Skip to main content

14 Result(s)

within E. J. O. Schrama Remove this filter

and

  1. No Access

    Article

    Assessment of observing time-variable gravity from GOCE GPS and accelerometer observations

    An assessment has been made of the possibility to estimate time-variable gravity from GPS-derived orbit perturbations and common-mode accelerometer observations of ESA’s GOCE Earth Explorer. A number of 20-day...

    P. N. A. M. Visser, W. van der Wal, E. J. O. Schrama… in Journal of Geodesy (2014)

  2. No Access

    Article

    An improved sampling rule for map** geopotential functions of a planet from a near polar orbit

    One of the limiting factors in the determination of gravity field solutions is the spatial sampling. Especially during phases, when the satellite repeats its own track after a short time, the spatial resolutio...

    Matthias Weigelt, Nico Sneeuw, E. J. O. Schrama… in Journal of Geodesy (2013)

  3. No Access

    Chapter and Conference Paper

    Dependency of Resolvable Gravitational Spatial Resolution on Space-Borne Observation Techniques

    The so-called Colombo-Nyquist (Colombo, The global map** of gravity with two satellites, 1984) rule in satellite geodesy has been revisited. This rule predicts that for a gravimetric satellite flying in a (n...

    P. N. A. M. Visser, E. J. O. Schrama, N. Sneeuw, M. Weigelt in Geodesy for Planet Earth (2012)

  4. No Access

    Chapter and Conference Paper

    Surface Mass Loading Estimates from GRACE and GPS

    In this paper we discuss the properties of an Empirical Orthogonal Filter approach applied to monthly GRACE gravity solutions which are used to estimate surface mass thickness maps. The vertical loading effect...

    E. J. O. Schrama, B. Wouters in Gravity, Geoid and Earth Observation (2010)

  5. No Access

    Chapter

    Continental hydrology retrieval from GPS time series and GRACE gravity solutions

    Monitoring of continental hydrology by measuring gravity variations is one of the primary aims of the Gravity Recovery and Climate Experiment (GRACE) mission. We proposed to combine the GRACE measurements with...

    J. Kusche, E. J. O. Schrama, M. J. F. Jansen in Dynamic Planet (2007)

  6. No Access

    Article

    Accuracy assessment of the monthly GRACE geoids based upon a simulation

    The purpose of this paper is to demonstrate the effect of geophysical background model errors that affects temporal gravity solutions provided by the Gravity Recovery And Climate Experiment (GRACE). Initial pe...

    E. J. O. Schrama, P. N. A. M. Visser in Journal of Geodesy (2007)

  7. No Access

    Chapter and Conference Paper

    Space-borne gravimetry: determination of the time variable gravity field

    The gravity field of the Earth can be divided into a dominant quasi-static part and several relatively small but significant temporal constituents. Important examples of temporal sources are ocean tides, atmos...

    P.N.A.M. Visser, E.J.O. Schrama in Gravity, Geoid and Space Missions (2005)

  8. No Access

    Chapter and Conference Paper

    Mass redistribution from global GPS timeseries and GRACE gravity fields: inversion issues

    Monitoring hydrological redistributions through their integrated gravitational effect is one of the primary aims of the GRACE mission. Yet it has been proposed that at larger scales this may be achieved indepe...

    J. Kusche, E.J.O. Schrama in Gravity, Geoid and Space Missions (2005)

  9. No Access

    Article

    Error Characteristics Estimated from Champ, GRACE and GOCE Derived Geoids and from Satellite Altimetry Derived Mean Dynamic Topography

    This paper presents a review of geoid error characteristics of three satellite gravity missions in view of the general problem of separating scientifically interesting signals from various noise sources. The p...

    E.J.O. Schrama in Space Science Reviews (2003)

  10. No Access

    Chapter

    Error Characteristics Estimated from Champ, GRACE and GOCE Derived Geoids and from Satellite Altimetry Derived Mean Dynamic Topography

    This paper presents a review of geoid error characteristics of three satellite gravity missions in view of the general problem of separating scientifically interesting signals from various noise sources. The p...

    E. J. O. Schrama in Earth Gravity Field from Space — From Sensors to Earth Sciences (2003)

  11. No Access

    Chapter and Conference Paper

    Calibration and Error Assessment of GOCE Data

    The GOCE level lb data products consist, among others, of time lines of calibrated and corrected gravity gradient data and SST data. The calibration for GOCE can be described as a multi-step procedure consisti...

    R. Koop, J. Bouman, E. J. O. Schrama, R. Visser in Vistas for Geodesy in the New Millennium (2002)

  12. No Access

    Chapter and Conference Paper

    Combination of Space Techniques into one Integrated Processing Model

    In the determination of the reference system satellite orbit determination plays an important role. With purely geometric techniques it is not possible to determine e.g. the position of the Earth’s centre of m...

    Remko Scharroo, E. J. O. Schrama… in Towards an Integrated Global Geodetic Obse… (2000)

  13. No Access

    Chapter

    Satellite altimetry, ocean dynamics and the marine geoid

    E. J. O. Schrama in Geodetic Boundary Value Problems in View of the One Centimeter Geoid (1997)

  14. No Access

    Chapter and Conference Paper

    Gravity Research Missions reviewed in light of the indirect ocean tide potential.

    In the last 15 years a number of proposals have been made for the realization of a dedicated gravity research mission, hereafter referred to as a GRM. We deliberately avoid a lengthy summary of all the differe...

    E. J. O. Schrama in Global Gravity Field and Its Temporal Variations (1996)