Volume XLII-4/W18
Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci., XLII-4/W18, 597–603, 2019
https://doi.org/10.5194/isprs-archives-XLII-4-W18-597-2019
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.
Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci., XLII-4/W18, 597–603, 2019
https://doi.org/10.5194/isprs-archives-XLII-4-W18-597-2019
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

  18 Oct 2019

18 Oct 2019

INTERFEROMETRIC PATH MODELS FOR GNSS GROUND-BASED PHASE ALTIMETRY

S. Khajeh1, A. A. Ardalan1, and H. Schuh2 S. Khajeh et al.
  • 1School of Surveying and Geospatial engineering, Faculty of Engineering, University of Tehran, Iran
  • 2Department 1 Geodesy, GFZ German Research Centre for Geosciences, Potsdam, Germany

Keywords: GNSS, Reflectometry, Altimetry, Planar Model, Tropospheric Correction, Ray-Tracing

Abstract. Altimetry by using GNSS (Global Navigation Satellite Systems) reflectometry is regarded as a new promising technique. One important step to utilize this technique is modeling the interferometric path (the difference between the direct and the reflected signal paths). This paper evaluates three models: the planar model, the planar model with tropospheric correction and a model based on ray-tracing. If decimeter level accuracy for water surface fluctuation is required, the planar model cannot be used when a receiver is at an altitude of a few hundred meters and observations are taken at low elevation angles. On the other hand, depending on the mapping function and zenith total delay in the tropospheric correction, the planar model with tropospheric correction can provide decimeter level accuracy for low altitude stations. If simulated observations with a 1 cm accuracy have been employed to estimate Sea Surface Height (SSH) by the model based on ray-tracing the numerical results present 1 cm as RMSE for phase retrieval and 5 cm for Doppler retrieval. The planar model with tropospheric correction does not yield RMSE better than some decimeters for the same condition.