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Noll, Carey E.

Publications and source records attributed to Noll, Carey E..

16 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2018

Important Changes to User Access at the NASA CDDIS

The Crustal Dynamics Data Information System (CDDIS) supports data archiving and distribution activities for the space geodesy and geodynamics community. The main objectives of the system are to make space geodesy and geodynamics related data and derived products available in a central archive, to maintain information about the archival of these data, to disseminate these data and information in a timely manner to a global scientific research community, and to provide user based tools for the exploration and use of the archive. Since its inception, the user community has utilized anonymous ftp for accessing and downloading files from the CDDIS archive. Although this protocol allows users to easily automate file downloads, many organizations, data systems, and users have already migrated from ftp or are actively pursuing a move away from the protocol due to problems from a system and security standpoint. Furthermore, U.S. Government agencies have become increasingly concerned about this legacy protocol and ensuring data integrity for the user community have begun recently to disallow the use of the ftp protocol. The CDDIS, operated by NASA GSFC, must therefore address these concerns and provide alternative methods for access to its archive for continued easy and automated download of its contents. This poster will discuss the upcoming changes at CDDIS and provide examples on transitioning from anonymous ftp.

Noll, Carey E.↗
NASA NTRS2018

Survey of Localized Solar Flare Signatures in the Ionosphere with GNSS, VLF, and GOES Observations

Global navigation satellite system (GNSS) phase measurements of the total electron content (TEC) and ionospheric delay are sensitive to sudden increases in electron density in the layers of the Earth’s ionosphere. These sudden ionospheric disruptions, or SIDs, are due to enhanced X-ray and extreme ultraviolet radiation from a solar flare that drastically increases the electron density in localized regions. SIDs are solar flare signatures in the Earth’s ionosphere and can be observed with very low frequency (VLF ~ 3-30 kHz) monitors and dual-frequency GNSS (L1 = 1575.42 MHz, L2 = 1227.60 MHz) receivers that probe lower (D-region) to upper (F-region) ionospheric layers, respectively.

Blevins, Sandra↗
NASA NTRS2018

Bureau of Networks and Observations

Role of the Bureau: To advocate and encourage implementation of the Core and Co-location Network to satisfy GGOS requirements, to monitor the status of the network and project its future condition, and to support and advocate for infrastructure critical for the development of data products essential to GGOS.

Pearlman, Michael R.↗
NASA NTRS2014

The International DORIS Service (IDS) - Recent Developments in Preparation for ITRF2013

The International DORIS Service (IDS) was created in 2003 under the umbrella of the International Association of Geodesy (IAG) to foster scientific research related to the French DORIS tracking system and to deliver scientific products, mostly related to the International Earth rotation and Reference systems Service (IERS). We first present some general background related to the DORIS system (current and planned satellites, current tracking network and expected evolution) and to the general IDS organization (from Data Centers, Analysis Centers and Combination Center). Then, we discuss some of the steps recently taken to prepare the IDS submission to ITRF2013 (combined weekly time series based on individual solutions from several Analysis Centers). In particular, recent results obtained from the Analysis Centers and the Combination Center show that improvements can still be made when updating physical models of some DORIS satellites, such as Envisat, Cryosat-2 or Jason-2. The DORIS contribution to ITRF2013 should also benefit from the larger number of ground observations collected by the last generation of DGXX receivers (first instrument being onboard Jason-2 satellite). In particular for polar motion, sub-millarcsecond accuracy seems now to be achievable. Weekly station positioning internal consistency also seems to be improved with a larger DORIS constellation.

tracking↗
NASA NTRS2013

ILRS Station Reporting

Network stations provided system configuration documentation upon joining the ILRS. This information, found in the various site and system log files available on the ILRS website, is essential to the ILRS analysis centers, combination centers, and general user community. Therefore, it is imperative that the station personnel inform the ILRS community in a timely fashion when changes to the system occur. This poster provides some information about the various documentation that must be maintained. The ILRS network consists of over fifty global sites actively ranging to over sixty satellites as well as five lunar reflectors. Information about these stations are available on the ILRS website (http://ilrs.gsfc.nasa.gov/network/stations/index.html). The ILRS Analysis Centers must have current information about the stations and their system configuration in order to use their data in generation of derived products. However, not all information available on the ILRS website is as up-to-date as necessary for correct analysis of their data.

satellites↗
NASA NTRS2013

ILRS Website Update

The ILRS website, http://ilrs.gsfc.nasa.gov, is the central source of information for all aspects of the service. The website provides information on the organization and operation of the ILRS and descriptions of ILRS components data, and products. Furthermore, the website provides an entry point to the archive of these data products available through the data centers. Links are provided to extensive information on the ILRS network stations including performance assesments and data quality evaluations. Descriptions of suported satellite missions (current, future, and past) are provided to aid in station acquisition and data analysis. The website was reently redesigned. Content was reviewed during the update process, ensuring information is current and useful. This poster will provide specific examples of key sections, applicaitons, and webpages.

components↗
NASA NTRS2004

CDDIS 2001 Global Data Center Report

The Crustal Dynamics Data Information System (CDDIS) has supported the International GPS Service (IGS) as a global data center since 1992. The CDDIS activities within the IGS during 2001 are summarized below; this report also includes any changes or enhancements made to the CDDIS during the past year. General CDDIS background and system information can be found in the CDDIS data center summary included in the IGS 1994 Annual Report (Noll, 1995) as well as the subsequent updates (Noll, 1996, Noll, 1997, Noll, 1998, Noll, 1999, and Noll, 2001).

Noll, Carey E.↗
NASA NTRS2004

CDDIS 2002 Global Data Center Report

The Crustal Dynamics Data Information System (CDDIS) has supported the International GPS Service (IGS) as a global data center since 1992. The CDDIS activities within the IGS during 2002 are summarized below; this report also includes any changes or enhancements made to the CDDIS during the past year. General CDDIS background and system information can be found in the CDDIS data center summary included in the IGS 1994 Annual Report (Noll, 1995) as well as the subsequent updates (Noll, 1996, Noll, 1997, Noll, 1998, Noll, 1999, and Noll, 2001).

Noll, Carey E.↗
NASA NTRS2004

IGS Data Center Working Group Report

At its 18th meeting held December 09, 2001 in San Francisco, the IGS Governing Board recommended the formation of a working group to focus on data center issues. This working group will tackle many of the problems facing the IGS data centers as well as develop new ideas to aid users both internal and external to the IGS. The direction of the IGS has changed since its start in 1992 and many new working groups, projects, data sets, and products have been created and incorporated into the service since that time. Therefore, this may be an appropriate time to revisit the requirements of data centers within the IGS.

Noll, Carey E.↗
NASA NTRS2004

Archiving Space Geodesy Data for 20+ Years at the CDDIS

Since 1982, the Crustal Dynamics Data Information System (CDDIS) has supported the archive and distribution of geodetic data products acquired by NASA programs. These data include GPS (Global Positioning System), GLONASS (GLObal NAvigation Satellite System), SLR (Satellite Laser Ranging), VLBI (Very Long Baseline Interferometry), and DORIS (Doppler Orbitography and Radiolocation Integrated by Satellite). The data archive supports NASA's space geodesy activities through the Solid Earth and Natural Hazards (SENH) program. The CDDIS data system and its archive have become increasingly important to many national and international programs, particularly several of the operational services within the International Association of Geodesy (IAG), including the International GPS Service (IGS), the International Laser Ranging Service (ILRS), the International VLBI Service for Geodesy and Astrometry (IVS), the International DORIS Service (IDS), and the International Earth Rotation Service (IERS). The CDDIS provides easy and ready access to a variety of data sets, products, and information about these data. The specialized nature of the CDDIS lends itself well to enhancement and thus can accommodate diverse data sets and user requirements. All data sets and metadata extracted from these data sets are accessible to scientists through ftp and the web; general information about each data set is accessible via the web. The CDDIS, including background information about the system and its user communities, the computer architecture, archive contents, available metadata, and future plans will be discussed.

Noll, Carey E.↗
NASA NTRS2001

CDDIS Data Center Report

This report summarizes activities for the year 2000 and future plans of the Crustal Dynamics Data Information System (CDDIS) with respect to the International Very Long Base Interferometry (VLBI) Service for Geodesy and Astrometry (IVS). Included in this report are background information about the CDDIS, the computer architecture, staffing supporting the system, archive contents, and future plans for the CDDIS within the IVS.

Noll, Carey E.↗
NASA NTRS2001

CDDIS Support of IGS LEO Activities

The Crustal Dynamics Data Information System (CDDIS) has served as a global data center for the International GPS Service (IGS) since its start in June 1992, providing on-line access to data from over 175 sites on a daily and hourly basis. This paper will present an overview about the current status of the CDDIS GPS data and products archive with a look to the future support of LEO (Low Earth Orbiting missions), including the archive of high-rate data and on-board GPS receiver data.

Noll, Carey E.↗
NASA NTRS2000

The DORIS Data Center at the CDDIS

The DORIS system (Doppler Orbitography and Radio positioning Integrated by Satellite) was designed and developed by CNES, the National Geographic Institute, IGN (Institut G6ographique National), and the Space Geodesy Research Group, GRGS (Groupe de Recherches de Geodesie Spatiale - CNES/CNRS/Universite Paul Sabatier) to meet new needs for the precise determination of satellite positions on their orbits and for precise positioning of terrestrial beacons. This system has been carried since 1990 on the French SPOT 2 satellite, since 1992 on the French/American satellite TOPEX/POSEIDON, and since 1998 on the French SPOT 4 satellite. It will be part of the JASON (CNES/NASA) and ENVISAT (ESA) altimetric missions and also the SPOT follow-on Earth observation missions. DORIS is a radio-electrical system which takes Doppler measurements between a satellite in low orbit and a permanent global network for the purpose, on the one hand, of determining the satellite's position in orbit, and on the other hand, of locating ground beacons with a high degree of precision.

Noll, Carey E.↗
NASA NTRS1988

Crustal Dynamics Project: Catalogue of site information

This document represents a catalog of site information for the Crustal Dynamics Project. It contains information on and descriptions of those sites used by the Project as observing stations for making the precise geodetic measurements necessary for studies of the Earth's crustal movements and deformation.

Noll, Carey E.↗
NASA NTRS1987

Quick-look guide to the crustal dynamics project's data information system

Described are the contents of the Crustal Dynamics Project Data Information System (DIS) and instructions on the use of this facility. The main purpose of the DIS is to store all geodetic data products acquired by the Project in a central data bank and to maintain information about the archive of all Project-related data. Access and use of the DIS menu-driven system is described as well as procedures for contacting DIS staff and submitting data requests.

Noll, Carey E.↗