Simulations of VLBI observations to satellites enabling co-location in space

2020 ◽  
Author(s):  
Nicat Mammadaliyev ◽  
Patrick Schreiner ◽  
Susanne Glaser ◽  
Karl Hans Neumayer ◽  
Rolf Koenig ◽  
...  
Keyword(s):  
Reference Frame ◽  
Orbit Determination ◽  
Precise Orbit Determination ◽  
Terrestrial Reference Frame ◽  
Observation Time ◽  
Measurement Noise ◽  
Potential Influence ◽  
Vlbi Observations ◽  
Space Geodetic Techniques ◽  
The Impact

<p>The exceptional situation of simultaneously observing a dedicated near-Earth orbiting satellite via the four main space geodetic techniques opens the unique opportunity to investigate the additional benefits on the realization of global terrestrial reference frame using co-location in space. Applying co-location in space requires a precise orbit determination (POD) of dedicated satellites for all techniques. In this regard, current VLBI infrastructure is extended by the observation to satellites and the impact of such observation concept on the VLBI estimates is assessed. Thus the main geodetic products including the terrestrial reference frame are investigated within the GGOS-SIM-II project. In this study, the potential influence of orbital errors on the estimates and capability of VLBI observations to satellites within the POD are investigated for different scenarios with varying networks, observation time and measurement noise.  </p>

Simulation studies on single-satellite space ties and their potential to achieve the Global Geodetic Observing System goals.

2020 ◽  
Author(s):  
Patrick Schreiner ◽  
Nicat Mammadaliyev ◽  
Susanne Glaser ◽  
Rolf Koenig ◽  
Karl Hans Neumayer ◽  
...  
Keyword(s):  
Reference Frame ◽  
Precise Orbit Determination ◽  
Terrestrial Reference Frame ◽  
German Research Foundation ◽  
Station Coordinates ◽  
Earth Rotation Parameters ◽  
German Research ◽  
Space Geodetic Techniques ◽  
The Impact ◽  
Space Ties

<p>The German Research Foundation (DFG) project GGOS-SIM-2, successor of project GGOS-SIM, is a collaboration between the Helmholtz Center Potsdam - German Research Center for Geosciences (GFZ) and the Technische Universität Berlin (TUB). The project aims at investigating the feasibility of meeting the requirements specified by the Global Geodetic Observing System (GGOS) for a global terrestrial reference frame (TRF) with the help of simulations. In GGOS-SIM-2 the potential of so-called space ties is examined in relation to the GGOS targets, 1 mm accuracy in position and 1 mm / decade long-term stability, which have not yet been achieved by the recent International Terrestrial Reference Frame (ITRF). Space ties are provided by a satellite that carries two, three or all the four main space-geodetic techniques, i.e. DORIS, GPS, SLR and VLBI. This allows for a quantification of the impact of systematic errors on the derived orbits and subsequent results of the dynamic method as the TRF. Proposed co-location in space missions such as GRASP and E-GRASP anticipate such a scenario. We therefor simulate the space-geodetic observations based on Precise Orbit Determination (POD) with real observations from various missions and evaluate their potential for determining a TRF. So far, we simulated DORIS and SLR observations to six orbit scenarios, including a GRASP-like and an E-GRASP-like one, and generated TRFs based on each scenario either technique-wise or combined via the space-ties or in combination with ground data. We quantify the effect on the TRF in terms of changes of origin and scale and of formal errors of the ground station coordinates and of the Earth rotation parameters.</p>

Preliminary DORIS results on Precise Orbit Determination and on geocenter and scale solutions from CNES/CLS IDS Analysis Center contribution to the ITRF2020

2020 ◽  
Author(s):  
Hugues Capdeville
Keyword(s):  
Orbit Determination ◽  
Precise Orbit Determination ◽  
Model Error ◽  
Terrestrial Reference Frame ◽  
Force Model ◽  
Precise Orbit ◽  
Analysis Center ◽  
The Stability ◽  
The Impact ◽  
Processing Configuration

<p>The processing configuration for our IDS contribution to the International Terrestrial Reference Frame (ITRF2020) realization was defined. We adopted the last standards and models recommended by IERS. We took into account the IDS recommendations to mitigate the non-conservative force model error on satellites, to mitigate the effect of the South Atlantic Anomaly on the DORIS receivers and to improve the stability of the DORIS scale.</p><p>A Precise Orbit Determination (POD) status for DORIS satellites by taking into account all these improvements will be presented for the processed time span. We will give statistical results such as one per revolution empirical acceleration amplitudes and orbit residuals. We will also give some comparisons to some external precise orbits used for altimetry. Some external validations of our orbits will be done, such as with independent SLR measurements processing as well as through the use of altimeter crossovers when available. We will also look at the impact of our new ITRF2020 configuration on the DORIS geocenter and scale.</p><p> </p>

DORIS results on Precise Orbit Determination and on geocenter and scale solutions from CNES/CLS IDS Analysis Center contribution to the ITRF2020 

2021 ◽  
Author(s):  
Hugues Capdeville ◽  
Adrien Mezerette ◽  
Jean-Michel Lemoine
Keyword(s):  
Orbit Determination ◽  
Precise Orbit Determination ◽  
Model Error ◽  
Terrestrial Reference Frame ◽  
Force Model ◽  
Precise Orbit ◽  
Analysis Center ◽  
The Stability ◽  
The Impact ◽  
Processing Configuration

<p>The processing configuration for our IDS contribution to the International Terrestrial Reference Frame (ITRF2020) realization was defined. We adopted the last standards and models recommended by IERS. We took into account the IDS recommendations to mitigate the non-conservative force model error on satellites, to mitigate the effect of the South Atlantic Anomaly on the DORIS receivers and to improve the stability of the DORIS scale.</p><p>A Precise Orbit Determination (POD) status for DORIS satellites by taking into account all these improvements will be presented for the processed time span. We will give statistical results such as one per revolution empirical acceleration amplitudes and orbit residuals. We will also give some comparisons to some external precise orbits used for altimetry. Some external validations of our orbits will be done, such as with independent SLR measurements processing as well as through the use of altimeter crossovers when available. We will also look at the impact of our new ITRF2020 configuration on the DORIS geocenter and scale.</p>

Simulation of Orbit Determination of HaiYang-2 Satellite on DORIS

2013 ◽  
Vol 353-356 ◽  
pp. 3456-3459 ◽  
Author(s):  
Qiao Li Kong ◽  
Jin Yun Guo ◽  
Li Tao Han
Keyword(s):  
Orbit Determination ◽  
Tracking System ◽  
Precise Orbit Determination ◽  
Computation Time ◽  
Satellite Orbit ◽  
The World ◽  
Space Geodetic Techniques ◽  
Orbit Tracking ◽  
The Relationship

DORIS is a kind of advanced space-geodetic techniques applied in satellite orbit tracking and measuring. As the first ocean dynamic environmental satellite in China, the HY-2 satellite is equipped with the Doppler orbitography and radiopositioning integrated by satellite (DORIS) tracking system for the precise orbit determination. In particular, the investigation of our work has focused on accuracy analysis of orbit determination using simulated DORIS data given different observation noises, besides the relationship is investigated between accuracy and computation time and the number of ground beacons evenly distributed around the world. Experiment results show that observation noises can affect the accuracy of orbit determination directly, and the number of DORIS ground beacons decides the accuracy and computation time of obit determination in the condition of ground beacons are evenly distributed around the world, therefore, during the process of obit determination, we should optimize the ground beacon station distribution to achieve the best accuracy of obit determination using DORIS tracking data.

scholarly journals Impact of ECOM Solar Radiation Pressure Models on Multi-GNSS Ultra-Rapid Orbit Determination

2019 ◽  
Vol 11 (24) ◽  
pp. 3024
Author(s):  
Yang Liu ◽  
Yanxiong Liu ◽  
Ziwen Tian ◽  
Xiaolei Dai ◽  
Yun Qing ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Real Time ◽  
Radiation Pressure ◽  
Orbit Determination ◽  
Precise Orbit Determination ◽  
Solar Radiation Pressure ◽  
Satellite System ◽  
Ambiguity Fixing ◽  
Global Navigation Satellite ◽  
The Impact

The Global Navigation Satellite System (GNSS) ultra-rapid precise orbits are crucial for global and wide-area real-time high-precision applications. The solar radiation pressure (SRP) model is an important factor in precise orbit determination. The real-time orbit determination is generally less accurate than the post-processed one and may amplify the instability and mismodeling of SRP models. Also, the impact of different SRP models on multi-GNSS real-time predicted orbits demands investigations. We analyzed the impact of the ECOM 1 and ECOM 2 models on multi-GNSS ultra-rapid orbit determination in terms of ambiguity resolution performance, real-time predicted orbit overlap precision, and satellite laser ranging (SLR) validation. The multi-GNSS observed orbital arc and predicted orbital arcs of 1, 3, 6, and 24 h are compared. The simulated real-time experiment shows that for GLONASS and Galileo ultra-rapid orbits, compared to ECOM 1, ECOM 2 increased the ambiguity fixing rate to 89.3% and 83.1%, respectively, and improves the predicted orbit accuracy by 9.2% and 27.7%, respectively. For GPS ultra-rapid orbits, ECOM 2 obtains a similar ambiguity fixing rate as ECOM 1 but slightly better orbit overlap precision. For BDS GEO ultra-rapid orbits, ECOM 2 obtains better overlap precision and SLR residuals, while for BDS IGSO and MEO ultra-rapid orbits, ECOM 1 obtains better orbit overlap precision and SLR residuals.

Potential of VLBI observations to satellites for precise orbit determination

2021 ◽  
Author(s):  
Nicat Mammadaliyev ◽  
Patrick Schreiner ◽  
Susanne Glaser ◽  
Karl Hans Neumayer ◽  
Rolf Koenig ◽  
...  
Keyword(s):  
Orbit Determination ◽  
Precise Orbit Determination ◽  
Satellite Observations ◽  
Satellite Orbits ◽  
Error Sources ◽  
Interferometric Technique ◽  
Precise Orbit ◽  
Vlbi Observations ◽  
Low Earth Orbits ◽  
Earth Orbits

<p>Besides the natural extra-galactic radio sources, observing an artificial Earth-orbiting radio source with the Very Long Baseline Interferometry (VLBI) permits to extend the geodetic and geodynamic applications of this highly accurate interferometric technique. Furthermore, combining aforementioned observations provides a promising method to determine the satellite orbit and delivers the new type of observations such as group delay and delay rate which might be employed to validate the orbit independent of other space geodetic techniques.</p><p>In this research, the potential of the interferometric satellite tracking for the Precise Orbit Determination (POD) has been explored based on simulated observations for different scenarios with various VLBI networks, satellite orbits (eccentric low Earth orbits or circular medium Earth orbits) and error sources. POD of the Earth-orbiting satellites is studied on the basis of daily VLBI sessions where satellite observations are scheduled together with the quasar observation for regionally or globally distributed legacy as well as next generation VLBI station networks. In order to simulate VLBI to satellite observations, the influence of the most prominent random error sources in VLBI as well as mismodelling of different force models acting on the satellite are utilized. This study indicates that POD is feasible with VLBI observations and the accuracy mainly depends on the observation geometry.</p>

A preliminary assessment of the accuracy of the VGOS geodetic products: implications for the terrestrial reference frame and Earth orientation parameters

2021 ◽  
Author(s):  
Dhiman Mondal ◽  
Pedro Elosegui ◽  
John Barrett ◽  
Brian Corey ◽  
Arthur Niell ◽  
...  
Keyword(s):  
Reference Frame ◽  
Mixed Mode ◽  
Daily Basis ◽  
Terrestrial Reference Frame ◽  
Preliminary Assessment ◽  
Earth Orientation Parameters ◽  
Vlbi Observations ◽  
International Vlbi Service ◽  
Single Baseline ◽  
Orientation Parameters

<p>The next-generation VLBI system called VGOS (VLBI Global Observing System) has been designed and built as a significant improvement over the legacy geodetic VLBI system to meet the accuracy and stability goals set by the Global Geodetic Observing System (GGOS). Improved geodetic products are expected as the VGOS technique transitions from demonstration to operational status, which is underway. Since 2019, a network of nine VGOS stations has been observing bi-weekly under the auspices of the International VLBI Service for Geodesy and Astrometry (IVS) to generate standard geodetic products. These products, together with the mixed-mode VLBI observations that tie the VGOS and legacy networks together will be contributions to the next realization of the International Terrestrial Reference Frame (ITRF2020). Moreover, since 2020 a subset of 2 to 4 VGOS stations has also been observing in a VLBI Intensive-like mode to assess the feasibility of Earth rotation (UT1) estimation using VGOS. Intensives are daily legacy VLBI observations that are run on a daily basis using a single baseline between Kokee Park Geophysical Observatory, Hawaii, and Wettzell Observatory, Germany, made with the goal of near-real-time monitoring of UT1. In this presentation, we will describe the VGOS observations, correlation, post-processing, and preliminary geodetic results, including UT1. We will also compare the VGOS estimates to estimates from legacy VLBI, including estimates from mixed-mode observations, to explore the precision and accuracy of the VGOS products.</p>

GPS z-PCO and GNSS-based scale determined by integrated processing with LEOs and Galileo

2021 ◽  
Author(s):  
Wen Huang ◽  
Benjamin Männel ◽  
Andreas Brack ◽  
Harald Schuh
Keyword(s):  
Reference Frame ◽  
A Priori ◽  
Terrestrial Reference Frame ◽  
International Gnss Service ◽  
Satellite Transmitter ◽  
Ground Station ◽  
Station Coordinates ◽  
Integrated Processing ◽  
Current Constellation ◽  
The Impact

<p>The Global Positioning System (GPS) satellite transmitter antenna phase center offsets (PCOs) in z-direction and the scale of the terrestrial reference frame are highly correlated when neither of them is constrained to an a priori value in a least-squares adjustment. The commonly used PCO values offered by the International GNSS Service (IGS) are estimated in a global adjustment by constraining the ground station coordinates to the current International Terrestrial Reference Frame (ITRF). As the scale of the ITRF is determined by other techniques, the estimated GPS z-PCOs are not independent. Consequently, the z-PCOs transfer the scale to any subsequent GNSS solution. To get a GNSS-based scale that can contribute to a future ITRF realization, two methods are proposed to determine scale-independent GPS z-PCOs. One method is based on the gravitational constraint on Low Earth Orbiters (LEOs) in an integrated processing of the GPS satellites and LEOs. The correlation coefficient between the GPS PCO-z and the scale is reduced from 0.85 to 0.3 by supplementing a 54-ground-station network with seven LEOs. The impact of individual LEOs on the estimation is discussed by including different subsets of the LEOs. The accuracy of the z-PCOs of the LEOs is very important for the accuracy of the solution. In another method, the GPS z-PCOs and the scale are determined in a GPS+Galileo processing where the PCOs of Galileo are fixed to the values calibrated on ground from the released metadata. The correlation between the GPS PCO-z and the scale is reduced to 0.13 by including the current constellation of Galileo with 24 satellites. We use the whole constellation of Galileo and the three LEOs of the Swarm mission to perform a direct comparison and cross-check of the two methods. The two methods provide mean GPS z-PCO corrections of -186±25 mm and -221±37 mm with respect to the IGS values, and +1.55±0.22 ppb (part per billion) and +1.72±0.31 ppb in the terrestrial scale with respect to the IGS14 reference frame. The results of both methods agree with each other with only small differences. Due to the larger number of Galileo observations, the Galileo-PCO-fixed method leads to more precise and stable results. In the joint processing of GPS+Galileo+Swarm in which both methods are applied, the constraint on Galileo dominates the results. We also discuss how fixing either the Galileo transmitter antenna z-PCO or the Swarm receiver antenna z-PCOs in the GPS+Galileo+Swarm processing propagates to the respective freely estimated z-PCOs of Swarm or Galileo.</p>

scholarly journals Formation of The International Celestial Reference Frame

1998 ◽  
Vol 11 (1) ◽  
pp. 281-286
Author(s):  
C. Ma ◽  
E.F. Arias ◽  
T.M. Eubanks ◽  
A.L. Fey ◽  
A.-M. Gontier ◽  
...  
Keyword(s):  
Reference Frame ◽  
Reference Frames ◽  
Terrestrial Reference Frame ◽  
Naval Research ◽  
Dual Frequency ◽  
Cooperative Effort ◽  
Space Navigation ◽  
Vlbi Observations ◽  
Crustal Dynamics ◽  
Celestial Reference Frame

The goal of the work described here is to create the definitive catalogue for the new International Celestial Reference Frame (ICRF) using the best data and methods available at the time the work was done. This work is the joint cooperative effort of a subgroup of the IAU Working Group on Reference Frames which was formed expressly for this purpose in February 1995. The authors of this report constituted the subgroup. A fuller account of this report can be found in the introduction to the ICRF catalog (IERS 1997). The ICRF of 608 sources presented here is based on essentially all the VLBI observations accu-mulated over about 15 years in several worldwide programs. Dual frequency Mark III data have both geodetic and astrometric applications. Most of the data (95% of nearly 2 million observations) were acquired primarily for geodetic purposes. The major geodetic programs include: NASA’s Crustal Dynamics Project/Space Geodesy Program and USNO’s NAVEX sessions for the terrestrial reference frame, as well as IRIS, NAVNET and NEOS sessions for monitoring Earth rotation. The geodetic programs have used the brightest radio sources, gradually concentrating on the most com-pact as sensitivity improved. These geodetic sources were also the foundation of astrometric work because of the large number of observations for the ~150 most commonly used. The astrometric programs which densify the sky include the Radio-Optical Reference Frame sessions done by US Naval Research Laboratory (NRL) and USNO and the space navigation efforts of Jet Propulsion Laboratory (JPL).

Sign in / Sign up

Export Citation Format

Share Document