a log history with playback and Application Program Interface sets so integrated systems can call and monitor for quick assessment through preconfig-ured maps.

The future looks promising. Since it is WiFi, you may be able to address the entire sensory zone through computer interface or mobile app to call up its URL and monitor data, change sensitiv-ity and stream data.

The next 15 years of evolution, adaptation, and reinvention of radio frequency based security sensors using aggregation of technologies will continue to be one of the most aggressive se-curity growth markets.

G. I. “Dutch” Forstater is CEO, COO and chief engineer of Professional Systems Engineering LLC, which he founded in 1986 and which is nationally known for its expertise in design and engineering of integrated systems for complex critical infrastructure projects. Forstater has 35 years’ experience in data communications, including network distribution/control, data center design and protection, advance UPS/ATS/generator design and physical/virtual network security.

Invisibility Detection

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