Recent advances in miniaturized optical gyroscopes

Low-cost chip-scale optoelectronic gyroscopes having a resolution ≤ 10 °/h and a good reliability also in harsh environments could have a strong impact on the medium/high performance gyro market, which is currently dominated by well-established bulk optical angular velocity sensors. The R&D activity aiming at the demonstration of those miniaturized sensors is crucial for aerospace/defense industry, and thus it is attracting an increasing research effort and notably funds.  In this paper the recent technological advances on the compact optoelectronic gyroscopes with low weight and high energy saving are reviewed. Attention is paid to both the so-called gyroscope-on-a-chip, which is a novel sensor, at the infantile stage, whose optical components are monolithically integrated on a single indium phosphide chip, and to a new ultra-high Q ring resonator for gyro applications with a configuration including a 1D photonic crystal in the resonant path. The emerging field of the gyros based on passive ring cavities, which have already shown performance comparable with that of optical fiber gyros, is also discussed

Photonic Integrated Circuit (PIC) Device Structures: Background, Fabrication Ecosystem, Relevance to Space Systems Applications, and Discussion of Related Radiation Effects

Electronic integrated circuits are considered one of the most significant technological advances of the 20th century, with demonstrated impact in their ability to incorporate successively higher numbers transistors and construct electronic devices onto a single CMOS chip. Photonic integrated circuits (PICs) exist as the optical analog to integrated circuits; however, in place of transistors, PICs consist of numerous scaled optical components, including such "building-block" structures as waveguides, MMIs, lasers, and optical ring resonators. The ability to construct electronic and photonic components on a single microsystems platform offers transformative potential for the development of technologies in fields including communications, biomedical device development, autonomous navigation, and chemical and atmospheric sensing. Developing on-chip systems that provide new avenues for integration and replacement of bulk optical and electro-optic components also reduces size, weight, power and cost (SWaP-C) limitations, which are important in the selection of instrumentation for specific flight projects. The number of applications currently emerging for complex photonics systems-particularly in data communications-warrants additional investigations when considering reliability for space systems development. This Body of Knowledge document seeks to provide an overview of existing integrated photonics architectures; the current state of design, development, and fabrication ecosystems in the United States and Europe; and potential space applications, with emphasis given to associated radiation effects and reliability

Integrated Microphotonic-MEMS Inertial Sensors

Au cours de la dernière décennie, le développement du contrôle d'attitude de petits satellites a évolué vers une stabilisation complète à trois axes et un contrôle précis alors que leur application augmente dans les télécommunications et les missions de connaissance de l'espace. Pour les systèmes spatiaux, les principaux facteurs sont la puissance, la masse et la fiabilité dans l'environnement spatial. Ceci est associé à une nécessité croissante de systèmes de navigation inertielle compacts et de faible puissance. Les systèmes de navigation actuels d'engins spatiaux consistent en différents capteurs et processeurs qui ne sont pas optimisés pour fonctionner ensemble. Cela est coûteux et peut exiger une réduction considérable de la masse et des ressources en puissance disponibles sur un petit engin spatial. Par conséquent, les composants doivent être optimisés par rapport à leur taille, design et procédé de fabrication. L'objectif de cette thèse est de concevoir, simuler, fabriquer et caractériser des accéléromètres et des capteurs de vitesse de rotation (gyroscopes) planaires miniatures à haute sensibilité et faible coût à base de microsystèmes électromécaniques (MEMS) à bande interdite photonique (PBG) sur un substrat silicium-sur-isolant (SOI) afin d'intégrer un réseau à deux axes de ces capteurs sur une même plate-forme SOI. L'utilisation de dispositifs optiques à guide d’ondes intégrés avec des MEMS sur SOI pour les systèmes de capteurs multicanaux/multifonctions permet l'utilisation de capteurs multiples pour étendre la gamme de mesure et la précision. Cela fournit une redondance essentielle qui rend possible une fiabilité à long terme dans l'environnement spatial, réduisant ainsi la possibilité de défaillance du système. Un navigateur sur puce représente également la capacité à accommoder divers capteurs d'attitude et inertiels sur la même puce afin d'éliminer le besoin de nombreux capteurs séparés. Le produit final présente une réduction de plusieurs ordres de grandeur de la masse et de la taille du système. En outre, la redondance améliore la performance nette et la précision des systèmes de mesure de navigation. Deux classes d'accéléromètres/gyroscopes optiques sont examinées dans cette thèse pour application dans la navigation de petits satellites, l'une fondée sur un filtre accordable Fabry-Perot (FP), où le capteur est actionné par l'accélération appliquée fournissant un décalage de la longueur d'onde d'opération qui varie linéairement avec l'accélération appliquée, et l'autre fondée sur un atténuateur optique variable (VOA), où le capteur est actionné par l'accélération appliquée fournissant pour les petits déplacements un changement linéaire de l'intensité relative du signal ----------Abstract Over the last decade, the development of small satellites attitude control has moved towards full three axis stabilization and precise control as their application increases in telecom and space knowledge missions. For space-based systems, the major drivers are power, mass and reliability in the space environment. This is associated with an increasing necessity for compact, low-power inertial navigation systems. Current spacecraft navigation systems consist of various sensors and processors that are not optimized to operate together. This is costly and can require a considerable reduction of the mass and power resources available on a small spacecraft. Therefore the components need to be optimized relative to their size, design, and fabrication process. The objective of this thesis is to design, simulate, fabricate and characterize high sensitive low cost in-plane photonic-band-gap (PBG)-micro electromechanical systems (MEMS)-based miniature accelerometers and rotational rate sensors (gyroscopes) on a silicon-on-insulator (SOI) substrate in order to enable the integration of an array of two-axis of these sensors on a single SOI platform. Use of guided-wave optical devices integrated with MEMS on SOI for multichannel/multifunction sensor systems allows the use of multiple sensors to extend the measurement range and accuracy. This provides essential redundancy which makes long-term reliability in the space environment possible therefore reducing the possibility of system failure. The navigator microchip also represents the ability of accommodating diverse attitude and inertial sensors on the same microchip to eliminate the need of many separate sensors. The end product exhibits orders of magnitude reduction in system mass and size. Furthermore, redundancy improves the net performance and precision of the navigation measurement systems. Two classes of optical accelerometers/gyroscopes are considered in this thesis for application in smallsats navigation, one based on tunable Fabry-Perot (FP) filter, where the sensor is actuated by the applied acceleration providing a shift in the operating wavelength that varies linearly with the applied acceleration and the other one based on variable optical attenuator (VOA), where the sensor is actuated by the applied acceleration providing a linear change for small displacements around the waveguide propagation axis in the relative signal intensity with the applied acceleration. In the case of FP-based sensors, the FP microcavity consists of two distributed Bragg reflectors (DBR) in which one DBR mirror is attached to the proof mass of the system. A

Characterization of errors and noises in MEMS inertial sensors using Allan variance method

This thesis work has addressed the problems of characterizing and identifying the noises inherent to inertial sensors as gyros and accelerometers, which are embedded in inertial navigation systems, with the purpose of estimating the errors on the obtained position. The analysis of the Allan Variance method (AVAR) to characterize and identify the noises related to these sensors, has been done. The practical implementation of the AVAR method for the noises characterization has been performed over an experimental setup using the IMU 3DM-GX3 -25 data and the Matlab environment. From the AVAR plots it was possible to identify the Angle Random Walk and the Bias Instability in the gyros, and the Velocity Random Walk and Bias Instability in the accelerometers. A denoising process was also performed by using the Discrete Wavelet Transforms and the Median Filter. After the filtering the AVAR plots showed that the ARW was almost removed or attenuated using Wavelets, but not good results were obtained with the Median Filter

Applications of microsystems in small satellites

The past decades have experienced radical changes in fabrication and mass production of electronic systems. Sub-micrometer technologies have led to highly integrated systems with even increasing complexity and functionality. Microelectromechanical systems (MEMS) were developed to support the progress in microelectronics by providing similar integration levels in sensors and actuators. Nowadays, microsystems have widely been adopted in consumer electronics, including many critical applications, avionics, and health care. Adoption of microsystems has allowed increases in both performance and functionalities. Space technology is on the verge of similar development. The advent of small satellites, driven by the need of cost reduction, has created a demand for miniature systems that would improve the performance of spacecraft and enable new missions. The miniaturization of space systems can have significant influence on space technology all the more so as major restriction is high launch cost per kilogram. Currently, microsystems for space are still in their infancy and only a few systems have been operated in space. Reliability concerns and the conservative nature of space technology are preventing microsystems from being routinely integrated in satellites. However, small satellites offer a well suited platform for the demonstration of such systems in space. This thesis maps current situation of microsystem usage in space applications and pinpoints the most potential technologies for future usage. The work presents also analysis of factors restricting the wider usage of microsystems in space and propose strategies to tackle current problems. As the thesis work is located at the crossing point of two disciplines, an overview of both areas is given to help readers who might have background only from one area

Seamless Positioning and Navigation in Urban Environment

L'abstract è presente nell'allegato / the abstract is in the attachmen

SciTech News Volume 71, No. 2 (2017)

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NASA Thesaurus. Volume 2: Access vocabulary

The NASA Thesaurus -- Volume 2, Access Vocabulary -- contains an alphabetical listing of all Thesaurus terms (postable and nonpostable) and permutations of all multiword and pseudo-multiword terms. Also included are Other Words (non-Thesaurus terms) consisting of abbreviations, chemical symbols, etc. The permutations and Other Words provide 'access' to the appropriate postable entries in the Thesaurus

Quantum Communication, Sensing and Measurement in Space

The main theme of the conclusions drawn for classical communication systems operating at optical or higher frequencies is that there is a well‐understood performance gain in photon efficiency (bits/photon) and spectral efficiency (bits/s/Hz) by pursuing coherent‐state transmitters (classical ideal laser light) coupled with novel quantum receiver systems operating near the Holevo limit (e.g., joint detection receivers). However, recent research indicates that these receivers will require nonlinear and nonclassical optical processes and components at the receiver. Consequently, the implementation complexity of Holevo‐capacityapproaching receivers is not yet fully ascertained. Nonetheless, because the potential gain is significant (e.g., the projected photon efficiency and data rate of MIT Lincoln Laboratory's Lunar Lasercom Demonstration (LLCD) could be achieved with a factor‐of‐20 reduction in the modulation bandwidth requirement), focused research activities on ground‐receiver architectures that approach the Holevo limit in space‐communication links would be beneficial. The potential gains resulting from quantum‐enhanced sensing systems in space applications have not been laid out as concretely as some of the other areas addressed in our study. In particular, while the study period has produced several interesting high‐risk and high‐payoff avenues of research, more detailed seedlinglevel investigations are required to fully delineate the potential return relative to the state‐of‐the‐art. Two prominent examples are (1) improvements to pointing, acquisition and tracking systems (e.g., for optical communication systems) by way of quantum measurements, and (2) possible weak‐valued measurement techniques to attain high‐accuracy sensing systems for in situ or remote‐sensing instruments. While these concepts are technically sound and have very promising bench‐top demonstrations in a lab environment, they are not mature enough to realistically evaluate their performance in a space‐based application. Therefore, it is recommended that future work follow small focused efforts towards incorporating practical constraints imposed by a space environment. The space platform has been well recognized as a nearly ideal environment for some of the most precise tests of fundamental physics, and the ensuing potential of scientific advances enabled by quantum technologies is evident in our report. For example, an exciting concept that has emerged for gravity‐wave detection is that the intermediate frequency band spanning 0.01 to 10 Hz—which is inaccessible from the ground—could be accessed at unprecedented sensitivity with a space‐based interferometer that uses shorter arms relative to state‐of‐the‐art to keep the diffraction losses low, and employs frequency‐dependent squeezed light to surpass the standard quantum limit sensitivity. This offers the potential to open up a new window into the universe, revealing the behavior of compact astrophysical objects and pulsars. As another set of examples, research accomplishments in the atomic and optics fields in recent years have ushered in a number of novel clocks and sensors that can achieve unprecedented measurement precisions. These emerging technologies promise new possibilities in fundamental physics, examples of which are tests of relativistic gravity theory, universality of free fall, frame‐dragging precession, the gravitational inverse‐square law at micron scale, and new ways of gravitational wave detection with atomic inertial sensors. While the relevant technologies and their discovery potentials have been well demonstrated on the ground, there exists a large gap to space‐based systems. To bridge this gap and to advance fundamental‐physics exploration in space, focused investments that further mature promising technologies, such as space‐based atomic clocks and quantum sensors based on atom‐wave interferometers, are recommended. Bringing a group of experts from diverse technical backgrounds together in a productive interactive environment spurred some unanticipated innovative concepts. One promising concept is the possibility of utilizing a space‐based interferometer as a frequency reference for terrestrial precision measurements. Space‐based gravitational wave detectors depend on extraordinarily low noise in the separation between spacecraft, resulting in an ultra‐stable frequency reference that is several orders of magnitude better than the state of the art of frequency references using terrestrial technology. The next steps in developing this promising new concept are simulations and measurement of atmospheric effects that may limit performance due to non‐reciprocal phase fluctuations. In summary, this report covers a broad spectrum of possible new opportunities in space science, as well as enhancements in the performance of communication and sensing technologies, based on observing, manipulating and exploiting the quantum‐mechanical nature of our universe. In our study we identified a range of exciting new opportunities to capture the revolutionary capabilities resulting from quantum enhancements. We believe that pursuing these opportunities has the potential to positively impact the NASA mission in both the near term and in the long term. In this report we lay out the research and development paths that we believe are necessary to realize these opportunities and capitalize on the gains quantum technologies can offer

SciTech News- 68(4)-2014

Columns and Reports From the Editor 5 SciTech News Call for Articles 5 Conference Report, Diane K. Foster International Student Travel Award Recipient 8 Conference Report, S. Kirk Cabeen Travel Stipend Award Recipient 9 Conference Report, Bonnie Hilditch International Librarian Award Recipient 11 Conference Report, IEEE Continuing Education Award Recipient 19 Division News Science-Technology Division 6 Chemistry Division 14 Engineering Division 17 Call for Nominations & Applications Bonnie Hilditch International Librarian Award 13 IEEE Continuing Education Stipend 20 Engineering Librarian of the Year Award 21 SPIE Digital Library Student Travel Stipend 22 Reviews Sci-Tech Book News Reviews 23 Advertisements Annual Reviews 3 IEEE