Daniela Thaller

• PhD
• Head of Department at Federal Agency for Cartography and Geodesy

An assessment of the tropospheric parameters independently derived from the analysis of Very Long Baseline Interferometry (VLBI) and Global Navigation Satellite Systems (GNSS) data serves as a cross-validation of the two space geodetic techniques on the parameter level. Time series of the tropospheric parameters are studied for the most frequently...

Growing interest in Earth Orientation Parameters (EOP) resulted in various approaches to the EOP prediction algorithms, as well as in the exploitation of distinct input data, including the observed EOP values from various operational data centers and modeled effective angular momentum functions. Considering these developments and recently emerged n...

With all four space geodetic techniques onboard, the Genesis mission will support the realization of the International Terrestrial Reference System by providing space ties between the technique-specific terrestrial reference frames (TRF). For a rigorous combination of the four space techniques, the proper handling of the orbit of the spacecraft is...

The Earth Orientation Parameters (EOPs) describe the rotation between the Terrestrial Reference Frame and the Celestial Reference Frame and represent an essential component of the Global Geodetic Reference Frame. This study presents the current activities of BKG in the area of combined processing of GNSS and VLBI data in one common adjustment with...

In 2021, the International Earth Rotation and Reference Systems Service (IERS) established a working group tasked with conducting the Second Earth Orientation Parameters Prediction Comparison Campaign (2nd EOP PCC) to assess the current accuracy of EOP forecasts. From September 2021 to December 2022, EOP predictions submitted by participants from v...

Real-time Earth Orientation Parameters (EOP) are crucial in various space geodetic applications, from satellite navigation to weather forecasting. This study introduces a refined prediction package leveraging diverse EOP series from the Federal Agency of Cartography and Geodesy (BKG), including rapid and final series, Satellite Laser Ranging (SLR)...

Predicting Earth Orientation Parameters (EOP) is crucial for precise positioning and navigation both on the Earth’s surface and in space. In recent years, many approaches have been developed to forecast EOP, incorporating observed EOP as well as information on the effective angular momentum (EAM) derived from numerical models of the atmosphere, oce...

The difference UT1-UTC is the most variable quantity among the Earth Orientation Parameters (EOP) with significant unpredictable variation. It can be measured only with the quasi-space-fixed technique VLBI. The IVS organizes two different VLBI observation campaigns: The bi-weekly 24-hour Rapid campaigns and the daily 1-hour Intensive sessions. As a...

The accurate knowledge of the Earth’s orientation and rotation in space is essential for a broad variety of scientific and societal applications. Among others, these include global positioning, near-Earth and deep-space navigation, the realisation of precise reference and time systems as well as studies of geodynamics and global change phenomena. I...

The publicly available Earth Orientation Parameter (EOP) time series provided by the Earth Orientation Centre of the IERS (e.g., IERS Bulletin A, IERS 14 C04) result from the combination of individual space-geodetic solutions on a daily basis, i.e., a parameter-level combination. Current activities of the Federal Agency for Cartography and Geodesy...

The ITRF2020 is the upcoming official solution of the International Terrestrial Reference Frame and is the successor to the currently used ITRF2014. The global ITRF2020 solution is based on an inter-technique combination of the four space-geodetic techniques VLBI, GNSS, SLR, and DORIS. In this context, the Combination Centre of the IVS (Internation...

In the present study, we estimate the correlations of the Helmert transformation's parameters for various Terrestrial Reference Frame realizations (TRFs). The correlations can be served as an auxiliary diagnostic tool on assessing the quality of the Helmert transformation parameters (origin, scale, orientation and associated rates, respectively). P...

The accuracy and the consistency of the Terrestrial Reference Frames (TRFs) are mainly assessed through the well-known Helmert transformation parameters. The magnitude of the estimated Helmert parameters which connect e.g. a technique-only and a combined solution of a global TRF, respectively, can identify possible inconsistencies or/and deficienci...

The importance of global satellite navigation systems for everyday life and for numerous surveying tasks is well known to every user. Wherever positioning or navigation tasks are involved, GNSS devices for the use of GPS, GLONASS, Galileo or Beidou are used, which provide coordinates in a reference frame of a global geodetic reference system. What...

Different Earth orientation parameter (EOP) time series are publicly available that typically arise from the combination of individual space geodetic technique solutions. The applied processing strategies and choices lead to systematically differing signal and noise characteristics particularly at the shortest periods between 2 and 8 days. We inves...

The Earth Orientation Parameters (EOPs) are published by the Earth Orientation Centre of the International Earth Rotation and Reference Systems Service (IERS). They are provided as the low-latency Bulletin A and the 30 d latency long-term EOP time series IERS 14 C04. The EOPs are a combined product derived from different geodetic space techniques,...

Satellite gravimetry allows for determining large scale mass transport in the system Earth and to quantify ice mass change in polar regions. We provide, evaluate and compare a long time-series of monthly gravity field solutions derived either by satellite laser ranging (SLR) to geodetic satellites, by GPS and K-band observations of the GRACE missio...

At the Astronomical Institute of the Univeristy of Bern (AIUB) long time-series (1995 – 2017) of low resolution (spherical harmonic degree/order 6) gravity field coefficients have been determined from a combination of LAGEOS and geodetic SLR satellites in low Earth orbit, namely: Beacon-C, Ajisai, Starlette, Stella, Larets, and Lares. Monthly gravi...

At the Astronomical Institute of the Univeristy of Bern (AIUB) long time-series (1995 – 2017) of low resolution (max. degree 6) gravity field coefficients have been determined from a combination of LAGEOS and geodetic SLR satellites in low Earth orbit (LEOs), namely: Beacon-C, Ajisai, Starlette, Stella, Larets, and Lares. Monthly gravity fields, ex...

We present our first results regarding the combination (at the NEQ level) of three different types of observations: I. SLR, II. SLR@GNSS and III. GNSS. Our aim is to derive TRF related parameters such as coordinates, EOPs and geocenter motion as well as to estimate the range biases to the GNSS satellites. We test various scenaria and we investigate...

Report of the IERS to IAU Commission A2 for the years 2015 to 2018

Davos, Switzerland

In this paper we investigate the impact of using the three ITRS realizations DTRF2014, ITRF2014, and JTRF2014 as a priori TRF for the VLBI combination on EOP and scale. The scale factor between the IVS routine combined solution and DTRF2014, ITRF2014, and JTRF2014 shows a significant offset of −0.59 ppb with respect to ITRF2014 and of 0.19 ppb with...

The Standing Committee on Performance Simulations and Architectural Trade-Offs (PLATO) was established by the Bureau of Networks and Observations of the Global Geodetic Observing System (GGOS) in order to support – by prior performance analysis – activities to reach the GGOS requirements for the accuracy and stability of the terrestrial reference f...

It is well known that the ITRF2014 shows some inconsistencies between the space-geodetic techniques with respect to its scale realization. It seems that the scale of the SLR and VLBI techniques deviate each other at the level of 1.37 ppb (8.8 mm), and shows a small drift of about 0.2 ppb/a (0.13 mm/a). There is a lot of speculation regarding the re...

In the present study, we show the results of the multi-year processing of SLR observations to GNSS satellites (both for GPS and GLONASS satellites), using the Bernese GNSS Software. The aim of the study is to investigate the associated SLR range residuals, defined as the differences between: (a) the observed SLR ranges and (b) the computed spatial...

The proceedings paper is 'on air'

Based on an approximately 15-year long time series of gravity field coefficients up to degree and order 6 from satellite laser ranging data, we want to elaborate on the impact of simultaneously estimated geodetic parameters such as Earth rotation parameters and station coordinates on the recovered gravity field coefficients. We will also discuss th...

Precise measurements of the Earth’s shape, gravity field, and rotation provide critical data for many geoscientific disciplines. In order to obtain reliable data, an accurate, stable, and global reference frame is required. The International Terrestrial Reference Frame, where station positions are modeled linearly, is commonly used throughout the g...

Precise measurements of the Earth’s shape, gravity field, and rotation provide critical data for many geoscientific disciplines. In order to obtain reliable data, an accurate, stable, and global reference frame is required. The International Terrestrial Reference Frame, where station positions are modeled linearly, is commonly used throughout the g...

The consistent estimation of terrestrial reference frames (TRF), celestial reference frames (CRF) and Earth orientation parameters (EOP) is still an open subject and offers a large field of investigations. Until now, source positions resulting from Very Long Baseline Interferometry (VLBI) observations are not routinely combined on the level of norm...

Every few years the International Terrestrial Reference System (ITRS) Center of the International Earth Rotation and Reference Systems Service (IERS) decides to generate a new version of the International Terrestrial Reference Frame (ITRF). For the upcoming ITRF2014 the official contribution of the International VLBI Service for Geodesy and Astrome...

Starting with the ITRF2005, the IVS contribution to the ITRF is an intra-technique combined solution using multiple individual contributions from different institutions. For the IVS contribution to the ITRF2014 nine international institutions were used for a combined solution. The data files contain 24-h VLBI sessions from the late 1970s until the...

Homogeneously reprocessed combined GPS/GLONASS 1- and 3-day solutions from 1994 to 2013, generated by the Center for Orbit Determination in Europe (CODE) in the frame of the second reprocessing campaign REPRO-2 of the International GNSS Service, as well as GPS- and GLONASS-only 1- and 3-day solutions for the years 2009 to 2011 are analyzed to asses...

In standard combination approaches (e.g., for the International Terrestrial Reference Frame), the space-geodetic techniques are connected by the Earth rotation parameters and by the station coordinates at co-located sites, using the so-called local ties. These local ties are usually derived from terrestrial measurements together with GNSS measureme...

User manual of the Bernese GNSS Software, Version 5.2. http://www.bernese.unibe.ch/docs/DOCU52.pdf

The time variable Earth’s gravity field contains information about the mass transport within the system Earth, i.e., the relationship between mass variations in the atmosphere, oceans, land hydrology, and ice sheets. For many years, satellite laser ranging (SLR) observations to geodetic satellites have provided valuable information of the low-degre...

Satellite Laser Ranging (SLR) to GNSS satellites provides valuable information about the accuracy and quality of GNSS satellite orbits, e.g., by detecting degradations of the orbits due to deficiencies in the modeling of solar radiation pressure. However, SLR observations are biased by various systematic effects, such as the satellite signature eff...

Report of the International Earth Rotation and Reference Systems Service (IERS) to IAU Commission 19 (Earth Rotation) for the years 2012 to 2015

Satellite laser ranging (SLR) to the satellites of the global navigation satellite systems (GNSS) provides substantial and valuable information about the accuracy and quality of GNSS orbits and allows for the SLR-GNSS co-location in space. In the framework of the NAVSTAR-SLR experiment two GPS satellites of Block-IIA were equipped with laser retror...

We process 20 years of SLR observations to GPS and GLONASS satellites using the reprocessed 3-day and 1-day microwave orbits provided by the Center for Orbit Determination in Europe (CODE) for the period 1994-2013. We study the dependency of the SLR residuals on the type, size, and a number of corner cubes in satellite laser reflector arrays (LRA)....

We present the results from a simultaneous estimation of the gravity field, Earth rotation parameters, and station coordinates from combined SLR solutions incorporating up to nine geodetic satellites: LAGEOS-1/2, Starlette, Stella, AJISAI, Beacon-C, Lares, Blits and LARES. These solutions cover all three pillars of satellite geodesy and ensure full...

The IERS held a two-day retreat in Paris on May 23-24, 2013. The outcome of the discussions at the retreat are presented with respect to Earth Rotation studies. Special focus is given on the plans to improve the Earth rotation products of the IERS.

The contribution of the International VLBI Service for Geodesy and Astrometry (IVS) to the ITRF2014 generation is presented. The ITRF2014 is an inter-technique combined product of the IERS ITRS Center, combining contributions from the four space geodetic techniques -DORIS, GNSS, SLR, and VLBI. The VLBI contribution is provided by the IVS Combinatio...

Precise measurements of the shape, the gravity field and the rotation of the Earth are important for many fields of geosciences. Beside high quality sensors an accurate, stable and global reference frame is required to get reliable results. In the scientific community the International Terrestrial Reference Frame (ITRF) is commonly used, where poin...

Meindl et al. (Adv Space Res 51(7):1047–1064, 2013) showed that the geocenter z-component estimated from observations of global navigation satellite systems (GNSS) is strongly correlated to a particular parameter of the solar radiation pressure (SRP) model developed by Beutler et al. (Manuscr Geod 19:367–386, 1994). They analyzed the forces caused...

Mit modernen Erdbeobachtungsverfahren ist es möglich das System Erde mit einer hohen zeitlichen- und räumlichen Auflösung zu vermessen und zu untersuchen. Referenzsysteme wie das ITRS und deren Realisierungen (ITRF) bilden dabei die Grundlage für hochpräzise geodätische Produkte. GGOS hat sich zum Ziel gesetzt einen globalen, hochgenauen und langze...

The main 'three pillars' of satellite geodesy can be summarized as: • precise determination of geometrical three-dimensional positions and velocities (geometry), • modeling and observing of geodynamical phenom-ena including the Earth rotation parameters (ERP, rotation), • determination of the Earth's gravity field and its temporal variations (gravi...

The contribution of Starlette, Stella, and AJISAI is currently neglected when defining the International Terrestrial Reference Frame, despite a long time series of precise SLR observations and a huge amount of available data. The inferior accuracy of the orbits of low orbiting geodetic satellites is the main reason for this neglect. The Analysis Ce...

The temporal variations in Earth's oblateness are typically derived from the SLR observations to geodetic satellites, as well as from the satellite missions dedicated to gravity recovery, i.e., CHAMP, GRACE, and GOCE. We recover the Earth's oblateness parameter C20 and low-degree gravity �eld coe�cients up to degree/order 4/4 using microwave observ...

Satellite Laser Ranging (SLR) observations to GNSS satellites provide an independent validation of the orbits determined from microwave observations, thus, allow us to assess the quality of the GNSS orbits. Today, the time-spam of precise SLR observations to two GPS satellites exceeds twenty years. In 2010 the first SLR station began to track the f...

The time-variable gravity field provides the information about the mass redistribution in the system Earth, i.e. the relationship of mass transport between atmosphere, oceans, and land hydrology. We recover the low-degree parameters of the temporal gravity field variations using microwave observations from GPS and GLONASS satellites and from SLR da...

High quality Earth observations require an accurate, stable and global reference frame. One GGOS goal is to provide the observational basis for such a frame with 1 mm accuracy. In order to reach this ambitious goal the technique specific functional models must be improved. Beside the well known tidal effects associated with the geophysical fluids t...

LARES is a new spherical geodetic satellite designed for SLR observations. It is made of solid tungsten alloy covered with 92 corner cubes. Due to a very small area-to-mass ratio, the sensitivity of LARES orbits to non-gravitational forces is greatly minimized. We processed 82 weeks (Feb12-Aug13) of LARES observations from a global SLR network and...

The indirect solar radiation pressure caused by reflected or re-emitted radiation by the Earth's surface is an important non-gravitational force perturbing the orbits of geodetic satellites (Rubincam and Weiss, 1986; Martin and Rubincam, 1996). In the case of LAGEOS this acceleration is of the order of 15% of the direct solar radiation pressure. Th...

Currently, the contributions of Starlette, Stella, and AJISAI are not taken into account when defining the International Terrestrial Reference Frame (ITRF), despite the large amount of data collected in a long time-span. Consequently, the SLR-derived parameters and the SLR part of the ITRF are almost exclusively defined by LAGEOS-1 and LAGEOS-2. We...

The temporal variations in the Earth’s gravity field affect in particular GNSS orbits, and thus, also GNSS-derived estimates of the Earth rotation parameters (ERPs). GPS satellites are very sensitive to some of the gravity field parameters due to the deep 2:1 resonance w.r.t. the satellite revolution period. We process ten years of GPS and GLONASS...

The call for participation for the ITRF2013 asked for the first time for pre-combined contributions, although it is thought that they won’t be included in the ITRF2013 solution. But studies will be carried out how to combine single-technique and pre-combined contributions best in order to have adequate procedures ready for the next ITRF. Among the...