Even though ESA’s three-satellite low-earth orbit (LEO) mission Swarm is primarily a magnetic fieldmission, it can also serve as a gravity field mission. Located in a near-polar orbit with initial altitudes of 480 km for Swarm A and Swarm C and 530 km for Swarm B and equipped with geodetic-type dual frequency Global Positioning System (GPS) receivers, it is suitable for gravityfield computation. Of course, the Swarm GPS-only gravityfields cannot compete with the gravity fields derived from the ultra-precise Gravity Recovery And Climate Experiment (GRACE) K-band measurements. But for various reasons like the end of the GRACE mission in October 2017, datagaps in the previous months due to battery aging, and the gap between GRACE and the recently launched GRACE Follow-On mission, Swarm gravity fields became important to maintain a continuous time series and to bridge the gap between the two dedicated gravity missions. By comparing the gravity fields derived from Swarm kinematic positions to the GRACE gravity fields, systematic errors have been ob-served in the Swarm results, especially around the geomagnetic equator. These errors are already visible in the kinematic positions as spikes up to a few centimeters, from where they propagate into the gravity field solutions. We investigate these systematic errors by analyzing the geometry-free linear combination of the GPS carrier-phase observations and its time derivatives using a combination of a Gaussian filter and a Savitzky–Golay filter and the Rate of Total Electron Content (TEC) Index (ROTI). Based on this, we present different weighting schemes and investigate their impact on the gravity field solutions in order to assess the success of different mitigation strategies. We will show thata combination of a derivative-based weighting approach with a ROTI-based weighting approach is capable of reducing the geoid rms from 21.6 to 12.0 mm for a heavily affected month and that almost 10 % more kinematic positions can be preserved compared to a derivative-based screening.


    Access

    Download


    Export, share and cite



    Title :

    Mitigation of ionospheric signatures in Swarm GPS gravity field estimation using weighting strategies



    Publication date :

    2019-01-01


    Remarks:

    Schreiter, Lucas Fabian; Arnold, Daniel; Sterken, Veerle Jasmin; Jäggi, Adrian (2019). Mitigation of ionospheric signatures in Swarm GPS gravity field estimation using weighting strategies. Annales geophysicae, 37(1), pp. 111-127. Copernicus Publications 10.5194/angeo-37-111-2019



    Type of media :

    Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English


    Keywords :

    Classification :

    DDC:    629



    Mitigation of ionospheric effects on Swarm GPS observations and kinematic orbits

    Ren, Le / Lück, Christina / Kermarrec, Gael et al. | BASE | 2019

    Free access


    Assessment of individual and combined gravity field solutions from Swarm GPS data and mitigation of systematic errors

    Jäggi, Adrian / Meyer, Ulrich / Schreiter, Lucas Fabian et al. | BASE | 2018

    Free access

    Observations of ionospheric convection vortices: Signatures of momentum transfer

    McHenry, M.A. / Clauer, C.R. / Friis-Christensen, E. et al. | Elsevier | 1989


    Asteroid gravity field estimation using a gravity gradiometer

    Coll Ibars, Sergio / Scheeres, Daniel / Axelrad, Penina | AIAA | 2024