Missile Warning Research Articles

Excellent Wavelength Selectivity of p-AlGaN/n-Ga2O3 Solar-Blind UVC PD.

Due to the advantages of ultrawide bandgap, chemical stability, self-powered, and low cost, gallium oxide (Ga2O3) based photodetectors (PDs) are considered as one of the most promising solar-blind ultraviolet PDs, having garnered significant attention in fields such as missile warning and flame arc detection. High selective ratios and excellent responsivity are important to reduce the false alarm rate in solar-blind detection. However, due to the lack of p-type Ga2O3, existing Ga2O3-based PN PDs utilized heterostructures with narrower bandgap p-type semiconductors (e.g., p-GaN, p-SiC, etc.), inducing poor selective ratios with visible light and ultraviolet-A/B (UVA/B). Therefore, a high Al content AlGaN was used in this study to form a p-AlGaN/n-Ga2O3 solar-blind ultraviolet-C (UVC) PD. Since the bandgap of p-AlGaN aligned with the UVC region, the device exhibited exceptionally high selective ratios with R247nm/R360nm = 3.71 × 105 and R247nm/R300nm = 1.47 × 105 at 0 V, which surpassed the reported Ga2O3-based PN PDs. The formation of the type-II heterojunction facilitated the effective separation and transport of photogenerated carriers, resulting in high responsivity (0.36 A/W) under zero bias. Overall, the high selective ratios and high responsivity of the p-AlGaN/n-Ga2O3 PD in this paper provided a reliable pathway for self-powered solar-blind PDs with a low false alarm rate.

High-performance single crystal diamond pixel photodetector with nanosecond rise time for solar-blind imaging

Solar-blind ultraviolet imaging detector is widely applied in many commercial and military fields, such as missile warning, guidance, ultraviolet communication, biomedical analysis, and police reconnaissance. High-performance pixel photodetector is the core of imaging technology. Therefore, its construction attracts intensive attentions in recent years. In this work, 8 × 8 planar pixels were constructed on high quality single crystal diamond using ultraviolet direct writing lithography. A typical pixel photodetector in metal-semiconductor-metal (MSM) structure achieved outstanding photo-response properties of a low dark current of 10−13–10−12 A at 50 V, a high light-dark current switching ratio over 105), a high responsivity of 22.6 A/W, and a decent specific detectivity of 4.2 × 1014 Jones. Moreover, the detector has a fast response time of 13 ns. Additional optoelectronic studies demonstrate the strong homogeneity and repeatability of the photodetectors array, enabling it to serve as a reliable solar-blind imaging photodetector with high spatial resolution.

Spectrally Selective Hole Extraction Structure Enables a Self‐Powered Perovskite Solar‐Blind Photodetector with Record Responsivity and Detectivity

AbstractPhotodiode‐type solar‐blind photodetectors (SBPDs) with the self‐powered feature hold great promise for applications in unattended secure communication, flame detection, and missile warning. However, the responsivity of SBPDs is usually limited due to the severe solar‐blind (SB) light extinction in substrates and charge transport layers. Herein, a spectrally selective hole extraction structure (SHE) is proposed for high‐efficiency perovskite SBPDs. The SHE consisting of a tandem Fabry–Perot cavity and energy‐level‐matched hole transport layer endows the device with narrowband absorption in the SB region and optimized charge extraction capability from the CsPbI2Br perovskite. The optimized SHE exhibits a peak transmittance of 27% at 255 nm and a half maximum at full width of 28 nm. Under SB light illumination, the champion device achieves a responsivity of 56.20 mA W−1 and a detectivity (D*) of 2.86 × 1013 Jones, which are the record values among the reported results. The approach demonstrated here paves the way for the optical and electrical design of perovskite photodetectors with spectrally selective detection.

High-Performance Carbon Nanodots/Graphene Heterojunction Solar-Blind Ultraviolet Photodetector via Vertical Structure

The vertical-structure heterojunction has been highlighted as a promising candidate for the solar-blind ultraviolet (UV) photodetector (PD) due to the control of its channel length and the strong electric field-induced high carrier mobility. Meanwhile, carbon nanodot (CND) has drawn great attention to be playing an essential role in absorbing solar-blind UV waves as the active layer of the PD. However, CND prepared for solar-blind UV PDs, independent of sophisticated manufacturing method and extreme process conditions, has yet to be well developed. Herein, for the very first time, a vertical structure CNDs/graphene heterojunction type solar-blind UV PD is introduced, where the CND and the graphene are used as the photosensitive layer and the transparent electrode, respectively. Particularly, the CND is fabricated with a low-cost and one-step electrochemical strategy. The device realizes an optimized performance tradeoff, presenting responsivity of 76.01 mA/W, normalized detectivity of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4.17\times 10^{{10}}$ </tex-math></inline-formula> Jones, and rise/decay time of 0.54/0.27 s under the illumination of 1.47 mW/cm2 at 254-nm wavelength, along with the bias voltage of −5 V and the substrate voltage of 10 V applied. The results show that this work has unlocked the critical bottleneck of developing a graphene-based solar-blind UV PD with higher responsivity, greater detectivity, and shorter response time, unveiling the potential for missile warning, flame detection, and other areas of interest.

Development of military satellite communications constellations and the US missile attack warning system: modern state and prospects

In the modern world, the armed forces of technologically developed countries are active consumers of satellite information, and in some cases critically depend on it. This primarily concerns Russia and the United States, which have both military satellite constellations for various purposes (in particular, satellite missile attack warning systems), and make specialized purchases from commercial owners and operators of satellite systems in the interests of their military departments. This article proposes to consider the American military satellite communication systems and missile attack warning systems (MAWS), the reasons and process of their modernization, which took place in 2018-2023, as well as long-term development plans.

Characteristics of Ultraviolet Sensor Based on PEDOT:PSS/Al Doped ZnO Film.

Ultraviolet (UV) sensors have application in many different areas such as flame and hightemperature detection, space research, environmental monitoring, ozone layer monitoring, and missile warning systems. Among them, ZnO thin-film-based UV sensors have been attracting attention among research groups and are being continuously studied. The incorporation of ZnO/organic hybrid structures into solar cells and other photoelectrochemical applications has been extensively reported. However, little research has been performed on ZnO/polymer-based UV sensors. In this study, a simple UV sensor based on an Al:ZnO/polymer is demonstrated. Al-doped ZnO enables effective UV detection with excellent performance at low operating voltages using a simple and inexpensive process.

Going Viral: The 3 Rs of Social Media Messaging during Public Health Emergencies.

Going Viral: The 3 Rs of Social Media Messaging during Public Health Emergencies.

The enhanced of photoresponse of ZnO nanorods film-coated by Cu2O

Light detectors are widely used in generating energy from sunlight, medicine, space communications, ozone layer monitoring and missile warning systems, and others. The active materials that potential used as a detector of visible light and UV is ZnO. However, ZnO has a high bandgap of 3.04 eV so it is not suitable for absorbing light at short wavelengths. Cuprous oxide (Cu2O) is a p-type of semiconductor with a small band, therefore it can increase the wavelength absorption range. The aim of this study is to improve the light response of ZnO nanorods by coating Cu2O. The samples were characterized by X-ray Diffractometer (XRD), Scanning Electron Microscopy (SEM), UV-Vis Spectrometry, FTIR, and photoresponse test. The results show coating Cu2O on ZnO nanorods succeeded in reducing the bandgap value, which is 2.47 eV. Reducing the band gap value is in accordance with the photoresponse test. The response of a sample that has a small bandgap is a fast response.

Principles of creation of the big territorially distributed automated systems

The article defines large territorially distributed automated systems, which include systems that collect and process information from spatially spaced sensors on objects. Examples of such automated systems are military systems, such as a missile attack warning system, a space control system, strategic and non-strategic missile defense systems, and civil systems, such as the state automated Control system, the air traffic control system and other systems. The purpose of these systems is the continuous monitoring of the state of a set of certain objects, the environment of their functioning, the constant assessment of the parameters of objects, the identification of dangerous situations in the behavior of objects and the environment, as well as the development of measures to reduce the level of possible security threats and eliminate dangerous situations. The typical structure of large territorially distributed automated systems includes sources and consumers of information, telecommunication facilities, as well as a center for processing input data and preparing information for consumers. The sources of information are operators, technical means of observation and specialized measuring instruments. Telecommunication means of big territorially distributed automated systems are formed in two ways. The first option uses existing global data net-works. In the second variant, self-made data transmission networks are formed on the basis of specially created means of data transmission and the use of dedicated data channels. The center of input data processing and information preparation contains a complex of automation tools and personnel providing maintenance, repair and operation. The functions and the most significant hardware and software components of large territorially distributed automated systems are presented. The main indicators of quality of their functioning and stages of life cycle are characterized: development of requirements, creation of a prototype, certification, mass production, operation, modernization, the end of operation and utilization.

Vertical α/β-Ga2O3 phase junction nanorods array with graphene-silver nanowire hybrid conductive electrode for high-performance self-powered solar-blind photodetectors

Gallium oxide semiconductor, with a bandgap energy of 4.9 eV, is regarded as a hopeful candidate for next-generation solar-blind photodetectors. However, the construction of photodetector based on Ga2O3 pn junction is still challengeable due to immature doping technology of p-Ga2O3. By considering the small lattice mismatch (＜3%) and similar band gap structure of α-Ga2O3 and β-Ga2O3, a well-designed solar-blind photodetector was built, based on vertical α/β-Ga2O3 junction nanorod arrays (NRAs) with a graphene-silver nanowires (Ag NWs) hybrid top electrode. Thanks to the high conductivity and optical transmittance of graphene-Ag NWs top electrode, the photodetector based on α/β-Ga2O3 junction NARs displayed excellent photoelectric performance. Meanwhile, the matched band structure of Π type formed at the interface of α/β-Ga2O3 junction promoted the automatic separation of photogenerated carriers and their transfer to the corresponding electrodes. A fast photoresponse time of 0.54 s, a high light-to-dark ratio about 2000, and a high rejection ratio (R254/R365) of 2.7 × 103 under the zero bias, were realized. The excellent photoelectrical performance of α/β-Ga2O3 junction photodetector even in vacuum environment forecasts its potential application in some low air density fields, such as missile early warning and tracking and ozone hole monitoring.

Characteristics of Ga-doped ZnO thin-film ultraviolet photodetectors fabricated on patterned Si substrate

Ultraviolet (UV) photodetectors have demonstrated wide applications in both civil and military fields such as pollution monitoring and missile warning. ZnO-based UV photodetectors have attracted tremendous attention due to the advantages of low cost and high chemical and thermal stability. In this work, Ga-doped ZnO (GZO) films were grown with the technique of RF magnetron sputtering and metal–semiconductor–metal (MSM) UV detectors were fabricated with the GZO films as the active detection layers. The as-sputtered films were further treated by the means of thermal annealing such that reduced oxygen vacancy and improved crystallization were achieved for the films. The effect of patterned Si substrates on the GZO UV detectors performance was revealed for the first time. With optimized annealing temperature and delicately designed substrate patterns, the responsibility of GZO MSM photodetectors has been greatly enhanced (e.g. about 2.5-folds higher than ones fabricated on non-patterned Si substrate). Our work on the GZO material and the structural design may pave a new way towards developing low-cost but high-performance UV detectors.

Sea ice detection from persistent single-channel shortwave infrared satellite data

The US Air Force has demonstrated an interest in deriving imagery products from classified military remote sensing platforms and making them available for civil and commercial operations. The US Air Force's Overhead Persistent Infrared (OPIR) is one such satellite constellation. A novel aspect of OPIR imagery is its near-continuous capture of single channel shortwave infrared data over the Arctic. Although traditionally used for missile warning and strategic defense, the exceptionally high temporal resolution of the OPIR data stream makes it an attractive source for Arctic remote sensing, particularly as the Arctic has warmed at a rate nearly double that of lower latitudes. This work assesses the feasibility of using Geostationary Operational Environmental Satellite – 16 (GOES-16) data as a proxy for OPIR imagery in the Arctic. Specifically, we seek to determine whether a single channel shortwave infrared (SWIR) approach can be used to detect and chart Arctic sea ice. We used a series of 32-image daily sets (4 images per hour x 8 h) over four-day periods acquired by GOES-16 in late April 2016 (as well as mid-March, mid-May, and mid-June) to chart sea ice, clouds and water in Hudson Bay, Canada. To do this, we applied image enhancement techniques to raw data imagery and then employed a time-based classification algorithm to the enhanced data cube. Overall, our method successfully discriminated sea ice from water and clouds when all conditions were present with improved discrimination over current daily products for sea ice charting in the Northern Hemisphere. The simple methodology of the developed algorithm is critical to ensuring the temporal resolution of the sensor is capitalized. The rapid timeline for production of this type of data is essential to the relevancy to military operations as well as emergency response/preparedness operations in the Arctic as it becomes more accessible in coming years. Our results make a compelling argument for the application of Air Force Missile Warning data to assist in the mapping, tracking, and assessment of sea ice in the high Arctic.

Аналіз можливостей існуючих систем оповіщення про ракетну атаку, які встановлені на літальних апаратах

The study of new systems of individual protection of aircraft from all types of guided missile weapons with infrared homing heads and radio-controlled missile weapons, which occupy a special role in the performance of tasks by flight crews in modern combat conditions, is gaining increasing relevance every day. This area has been the subject of scientific research institutions of the Ministry of Defense and state-owned enterprises of the military-industrial complex of Ukraine. The results of the analysis of the capabilities of existing missile attack warning systems, which are installed on aircraft developed in advanced countries of the world, enabled the author to come to the definition of the direction of research of promising systems for protecting aircraft against air defense systems. One of the promising such studies is the creation of an automated complex for the active protection of the aircraft, with the aim of increasing the efficiency of using the onboard aircraft weapon control systems. The article provides an analysis of existing warning systems for a rocket attack of the advanced countries of the world from air-to-air and air-to-surface missiles. Existing common missile warning systems of advanced countries from shut downing the air-to-air and air-to-surface missiles were studied in this article. According to the results of the analysis of technical and scientific literature carried out by the author, offered the perspective directions of developing an automated complex of active protection of aircraft of Ukrainian Air Force.

CONCEPT OF INTEGRATED SYSTEM OF MISSILE AND SPACE DEFENSE OF RUSSIA

The paper discusses the principles of creating an integrated system of missile and space defense (MSD) of the Russian Federation, as well as the tasks and areas for the development of its components: missile attack warning system, space control system and missile defense system. The importance of MSD as a basic component of the aerospace defense of Russia is noted, which necessitates the coordinated development of these systems. It is emphasized that modern ground and space based information and measuring systems of the MSD system can be effectively used in peacetime in order to solve a wide range of scientific and socio‑economic problems. The conclusion is made about the importance of accelerated coordinated development of the domestic MSD, which requires concentration of the potential of industry research organizations and manufacturing enterprises.

“Death was not in the agenda for the day”: Emotions, behavioral reactions, and perceptions in response to the 2018 Hawaii Wireless Emergency Alert

This research has three main aims: to identify perceptions about the false alarm ballistic missile warning that occurred in Hawaii (United States) in January of 2018, to identify what kind of behavior or actions people took upon receiving the warning, and to identify what situational or contextual factors are related to these perceptions and behaviors. We use a mixed-methods approach to address these research aims. We recruited respondents through social media and email networks (volunteer sampling) to complete a survey that contained categorical and open-ended questions about information gathering, perceptions of self and others during the event, demographic information, and thoughts about trust in future warnings. Using content analysis coding, four main themes emerged from the responses: emotional reactions, protective action, vulnerability and situational factors, and statements about information and trust. Participants sought additional information and cues about the potential threat, observed others engaging in milling, and some accounts of fatalism (during the event) and lingering symptoms associated with traumatic stress (after the event). These findings may be useful for emergency managers and planners designing future warning messaging systems.

Preparing for a Russian ‘Space Pearl Harbor’

Today, the United States is susceptible to a “Space Pearl Harbor” more than at any other time. The United States depends on satellites more than any other country in the world for its most basic functions. Everything from military communications, to early missile warning systems, to civilian banking transactions is conducted, in part, through satellite constellations. The American way of war depends on instantaneous communication and coordination that satellite constellations provide. Take away these advantages and the United States military is made deaf, dumb, and blind. For a militarily weaker foe, like Russia, with grand geopolitical ambitions and a rapidly closing window of opportunity to accomplish its geostrategic ambitions, debilitating U.S. forces charged with defending Eastern Europe is essential. This essay assesses the threat that Russian co-orbital satellites—better known as Space Stalkers—pose to vital U.S. military satellite constellations in geosynchronous orbit, such as the Wideband Global Satcom constellation.

Characterization of Al-doped ZnO nanorods grown by chemical bath deposition method

Introduction: In recent years a metal oxide semiconductors have been paid attention due to their excellent chemical and physical properties.ZnO (Zinc oxide) is considered as one of the most attractive semiconductor materials for implementation in photo-detectors, gas sensors, photonic crystals, light emitting diodes, photodiodes, and solar cells, due to its novel electrical and optoelectronic properties. There are different uses of metal oxide semiconductors such us, UV photodetectors which are useful in space research’s, missile warning systems, high flame detectors, air quality spotting, gas sensors, and precisely calculated radiation for the treatment of UV-irradiated skin. ZnO is a metal oxide semiconductors and it is used as a transparent conducting oxide thin film because it has the best higher thermal stability, best resistance against the damage of hydrogen plasma processing and relatively cheaper if one compares it with ITO. Materials and Methods: On glass substrates, Al-doped ZnO (AZO) nanorods have been grown by a low -cost chemical bath deposition (CBD) method at low temperature. The seed layer of ZnO was coated on glass substrates. The effect of the Al-doping on the aligned, surface morphology, density, distribution, orientation and structure of ZnO nanorods are investigated. The Al-doping ratios are 0%, 0.2%, 0.8% and 2%. The Aluminum Nitrate Nonahydrate (Al (NO3)3.9H2O) was added to the growth solution, which is used as a source of the aluminum dopant element. The morphology and structure of the Al-doped ZnO nanorods are characterized by field emission scanning electron microscopy (FESEM) and high-resolution X-ray diffractometer (XRD). using the radio RF (Radio frequency) magnetron technique. Results and Discussion: The results show that the Al-doping have remarkable effects on the topography parameters such as diameter, distribution, alignment, density and nanostructure shape of the ZnO nanorods. These topography parameters have proportionally effective with increases of the Al-doping ratio. Also, X-ray diffraction results show that the Al-doping ratio has a good playing role on the nanostructure orientation of the ZnO nanorods. Conclusions: The Aluminum Nitride Nanohydrate considered as a good Aluminu source for doping ZnONR. It is clear from FESEM results that the Al-doping of ZnONR has a remarkable effect on the surface topography of nanorods for all aluminum doping ratios. From XRD patterns, it concludes that as the Al-doping ratio increases, the reorientation of the nanostructure of ZnO increases towards [100] direction. The results obtained also have shown that the average diameter of a nanorod is increased with increasing the ratio of Al-doping.

Solar blind avalanche photodetector based on the cation exchange growth of β-Ga2O3/SnO2 bilayer heterostructure thin film

Solar blind photodetectors have shown a paramount encouragement owing to their promising applications in the fields of ultraviolet (UV) astronomy, fire alarms, missile warning, environmental studies, biological/chemical analysis and short range communication security. Due to the weak solar blind signal, there is a real need to develop solar blind avalanche photodiode (APD) with high internal avalanche gain to compete with the commercial Si APDs and photomultiplier tubes. Herein, we report the development of APD based on the growth of two wide band gap metal oxides operating within the solar blind region of the UV-spectrum (200–280nm). It was found that the growth of β-Ga2O3 on SnO2 thin film via cation exchange mechanism results in the development of a solar blind photodetector with ultrahigh sensitivity, high spectral selectivity, very fast response, high stability and high signal to noise ratio. The high external quantum efficiency of the APD developed was assigned to the avalanche multiplication effect.

Global performance analysis for space-based missile warning system

Global tracking performance analysis in near-real time for the space-based missile warning system is an architecture level demand for the system designers. The traditional method which based on Monte Carlo simulations cannot meet the demand for its time-consuming nature. In this paper, non-simulation rapid performance prediction methods in stereopsis and monocular observation conditions are studied. The latter, though inevitable, has not been taken into account in other literatures. Furthermore, we also find the geometrical symmetry for monocular observation and propose a rapid analysis method called compass of performance based on this symmetry.

English

In current warfare scenario stealth and passive threat detection capabilities are considered as prime requirements to accomplish desired mission by the fighter aircrafts. To improve the stealth of an aircraft, the trend is towards detecting threats with the help of passive sensors (Electro Optic or Infrared). Current situation caters for systems like Infra-red Search and Track (IRST) and Passive Missile Warning Systems (PMWS). IRST system is a passive target detection system, used for detecting aerial & ground targets. PMWS is a threat detection system used for detecting missiles approaching towards aircraft. Both of these systems detect targets of interest by processing IR images acquired in mid-IR region. The prime challenge in IRST system or PMWS is detecting a moving target of size typically 1~2 pixels in acquired image sequences. The temporal change caused by moving target in consecutive frames can be considered as one important factor to detect them. The temporal change caused by moving target is identified through absolute frame differencing of successive frames. This principle has limitation in application to IRST & PMWS as the imaging sensor with the aircraft is moving. This motion also imparts temporal change in the acquired images. In this paper authors are proposing a method for removing the temporal change caused by the platform motion in two consequently acquired frames using registration process. The proposed method uses the platform attitude information at frame sampling times. Authors have analyzed the sensitivity of registration process to noisy platform attitude information. Defence Science Journal, 2014, 64(2), pp. 130-135. DOI: http://dx.doi.org/10.14429/dsj.64.5460