Papers by Erricos C. Pavlis
The European Physical Journal Plus, Nov 28, 2023
Technological changes in recent years and new missions such as LRO and T2L2 with novel use of las... more Technological changes in recent years and new missions such as LRO and T2L2 with novel use of laser signals mandated the revision and consolidation of the various ILRS data formats. The new laser data format is required to accommodate higher precision laser data and include additional data fields with ancillary information. After several years of development, the Consolidated laser Ranging Data (CRD) format, which accommodates fullrate, sampled engineering, and normal point data in a unified, expanded, flexible format, is ready to be implemented throughout the ILRS network. The first step in implementation requires the Operations Centers (OCs) and Data Centers (DCs) to be able to accept and distribute data in the CRD format. Next, a number of analysis centers (ACs) must be able to ingest data in the new format for testing and validating each station's transition from old to new format. Finally, the stations need to produce the CRD format. Owing to the changes in precision and to...
LARES is an Italian Space Agency mission designed to test General Relativity in the weak field of... more LARES is an Italian Space Agency mission designed to test General Relativity in the weak field of Earth. In particular, the satellite will be able to measure frame-dragging with an accuracy of about 1%. The difficulty of the measurement is mainly due to the perturbations acting on the satellite and the relatively tiny size of the effect, amounting to about 118 milliarcseconds/year. LARES will also provide data to geodesists and it will contribute to GNSS by improving the origin definition of the International Terrestrial Reference Frame. The mission was designed and the satellite subsystems built and tested in less than four years. The short time to launch and the very limited budget of the LARES mission, raised doubts whether LARES could be, as expected by design, one of the best satellite laser ranging targets. The best way to confirm the success of the mission is to look at the range residuals from the primary stations of the International Laser Ranging Service (ILRS). In the pap...
NASA's renewed commitment to the deployment of a new network of "core" space geodet... more NASA's renewed commitment to the deployment of a new network of "core" space geodetic sites requires careful planning and consideration for location selection, instrument and facility layout, and required infrastructure. Following on National Research Council (NRC) recommendations [1] to upgrade U.S. stations with modern SLR, VLBI, and GNSS systems, and make a long-term commitment to maintaining the ITRF (among others), the Space Geodesy Project (SGP) at NASA Goddard has been defining the exact requirements and layout for a "typical" geodetic site, which includes Satellite Laser Ranging--SLR, Very Long Baseline Interferometry--VLBI, Global Navigation Satellite System--GNSS, and Doppler Orbitography and Radiopositioning Integrated by Satellite--DORIS stations (French system provided by CNES, France) tied together with a Vector Tie System (VTS), utilizing a Robotic Total Station (RTS). Within programmatic constraints, Core Site (CS) identification follows a sys...
Sea level monitoring is a common objective of GOOS and GGOS, both systems under GEOSS, but with q... more Sea level monitoring is a common objective of GOOS and GGOS, both systems under GEOSS, but with quite different goals. Tide gauges provide ground truth for altimeter calibration and in situ monitoring of MSL, while precise positioning of such sites with Continuously Observing Reference Stations (CORS) help separate local tectonics from oceanographic signals. We are presenting here the extension of the regional eastern Mediterranean Altimeter Calibration network —eMACnet, to an Aegean-wide network in the Eastern Mediterranean. Coastal tide gauges equipped with GNSS receivers and offshore buoys near OSTM groundtracks (ACTION - Altimeter Calibration and Tectonics Inference Oceanographic Network) will provide better area coverage and timely data availability in support of satellite calibration, MSL and environmental monitoring, tsunami warning, etc. The original network was established with EU's 5th FP and NASA's OSTMST funding in 2001. Since 2008, our collaboration with the Dio...
La Camera Spaziale Climatica (CSC) in allestimento ai LNF è un progetto integrato con applicazion... more La Camera Spaziale Climatica (CSC) in allestimento ai LNF è un progetto integrato con applicazioni di fisica fondamentale e di ricaduta e trasferimento tecnologico per usi civili ed industriali . Nella CSC, infatti, si intendono studiare sperimentalmente le caratteristiche ottiche e termiche delle componenti dei satelliti LAGEOS I e II (già operativi) e la loro evoluzione LARES (in via di realizzazione ai LNF). Lo scopo è quello di migliorare l'accuratezza della misura del trascinamento dei sistemi inerziali in Relatività Generale (effetto Lense-Thirring [1] [2]) e delle applicazioni di Geodesia. Gli elementi orbitali vengono determinati con inseguimento via laser da Terra dei satelliti (Satellite Laser Ranging, SLR). L'applicazione tecnologica più importante è il contributo fondamentale alla definizione del sistema internazionale di riferimento di posizione terrestre (ITRF, Intern. Terrestrial Reference Frame), emesso dallo IERS (Intern. Earth Reference Service), lo standar...
implementation in their s/w and procedures o ASI – AC & CC o BKG o DGFI – AC & CC o GA o GFZ o GR... more implementation in their s/w and procedures o ASI – AC & CC o BKG o DGFI – AC & CC o GA o GFZ o GRGS/OCA o JCET o NSGF Recent data analysis issues – 1993 – present: o Stanford corrections for additional sites???- GA o Station bias adjustment, revision of current list, implementation – CL, ECP,? o Core site re-classification (update?) – CL o SLRF2005: proposal to adopt as JASON-2 POD standard- JR Historical data analysis – 1983 – 1993: o Status, AC contributions, CC combinations o Core-site selection for the historical network- CL o 1983 – present product: Combination results? – CS & RK Final results by? …(ITRF2008+ needs input!!!) New/Returning station qualification: o define and implement the activity and identify primary and back-up centers and procedures – HM,? Other products from Pilot Projects, Modeling issues, etc.: o Daily “weekly ” analysis & pos+eop report for station feedback – ECP,?
European geosciences union general assembly, 2005
From Mars to Greenland: Charting Gravity With Space and Airborne Instruments, 1992
ABSTRACT An improved model of the Earth's gravitational field is developed from a combina... more ABSTRACT An improved model of the Earth's gravitational field is developed from a combination of conventional satellite tracking, satellite altimeter measurements, and surface gravimetric data (GEM-T3). This model gives improved performance for the computation of satellite orbital effects as well as a superior representation of the geoid from that achieved in any previous Goddard Earth Model. The GEM-T3 model uses altimeter data directly to define the orbits, geoid, and dynamic height fields. Altimeter data acquired during the GEOS-3 (1975-1976), SEASAT (1978), and GEOSAT (1986-1987) missions were used to compute GEM-T3. In order to accommodate the non-gravitational signal mapped by these altimeters, spherical harmonic models of the dynamic height of the ocean surface were recovered for each mission simultaneously with the gravitational field. The tracking data utilized in the solution includes more than 1300 arcs of data encompassing 31 different satellites. The observational data base is highly dependent on SLR, but also includes TRANET Doppler, optical, S-Band average range-rate and satellite-to-satellite tracking acquired between ATS-6 and GEOS-3. The GEM-T3 model has undergone extensive error calibration.
Atmospheric refraction is an important accuracy-limiting factor in the use of satellite laser ran... more Atmospheric refraction is an important accuracy-limiting factor in the use of satellite laser ranging (SLR) for high-accuracy science applications. In most of these applications, and particularly for the establishment and monitoring of the TRF, of great interest is the stability of its scale and its implied height system. The modeling of atmospheric refraction in the analysis of SLR data comprises the determination of the delay in the zenith direction and subsequent projection to a given elevation angle, using a mapping function. Standard data analyses practices use the 1973 Marini-Murray model for both zenith delay determination and mapping. This model was tailored for a particular wavelength and is not suitable for all the wavelengths used in modern SLR systems. Improved refraction modeling is essential in reducing errors in SLR measurements that study variations in the Earth's gravity field and crustal motion (especially for the vertical component), as well as monitoring sea-...
Journal of Geodesy, 2019
LARES 2 is an Italian Space Agency (ASI) satellite designed for testing with unprecedented accura... more LARES 2 is an Italian Space Agency (ASI) satellite designed for testing with unprecedented accuracy frame-dragging, a fundamental prediction of General Relativity, and to contribute to space geodesy with a precision higher than any other satellite presently in orbit. The choice of the material for the body of LARES 2 satellite determines, along with its dimensions, the surface-to-mass ratio minimization which is the main requirement for the satellite. The paper will report the studies conducted for the fulfilment of the above mentioned requirement and the tests performed to qualify the materials for construction of the the satellite.
Journal of Geodesy, 2018
NASA maintains and operates a global network of Very Long Baseline Interferometry (VLBI), Satelli... more NASA maintains and operates a global network of Very Long Baseline Interferometry (VLBI), Satellite Laser Ranging (SLR), and Global Navigation Satellite System ground stations as part of the NASA Space Geodesy Program.
2015 IEEE Metrology for Aerospace (MetroAeroSpace), 2015
LARES is an Italian Space Agency satellite specifically designed, built and launched to test gene... more LARES is an Italian Space Agency satellite specifically designed, built and launched to test general relativity. It is a passive satellite covered with Cube Corner Reflectors that reflect laser pulses from tracking stations, thus allowing accurate measurement of the distance. That in turn enables accurate orbit reconstruction that is a key ingredient to allow the measurement of the tiny Lense-Thirring effect predicted by general relativity. The International Space Time Analysis Research Center provides the International Laser Ranging Service-ILRS, the orbital predictions for LARES for pointing of the tracking telescopes toward the target. The paper describes the technical aspects of generating the orbital predictions.
International Association of Geodesy Symposia, 2015
Satellite Laser Ranging (SLR) data have been fundamental over the past three decades for the real... more Satellite Laser Ranging (SLR) data have been fundamental over the past three decades for the realization of the International Terrestrial Reference Frame (ITRF), which is based on an intertechnique combination of the geodetic solutions obtained from an intra-technique combination strategy performed at each IAG Technique Centre. This approach provides an opportunity to verify the internal consistency for each technique and a comparison of Analysis Center (AC) adherence to internal procedures and adopted models. The International Laser Ranging Service (ILRS) contribution is based on the current IERS Conventions 2010 as well as on internal ILRS ones, with a few documented deviations. The main concern in the case of SLR is monitoring systematic errors at individual stations, accounting for undocumented discontinuities, and improving the satellite target signature models. The SLR data re-analysis for ITRF2013 extends from 1983 to the end of 2013 and was carried out by 8 ACs according to the guidelines defined by the ILRS Analysis Working Group (AWG). These individual solutions have been then combined in the official solution by the ILRS Combination Center. This work allows point-wise monitoring of the quality of the SLR contribution and a thorough investigation on the time behaviour of its characteristic products, i.e. origin and scale of ITRF. The stability and consistency of these products are discussed for the individual and combined SLR time series. The critical issues from this analysis will be presented to highlight the key points that SLR should take into account to contribute in the best possible way to the present and future ITRF realizations.
International Association of Geodesy Symposia, 1996
The NASA Goddard Space Flight Center (GSFC) and the U.S. Defense Mapping Agency (DMA) with the ai... more The NASA Goddard Space Flight Center (GSFC) and the U.S. Defense Mapping Agency (DMA) with the aid of other organizations such as The Ohio State University are cooperating in a joint effort to determine a significantly improved degree 360 spherical harmonic model representing the Earth’s gravitational potential. This new model will be of immediate use in defining an undulation model that will be the basis for an enhanced WGS-84 geoid, but the model will be general in use and will provide enhancements for a wide range of applications. The development of the new model is driven, in part, by the need to determine an accurate geoid undulation model that will be the vertical reference surface for WGS-84. In addition, the new geoid model will help satisfy increasingly important studies in ocean circulation (sea surface topography) and geodetic positioning through GPS.
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Papers by Erricos C. Pavlis