Quantum radars expose stealth planes

Following the successful development of aircraft jet engines during World War II (WWII), the United States Navy began exploring the advantages of gas turbine engines for ship and boat propulsion. Early development soon focused on aircraft derivative (aero derivative) gas turbines for use in the United States Navy (USN) Fleet rather than engines developed specifically for marine and industrial applications due to poor results from a few of the early marine and industrial developments. Some of the new commercial jet engine powered aircraft that had emerged at the time were the Boeing 707 and the Douglas DC-8. It was from these early aircraft engine successes (both commercial and military) that engine cores such as the JT4-FT4 and others became available for USN ship and boat programs. The task of adapting the jet engine to the marine environment turned out to be a substantial task because USN ships were operated in a completely different environment than that of aircraft which caused different forms of turbine corrosion than that seen in aircraft jet engines. Furthermore, shipboard engines were expected to perform tens of thousands of hours before overhaul compared with a few thousand hours mean time between overhaul usually experienced in aircraft applications. To address the concerns of shipboard applications, standards were created for marine gas turbine shipboard qualification and installation. One of those standards was the development of a USN Standard Day for gas turbines. This paper addresses the topic of a Navy Standard Day as it relates to the introduction of marine gas turbines into the United States Navy Fleet and why it differs from other rating approaches. Lastly, this paper will address examples of issues encountered with early requirements and whether current requirements for the Navy Standard Day should be changed. Concerning other rating approaches, the paper will also address the issue of using an International Organization for Standardization, that is, an International Standard Day. It is important to address an ISO STD DAY because many original equipment manufacturers and commercial operators prefer to rate their aero derivative gas turbines based on an ISO STD DAY with no losses. The argument is that the ISO approach fully utilizes the power capability of the engine. This paper will discuss the advantages and disadvantages of the ISO STD DAY approach and how the USN STD DAY approach has benefitted the USN. For the future, with the advance of engine controllers and electronics, utilizing some of the features of an ISO STD DAY approach may be possible while maintaining the advantages of the USN STD DAY.

Quantum radar has been proposed in the quantum information science literature as a novel approach to sensing that can offer a substantial gain over existing, classical sensors. In particular, a quantum radar based on quantum entanglement, termed quantum illumination radar, has been theoretically shown to demonstrate superiority over the optimal classical sensor, and there have been some experimental validation. However, all of the existing literature in the subject is in language, terminology and metrics that are completely unfamiliar (or relevant) to classical radar experts, and as a result there is understandable skepticism among the radar experts. This paper attempts to bridge the large gap between practical radar scientists and quantum information science (QIS) experts working in the field. We review the theoretical state-of-the-art in field and examine some of the claims in the literature in terms of metrics of relevance to radar detection, tracking and sensor fusion. We also discuss some possible technological routes to building such a radar across the electromagnetic spectrum.

This paper presents the design and experimental demonstration of a precise microwave electric field (E-field) measurement technique generated by a transmission line using Rubidium atoms excited to Rydberg states, which function as quantum-based atomic sensors. A compact coplanar microstrip transmission line (45 mm × 56.25 mm) is developed to generate a spatially uniform E-field across a vapor cell over a broad frequency range from 8 GHz to 18 GHz. The Autler–Townes splitting (ATS) of the Electromagnetically Induced Transparency (EIT) signal is employed for E-field quantification, providing direct traceability to Planck’s constant. E-field measurements are performed at 10.22 GHz, 13.43 GHz, and 17.04 GHz, covering the X and Ku bands. The minimum detectable E-field amplitude is 0.35 V/m at input powers of 630 µW and 40 µW for 10.22 GHz and 13.43 GHz, respectively, while an E-field of 0.36 V/m is measured for an input power of 251 µW at 17.04 GHz. The experimental results show good agreement with simulated field distributions. A linear relationship is observed between the measured E-field strength and the square root of the applied RF power, consistent with theoretical predictions. The proposed atomic E-field sensing platform enables accurate characterization of microwave structures and finds potential applications in electromagnetic compatibility (EMC) analysis, RF metrology, atomic RF receivers, quantum radar, and quantum communication. The compact, broadband, and uniform field-generating properties of the microstrip line also support its integration with vapor cells in heterodyne detection architectures, enabling miniaturized, highly sensitive, and frequency-tunable quantum sensors without the need for multiple antennas.

Contrary to claims made Multiple Input and Multiple Output (MIMO) radars do not provide an order of magnitude better angle resolution, accuracy and identifiability over conventional radars. What is claimed: MIMO array radar system consisting of a full transmit array and thinned receive array (or vice versa; called here a full/thin array) provides an order of magnitude or more of accuracy, resolution and identifiability, the ability to resolve and identify targets than a conventional array. This claim for MIMO results from making the wrong comparison to a full conventional array rather than to a conventional full/thin array. It is shown here that a conventional full/thin array radar can have the same angle accuracy, resolution and identifiability as a MIMO full/thin array. Moreover the conventional full/thin array example given here can have a better search energy efficiency. Where does the MIMO radar provide a better angle accuracy than a conventional radar? A monostatic MIMO array radar does provide a better angle accuracy than its conventional monostatic equivalent, but it is only about a factor of 1/ √2 (29 percent) better and its resolution is the same. Alternately, a monostatic MIMO array radar can offer the advantage of the same accuracy as a conventional monostatic array radar with a smaller aperture size, one that is 1/ √2 = 0.707 smaller, or equivalently 29 percent smaller. This improved accuracy comes at a heavy computation cost. For a MIMO monostatic linear array of N elements ≥ N <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> matched filters (MFs) are needed versus just N for its conventional equivalent. The factor ≥ results from the need for a bank of F ≥ 1 MFs being needed for the MIMO array. A bank of F MFs are need because the MF for an orthogonal waveform is usually Doppler intolerant. In contrast a conventional array would use a linear FM waveform (chirp waveform) which is Doppler tolerant. An alternate approach for achieving this factor of √2 advantage is to simply increase the radiated power of a conventional radar by a factor of 2. This latter approach to getting the √2 advantage has to be traded off against the cost resulting from the throughput increase required when using MIMO. MIMO radar is best for search not for track, unless track-while-scan. For track, conventional array processing should be used for maximum energy efficiency and to reduce the signal processing requirements. When a MIMO array is used to search a large scan angle, it is best for maximum search energy efficiency to use subarrays of the array as the elements of the MIMO array to form what we call a subarray-MIMO (SA-MIMO). When searching a small scan angle, the subarrays should be sized so that the volume of space illuminated by the subarrays of the SA-MIMO array matches, or is smaller than, the volume of space to be searched. Using SA-MIMO reduces the processing throughput requirements. MIMO radar in the near term will be useful for coherent and incoherent combining of existing radars to achieve about a 9 dB better power-aperture-gain (PAG).

Reviewed by: Battle Line: The United States Navy, 1919–1939 Branden Little Battle Line: The United States Navy, 1919–1939. By Thomas C. Hone and Trent Hone. Annapolis, Md.: Naval Institute Press, 2006. ISBN 1-59114-378-0. Photographs. Figures. Tables. Appendixes. Notes. Bibliography. Index. Pp. xi, 244. $34.95. Battle Line reveals aspects of the U.S. Navy of the interwar period that many naval histories ignore. The authors, a father and son team, are experts in naval technology and administration. In this new book they provide a "portrait" of a navy groping with the challenges of transformation during the critical era between the world wars (p. 1). Battle Line examines much more than its title suggests, and covers in considerable detail the on-the-job training of officers and men aboard ship, the routines of life at sea, and the procurement and development of weapons systems. One of the book's greatest strengths is its how-to approach to explaining many aspects of navy life that are often left out of standard histories. For example, the intricacies of mooring a large warship and loading naval guns are superbly detailed. Moreover, the integration of oral histories, including Vice Admiral Lloyd M. Mustin's recollections, and excerpts from classics such as Richard McKenna's The Sand Pebbles (1962) greatly enriches the text. Battle Line persuasively argues that the navy's fighting effectiveness was (and remains) utterly dependent upon well-organized, highly trained, and motivated personnel. Mahanian precepts of decisive battle permeated the navy in this era, but Battle Line barely addresses the navy's intellectual heritage. The deficiency this creates is that a reader may learn from this book how sailors handled ships but misunderstand the reasons why the navy intended to use its ships in a particular way. Injecting Mahan into this narrative would help to explain why the "Gun Club" was so very powerful and why capable officers who were not members of that fraternity were less likely to be promoted to high rank. Its obeisance to Mahanian dictums further indicates why the navy stubbornly resisted the joint development of amphibious doctrine, technology, and tactics. Many officers enticed by the lure of rival fleet engagements could not fathom a supporting role for the fleet. The authors are perhaps too forgiving of the navy's reverence for its increasingly obsolescent gun-centric fleet and for failing to adequately prepare for amphibious warfare. Battle Line contends that in the interwar years the navy laid many foundations for the future Allied victory. Although it acknowledges the monumental contributions to victory made by naval cryptologists, logisticians, desk-bound bureaucrats, and marines, the book gives disproportionate attention to warship crews and the warships themselves. More equitable coverage would actually demonstrate the importance of these other indispensable participants. [End Page 250] The book could also be improved if its chapters were more effectively integrated. They are not, however, due to the authors' admirable but somewhat inelegant attempt to mix the history of naval science, technology, and administration with traditional social history. The best syntheses of this type are David C. Evans's and Mark R. Peattie's study of the Japanese Navy, Kaigun (1997), and Ronald H. Spector's At War At Sea (2001). Battle Line is written for a lay audience, but its uneven coverage will likely prove a disappointment to readers seeking a fluid narrative. Nevertheless, Battle Line is worthwhile reading as an anthology containing discrete yet interrelated chapters. Its chapters on aviation and submarines are superb, and the entire volume will serve as a useful guide for continued investigation of the interwar navy. Branden Little University of California, Berkeley Berkeley, California Copyright © 2007 Society for Military History

: The final goal of this project is to provide the US Navy with an increased capability of using Doppler radar observations in the detection and prediction of hazardous weather events that usually have a strong randomness in nature and affect the Navy operations, especially over oceans and in remote areas. By developing a high-resolution data assimilation capability that can effectively assimilate Doppler radar observations along with other conventional and remotely-sensed data, the US Navy will have the ability to analyze and forecast the battlespace atmospheric conditions with sufficient detail and accuracy for supporting the Navy mission in threat detection, weapons deployment, and weather safe operations. The objective of the study is to develop an advanced ensemble-based radar data assimilation system for the US Navy and to address some critical scientific and technique issues associated with ensemble radar data assimilation. The radar data system that will be developed will use flow-dependent background error covariance (instead of the static background error covariance) to account for the complexity and rapid change in the dynamical and microphysical structures inside and outside storms. The system will assimilate all the observed variables from different types of sensors, including Doppler radars, satellites, UASs, and conventional meteorological observations, simultaneously to allow full interactions among the assimilated variables during the data assimilation to keep the balances among the dynamics, thermodynamics and microphysics in the model initial fields. The system will be able to use the observations from many types of radars on different platforms (WSR-88D, DoD meteorological radars and tactical radars both on-land and shipboard, etc.) with an appropriate quality control. Multi-scale data assimilation capability will also be one of the major features of the new radar data assimilation system that allows observational data at different scales to be as

The Lawrence Livermore National Laboratory (LLNL) has developed radar and imaging technologies with potential applications in mine detection by the armed forces and other agencies involved in demining efforts. These new technologies use a patented ultra-wideband (impulse) radar technology that is compact, low-cost, and low power. Designated as Micropower Impulse Radar, these compact, self-contained radars can easily be assembled into arrays to form complete ground penetrating radar imaging systems. LLNL has also developed tomographic reconstruction and signal processing software capable of producing high-resolution 2-D and 3-D images of objects buried in materials like soil or concrete from radar data. Preliminary test results have shown that a radar imaging system using these technologies has the ability to image both metallic and plastic land mine surrogate targets buried in 5 to 10 cm of moist soil. In dry soil, the system can detect buried objects to a depth of 30 cm and more. This report describes LLNL`s unique capabilities and technologies that can be applied to the demining problem.

This article presents a comprehensive survey on the integration of Generative Artificial Intelligence (AI) technologies in radar applications, with a focus on enhancing radar data processing and system capabilities. Generative AI techniques, particularly Generative Adversarial Networks (GANs) and Variational Autoencoders (VAEs), are explored for their potential to address persistent challenges in radar technology such as noise management, data augmentation, and target classification. The study investigates how GANs can generate synthetic radar datasets, aiding in model training when actual data is scarce, and how VAEs contribute to signal processing by denoising and reconstructing accurate radar signals. The analysis includes case studies on clutter suppression, radar data augmentation, beam blockage correction, and data fusion, highlighting the transformative impact of Generative AI on radar systems. This paper aims to provide insights into the current advancements and future directions of Generative AI applications in radar, suggesting that these technologies hold significant promise for improving the accuracy and efficiency of radar systems in diverse and dynamic environments.

Quantum two-mode squeezed (QTMS) radar, inspired by quantum illumination but without joint measurements in the receiver, has shown promise in target detection. However, the current prototype of quantum radar, using full-microwave superconducting components, faces challenges in achieving long-range performance. In this study, we propose the integration of an array of Josephson parametric amplifiers (JPAs) in a dilution refrigerator to enhance the performance of QTMS quantum radar. Through the evaluation of signal-to-noise ratio (SNR) and receiver operating characteristic (ROC) metrics, we demonstrate the effectiveness of this enhancing strategy. Our results indicate that the presence of an array of two JPAs significantly improves both the SNR and the detection probability compared to a single JPA configuration, thereby boosting the overall performance of QTMS radar. The key factor of this improvement is the cross-correlation between JPAs, which has a notable impact on the analytical outcomes of the quantum radar. This research provides valuable insights to engineers who want to optimize the design of advanced quantum QTMS radar systems.

Terahertz dielectric resonator antennas (DRAs) provide ultrafast data transfer rates using large bandwidth and multimode operations, which make them ideal for high speed communication due to their low loss and high efficiency. They can work at microwave, terahertz or optical frequencies, and are compact in size, which makes them well suited for advanced applications in sensing, scanning and imaging. New geometries are being developed for conical optical DRAs, cylindrical optical DRAs and spherical optical DRAs. Spherical optical DRAs have features of super directivity which can be used in quantum radars. Cylindrical optical DRAs with photo diodes can be used for wireless energy harvesting. This book covers the theory, modelling, design and implementation of DRA technologies at the microwave, terahertz or optical regime for future applications in wireless high-speed communication, wireless personal communication and sensor networks. Case studies on new geometries with prototype models are included at the end of this book.

&lt;div class="htmlview paragraph"&gt;This paper describes an advanced vehicle radar system operating at a frequency of 60.5 GHz that has been jointly developed for the Japanese automobile and truck market by Eaton VORAD Technologies of San Diego, California, and Hitachi, Ltd. of Japan. The radar system is used for both collision warning system (CWS) applications and for adaptive cruise control (ACC) applications.&lt;/div&gt; &lt;div class="htmlview paragraph"&gt;The radar system employs monopulse radar technology to measure azimuth angle to each vehicle in the forward direction. The techniques used to reduce cost and complexity of monopulse radar for low cost use on commercial vehicles are described. These techniques combine Doppler radar technology with digitally derived monopulse processing.&lt;/div&gt; &lt;div class="htmlview paragraph"&gt;Japan is the only country that has selected the frequency band of 60 GHz for vehicle radar systems. The reasons for this selection are discussed and the advantages and disadvantages of this frequency band are presented. The Japanese Ministry of Post and Telecommunications (MPT) specifies radiation limitations differently than the United States and has unique testing and transmission requirements which are discussed.&lt;/div&gt; &lt;div class="htmlview paragraph"&gt;The radar system has completed the prototype phase and preproduction has commenced. The radar system will be co-produced by Eaton VORAD Technologies in the United States and by Hitachi, Ltd. in Japan. The paper also presents system specifications, component assemblies, block diagrams, and installation considerations&lt;/div&gt;

This research project aims to expand the capability of current US Navy Automated Test Equipment (ATE) family of testers known as the Consolidated Automated Support System (CASS). Industry research is now focused on breaking the historical construct of test equipment. Advances in the field of Synthetic Instruments have opened the door to test avionics in new ways. Every year new capabilities are developed using core hardware and increasingly capable software modules to create complex waveforms. This research creates a Digital Radio Frequency Memory (DRFM) Synthetic Instrument that can be programmed to perform a wide array of low latency Radio Frequency (RF) tests. Synthetic Instruments are defined as a concatenation of hardware and software modules used in combination to emulate a traditional piece of electronic instrumentation. This Synthetic Instrument couples high speed Analog-to-Digital Converters (ADC) to high speed Digital-to-Analog Converters (DAC) with Field Programmable Gate Arrays (FPGA) in between for digital signal processing. An RF front end is used to down convert the RF to baseband where it is sampled, modified, and up converted back to RF. The FPGA performs Digital Signal Processing (DSP) on the signal to achieve the desired output. Application of this DRFM in automated testing is demonstrated using a Reconfigurable Transportable Consolidated Automated Support System (RTCASS) tester at Naval Air Systems Command (NAVAIR) Jacksonville, FL. The Unit Under Test (UUT) is an ALQ-162 Defensive Electronic Countermeasures (DECM) receiver-transmitter. Ultra-low latency signals are generated to simulate enemy jamming stimulus. As the ALQ-162 detects and responds to the input, the DRFM switches to a new frequency. The time taken by the ALQ-162 to acquire, respond, and re-acquire is measured. This test confirms the internal Yttrium Iron Garnet (YIG) oscillator meets slew specifications. Currently Navy ATE can only test RF units using high latency steady state tests. This research project developed a supplemental unit that can be added to the VXI chassis in the CASS family of testers and conduct ultra-low latency active tests. The instrument acts as hardware-in-the-loop to perform real-time tests including a new capability to measure jamming response time from DECM avionics. Demonstrated performance capabilities include: latency <; 100 ns, output Spurious-Free Dynamic Range (SFDR) > 80 dBc, input SFDR > 60 dBc, frequency tuning resolution <; 2 Hz, and frequency settling time <; 0.5 ns. New RF capabilities developed by this effort parallel similar research ongoing for digital test instruments like the Teradyne High Speed Subsystem. Incorporating this Digital RF Memory synthetic instrument into current and future ATE will improve readiness and supportability of the fleet. Improvements demonstrated by this research project will expand the type and quantity of assets able to be tested by current and future ATE.

An extensive risk assessment of oil transportation in Prince William Sound, Alaska was finalized in 1996 that identified drifting icebergs, from Columbia Glacier, as one of the most significant oil spill risks remaining to be addressed. The Prince William Sound Regional Citizens’ Advisory Council (PWS RCAC) was a major participant in this risk analysis. As part of the groundwork for the ice detection project, PWS RCAC has also sponsered extensive studies of Columbia Glacier calving and drift patterns, iceberg size and distribution. A collaborative project, called the ice detection project, was developed by a multi stakeholder working group and provides an opportunity for an immediate and long-term solution using existing technology. One objective of the project is to verify the efficiency, effectiveness and reliability of existing radar technologies to provide mariners and the United States Coast Guard with real time information regarding ice conditions. A secondary objective is to promote the research and development through field testing of new and emerging technologies to determine the possible enhancement of conventional radar. In addition to PWS RCAC, stakeholders responsible for spearheading this project are: Alyeska Pipeline Service Company, Alaska Department of Environmental Conservation, Oil Spill Recovery Institute, United States Coast Guard, Prince William Sound Community College and National Oceanic and Atmospheric Administration. Each of the seven participants brings expertise and backing from the stakeholder they represent. The site chosen for the ice detection radar project is Reef Island (illustration 1), located adjacent to Bligh Reef, Prince William Sound. This location is ideal because of its proximity to Columbia Glacier, the source of the icebergs, as well as providing an unobstructed view of the shipping lanes. A fifty foot tower was installed at the site during the fall of 2001 and a conventional radar system is currently being configured for installation. The expectation is that the system will be up and running by July of 2002, giving real time information on ice in the tanker lanes to mariners in Prince William Sound. A second field test of an UHF radar prototype is planned for the summer of 2002. Field testing and ground truthing of the radar system is scheduled for the next five years.

The end of the Cold War marked the end of an era in twentieth-century naval history. Although competition between the navies of the United States and the Soviet Union never resulted in open conflict, the prospect of confrontation fuelled the development of plans and programmes on both sides for more than four decades. The global war which was feared and anticipated was the subject of endless study and analysis. How might it begin? How would it be fought? Which side was in the stronger position? What strategic and technical innovations might shift the military balance? The plans, strategies, and weapons ultimately went untested, but the story of their creation constitutes an important chapter in twentieth-century naval history.

When Franklin Roosevelt died in April 1945, his closest wartime collaborator during the previous three years was devastated. He wrote in his private diary, beginning with a sentiment of general grief that could have been written in a mainstream newspaper. “This world tragedy deprives the Nation of its leader at a time when the war to preserve civilization is approaching its end with accelerated speed, and when a vital need for competent leadership in the making and preservation of world peace is at least seriously prejudiced by the passing of President Roosevelt who was a world figure of heroic proportions.” Then Admiral William Leahy, Chief of Staff to the Commander in Chief of the Army and Navy of the United States, went in an entirely different direction, one that makes him stand out within the functioning of the American government, and the creation of American grand strategy, during the war. “His death is also a personal bereavement to me in the loss of a devoted friend whom I have known and admired for thirty-six years, since we first worked together in World War I.” Three days later, after Leahy had accompanied Roosevelt's body to its interment in Hyde Park, New York, the President's family estate, the admiral was once again overcome with grief. At the end of the burial he wrote about “a long day that was for me full of sad memories, and that also for me probably was my last visit to the home of my friend who will live in history as one of our greatest Presidents. He was a great gentleman and a true friend.”