Microwave Solutions Guard Against Mounting Threats

June 17, 2009
From systems that perform surveillance, reconnaissance, and detection to the communications that deliver their findings, microwave technologies are being applied on the front lines of the battle against terrorism.

Terrorism continues to plague the US, as evidenced by the recent arrest of four men who planned to bomb synagogues in New York City. From a law-enforcement perspective, the problem with such threats is the varied forms that they take. The plan that was just foiled, while harmful and frightening, was localized. Yet the events of September 11, 2001 clearly were not. Those working in counter-terrorism must imagine every possible attack scenario and figure out how to prevent it. For help, both local and federal agencies have turned increasingly to technology. Microwave, millimeterwave, and terahertz electronic systems are performing an increasing amount of weapon, explosive, and chemical detection as well as surveillance. Microwave systems then enable this crucial information to be transmitted back so that diverse agencies can efficiently react.

Surveillance and reconnaissance are two of the main goals of unmanned aerial vehicles (UAVs), which have become a hotbed of development for defense applications. When rescue helicopters and aircraft are grounded due to heavy fog or smoke from wild fires, for example, remote-controlled, Global Positioning System (GPS) UAV Air Drones can be called in to continue search and rescue missions. Hailing from AirStar, part of the Mundus Group, Inc., the Air Drone boasts ducted fan technology and self-stabilizing counter-rotating propellers in a completely enclosed shell. As a result, it can safely operate near pedestrian bystanders, trees, buildings, bridges, traffic, and other infrastructure. With the Optics and Surveillance packages from sister company Air Intel Systems, police can observe, automatically monitor, and track moving vehicles while sending pinpoint-accuracy GPS coordinates and real-time, high-definition video images to enforcement agencies.

According to Joe Hajduk, CEO of dB Control, "Within the Department of Homeland Security, the Customs and Border Protection Agency is charged with securing our nation's borders, including detecting and preventing the entry of terrorists, weapons of mass destruction, and unauthorized aliens into the country. In its July 15, 2008 report to Congress, the DHS noted that it considers UAVs to be force multipliers' that allow the Border Patrol to deploy fewer agents in a specific area while maintaining the ability to detect and counter intrusions.' As such, UAVs are increasingly becoming integral to day-to-day operations. For instance, the Predator B monitors the US' southwest and northern borders from 65,000 feet above."

The traveling-wave-tube (TWT) amplifiers from dB Control are well suited for UAV applications (Fig. 1). Hajduk notes, "dB Control's TWT amplifiers are onboard several UAV platforms including General Atomics Aeronautical Systems' Predator A & B and Northrop Grumman's Global Hawk and Fire Scout. At any given second, there are more than 25 Predators in the air equipped with Lynx SAR/GMTI radar systems powered by dB Control's TWT amplifiers. It's the reliability of our amplifiers that enables the UAVs' radar systems to transmit near-real-time, fullmotion images of objects on the ground with resolutions as fine as 4 inches. Amazingly, these images can be captured from 16 miles above, in total darkness, through clouds and rain."

With cutting-edge developments ongoing in the UAV space, these drones are guaranteed to become more critical to DHS operations going forward. An example is a UAV that takes off vertically, but then flies like a high-speed plane matching the speeds of the MY-22 Osprey (about 240 miles per hour). Dubbed the AD-150 from American Dynamics Flight Systems, Inc., this plane underwent a wind-tunnel test at the A. James Clark School of Engineering's Glenn L. Martin Wind Tunnel. In the test, the wind tunnel's large turbine blew highspeed wind over a model of the AD-150 while sensors measured the resulting forces and moments from which flight behavior can be predicted (Fig. 2). The AD-150, which is slated as a reconnais sance vehicle to run scouting missions for the Osprey, can carry weaponry, an array of sensors, spy gear, or wounded soldiers utilizing its 500-lb. payload.

Another impressive UAV development will be witnessed at the end of this year, when Swarm Systems Ltd. will demonstrate 18 swarm innovations. Last November, the firm was awarded a UK Ministry of Defence (MOD) contract for developing and demonstrating an "Autonomous Hovering Micro Air Vehicle (MAV) Swarm." Several of these innovations will be demonstrated in a "perch, grip, and stare" capability in which a swarm of MAVs can settle in an area of interest and send back video and sensor information around the clock.

UAVs also are making headway in chemical, explosive, and drug detection. Through its subsidiary, Ionfinity, VIASPACE, Inc. is developing a sensitive miniaturized "sniffer" in a joint collaboration with NASA's Jet Propulsion Laboratory, Caltech, General Dynamics, Sionex, and Imaginative Technologies. The sensor is a compact standalone chemical device consisting of a detector known as a Differential Mobility Spectrometer, a non-radioactive ionization method that does not fragment or multiply-ionize sampled specimens, and a micro-gas chromatograph for confirmation and enhanced detection capability. The device will detect chemicals and materials of interest at parts-perbillion (ppb) levels after 6 s. The sensor is self contained with respect to power and communications.

Increasing innovation in radiological detection also is being seen outside of the UAV market. Although many of these sniffers are based on non-microwave technologies, they all rely on an RF communications backbone to report their findings. Last month, Raytheon Co. received an award for its Mobile Nuclear Radiation Detection System from Florida's Department of Transportation. Using advanced spectroscopic technology, this system detects and identifies nuclear radiation in mobile and stationary operations. The system will expand the state's ability to operate in urban environments in order to safeguard against nuclear threats on highways, bridges, overpasses, tunnels, ports of entry, and public venues like major sporting events.

To secure base aircraft hangars and flight lines, Median Communications has been awarded a contract to install a Defentect gammaradiation detection system at Offutt Air Force Base. Defentect's gamma-radiationdetection network continuously gathers data from an unattended, wide-area sensor grid. It analyzes that data at the system's incident command center using proprietary algorithms to determine the character and significance of a radiation threat. The communications subsystem passes crucial information to first responders so that they can act on it.

Such integrated solutions also are being implemented in airports and ports. At the May Airport Show in Dubai, Northrop Grumman Corp. debuted its airport security solution. Dubbed Airtight, it uses data from existing airport sensors and infrastructure to create a common operating picture that can be shared with emergency services and first responders. The sensor-fusion capabilities of Airtight make it possible to integrate traditional motion sensors and cameras as well as technologies like surveillance radar and surface-movement guidance and control systems (SMGCS), thereby offering a complete operational picture. Airtight provides a multi-layered and scalable solution that offers a range of airport security capabilities from threat analysis, detection, and assessment to planning and directing the actions of first responders. It leverages existing security assets including cameras, motion sensors, and access-control systems.

An integrated system from Raytheon was recently chosen by Providence, RI to improve port surveillance. Specifically, the program will improve port security with extended-radar and video-surveillance capabilities for northern Narragansett Bay and the Port of Providence. Raytheon Integrated Defense Systems has delivered sensors to include mobile video. Those sensors are integrated with an Athena data-fusion and operations center, giving city officials advanced warning and improved situational awareness in the region.

A system from DSIT Solutions Ltd., a subsidiary of Acorn Energy, Inc., also takes advantage of sensorsthis time to secure ports underwater. DSIT recently received a $2.3-million order for multiple sensors, which will protect a strategic site against underwater intrusion. The company's AquaShield intruder-detection sonar system automatically detects, tracks, classifies, and issues alerts for any kind of underwater threat approaching the site. The system supports real-time pinpoint tracking of the threat. It can be installed on a pier, jetty, breakwater, or on the seabed.

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Of course, all of these systemsand emergency responders in generalare largely compromised if communications are down. To enable the instant creation of a reliable communications infrastructure when the land-based network backbone is inaccessible, Starling Advanced Communications created the StarCar antenna system for land vehicles. In this self-contained system, all of the RF and electronics are housed directly on the antenna. The unit is easily installed on any emergency vehicle for critical communications or homeland-security contingency planning. The StarCar solution leverages the firm's coherent multi-panel antenna (CoMPA) technology, providing up to 40 Mb/s to facilitate voice, streaming Internet and video, and the transmission of other types of heavy files.

Jacob Keret, Starling's VP of Marketing and Sales, notes that homeland-security, public-safety, and military agencies face many communications challenges. They must continue to provide reliable communication links during events while supporting decision-makers with online data/video from emergency/critical/event scenes. At the same time, they must enable the immediate and reliable transfer of information comprising video, heavy data files, and photos. As Keret emphasizes, "Information from the field is a big strategic advantage for tactical operations and homeland-security and public-safety incidents requiring immediate action." To bridge public-safety and military networks, Spectrum Signal Processing by Vecima recently partnered with Communications Research Centre Canada. Together, they ported the Association of Public-Safety Communications Officials (APCO) Project 25 (P25) public-safety waveform to Spectrum's flexComm SDR-4000 softwarereconfigurable radio (Fig. 3). Supporting this waveform on a software-reconfigurable radio allows military and other users to more easily communicate with public-safety personnel, thereby better co-coordinating joint emergency efforts. The SDR-4000 multi-purpose, softwarereconfigurable transceiver combines heterogeneous processing including digital signal processors (DSPs), generalpurpose processors (GPPs), and fieldprogrammable gate arrays (FPGAs) in a 3U CompactPCI form factor.

Later this month, what is hailed as the largest commercial satellite ever to be launched will take to the air with the goal of providing integrated satellite and terrestrial mobile services for critical communications. Ideally suited to provide critical services to government, emergency responders, rural communities, and commercial users, the satellite uses 2-GHz spectrum to provide voice, data, and video communications to satellite/terrestrial mobile devices the size of a typical smartphone. By working with Hughes Network Systems, Space Systems/Loral has developed a two-way, ground-based beamforming technology that enables the satellite to re-allocate resources based on demand, thereby maximizing capacity. The satellite will be capable of generating over 500 spot beams covering the continental US, Canada, Alaska, Hawaii, Puerto Rico, and the US Virgin Islands.

In addition to transitioning its lawenforcement department from analog to digital communications, the city of Houston, TX is adding video capabilities to its helicopter fleet. Nucomm and RF Central, part of the Vitec Group's RF Extreme business unit, are shipping $2.5 million worth of equipment to the city as part of a homeland-security grant. Sean Drew, Business Development Manager of Military, Aerospace, and Government Programs for the Vitec Group, states, "The helicopter transmit system consists of an Access Remote Control System, ChannelMaster 6.5-GHz COFDM transmitter with AES encryption of video, and audio that transmits from a high-gain collinear omni-antenna. The tower and building-based receive systems consist of three high-gain sector antennas and one high-gain steerable antenna. Each antenna output connects to a 1x4 splitter that inputs to each of the three diversity Rx's at each Rx site. Each of the 4 Rx sites, in turn, uses diversity Rx's that utilize maximal ratio combining (MRC) to take the signal from each antenna to reconstruct the COFDM signal. Multiple diversity Rx's at each Rx site allow the HPD to maximize spectral efficiency by using co-channel transmission."

Microwave companies are clearly innovating to satisfy the call for surveillance, reconnaissance, detection, and communications solutions. Although these varied solutions work to recognize and help eliminate the threats of today, those threats are constantly evolving. Recently, military experts have begun pinpointing the vulnerabilities arising from our dependence on fossil fuels and the nation's electric grid, which will only be exacerbated by energy demand and climate change. The microwave industry, which largely got its start during World War II, now finds itself with an indispensable role in a battle that has no end in the foreseeable future.

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