GOCE: precise orbit determination for the entire mission

Bock, Heike; Jäggi, Adrian; Beutler, Gerhard; Meyer, Ulrich

doi:10.1007/s00190-014-0742-8

Cited by 79 publications

(77 citation statements)

References 30 publications

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“…r 0com (t) = kinematic orbit), unless the opposite is explicitly stated. The exploited kinematic orbit is a part of the SST_PKI_2 product (EGG-C 2010; Bock et al 2014). Strictly speaking, only one initial kinematic position is needed in this case, as the position at the current epoch can be calculated as the sum of the initial position and the estimated position differences.…”

Section: Functional Model Of the Phase Methodsmentioning

confidence: 99%

“…One is the officially provided kinematic orbit, i.e. the SST_PKI_2 product (EGG-C 2010;Bock et al 2014), hereafter denoted as the ESA (European Space Agency) orbit and the orbit method in this case is denoted as the 'orbit-ESA method'. The other one is computed in house by the PANDA (Position And Navigation Data Analyst) software (Liu and Ge 2003), which was developed at Wuhan University; hereafter, this orbit is denoted as the WHU orbit and the orbit method in this case is denoted as the 'orbit-WHU method'.…”

Section: Introductionmentioning

confidence: 99%

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Earth’s gravity field modelling based on satellite accelerations derived from onboard GPS phase measurements

Guo

Ditmar

Zhao

et al. 2017

J Geod

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GPS data collected by satellite gravity missions can be used for extracting the long-wavelength part of the Earth's gravity field. We propose a new data processing method which makes use of the 'average acceleration' approach to gravity field modelling. In this method, satellite accelerations are directly derived from GPS carrier phase measurements with an epoch-differenced scheme. As a result, no ambiguity solutions are needed and the systematic errors that do not change much from epoch to epoch are largely eliminated. The GPS data collected by the Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) satellite mission are used to demonstrate the added value of the proposed method. An analysis of the residual accelerations shows that accelerations derived in this way are more precise, with noise being reduced by about 20 and 5% at the cross-track component and the other two components, respectively, as compared to those based on kinematic orbits. The accelerations obtained in this way allow the recovery of the gravity field to a slightly higher maximum degree compared to the solution based on kinematic orbits. Furthermore, the gravity field solution has an overall better performance. Errors in spherical harmonic coefficients are smaller, especially at low degrees. The cumulative geoid height error is reduced by about 15 and 5% up to degree 50 and 150, respectively. An analysis in the spatial domain shows that large errors along the geomagnetic equator, which are caused by a high electron density coupled with large short-term variations, are substantially reduced. Finally, the new method allows for a better observation of mass transport signals. In particular, sufficiently realistic signatures of regional mass anomalies in North America and south-west Africa are obtained.

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Section: Functional Model Of the Phase Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Earth’s gravity field modelling based on satellite accelerations derived from onboard GPS phase measurements

Guo

Ditmar

Zhao

et al. 2017

J Geod

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“…The pseudo-range observations were used only for the initial receiver clock synchronization and to obtain a very first a priori orbit from a kinematic code point positioning. Using the latest version of the Bernese GNSS Software v5.3 (Dach et al 2015), the GPS data were processed at the full sampling of 1 Hz, together with the attitude data delivered by the on-board star cameras according to Bock et al (2014). The GPS orbits, the 5 s GPS clock corrections, and the Earth rotation parameters of the Center for Orbit Determination in Europe (CODE; Bock et al 2009;Dach et al 2009) were used, to guarantee the highest consistency between the GOCE orbit determination and the GPS orbit determination, which is also performed with the Bernese GNSS Software.…”

Section: Total Density Dataset Of Goce In the Re-entry Phasementioning

confidence: 99%

“…For the performance of the GOCE POD during the Science Mission phase, the reader is referred to Bock et al (2014). In particular, the independent orbit validation by means of Satellite Laser Ranging (SLR) yielded a mean value of He, T (1973He, T ( -1978 15 s AE-C/D/E MESA density (1973)(1974)(1975)(1976)(1977)(1978) 15 s CACTUS (07/1975-01/1979) 15-600 s OGO-6, San Marco-3 N 2 , O, He SETA density (1982)(1983)(1984) 20 1 mm and a root mean square (RMS) of 24.2 mm for the SLR residuals of the kinematic orbits over the entire Science Mission phase.…”

Section: Total Density Dataset Of Goce In the Re-entry Phasementioning

confidence: 99%

Semi-empirical thermosphere model evaluation at low altitude with GOCE densities

Bruinsma¹,

Arnold

Jäggi

et al. 2017

J. Space Weather Space Clim.

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Aims: The quality of the Committee on Space Research (COSPAR) International Reference Atmosphere models NRLMSISE-00, JB2008, and DTM2013 in the 150-300 km altitude range has never been thoroughly evaluated due to a lack of good density data. This study aims at providing the model accuracies thanks to the recent high-resolution high-accuracy Gravity field and steadystate Ocean Circulation Explorer (GOCE) density dataset. The evaluation was performed on yearly, monthly, and daily time scales, which are important for different applications such as mission design, mission operation, or re-entry predictions. Methods: The accuracy of the models was evaluated by comparing to the GOCE density observations of the Science Mission (1 November 2009-20 October 2013) and new density data at the lowest altitudes derived for the last weeks before the re-entry (22 October-8 November 2013) according to a metric, which consists of computing mean, standard deviation and root mean square (RMS) of the observed-to-model ratios, and correlation. Mean statistics are then calculated over the three time scales. Results: The range of model biases, standard deviations, and correlations becomes larger when the time interval decreases, and this study provides COSPAR International Reference Atmosphere (CIRA) model statistics in the altitude range of 275-170 km. DTM2013 is the least biased and most accurate model on all time scales, essentially thanks to the database, notably containing two years of GOCE densities, to which it was fitted. NRLMSISE-00 performs worst, with considerable bias of about 20% in 2009 and 2013, and systematically higher standard deviations (lower correlations) than JB2008 and DTM2013. The performance of JB2008 is presently only slightly behind DTM2013, thanks to the new release 4_2g solar activity proxies. However, it still presents some weakness under the lowest solar activity conditions in 2009 and 2010. Comparison to Challenging Mini-Satellite Payload (CHAMP) density data showed that the results based on GOCE densities, despite limited local solar time coverage of 6-8 am & pm, are representative of model performance.

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“…The remaining drag-free system residuals are treated here by estimating empirical accelerations such as bias and one cycle per revolution perturbations for the along-track and cross-track components. The available GOCE precise orbit data (Bock et al 2011(Bock et al , 2014 include the kinematic orbit data (used here as observations) and the reduced-dynamic orbit data. The GOCE estimated dynamic orbits, based on the aforementioned orbit modelling and the use of kinematic orbit positions as observations, are then compared to the precise reduced-dynamic orbit data.…”

Section: Goce and Grace Orbit Analysismentioning

confidence: 99%

Assessment of numerical integration methods in the context of low Earth orbits and inter-satellite observation analysis

Papanikolaou

Tsoulis

2016

Acta Geod Geophys

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The integration of differential equations is a fundamental tool in the problem of orbit determination. In the present study, we focus on the accuracy assessment of numerical integrators in what refers to the categories of single-step and multistep methods. The investigation is performed in the frame of current satellite gravity missions i.e. Gravity Recovery and Climate Experiment (GRACE) and Gravity Field and steady-state Ocean Circulation Explorer (GOCE). Precise orbit determination is required at the level of a few cm in order to satisfy the primary missions' scope which is the rigorous modelling of the Earth's gravity field. Therefore, the orbit integration errors are critical for these low earth orbiters. As the result of different schemes of numerical integration is strongly affected by the forces acting on the satellites, various validation tests are performed for their accuracy assessment. The performance of the numerical methods is tested in the analysis of Keplerian orbits as well as in real dynamic orbit determination of GRACE and GOCE satellites by taking into account their sophisticated observation techniques and orbit design. Numerical investigation is performed in a wide range of the fundamental integrators' parameters i.e. the integration step and the order of the multistep methods.

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GOCE: precise orbit determination for the entire mission

Cited by 79 publications

References 30 publications

Earth’s gravity field modelling based on satellite accelerations derived from onboard GPS phase measurements

Earth’s gravity field modelling based on satellite accelerations derived from onboard GPS phase measurements

Semi-empirical thermosphere model evaluation at low altitude with GOCE densities

Assessment of numerical integration methods in the context of low Earth orbits and inter-satellite observation analysis

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