Search NASA⌕ Search

SEARCH · Search NASA

Results for “DIGITAL SYSTEMS”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4

Information Systems Technology for NASA Earth Systems Digital Twins (ESDT)

The term “Digital Twin” was first used in 2002 for product lifecycle management. Since then, Digital Twin concepts have been proposed in various domains until very recently for Earth Science. For NASA’s Advanced Information Systems Technology (AIST) Program, an Earth System Digital Twin (ESDT) is defined as composed of three components: 1. A Digital Replica, i.e., an integrated picture of the past and current states of Earth systems 2. Forecasting capabilities, providing an integrated picture of how Earth systems will evolve in the future from the current state 3. Impact Assessment capabilities, providing an integrated picture of how Earth systems could evolve under different hypothetical what-if scenarios. Developing such a vision will require technologies related to: integrating continuous observations from various disparate sources; developing frameworks that builds on inter-connected models; improving the speed and accuracy of integrated prediction, analysis and visualization capabilities (e.g., by using machine learning); and utilizing causality and uncertainty quantification to improve our understanding of the evolution of Earth Science systems as a function of their interactions with other Earth and human systems. In addition, AIST is also investigating interoperability standards to federate multiple Digital Twins, as well as computational resources required by those systems.

Earth Science Remote Sensing; Information Systems↗

Digital system provides superregulation of nanosecond amplifier-discriminator circuit

Feedback system employing a digital logic comparator to detect and correct amplifier drift provides stable gain characteristics for nanosecond amplifiers used in counting applications. Additional anticoincidence logic enables application of the regulation circuit to the amplifier and discriminator while they are mounted in an operable circuit.

Forges, K. G.↗

Towards Earth System Digital Twins (ESDT)

I will present an overview (in French) of the AIST Program with a particular emphasis on Earth system Digital Twins (ESDT) and on the collaborative work the AIST Program is currently conducting with CNES.

Earth Science Remote Sensing; Information Systems↗

Very high frequency digital rangine system

Digital ranging system measures slant range /from 500 feet to 200 nautical miles/ and provides digital range readout during range tracking between any two airborne vehicles.

Sobel, S. E.↗

Modeling and Simulation of Upset-Inducing Disturbances for Digital Systems in an Electromagnetic Reverberation Chamber

This report describes a modeling and simulation approach for disturbance patterns representative of the environment experienced by a digital system in an electromagnetic reverberation chamber. The disturbance is modeled by a multi-variate statistical distribution based on empirical observations. Extended versions of the Rejection Samping and Inverse Transform Sampling techniques are developed to generate multi-variate random samples of the disturbance. The results show that Inverse Transform Sampling returns samples with higher fidelity relative to the empirical distribution. This work is part of an ongoing effort to develop a resilience assessment methodology for complex safety-critical distributed systems.

Torres-Pomales, Wilfredo↗

Los Alamos Portable Pulser (LAPP) Marx Bank and Digitizer System Characterization

Over the duration of June 22 nd to July 15 th , I interned at Los Alamos National Laboratory within ISR-2 on the Los Alamos Portable Pulser (LAPP) Program. This program concerns a radar dish used for characterizing signal propagation through earth’s ionosphere. The bulk of my internship consisted of characterizing the delay of a Marx Bank Generator and writing hardware-interface C/C++ code for the pulse-recording Digitizer System.

47 OTHER INSTRUMENTATION↗

Field-Deployable Acoustic Digital Systems for Noise Measurement

Langley Research Center (LaRC) has for years been a leader in field acoustic array measurement technique. Two field-deployable digital measurement systems have been developed to support acoustic research programs at LaRC. For several years, LaRC has used the Digital Acoustic Measurement System (DAMS) for measuring the acoustic noise levels from rotorcraft and tiltrotor aircraft. Recently, a second system called Remote Acquisition and Storage System (RASS) was developed and deployed for the first time in the field along with DAMS system for the Community Noise Flight Test using the NASA LaRC-757 aircraft during April, 2000. The test was performed at Airborne Airport in Wilmington, OH to validate predicted noise reduction benefits from alternative operational procedures. The test matrix was composed of various combinations of altitude, cutback power, and aircraft weight. The DAMS digitizes the acoustic inputs at the microphone site and can be located up to 2000 feet from the van which houses the acquisition, storage and analysis equipment. Digitized data from up to 10 microphones is recorded on a Jaz disk and is analyzed post-test by microcomputer system. The RASS digitizes and stores acoustic inputs at the microphone site that can be located up to three miles from the base station and can compose a 3 mile by 3 mile array of microphones. 16-bit digitized data from the microphones is stored on removable Jaz disk and is transferred through a high speed array to a very large high speed permanent storage device. Up to 30 microphones can be utilized in the array. System control and monitoring is accomplished via Radio Frequency (RF) link. This paper will present a detailed description of both systems, along with acoustic data analysis from both systems.

Shams, Qamar A.↗

Characterization of a 16-bit Digitizer System for Lidar Data Acquisition

A new 16-bit 6-MHz compact, lightweight waveform digitizer module has been tested using actual 300-nm lidar atmospheric returns. The noise level of this digitizer was tested and found to be substantially below the ozone number density to be measured. The digitizer is inexpensive and compact enough to be deployed in UAV aircraft and spacecraft environments. With 16-bit digitizers a resolution of 0.046 mV/step can be achieved, substantially improving resolution over 12-bit systems. This digitizer will find widespread use in future DIAL receiver systems.

Williamson, Cynthia K.↗

NASA Earth Science Technology Office (ESTO) Advanced Information Systems Technology (AIST) Program: Earth Systems Digital Twins (ESDT) Standards for Interoperable Digital Twins Workshop Presentations

On September 18, 2023, NASA Earth Science Technology Office (ESTO) Advanced Information Systems Technology (AIST) Program conducted a mini-workshop that brought together seven experts to survey and discuss "Standards for Interoperable Digital Twins". Since three years, the AIST Program has been developing technologies and prototypes for Earth System Digital Twins (ESDT). During those developments and after the ESDT Workshop held in October 2022, it became clear that standard for ESDT interoperability were needed and should be defined as soon as possible. To address this challenge, the AIST program will survey ongoing development for Digital Twins standards in various domains and the September 18, 2023 Workshop represented the first step towards this understanding. Speakers during this event included: Michael Grieves (Digital Twin Institute), Siri Jodha Singh Khalsa (IEEE GRSS Standards), Trent Tinker (OGC), Ryan Berkheimer (NOAA), John Stone (NVIDIA), Thomas Geenen (ECMWF-DestinE) and Arne Berre (SINTEF-Iliad DTO and EDITO). This presentation regroups all the speakers' presentations.

Earth Science Remote Sensing; Information Systems↗

Logic redundancy improves digital system reliability

Redundant-channel system automatically corrects any single error in a set of three binary signal channels. This system is especially applicable to digital computers where data is transmitted in parallel channels.

Source record↗