Technical Digest

It has been nearly 18 years since the publication of the three Johns Hopkins APL Technical Digest issues dedicated to air defense. Since that time, many global events have shaped our national defense strategy and military capabilities. Just after the release of the second air defense issue, the 9/11 attacks occurred, followed by the global war on terror. The cost of this war, along with the financial crisis in 2008, strained the national defense budget. Even after recent budget increases, we still face many challenges. China’s economic rise has enabled its military buildup. North Korea has increased its development of nuclear weapons and long-range ballistic missiles. Instability in the Middle East, and the procurement of advanced weapons by our adversaries, presents significant concerns and challenges to our nation and allies. To meet these many new challenges, the Air and Missile Defense Sector of the Johns Hopkins University Applied Physics Laboratory (APL) has focused its efforts on the integration of air defense and missile defense as well as of defense resources across the battle force. This issue highlights the challenges our nation faces in air and missile defense and APL’s contributions to shape future solutions.

At the turn of the century, air and missile defense (AMD) warfighting challenges had become increasingly complex, requiring defensive systems to be more capable, resilient, robust, and able to fulfill multiple missions. In response to these challenges, the AMD community made significant advances in the use of multispectrum and multilayered engagement systems, as well as space systems, and cooperation with partners. The transformation of AMD capabilities during the early 21st century pushed the edges of technology integration, operational utility, and coordination of complex global systems of systems. At the forefront of these advances, the Johns Hopkins University Applied Physics Laboratory (APL) has provided game-changing thought leadership, capability innovations, and timely, pragmatic solutions. This article describes some of these transformative capabilities and is dedicated to the APL Air and Missile Defense Sector staff members who contributed to them.

Air and missile defense is a complex process involving the coordinated operation of equipment and computer programs. The most effective defense generally is multiple layers of defense using different technologies in each layer such as long-range hard-kill, followed by hard-kill area defense, followed by both hard-kill and soft-kill (electronic warfare) self-defense. A combat system must merge, fuse, and de-conflict many sources of sensor data to produce a single usable track picture for decision-making. Throughout, sensors are controlled and sensor resource use is managed to meet the overall defense needs. As technical direction agent and technical adviser for many of the combat system elements, the Johns Hopkins University Applied Physics Laboratory (APL) performs the systems engineering, analysis, and experimentation that helps the Navy select the most combat system capability at an affordable cost.

Integrated air and missile defense (IAMD) resource management can apply to many different commodities within today’s modern militaries. This article addresses radar resources, which are radio-frequency energy and time segments used to detect, track, and discriminate targets with a phased-array radar. IAMD radar resources can be managed at both the discrete dwell level and at the macro task level. The first part of this article presents an IAMD radar scheduling algorithm that uses a variation on interval and “earliest-deadline-first” scheduling to efficiently achieve desired search frame times while satisfying fixed task deadlines. The latter portion of the article then discusses the design of a track coordination algorithm for long-duration ballistic missile defense tasks. Both concepts are applicable to multifunction phased-array radars and were designed to improve efficiency while meeting existing performance parameters.

To develop a new combat system, the designer has to determine the optimal filter type, filter application point, and dynamic model assumption. The definition of an optimal filter will change depending on the filter’s purpose and can change drastically depending on its application within the plan–detect–control–engage sequence. Ideally, the designer could apply a single computationally efficient filter algorithm that adapts in real time to threat maneuver, system bias, and measurement noise level while maintaining an accurate estimate with a high level of confidence. In practice, however, several different filters (often of different types) are applied to a single combat system in separate parts of the plan–detect–control–engage sequence to ensure the best results for problems that include track consistency, association, filter errors, and correlation. There are several key factors in developing a robust filter with the flexibility for the technology upgrades that are required to keep up with threat evolution. This article describes a design methodology to provide robustness in the face of dynamic threat behavior, lack of a priori knowledge, and threat evolution.

The Combat Information Center (CIC) is the tactical command center for most US Navy ships. Because of the CIC’s dense integration of sailors and complex systems necessary to fulfill the multiple simultaneous missions it supports, adherence to human systems engineering and integration principles is paramount to both its current and future designs. The Johns Hopkins University Applied Physics Laboratory (APL) is undertaking efforts to envision the art of the possible for CIC technology advancements through independent research and development emphasizing collaboration between warfighters and APL engineers. Through forecasting future warfighter needs, skills, and mental models; anticipating future technology trends; and creating flexible, rapidprototyping environments, APL hopes to bring the Navy CIC into the future and help keep our sailors and country safe.

Sensors and communications systems are key components of air and missile defense systems, enabling those systems to search to long ranges; detect and track aircraft, missiles, satellites, and artillery; discriminate and identify threatening objects; and pass that information on to combat systems and weapons that act on it to defeat threats. Our adversaries’ cruise and ballistic missile threat capabilities continue to evolve, making it challenging for our modern systems to perform these functions with sufficient accuracy and timeliness to maintain defense superiority.

Every year, the Johns Hopkins University Applied Physics Laboratory (APL) honors the accomplishments of its staff members with an awards program. When the program was created more than three decades ago, it recognized staff members’ exceptional contributions to the scientific community via publication, and these publication awards are still presented today. Much like the Lab has evolved, its awards program has grown to include prizes recognizing extraordinary achievements in research and development and sponsored programs and, most recently, efforts that exemplify APL’s focus on transformative innovations. Awards are presented during a formal ceremony on APL’s campus in Laurel, Maryland. This article details the awards presented for achievements in 2018.