Recent debates and activism centered around possible immigration reform have once again highlighted a major problem for this country: the task of securing its borders. No matter what political stance one takes on the current state of immigration in the US, most agree that the nation's borders are open avenues to terrorists seeking to gain entry into this country. The thousands of individuals who crossed borders into the US can attest to that fact. Patrolling and performing surveillance on every stretch of our expansive borders is physically impossible at this point, howevereven if President Bush's recent plan of having the National Guard deployed at the borders is put into place. To compensate for this and other Homeland Security weaknesses, many engineering companies are developing innovative technology solutions.

In the area of border surveillance, for example, BAE Systems (Rockville, MD) has developed a number of systems with the goal of maintaining and enhancing the security and integrity of national boundaries. At the Milipol 2006 trade show this past May, the company launched its mobile Deployable Surveillance Unit (DSU). Designed to supplement traditional fixed security installations, the DSU offers both mobile and flexible surveillance. It provides all-weather day and night monitoring for suspicious activities.

The DSU combines radar, electricaloptical (E-O) and infrared (IR) cameras, and motion sensors with the company's flexible command and control system. Dubbed Spider, that system lies at the core of the DSU. The Spider system integrates a wide range of sensors for specific roles and requirements. It can operate independently or networked with other DSUs and fixed installations. In networked configurations, the situational awareness picture is automatically relayed to other units or the command headquarters via a fully integrated communication system including very-small-aperture-terminal (VSAT) satellite, UHF, and VHF radios (Fig. 1) .

Through Project Athena, Raytheon Co. (Waltham, MA) also has targeted border control. In April, the company announced the successful completion of an operational demonstration of Athena along the southwest border of Texas. The project's integrated command, control, communications, computers, intelligence, surveillance, and reconnaissance (C4ISR) and sensor system was fielded to support the US Customs and Border Protection (CBP) Rio Grande Sector and 14 other interagency partners. During a six-week mission, Athena and CBP detected, intercepted, and deterred transnational threats, drugs, and people smuggling across the US-Mexican border. The large joint-operations area included 160 miles of coastline, 120 miles of land border, and nine ports of entry.

During a DHS effort named " Operation Gulfview," Project Athena integrated multi-sensor and multi-source information. It included the deployment of 200 miles of secure, high-capacity/availability wireless networks, integrated air-ground surveillance sensors, computing and communications (C2) equipment, and improved C2 and processing services. The resulting system enabled the efficient and improved detection, identification, tracking, fusion, and dissemination of actionable intelligence to DHS law-enforcement agencies. From the mission's tactical operations center, CBP and joint interagency operators used Athena's shared situationalawareness picture to coordinate, synchronize, and execute air, ground, and maritime operations.

Wireless technology also is essential-to a border-improvement project being organized by the California-based immigrationreform group, NoInvaders.Org. The inspiration for this effort is derived largely from the Minute Mena group of volunteers who began patrolling the US-Mexico border over the past year or so. NoInvaders.Org's proposal is to build a man-and animal-tight barbedwire fence that will be secured with solar motion lights, electronic sensors, and solar wireless cameras. The cameras will upload a constant video feed of every fence and border section to a website: Participants can allow the activation of an audible "alarm" on their computer browsers anytime a crossing occurs. Depending on the nature of the activity, they can then alert the Border Patrol or nearest sheriff's department. As a result, those who live far from the USMexican border can still act as "Minute Men."

Of course, the US's sea entry points must be protected as stringently as its land borders. Many technologies and products have emerged to tighten port security. A team of nuclear engineers recently completed a radiation-detection system for both foreign and domestic seaport security. Scientists from New Mexico-based Technology Management Consulting Services and its subsidiary, the Global Transshipment Monitoring Co., have demonstrated their Mobile Point-of-Need Detection System (M-PONDS) for officials from both the US Congress and federal agencies.

M-PONDS, which was developed in conjunction with Thermo Electron Corp. (Waltham, MA), uses the latest spectroscopic radiation-detection technology. It promises to identify the radioactive contents of cargo containers in a drive-through mode. It even infers whether the source is shielded. Thanks to M-PONDS' mobility and versatility, each and every container can supposedly be scanned without impacting the flow of goods. The smallfootprint, self-contained system comes with its own power source and wireless communications.

Detectors like M-PONDS are a rising trend. A plethora of detectors have emerged to sniff out anything from radiation to biological weapons. HiEnergy Technologies (Irvine, CA) specializes in neutron-based diagnostic technology. In April, the company's scientific team completed work on a new algorithm that should allow its SIEGMA, CarBomb Finder, and STARRAY explosive-detection systems to quickly characterize and identify radioactive materials. In addition, those systems will be able to determine whether or not a suspicious package is a radiation-dispersal device like a "dirty bomb."

Biowarfare agents also are the focus of the NanoBioSentinel device from Microchip Biotechnologies (Dublin, CA). The US Department of Defense (DoD), through its Army Edgewood Chemical and Biological Center (ECBC), has awarded Microchip Biotechnologies a $365,000 SBIR Phase II one-year contract to continue the development of NanoBioSentinela handheld nanofluidic device that detects biowarfare agents. The objective of this effort is to design, build, test, and commercialize an advanced nanofluidic, microchipbased, automated nucleic-acid and immunoassay analyzer. The NanoBioSentinel will input liquid samples from aerosol samplers, wipes, and other sources. It also will implement bead-based techniques to capture and purify target organisms.

Another company that is active in bioagent detection is MicroFluidic Systems (Pleasanton, CA). In April, it was awarded a Phase II continuation of its Bioagent Autonomous Networked Detector (BAND) System development contract by the Department of Homeland Security's (DHS's) Homeland Security Advanced Research Projects Agency (HSARPA). The contract from HSARPA is for the development of an instantaneous bioaerosol detection system. The Phase II continuation program focuses on producing manufacturing prototypes of the proof-of-principal systems developed in the Phase I contract. In Phase III, additional systems will be built for testing as potential replacements for the nation's current BioWatch program.

Although the technology behind these systems may not include any RF innovations, such devices will rely on higher-frequency technologies to communicate their message. As such, they have an essential role in the information dispersement that is so vital to keeping the US safe. Some detection systems already include such communications capability. An example is Universal Detection Technology's BSM-2000 anthrax-spore-detection device. After detecting the presence of airborne bacterial spores, such as anthrax, the BSM-2000 alerts security and emergency-management personnel.

The LifeShirt 300 from VivoMetrics, Inc. (Ventura, CA) combines detection and communications capabilities with help from Thermo-Electron, Inc. (Waltham, MA).

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These companies are delivering a real-time monitoring ensemble to aid first responders and hazardous-material (hazmat) workers. The real-time monitoring system is worn beneath hazmat protective gear (Fig. 2) . It combines the Thermo Matrix CNET mesh network with environmental-hazard detection, global positioning, and the VivoMetrics LifeShirt 300 system. The LifeShirt 300 is a simple-to-use chest strap that monitors breath rate, heart rate, activity, posture, and skin temperature continuously and in real time.

Data from the LifeShirt is integrated-with a Thermo-Electron radiation dosimeter, which continuously collects radiation-exposure information. In addition, a Global Positioning System (GPS) radio uplink transmits the worker's geographic location. Data is transmitted wirelessly using a Thermo Electron "Mote"—an ad-hoc, self-healing mesh network that uses each responder's radio as a network node. As responders spread out across the incident zone, a constantly evolving network allows all data to be sent to the incident command center. The command centers can have a standoff distance that is up to two miles from the clean-up incident.

Although such detection capabilities are impressive, they would not be nearly as effective without a communications backbone to spread their message. This fact becomes quite daunting when one considers the interoperability problems and other communications failures that were brought to light after September 11, 2001. Thankfully, many companies have invested both research and engineering efforts in improving communications for first responders. Through a recent partnership, for instance, UTStarcom, Inc. (Alameda, CA) and QUALCOMM, Inc. (San Diego, CA) are focusing on rapidly deployable mobile communications. The companies are developing a QUALCOMM Deployable Base Station based on UTStarcom's MovingMedia 2000 all-IP Code Division Multiple Access (CDMA) wireless core-infrastructure technology.

Using third-generation (3G) CDMA cellular technology, the QDBS provides a highly portable, all-IP CDMA2000 800/1900-MHz network. That network enables reliable mobile voice and 153-kb/s data service in both standalone scenarios or when interoperating with commercial or other private networks. The MovingMedia 2000 from UTStarcom is designed to provide wireless operators with a complete, all-IP solution that reaps the benefits of 3G networks. The solution offers a smooth migration path for CDMA2000-based providers, allowing them to utilize broadband data technologies like CDMA2000 1xEV-DO. The system also is backwards compatible with second-generation (2G) CDMA (IS-95) technology.

Perhaps the ultimate achievement in deployability thus far can be credited to Raytheon Co. This past winter, a command and control system that Raytheon designed for the US Army demonstrated its ability to support the Army National Guard's homelanddefense mission. Called the Army Airborne Command and Control System (A2C2S), this mission-equipment package transforms selected helicopters into airborne command posts. When it is installed on Army UH-60L Black Hawks, the system allows commanders and their staffs to maintain digital command, control, and communications while moving through the battle space at more than 200 km/h.

That same airborne command and control (C2) capability allows emergency responders to maintain uninterrupted C2 no matter where they are. When the A2C2S is equipped with the Homeland Defense Communications Module, it can connect civilian emergency first responders with National Guard and active military units in a C2 network that enables all of them to support the mission. During a Homeland-Defense-Communications-Module concept demonstration, the system proved that it could track and control first-responder vehicles, retransmit video, and "crossband" otherwise incompatible communications systems.

Because all of these deployable communications solutions are wireless, it should not be a surprise to see a number of broadband approaches. In Motion Technology (New Westminster, BC, Canada) and SkyPilot Networks (Santa Clara, CA) are providing an endtoend solution for delivering missioncritical mobile broadband communications to first responders. Their mobile data-networking infrastructure integrates 4.9-GHz mesh-networking technology with carrier mobile data networks like EV-DO. In Motion's onBoard Mobile Gateway (oMG) enables multiple Ethernet, IEEE 802.11i, or serial devices in a public-safety vehicle to connect securely with agency headquarters over SkyPilot's 4.9-GHz technology or cellular data carrier networks (based on best available coverage). In addition to 4.9 GHz, the oMG currently supports GPRS, EDGE, 1xRTT, EV-DO, UMTS HSDPA, UMTS TDD, and Flash OFDM.

In May, Alvarion (Tel Aviv, Israel) announced an alliance with IBM (White Plains, NY) to offer and deliver wireless systems to municipalities and their public-safety agencies. The result is said to be a new approach for the delivery of scalable, multi-layer IP-based wireless networks that support data, voice, and video for both fixed and mobile applications. The IBM and Alvarion Information Communication Technology (ICT) system is based on a pilot wireless-network implementation in Fresno, CA. In that system, IBM's productivity-enhancing mobile applications are built on Alvarion's broadband and mobile wireless systems. The Fresno publicsafety network is intended to enable police officers to send and receive text messages, still images, and full-motion video using their car-based mobile data terminals and handheld personal digital assistants (PDAs). The broadband network features seamless switching at vehicular speeds in order to maintain session persistency with the police department's legacy 800-MHz narrowband network.

The deployment of high-quality broadband applications also is the goal of M/A-COM's (Lowell, MA) VIDAMAX System. This open-standardsbased broadband solution was created to deliver integrated, public-safety-grade wireless broadband video and data services for mission-critical applications. The VIDAMAX system applies the 802.16 open-standard, IEEE-based wireless-broadband-communications protocol to the 4.9-GHz public-safety band. By using both the 802.16 protocol and the licensed band, the system can provide features like guaranteed quality of service and scalable capacity. VIDAMAX should enable public-safety organizations to deploy high-quality broadband applications like video surveillance and vehicle access support. It is the company's newest airinterface component to take advantage of the company's VIDA IP network.

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Such communications networks hold the promise of providing interoperability and dependability in the event of emergencies and even a national crisis. Yet these networks only form the backbone of the communications infrastructure. The radios and other devices used by US military and first responders also must enable seamless communications. Innovations are taking place down to the component level to make such devices a reality. For example, engineers at the Georgia Tech Research Institute (GTRI) have created an approach to phased-array-antenna design that could allow a single ultrawideband (UWB) device to do the job of five conventional antennas (Fig. 3) .

The "Fragmented Aperture Antenna" is a computer-designed planar system. It has already demonstrated a 33:1 bandwidth, which compares more than favorably to the 10:1 ratio achieved by conventional designs. The researchers believe that they can extend that range to at least 100:1 for use in radar and communication applications. The GTRI design takes advantage of the electronic interaction between antenna elements known as "mutual coupling." The GTRI engineers realized that they could take advantage of this interaction by electrically connecting the elements.

The antenna also relied on computerdesigned innovations for its "broadband screen backplane," which is made up of foam and partially conductive films. Due to the limitations of conventional test systems, the 33:1 device had to be evaluated in three different antenna test facilities to cover the entire frequency range. The new design will reduce antenna volume and weight. Beyond potential use on military aircraft, ships, and ground vehicles, the technology could have applications for devices that would not need broad bandwidth. Examples include wearable antennas that could be incorporated into military uniforms or even tents.

In the area of Homeland Security, engineering innovation clearly remains continuous and strong. The US can increasingly rely on technology to secure its borders, ports, chemical facilities, and more. In addition, the country's citizens, first responders, and government agencies can trust detectors to warn of any harmful agents. Of course, all of this technology relies on a communications backbone for information delivery. With the plethora of technologies and solutions targeting that area, however, it is clear that emergency communications will only become more reliable.