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, however—even 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 Men—a 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: www.borderfenceproject.com. 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 NanoBioSentinel—a 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).