Sensing the Layers
Written by Harrison Donnelly
Jerome has held a variety of leadership positions in science and technology, engineering and technical management, and test and evaluation. He has also served in an Office of the Secretary of Defense staff assignment where he assisted the director of operational test and evaluation in prescribing policies and procedures for determining the operations and composition of the test and evaluation infrastructure for the Department of Defense. In addition, he served as the director’s principal staff specialist for all Base Realignment and Closure 2005 activities. Prior to assuming his current position, Jerome served as the deputy director of air, space and information operations, Air Force Materiel Command, Wright-Patterson AFB.
Q: What is the mission of the Sensors Directorate?
A: The mission of the U.S. Air Force is to fly, fight and win in air, space and cyberspace. As the USAF continues to rapidly morph from a post-Cold War force structure and adapt to the new challenges faced in places like Afghanistan and Iraq, USAF leadership looks to the Air Force Research Laboratory [AFRL] to help provide future capabilities allowing them to execute their mission. How does AFRL fit in? AFRL’s mission is to “lead the discovery, development and integration of affordable warfighting technologies for our air, space and cyberspace force.” It is the organization responsible for developing future technical capabilities keeping the USAF fully combat capable and ready to execute its mission in both the near and far term. The Sensors Directorate’s mission within AFRL is to “lead the discovery, development and integration of affordable sensor and countermeasure technologies for our warfighters.”
Q: How is the Sensors Directorate organized?
A: Technical planning within the Sensors Directorate is centered on seven core competencies: radio frequency sensing, electrooptic sensing, radio frequency electronic warfare, electro-optic electronic warfare, automatic target recognition/performance-based sensing, enabling sensor devices and components, and trust in complex systems.
Q: What are your primary goals for 2009?
A: In order to guide long-term research initiatives across AFRL, the Sensors Directorate developed a unifying “layered sensing” construct. Layered sensing represents a transformational C4ISR enterprise that will greatly influence development of future Department of Defense and USAF ISR technologies. Layered sensing will not only provide advanced war fighting capabilities to counter near-peer adversaries, but also represents a paradigm shift allowing the United States to adapt to and counter evolving threats in a timely and cost-effective manner. Layered sensing will drive execution of the Sensors Directorate’s vision statement to develop “robust sensors and adaptive countermeasures that guarantee complete freedom of air, space and cyber-operations for our forces, and deny these capabilities to our adversaries at times and places of our choosing.”
Layered sensing is defined as follows: “Layered sensing provides military and homeland security decision-makers at all levels with timely, actionable, trusted and relevant information necessary for situational awareness to ensure their decisions achieve the desired military/humanitarian effects. Layered sensing is characterized by the appropriate sensor or combination of sensors/platforms, infrastructure and exploitation capabilities to generate that situation awareness and directly support delivery of tailored effects.”
Layered sensing has 12 key attributes: persistent coverage, wide area coverage, assured global access, engagement quality information, timeliness, trusted sensing, information triage, robust/agile/adaptable, spectrum dominance/control, open architecture, anticipatory observation/interactive engagements and tailored performance.
Beginning in FY09 and continuing into FY10, the goal of the Sensors Directorate portfolio is to align our technology development with the intent of creating and integrating systems of systems, providing the USAF the capability to utilize layered sensing with all its attributes in future irregular or conventional conflicts while preventing our adversaries from achieving the same goal. The Sensors Directorate is working to develop the necessary systems engineering approaches to integrate C4ISR and to move away from stovepiped sensor systems.
Q: What are some of the key accomplishments and contributions of the directorate?
A: The Sensors Directorate and Ball Aerospace have completed the development and initial testing of a phased array antenna that can meet the Air Force’s requirements for a full-up geodesic dome phased array antenna. The advanced technology demonstration is part of a multiphase activity to upgrade the Air Force satellite control network. By replacing large dish antennas with advanced phased array antennas, a geodesic dome phased array antenna would greatly improve satellite communication links for the Air Force satellite control network.
The program is jointly sponsored by the Space and Missile Systems Center and AFRL in support of the Air Force Space Command, which manages the Air Force satellite control network. This effort is developing, integrating and testing advanced technology demonstration hardware, which will validate the concept of using a geodesic dome phased array antenna for ground-based satellite communication links. The phased-array technology will provide more flexible and reliable satellite telemetry, tracking and commanding capabilities for the Air Force.
Another key contribution of the directorate is the continuing improvement in the position, navigation and timing area. One of the key enablers for precision warfare, net-centric warfare, and the AFRL layered sensing concept is high-accuracy [on the order of a meter] position, navigation and timing. Currently the Global Positioning System [GPS] provides the required position, navigation and timing for many military systems; however, there are environments where GPS can be significantly degraded or not available. While the integration of an inertial navigation system is often used to augment global positioning systems, the position, navigation and timing performance of these integrated systems degrades rapidly when GPS is not available.
The development of lower-cost, high-accuracy imaging and ranging devices—for example, cameras, scanning laser detection and ranging [LADAR], flash-LADAR and mm-wave radar—have shown the promise to provide information that, without prior information, such as a terrain database, can be used to further aid a global positioning/ inertial navigation system in urban and other environments where GPS signals may be blocked or jammed. Research in “feature aided” integrated navigation has shown great promise toward increasing the operational environment in which high-accuracy position, navigation and timing is available, and the Sensors Directorate has been involved with various university-level research activities exploring techniques that would make such a feature-based integrated navigation system practical.
The LADAR electro-optical global positioning/inertial navigation system atomic-clock navigation demonstration [LEGAND] program is an effort aimed at transitioning feature-aided integrated navigation systems to industry and eventually operational systems. LEGAND is developing theory, algorithms and a prototype navigator that incorporates measurements extracted from imaging and ranging devices in a tightly coupled filter with GPS, inertial navigation system and atomic clock measurement. Currently LEGAND is in the second two of the three-year effort.
LEGAND is a multifaceted program led by AFRL Sensors Directorate and funded jointly by AFRL and the Army. LEGAND consists of research activities with the following entities: Consortium of Ohio Universities for Navigation and Time, including the Air Force Institute Technology, Miami University, Ohio State University and Ohio University; Honeywell Labs; and Northrop Grumman Navigation Systems Division.
Q: How are you working to improve the evaluation of sensor-exploitation techniques?
A: Evaluation of sensor exploitation is critical to both understanding the technology state of the art and projecting performance for its operational application. For two decades, the Sensors Directorate has led the community in advocating and enabling sensor-exploitation evaluation. The Comprehensive Performance Assessment of Sensor Exploitation [COMPASE] Center performs evaluation on products from both internal and external programs, and its operation has been widely recognized as a best practice. The COMPASE Center oversees data collections, maintains well-truthed databases and provides independent performance assessment for detection, tracking, registration, identification and sensor management functions across the electromagnetic spectrum.
The COMPASE Center also collaborates with the Human Effectiveness Directorate to develop techniques allowing evaluation of automated sensor exploitation and humans as a synergistic system. Many sensor exploitation systems have the automated system and human system working as a team, so techniques measuring joint performance result in overall improved performance of the integrated system. The current evaluation process is being improved by two efforts now in place, each intended to address growing complexity in Air Force sensing.
First, key improvements in sensor exploitation evaluation will stem from performance-theory efforts under way within the Automatic Target Recognition Center, a distributed center established two years ago. Progress in development of a predictive theory will allow extrapolation beyond measured performance. Additionally, this theory will provide upper bounds on performance for specific sensors and targets. Armed with this theory, evaluations can determine whether sensor exploitation systems are performing at their limits or whether there is opportunity for performance improvement.
A second improvement area is the increased development and employment of hybrid simulations to evaluate complex sensor exploitation systems, including multiple moving sensors and targets, communications and networking impacts, and the complex environments in which the Air Force operates. Such simulations capture needed fidelity from measurements and synthetic data while efficiently spanning large areas.
Both capabilities will make sensor exploitation evaluation less costly, allow accurate performance prediction, and provide the Air Force broader understanding of sensor exploitation impact on mission success.
Q: What are some of your organization’s recent achievements in the area of sensor fusion and networking?
A: Sensor fusion is an area of significant scope and complexity, so dividing the question into sensor fusion for detection, tracking, cueing, data basing and visualization will provide a clearer response.
In the detection area, we have shown that the fusion of radar and advanced electro-optical sensors provides significant reduction in false alarm rates, as one might expect, due to the difference in phenomenologies of the two sensors. Additionally, the use of same-sensor and cross-sensor change detection significantly reduces false cues.
In the tracking area, we have demonstrated multiplatform tracking of ground targets in difficult traffic conditions. We take advantage of the multiple lines of sight and different sensor performances as a function of the various sensor and target geometries. We have also demonstrated the ability of small UAVs, working in conjunction with unattended ground sensors, to track vehicles of high interest. This further illustrates the richness of the Sensors Directorate’s layered sensing vision as different platforms and sensors work together to perform a particular set of tasks.
In the cueing area, we have demonstrated single platform fusion, where a medium-altitude UAV employs a radar sensor to cue its video sensor to perform target acquisition, tracking and identification. We are also developing the ability to perform detection-level fusion with radar and passive electro-optical sensors to cue active electro-optical sensors to perform identification in difficult deployment conditions. This effort leverages the different fields of view and resolutions of the sensors in a complementary way to perform both search and final identification of the desired target.
We have also been successful in establishing databases essential to progress in sensor fusion. We developed and continue to improve databases to support change detection for our electro-optical, infrared and radar staring sensor investment. We have, in collaboration with the Human Effectiveness Directorate, collected sensor data on dismounts to characterize human signatures for detection, tracking and identification. Further, we have collected multiple types of sensor data on vehicles for use in detection and identification investigations.
In the visualization area, we are exploring, with significant success, the use of an interactive data table to allow exploration of multiple sets of data in support of exploitation tasks. This work is also in conjunction with the Human Effectiveness Directorate and illustrates the power of the layered sensor vision as the operator seamlessly explores data gathered by multiple sensors flying at differing altitudes and ranges carrying sensors in multiple spectral regions. Underlying the data table, hidden from the operator, are significant algorithm developments in multisensor registration [in time and space], detection, tracking and database management.
Q: What are your strategy and goals in the area of infrared countermeasures?
A: The Sensors Directorate is pushing beyond reactive infrared countermeasure approaches of the past that only responded when a shot was fired or a missile was in the air. We call this advanced concept proactive infrared countermeasures, where we seek to find the threats prior to the engagement and stop them from firing. We use advanced techniques that combine all-source intelligence and active search concepts to find threats and prevent them from tracking us. The concept also includes the potential to locate, target and engage infrared sensors before missile launch. This concept will increase aircraft survivability in high threat infrared seeker and sensor environments by providing layered protection starting with preemptive measures and ending with reactive infrared countermeasures.
Q: How do you view the challenges and opportunities of developing automatic target recognition?
A: Despite significant remaining challenges in providing automatic target recognition for Air Force applications, the opportunity—even the mandate—for these functions is enormous. The key challenges in automatic target recognition result from the tremendous variability of an object’s appearance in sensor data. This variability in turn creates confusion among objects and between objects and their environments. These challenges are being met in the Sensors Directorate by a strong understanding of the physics underlying observed phenomena as well as an understanding of sensor design and its impact on observations. These areas support well-founded algorithm development that can be matured, evaluated and applied to Air Force problems.
The need for automatic target recognition continues to grow, propelled by increasing numbers and types of sensors, the ubiquity of unmanned platforms, the pace of warfare, and the challenging environments in which the Air Force must operate. For this reason, emphasis on automatic target recognition for networked sensors includes both component technologies—registration, compression effects, cueing and multisensory automatic target recognition—and strides in system-level understanding. Such understanding can drive both sensor design and sensor employment and suggest integrated solutions across Air Force applications. The Sensors Directorate’s layered sensing vision is posturing the entire organization to tackle this growing opportunity.
The integrated approach to sensing and its exploitation—termed performance-driven sensing—closes the development loop and underpins our current sensor and exploitation developments. As an example, the current investment in staring sensing attacks target and environment variability, enabling algorithms such as change detection, by revisiting the same area continuously. This approach provides a more constrained scenario than in a traditional search mission where previous intelligence is lacking. Further, as the same area is sensed, models are developed that characterize the sensed area’s variability as a function of, for example, time of day. These models support “on the fly” performance estimates as well as further constraints for sensor exploitation algorithms.
The staring sensing mission provides an opportunity to synergize both model-based and machine learning technology to develop structured algorithms based on principled models whose parameters are learned or adapted, leveraging advances in the machine-learning community. Hence, the staring sensing mission can spawn a next generation of sensor exploitation algorithms that build competency over time and are capable of adapting to an elusive and flexible adversary.
Q: The Air Force announced last year that your organization had developed transparent transistors. What do you see as the implications of this effort?
A: Our transparent electronics technology thrust encompasses both the development of transparent conductors—imagine glass-like transparency in copper-like conductive films—and optically transparent transistors. Together, these innovative technologies provide an opportunity to integrate optical and radio frequency sensor arrays for co-centric operation, and hence improved spatial resolution of the combined sensor. Such sensor integration is important for small air platforms, such as UAVs, that are required to carry out more sophisticated sensor missions but have limited aperture sizes. Our transparent electronics have the potential to implement signal processing, microwave signal amplification and control electronics functions in phased array radars without getting in the way of optical sensors that may be placed behind it. ♦
