The automatic antenna position control system for the ATS synchronous orbit spin-stabilized satellite.
Automatic directional-antenna position control system for ATS synchronous orbit spin- stabilized satellite
SYNCHRONOUS SATELLITE↗
SEARCH · Engineering Papers
Results for “synchronization”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Synchronous satellite station-keeping.
Synchronous orbit stationkeeping techniques, examining thrust control requirements of spin- stabilized spacecraft
THRUST CONTROL↗
Evaluation of an ion propulsion system for a synchronous spacecraft mission.
Thrust, power and performance requirements for synchronous satellite simulated for evaluating ion propulsion feasibility
SPACECRAFT PROPULSION↗
Optimal control applications for electrothermal multijet systems on synchronous earth spacecraft.
Multijet electrothermal systems for attitude control and stationkeeping of synchronous communications satellite
STATIONKEEPING↗
Precious bits: frame synchronization in Jet Propulsion Laboratory's Advanced Multi-Mission Operations System (AMMOS)
The Jet Propulsion Laboratory's (JPL) Advanced Multi-Mission Operations System (AMMOS) system processes data received from deep-space spacecraft, where error rates are high, bit rates are low, and every bit is precious. Frame synchronization and data extraction as performed by AMMOS enhanced data acquisition and reliability for maximum data return and validity.
code↗
Quantum Atomic Clock Synchronization: An Entangled Concept of Nonlocal Simultaneity
We demonstrate that two spatially separated parties (Alice and Bob) can utilize shared prior quantum entanglement, as well as a classical information channel, to establish a synchronized pair of atomic clocks.
quantum information processing atomic clocks quant↗
Suppressed Carrier Synchronizers for ISI Channels
We demonstrate a class of suppressed carrier synchronization loops that are motivated by MAP estimation theory and in the presence of ISI outperform the conventional I-Q loop which is designed on the basis of zero ISI (wideband assumption). The measure of comparison used is the so-called.
synchronization loops↗
Acquisition Performance Comparison of the Generalized Maxium A Posteriori Symbol Synchronizer Versus the Data-Transition Tracking Loop
A generalized maxium a posteriori (MAP), symbol synchronizer for arbitrary nonoverlapping pulse shape and data-transition density is derived, and a simplified realization is presented.
Maxium A Posteriori (MAP) signal-to-noise ratio (S↗
Information-reduced Carrier Synchronization of Iterative Decoded BPSK and QPSK using Soft Decision (Extrinsic) Feedback
This paper addresses the carrier-phase estimation problem under low SNR conditions as are typical of turbo- and LDPC-coded applications. In previous publications by the first author, closed-loop carrier synchronization schemes for error-correction coded BPSK and QPSK modulation were proposed that were based on feeding back hard data decisions at the input of the loop, the purpose being to remove the modulation prior to attempting to track the carrier phase as opposed to the more conventional decision-feedback schemes that incorporate such feedback inside the loop. In this paper, we consider an alternative approach wherein the extrinsic soft information from the iterative decoder of turbo or LDPC codes is instead used as the feedback.
carrier synchronization↗
Frame Synchronization Without Attached Sync Markers
A new frame synchronizer was presented. It eliminates the need to transmit attached sync markers (ASMs). In approximately 10 iterations, the decoder can distinguish between sync and non-sync states.
Attached Sync Markers (ASMs)↗
Turbo-code performance with imperfect carrier synchronization
The threshold performance of deep-space telemetry is characterized for four turbo codes. The mathematical models given here are based on simulations that account for imperfect carrier synchronization.
turbo↗
Closed Loop Carrier Phase Synchronization Techniques Motivated by Likelihood Functions
This paper reexamines the notion of closed loop carrier phase synchronization motivated by the theory of maximum a posterior (MAP) phase estimation with emphasis on the development of new structures based on both maximum likelihood (ML) and average-likelihood (AL) functions.
Closed↗
Synchronized Formation Rotation and Attitude Control of Multiple Free-flying Spacecraft
In the observation slewing of long base-line interferometers formed by multiple free-flying spacecraft in formation, it is required to rotate the entire formation about a given axis, and to synchronize individual spacecraft rotation with formation rotation.
long↗
Architecture of High-Altitude Operations (HAO) Discovery and Synchronization Service (DSS)
The aviation industry is evolving at an unprecedented pace, necessitating the development of efficient, secure, and interoperable systems to manage increasingly complex air traffic. Moreover, the demand for High-Altitude Operations (HAO) is increasing. Furthermore, air traffic control services are limited in HAO environments. HAO industry participants will need airspace access and flexibility to perform their missions in this airspace that provides provisions for scalability. The Discovery and Synchronization Service (DSS) will be a cornerstone of the HAO ecosystem, enabling the effective sharing of critical airspace data, including operational intent, aircraft trajectories, and airspace usage among various stakeholders and operators. The DSS architecture addresses these challenges with a distributed, decentralized, and interoperable system that facilitates seamless integration across diverse airspaces. It prioritizes secure data exchange while safeguarding data ownership. This white paper presents the vision, architecture, and benefits of the DSS for HAO, underscoring its potential to streamline operations, reduce redundancies, and establish a foundation for safe and efficient airspace management.
HAO↗
SIW21-95: Hybridizing Synchronous Condensers with Grid-Forming Battery Energy Storage Systems
One of the main challenges associated with deployment of high shares of inverter-based resources (IBRs) in power grid is not only reduced system inertia but also degrading system strength that may cause severe stability impacts. A minimum level of system strength is needed for the power system to remain stable under normal conditions and to return to a steady state condition following a system disturbance. Significant system strength reduction is expected in almost all planned areas for solar and wind generation deployment. Synchronous condensers (SC) have been considered as one main technology to address the system strength issues for the areas with high levels of IBRs. SCs can help improving reliability and resiliency of power system but they do not provide the full range of services needed by power systems for reliable and economic integration of high shares of inverter-coupled variable generation such as PV generation. Services related to active power controls cannot be provided by SCs due to lack of prime mover. Even for provision of reactive power SCs have certain constraints based on their thermal and stability limits. NREL has been conducting research on a hybridized concept that combines SCs with grid forming (GFM) battery energy storage systems (BESS). This super flexible AC transmission system (SuperFACTS) that combines these two technologies in a single plant under the same controller offers a unique scalable set of services to the power system at all levels (transmission, sub-transmission, distribution, islands and isolated microgrids). Depending on use cases, SuperFACTS can be controlled to provide fully dispatchable and flexible operation using energy storage component, provide a full range of existing and future ancillary and reliability services to the grid (similar or better than conventional sources), maintain adequate levels of grid strength and inertia, and provide fault current for proper operation of protection systems. Therefore, this economic and easy to commercialize solution has potential for significant impacts on certain segments of global energy sector. All types of gird services (market based, reliability and resiliency) can be provided by SuperFACTS plants. GFM BESS can act as a self-black start source for each SuperFACTS module, which in turn can act a black start resource for co-located PV and wind power plants, segments of transmission and distribution networks, for conventional power plants, etc. The issue of in-rush currents during black start is addressed by overcurrent capability of SCs. In this paper we describe the results of modeling for SuperFACTS concept.
grid forming↗
Synchronous and asynchronous optimized Schwarz methods for one-way subdivision of bounded domains
Convergence of both synchronous and asynchronous optimized Schwarz algorithms for the shifted Laplacian operator on a bounded rectangular domain, in a one-way subdivision of the computational domain, with overlap, is shown. Convergence results are obtained under very mild conditions on the size of the subdomains and on the amount of overlap. A couple of results are also given, relating the convergence rate of the asynchronous method to changes in the size of the domain. Numerical experiments illustrate the theoretical results.
97 MATHEMATICS AND COMPUTING↗
Addition of transient kinetics capabilities to an infrared reflection absorption spectroscopy system through synchronized gas pulsing and data acquisition
Surface science methodologies for understanding thermodynamic aspects of surface processes are at an advanced level. However, instrumentation and approaches for extracting kinetic parameters from elementary steps are far less accessible. In this work, we present an approach combining the use of a fast gas pulsing valve synchronized with data acquisition to enable surface transient kinetics studies using infrared reflection absorption spectroscopy. This methodology applies to the study of reversible processes and borrows concepts and ideas from molecular beam scattering and temporal analysis of products. Here, a temporal resolution of ~67 ms is achieved, and this is illustrated through the study of CO adsorption and desorption on a Pd(111) crystal in the presence and absence of background O 2 . The same approach can be extended to other surface spectroscopies, such as X-ray photoelectron spectroscopy, to obtain spectra with high temporal resolution and signal-to-noise ratio and enable future multimodal surface transient kinetic studies aiming at elucidating reaction mechanisms.
36 MATERIALS SCIENCE↗
Adaptation of virtual synchronous generators to dynamic conditions in power grids
Virtual synchronous generators (VSGs) are widely adopted as grid-forming controls for inverter-based resources. However, when grid conditions vary significantly as characterized by changes in short-circuit ratio (SCR) and the reactance-to-resistance (X/R) ratio, fixed-gain designs and the commonly used P–Q decoupling assumption can become inaccurate. Such conditions can degrade transient power performance, leading to oscillations, prolonged settling, and overshoot, particularly in stiff-grid operating points. This paper quantifies how grid strength and impedance-dependent coupling affect the active–reactive power dynamics of a conventional VSG over a broad range of SCR and X/R values. An adaptive VSG tuning framework is then developed by combining (i) a coupling-explicit, impedance-parameterized state-space model to enable systematic controller synthesis, (ii) a full-state-feedback law designed via pole placement to meet prescribed damping and settling-time specifications, and (iii) a physics-informed neural network (PINN)–based online grid-impedance estimator that updates controller gains in real time as grid conditions vary. Offline simulations in MATLAB/Simulink and real-time validation on an OPAL-RT platform show that the proposed method preserves consistent damping and settling behavior with reduced overshoot across wide SCR and X/R ranges, compared with fixed-gain VSG baselines.
Adaptive control↗