Lincoln Laboratory is operated by MIT as a Federally Funded Research and Development Center for performing research and development in advanced electronics. During the past year, agencies of the Department of Defense (DoD), namely, the Air Force, the Army, the Navy, the Defense Advanced Research Projects Agency (DARPA), and the Ballistic Missile Defense Office (BMDO), supplied approximately 80% of the Laboratory's budgetary support. The Federal Aviation Administration (FAA) provided most of the non-DoD support, which also includes work for the National Aeronautics and Space Administration (NASA) and the National Oceanographic and Atmospheric Agency (NOAA). Lincoln Laboratory also carries out precompetitive research with industry under approved Cooperative Research and Development Agreements. For the federal fiscal year 1996, Lincoln Laboratory received $317 million, supporting the efforts of 1067 professional technical staff.
The following administrative changes occurred at the Laboratory Steering Committee level during the year: Mr. Frank D. Schimmoller became the Chief Financial Officer and Mr. Buckner M. Creel became Associate Head of the Administrative Division.
Activity at the Laboratory focuses on surveillance, identification, and communications technology development for the DoD, and on air traffic control technology for the FAA. Technical work areas include radar and optical sensors, measurements, and systems; communications; signal design and processing; lasers; solid state devices; digital technology, circuitry, and data systems; and tactical control systems. Unclassified summaries of several accomplishments during the past year are presented below.
SURVEILLANCE TECHNOLOGY
Lincoln Laboratory continues to support DARPA and the U.S. Air Force Wright Laboratory in their efforts to develop a foliage-penetration (FOPEN) synthetic aperture radar (SAR) system for the detection and discrimination of stationary ground targets that are obscured by foliage. Using data collected in 1995 by the Naval Air Warfare Center/Environmental Research Institute of Michigan P-3-aircraft-mounted ultrawideband SAR, Lincoln Laboratory has confirmed and extended earlier encouraging results applying change-detection and discrimination algorithms to the FOPEN automatic target recognition problem. Lincoln Laboratory is directing a DARPA-sponsored experiment planned for August 1997 that will utilize the P-3 SAR as well as the Swedish CARABAS II VHF SAR. Data from this exercise will allow comparisons between VHF and UHF SARs for detecting foliage-obscured targets.
Lincoln Laboratory has been supporting DARPA in the development, implementation and test of technologies and systems for detecting and recognizing stationary and moving ground targets using SAR imagery and moving target indicator (MTI) radar measurements. The Laboratory was a key participant in the development of a semiautomated system (only a few operators) for real-time exploitation of the large quantities of SAR imagery provided by current and future wide-area SAR systems. The baseline phase of this system, referred to as the Semi-Automated IMINT Processing (SAIP) system, was completed in the Spring of 1997 with an engineering evaluation in connection with field exercises at the National Training Center in California and the White Sands Missile Range in New Mexico. Current activities focus on an enhanced system to be completed in the Fall of 1997. The exploitation of SAR imagery for stationary targets is complemented by the development of technologies and system concepts for recognizing moving targets via radar-based one-dimensional (range profile) and two-dimensional, high-resolution images.
Lincoln Laboratory is responsible for the design, development, and demonstration of the Advanced Land Imager (ALI) that will be incorporated on the National Aeronautics and Space Administration's (NASA) Earth Orbiter-1 mission now scheduled for launch in May 1999. ALI will demonstrate advanced technology to reduce size, weight, and power requirements in order to meet NASA's Mission to Planet Earth science needs in the 21st century.
Lincoln Laboratory is collaborating with the MIT Civil and Environmental Engineering Department in remote monitoring of in-situ contamination using optical spectroscopy. This work uses miniature, fiber-coupled UV lasers to excite fluorescence in organic pollutants such as benzene, toluene, and xylene. The ultimate objective of the research is to develop a multiprobe system for long-term monitoring of contaminants in soils and ground water. This past year, field measurements were conducted to explore the performance of a single filter probe in realistic contaminated-soil conditions. In addition, lab measurements were conducted to investigate laser-induced-breakdown spectroscopy with microlasers.
In collaboration with the MIT Department of Earth and Planetary Science and the Haystack Observatory, Lincoln Laboratory has been investigating the feasibility of using the Haystack Long Range Imaging Radar (LRIR) to detect and track near-earth asteroids (NEAs). In the course of this investigation the LRIR successfully observed asteroid 4179 Toutatis at the range of 5.28 million kilometers. NEAs are potential targets for scientific exploration and could represent a possible collision threat. In the future, an upgraded Haystack Radar could be used to provide precise range and Doppler measurements on newly discovered NEAs to support cataloging efforts and asteroid exploration missions such as Clementine 2.
MISSILE DEFENSE
The Theater High-Altitude Area Defense (THAAD) system is currently undergoing field testing. The system is designed to provide large-area defense against theater ballistic missiles. During the past year, Lincoln Laboratory provided support to several key aspects of THAAD radar development. This sensor provides the surveillance and fire control for the THAAD system and came on-line early in the year. Laboratory support includes testing and analysis of the THAAD radar baseline discrimination architecture, characterization of radar performance, and analysis of the radar performance during THAAD flight tests at White Sands Missile Range for government evaluators. It also includes data analysis and performance evaluation of the THAAD radar for the Theater Missile Defense Critical Measurements missions conducted at Kwajalein.
The Kwajalein Missile Range (KMR), for which Lincoln Laboratory serves as Scientific Advisor, is preparing to support testing of theater missile defense components and measurement programs aimed at acquiring data essential to the development of advanced ballistic missile defense capabilities. The Laboratory has provided the U.S. Army Space and Strategic Defense Command, the sponsor of KMR, with a five-year plan for the modernization of the instrumentation assets. This effort, which will begin in FY98, will result in a more efficient operation of the measurement facilities through use of a common set of signal processing subsystems, central computers, recording systems, and software. It will result in the ability to develop software, carry out system health diagnostics, and conduct mission operations remotely from the Kwajalein Control Center and thereby reduce the commuter flights between Kwajalein and Roi Namur Islands. The Laboratory will continue to support KMR from Lexington in the test planning of missions and in the reduction and analysis of data.
Lincoln Laboratory is developing the prototype COBRA GEMINI radar system, which will be used to acquire data in rest-of-world (ROW) ballistic missile launches. Since the end of the Cold War and dissolution of the Soviet Union, the missile data collection effort has been focused on ROW countries rather than on Soviet systems. This air transportable mechanical scanning dish radar is also designed for operation on a TAGOS ship. COBRA GEMINI will be available for testing in 1998.
Over the past several years, Lincoln Laboratory and the Advanced Electronic Guidance and Instrumentation System (AEGIS) PMS-400 office have been supporting the development of the Navy Area (or lower tier) Theater Ballistic Missile Defense (TBMD) system. Much of the early work covered an analysis of AEGIS performance in autonomous and cued search modes. The studies quantified the cueing accuracies of systems such as the Defense Support Program satellites, netted AN/SPY-1 and Patriot radars, and airborne Infra-Red Space Telescope/Laser Detection and Ranging sensors. The AN/SPY-1 firm-track ranges and SM-2/BLK-IVA flyout capability were then related to potential defended footprints against a wide class of TBMs.
More recent work has covered a TBM debris environment characterization based on the measurement data base. Data from a number of sensors such as the Kwajalein radars, COBRA JUDY, and the Airborne Surveillance Testbed were used to quantify the radar and IR characteristics of TBM debris. The results of the analysis have been used to define system requirements for the Navy Area TBMD system. Current work focuses on the development of discrimination algorithms and timelines for the system.
More recently the Laboratory has begun systems analysis work for the Navy Theater-Wide (or upper tier) TBMD and Anti-Air Warfare Programs. This work has included an assessment of potential radar and IR discrimination metrics in the exoatmosphere. Other work has covered an analysis of new sensors and techniques for area defense against low-altitude cruise missiles. The results are being used to plan an acquisition strategy for developing new Navy surveillance and fire control systems.
AIR DEFENSE TECHNOLOGY
The Radar Surveillance Technology Experimental Radar (RSTER) system was redeployed at the Makaha Ridge site on the Pacific Missile Range Facility after the Cruise Missile Defense Advanced Concept Technology Demonstration Phase I (ACTD phase I) demonstration in order to continue the Navy/DARPA-sponsored advanced early warning (AEW) technology testing and demonstration. Data collection and analysis during 1997 includes the development and demonstration of advanced wideband and narrowband waveforms, beam forming and target-tracking techniques, and phenomenology data to support cruise missile defense. The summer of 1997 campaign will involve sensitivity and system stability verification, interference rejection, metric accuracy determination, and scenarios with simulated low-flying cruise missiles.
The Airborne Seeker Test Bed (ASTB) is based in a Gulfstream II aircraft which provides high-fidelity RF and IR reference instrumentation sensors that are used in parallel with special-purpose wing pod payloads carrying production seekers or sensors under test. The combination of the system under test with the instrumentation sensors yields powerful insights into the performance of sensor systems and advanced signal processing algorithms.
Improvements to the aircraft's internal computer network and real-time signal processing capabilities have enabled the in-flight demonstration of advanced countermeasure algorithms and better control and combination of data from the increasingly more intricate network of sensors. FY97 saw the addition of a new RF seeker pod which has been used in two major measurement campaigns in Nevada for a total of 26 data collection flights. During the most recent campaign the Test Bed passed the 400th mission mark. Near-term plans include two IR measurement campaigns in September and October, followed by the addition of two new IR seeker pods.
The modern battlefield requires that airborne early warning surveillance platforms, such as the E-2C, detect small targets in the presence of severe jamming and sea/land clutter. Adaptive signal processing techniques, such as space-time adaptive processing (STAP), enable enhanced target detection capability in the presence of clutter and jamming. These techniques use multiple receive antenna channels and digital signal processing algorithms to shape the receive beam pattern in the spatial and doppler domains. The current E-2C APS-145 radar has two receive channels. A significantly higher number of receive channels are required for STAP processing. Digital receiver technology will significantly reduce the receiver form factor by sampling directly at the RF frequencies and by eliminating most of the analog components. The down-conversion and the in-phase/quadrature signal generation are digitally performed by using a high-performace VLSI signal processor.
A single-board demonstration of the digital receiver concept has been completed. The receiver consisted of RF front-end circuitry, a high-speed analog-to-digital converter (ADC), and a VLSI digital down-conversion chip set. An 8-bit 3-GSPS Rockwell ADC was used for the initial prototype. For the digital down conversion, approximately 65 billion operations per second (GOPS) were required per channel. A full custom CMOS VLSI digital down-conversion chip set was developed using a very high performance scalable bit-level systolic cell library. Each chip in the chip set functions as a massively parallel signal processor and consists of tens of thousands of 1-bit processors. By using massively parallel signal processing, each chip can perform up to 45 GOPS using an established 0.6-um CMOS fabrication process. In the near future, the scalable bit-level systolic array cell library will be adapted to smaller feature sizes, which will enable the entire down-conversion process to be accomplished with a single chip.
COMPUTER-BASED RECOGNITION TECHNOLOGY
Under the Advanced Distributed Simulation Program, funded principally by DARPA and the Defense Modeling and Simulation Office (DMSO), Lincoln Laboratory developed software for a prototype run-time infrastructure (RTI) for linking together a broad range of DoD models and simulations. This software is a key element of the DoD High-Level Architecture for Modeling and Simulation, which is now required for all future DoD simulation applications. The prototype RTI software is being used in the Fall of 1997 in a major demonstration of DARPA's Synthetic Theater of War (STOW) program, an Advanced Concept Technology Demonstration (ACTD) being developed for use by the U.S. Atlantic Command (ACOM) in joint training exercises.
An enhanced version of the Lincoln Laboratory speaker identification system was tested along with systems from seven other laboratories in the 1997 National Institute of Standards and Technology (NIST) evaluation, and for the second consecutive year the Lincoln Laboratory system scored best in all categories. The Laboratory system was a Gaussian Mixture Model system with Universal Background Model and handset normalization. As an example of the results, for 30-second utterances with training and testing on the same handset, the Lincoln Laboratory system achieved a false-alarm rate of 1.5% at a 10% probability of a miss.
Lincoln Laboratory's English/Korean translation system has been significantly enhanced, and has been demonstrated at Combined Forces Command (CFC), Korea, at the April 1997 coalition exercises. A multi-stage, robust translation approach has been developed, which integrates state-of-the-art language understanding and generation technologies with specific adaptation of the system to the military domain. The system is currently being adapted for translation of the Commander's briefing material, in preparation for a capability demonstration of translation of operational material at a Fall 1997 coalition exercise at CFC.
Lincoln Laboratory completed an extensive analysis of a widely fielded intrusion detection system, based on four months of data provided by the Air Force Information Warfare Center (AFIWC) and found that the existing intrusion detection system only weakly discriminates serious incidents from normal user activity. The average number of transcripts human analysts must look through to detect one serious intrusion ranges from 310 to 4600 across different Internet services. This high ratio of false alarms to true hits implies many human analysts and person-hours would be needed to find true intrusions. To begin addressing this problem, Lincoln Laboratory has developed a new intrusion detection algorithm which searches transcripts of telnet sessions to detect suspicious cases where a user illegally obtains root-level privilege. This new algorithm was tested on the same four months of data, and detected 16 serious incidents where unauthorized users illegally gained root privileges. Human analysts examining these transcripts, it is believed, would have detected only one or two of these serious attacks. The new algorithm, by analyzing the sequence of events in telnet sessions and detecting where illegal transitions to root status are made, achieves dramatic improvements in performance over existing intrusion detection algorithms which rely primarily on key-word detection and do not parse or analyze the sequence of events in a user session.
Computational models of the human visual system (HVS) are being used as the basis for algorithms to compress, enhance, fuse, and display many different kinds of imagery for diverse applications. These include advanced color night vision based on the fusion of low-light visible and IR imagery, and exploitation aids for remote surveillance imagery, including synthetic aperture radar (SAR), IR, and electro-optical (EO) imagery. The fusion work on night vision has led to some initial experimentation with similar algorithms to combine multi-platform and multi-sensor surveillance data to produce superior image products for image analysts. Initial experiments have involved combining visible and SAR monochrome images into color-fused images for use by image analysts. The process involves image registration to compensate for different imaging geometries followed by HVS-based image enhancement and fusion algorithms. The superiority of fused imagery to either type of component imagery has been successfully demonstrated.
Processing requirements for computer-based recognition can range from modest to very large, depending upon the specific algorithm and the rate at which data must be interpreted. A goal of the Lincoln Portable Scalable Multiprocessor Software project is to demonstrate how to build efficient multiprocessor recognition software that is relatively easy to develop in the first place, scales easily with problem size (i.e., number of processors required to perform the task at hand), can easily take advantage of higher-performance processor hardware as it becomes available, and can be run in embedded real-time systems as well as on workstations and commercial off-the-shelf (COTS) multiprocessors. A message-passing programming model was selected to achieve these goals. A subset of the Message Passing Interface (MPI) standard for interprocessor communication was selected to support project goals while being small and fast enough for use in embedded systems. The subset was implemented for a commercial multiprocessor board for demonstration purposes. Several algorithms were coded using the MPI subset and the C programming language. These were then demonstrated to operate on networks of COTS workstations and on other multiprocessor systems with the number of processors ranging from 4 to 32. The MPI system was also instrumented to produce log files from which graphical performance (computational and communication) displays are generated for debugging and code optimization.
COMMUNICATIONS AND NETWORKING
The Wideband All-Optical Networks wavelength-division multiplexing (WDM) effort consists of developing architectures, technology components, and a test bed for the realization of scalable, high-speed (user data rates from 10 Mbps to 10 Gbps), high-capacity (~Tbps) transparent optical WDM networks. The architecture addresses all-optical transport over wide, metropolitan and local areas utilizing wavelength partitioning, wavelength routing, and active multiwavelength cross-connect switches to achieve a network that is scalable in the number of users, data rates, and geographic span. The network supports three optical services which can be point-to-multipoint, or multipoint-to-multipoint simplex or duplex connections. A 20-channel local and metropolitan area WDM test bed has been developed and deployed in the Boston metropolitan area based on these architectural principles using advanced components. Multiple rate and format connectors over a variety of optical services and over 130 Gbps of capacity through a metropolitan area hub have been demonstrated. A full all-optical network (AON) control and management system has also been developed and implemented.
In March 1996 the Advanced Technology Demonstration Network (ATDNet) was initiated to integrate AON technology into Washington, D.C. ATDNet is a DoD-sponsored networking initiative with six principal network nodes: the National Security Agency, Naval Research Laboratory, Defense Information Systems Agency, Defense Intelligence Agency, NASA, and DARPA. During this year, successful integration of the AON with ATDNet was accomplished. The interoperation of ATDNet with an advanced technology test bed from AON components is providing an early indication of the efficacy of AONs in a realistic DoD setting. Quantitative information concerning the utility, performance transparency, and the major increase in capacity of the WDM network was obtained. Practical issues involving use of commercial fiber circuits with the AON were resolved. Field evaluation of the two networking technologies is providing important qualitative and quantitative results for guiding future architecture, technology, application development, and procurement decisions.
The Military Communications Technology Program is responsive to evolving satellite communications service trends and challenges. One need is to lower costs via smaller, lighter-weight implementations. A performance-related goal is to increase capacities (especially to small, mobile terminals), allowing for interoperable networking (where satellite communications extend national/international information networks to remote areas and/or mobile users) and achieving robustness against co-user as well as intentional interference.
During this year, technical concepts and designs were accomplished for a tactical theater communications system utilizing airborne platforms as switching and routing nodes in a data network serving terrestrial users. Individuals with small, handheld radios will be able to link into the network through the airborne platforms; these platforms are interconnected by high-rate backbone circuits and then joined to entry points on the ground where interconnection with terrestrial (commercial and military) communications systems can be accomplished. Since the aircraft can be quickly flown into an area of operations, reducing logistic needs in establishing a communications capability on the ground. The network is also able to cover large areas from a single high-flying aircraft and is thus able to link together widely dispersed military units. The technology employed in such a system is derived from the Internet data networking technology and the satellite communications technology developed at the Laboratory.
AIR TRAFFIC CONTROL
By developing planning aids for air traffic controllers, Lincoln Laboratory is helping the FAA to enhance air safety, reduce controller workload, and increase airport capacity. The Center/TRACON Automation System (CTAS) helps coordinate activities between arrival controllers located at en route centers and final approach controllers located at airport radar control facilities.
Lincoln Laboratory has continued to support the FAA with the development of the CTAS Build 2 System specification, delivered in February 1997. This will provide information to final approach controllers to optimize arrivals. Additional work is now in progress for developing En Route Air Traffic Management Decision Support Tool (ERATMDST) specification by the Fall of 1999. This ERATMDST specification will describe the integration of ATM decision support tools such as Conflict Probe, Descent Advisor, and Traffic Management Advisor.
A new Lincoln Laboratory program has been initiated with NASA Ames Research Center under the Advanced Air Transportation Technologies program. The main purpose of the program is to investigate incorporating advanced weather products from systems such as the Integrated Terminal Weather System (ITWS) into air traffic automation tools such as the CTAS. An initial objective is to integrate the ITWS Terminal Winds product into the Final Approach Spacing Tool (FAST). The use of improved winds information will allow the FAST system to compute more accurate trajectories and should therefore improve performance.
Additional work is in progress relating to the User Preferred Routes and Expedite Departure Path projects. Investigations will be undertaken on incorporating convective weather products into these CTAS tools. The objective of this work is to allow dynamic rerouting of aircraft around storms in an efficient manner.
The Mode S radar beacon system was developed, prototyped, and tested at Lincoln Laboratory for the FAA and has been deployed at 137 sites nationwide. Mode S has an integral air-ground digital data link, and Lincoln Laboratory has developed data link applications for use by air transport and general aviation aircraft. The Traffic Information Service provides pilots with the location of nearby aircraft by uplinking surveillance information gathered by the Mode S radar. The Text Weather Service and Graphical Weather Service provide pilots with weather text and graphics uplinked via Mode S from ground-based weather sources, including weather radars. These data link applications have been implemented in an operational Mode S radar at Dulles International Airport and evaluated by representatives of the airlines and the general aviation community. The FAA will deploy the traffic information service nationwide by the end of 1997 and is considering national deployment of the weather text and graphics applications on the Mode S or a VHS data link. Several airlines are participating in a demonstration of text data link products derived from the Terminal Doppler Weather Radar and transmitted via a VHF data link.
A continuing multiple-year program to improve the FAA's ability to detect and predict weather conditions that impact aviation utilizes test bed sensors and advanced signal and data processing. The Terminal Doppler Weather Radar (TDWR) and ASR-9 Wind Shear Processor (WSP) systems provide wind shear information automatically to air traffic controllers and pilots. Lincoln Laboratory is supporting the refinement of the TDWR wind shear detection algorithms and adding a storm motion product to the Laboratory-designed TDWRs now deployed at major airports. The Laboratory-designed signal processing algorithms for estimating low-altitude Doppler velocity with fan beam radars enable the FAA's Airport Surveillance Radars (ASR-9) to provide similar wind shear warning and storm motion information at the nation's medium-density airports. The Laboratory-designed technology is being transitioned to the ASR-9 WSP full-scale developer.
The Laboratory-developed ITWS delineates hazardous airspace conditions and provides short-term forecasts of significance to aviation by integrating information from the FAA, the National Weather Service, and airline sensors (e.g., radars, lightning, winds). The Laboratory is supporting technology transfer of the ITWS product generation algorithms to the ITWS Flight Standards District Office contractor. The Laboratory is continuing to operate ITWS test beds in Memphis, Orlando, and Dallas-Fort Worth to increase the ITWS data base and test enhanced products (e.g., thunderstorm growth and decay predictions) as they become available. An additional experimental site in San Francisco supports the development of ceiling and visibility prediction products.
ELECTRONIC DEVICES
Working with the MIT Center for Space Research, the Lincoln Laboratory Microelectronics Group successfully completed the imaging spectrometer for NASA's Advanced X-ray Astrophysical Facility in March of this year. The image array consists of 10 large (1048 x 1048-element) charge-coupled-devices (CCDs) which were specially fabricated to be very sensitive to x-rays from 250 to 10,000 eV in energy. New techniques were created to fabricate the CCDs, and also to assemble them in the precision multi-device focal plane array. The flight array has successfully completed all its preflight tests at NASA Marshall Space Flight Center and is currently undergoing integration into the spacecraft. Advanced X-ray Astrophysical Facility (AXAF), which is one of the three NASA Great Observatories (the other two are the Hubble and the Compton Gamma Ray Observatory), is scheduled for launch on the shuttle in August 1998.
The fabrication of integrated circuits (ICs) with feature sizes of 180 to 250 nm required the development of new high-resolution optical lithography equipment and processes. Lincoln Laboratory, in collaboration with equipment manufacturers, has developed a prototype 193-nm-wavelength large-field optical stepper and has installed it in the Microelectronics Laboratory. This system has demonstrated 175-nm patterning using conventional chrome-on-quartz photomasks, and has achieved 100-nm patterning using phase-shift masks. In addition, researchers have built a 157-nm-wavelength illuminator as a tool for further reducing pattern features, and have recently produced 80-nm lines.
The 193-nm excimer lithography is approaching commercial acceptance, but the exploitation of the technology by IC manufacturers is still about two years away. As a look into that future, Laboratory researchers have used the prototype 193-nm tool in their state-of-the-art fabrication facility to define all eleven masking layers in a low power, high-performance, silicon-on-insulator CMOS process. First-pass success was achieved on both test devices and simple circuits with inverter delays of 29 ps at 3.0 V and 57 ps at 1 V. This represents a 10x reduction in power consumption and 2x improvement in speed performance when compared to a conventional 0.5-um technology.
Early warning of a potential biological attack is an essential capability for an effective biodefense system. Lincoln Laboratory has developed a real-time, point, bioaerosol sensor for early warning of threat aerosols and has successfully demonstrated its effectiveness in field tests performed in September 1996, in which Bacillus subtilis was used as a simulant of a biowarfare agent. The tests demonstrated that the discrimination capability of the sensor was effective in reducing the false-alarm rate due to the presence of natural biological and nonbiological aerosols.
The sensor is based on laser-induced fluorescence detection of aerosol particles and incorporates two spectral channels for discrimination of threat aerosols from background aerosols. The UV source of excitation is a miniature diode-pumped, passively Q-switched Nd:YAG laser that is frequency quadrupled to 266 nm. Air to be sampled is drawn by a fan to a region illuminated by the laser. Fluorescence emitted by a particle intercepted by the UV laser beam is simultaneusly observed in a UV and a visible channel, and the ratio between the signals from the two channels provides discrimination information.
W. E. Morrow, Jr.
MIT Reports to the President 1996-97