A zeppelin experiment to study airborne altimetry using specular Global Navigation Satellite System reflections

authored by: A. M. Semmling, J. Wickert, S. Schön, R. Stosius, M. Markgraf, T. Gerber, M. Ge, G. Beyerle
Abstract: This paper describes an altimetric method based on data recorded during experimental zeppelin flights over Lake Constance. Interferometric observations for this method are obtained using a Master-Slave receiver configuration. These observations contain the relative phasing of direct and reflected signals and are used for altimetry. Separated antennas are attached to the receiver to record direct and reflected signals at slant elevation angles. Filtering is required to remove direct contributions in this slant geometry. Filtered observations are corrected using an altimetric model, and thus Doppler residuals are retrieved. This correction reduces the width of the spectral reflection peak from 3 mHz to less than 10 mHz. Doppler residuals are sensitive to surface height. Lake level is estimated inversely for the residuals at different trial heights. A case study of reflection events is presented. Lake level is estimated using data from antennas with right-handed and left-handed circular polarization. Reference level is determined from tide gauge data for stations around the lake. Mean deviation of estimates from reference level is 50 cm. Doppler shifts of different model corrections are compared. The altimetric correction is the most important, with mean Doppler shifts between 316 and 560 mHz. Mean Doppler shifts are much smaller for baseline correction (less than 0.2 mHz) and water-vapor correction (0.1-1.0 mHz). In addition, the geoid undulation effect (up to 25 cm amplitude) is predicted with mean Doppler shifts between 0.1 and 0.9 mHz. Precision of Doppler residuals (0.5-0.6 mHz) is insufficient to resolve the geoid undulation effect. The resolution from phase residuals is better. The effect of geoid undulation, however, is not dominant in phase residuals. Key Points A GNSS Reflectometry setup is presented for airborne altimetry A spectral retrieval yields decimeter precision validated with in situ data Phase data is retrieved for precise resolution of residuals
Organisation(s): Institute of Geodesy
External Organisation(s): Helmholtz Centre Potsdam - German Research Centre for Geosciences
Enviscope GmbH
German Aerospace Center (DLR)
Type: Article
Journal: Radio science
Volume: 48
Pages: 427-440
No. of pages: 14
ISSN: 0048-6604
Publication date: 15.07.2013
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Condensed Matter Physics, Earth and Planetary Sciences(all), Electrical and Electronic Engineering
Electronic version(s): https://doi.org/10.1002/rds.20049 (Access: Unknown)
: Details in the research portal "Research@Leibniz University"

BibTeX

@article{61c60604c7794226bb52ecfbb8573f08,
title = "A zeppelin experiment to study airborne altimetry using specular Global Navigation Satellite System reflections",
abstract = "This paper describes an altimetric method based on data recorded during experimental zeppelin flights over Lake Constance. Interferometric observations for this method are obtained using a Master-Slave receiver configuration. These observations contain the relative phasing of direct and reflected signals and are used for altimetry. Separated antennas are attached to the receiver to record direct and reflected signals at slant elevation angles. Filtering is required to remove direct contributions in this slant geometry. Filtered observations are corrected using an altimetric model, and thus Doppler residuals are retrieved. This correction reduces the width of the spectral reflection peak from 3 mHz to less than 10 mHz. Doppler residuals are sensitive to surface height. Lake level is estimated inversely for the residuals at different trial heights. A case study of reflection events is presented. Lake level is estimated using data from antennas with right-handed and left-handed circular polarization. Reference level is determined from tide gauge data for stations around the lake. Mean deviation of estimates from reference level is 50 cm. Doppler shifts of different model corrections are compared. The altimetric correction is the most important, with mean Doppler shifts between 316 and 560 mHz. Mean Doppler shifts are much smaller for baseline correction (less than 0.2 mHz) and water-vapor correction (0.1-1.0 mHz). In addition, the geoid undulation effect (up to 25 cm amplitude) is predicted with mean Doppler shifts between 0.1 and 0.9 mHz. Precision of Doppler residuals (0.5-0.6 mHz) is insufficient to resolve the geoid undulation effect. The resolution from phase residuals is better. The effect of geoid undulation, however, is not dominant in phase residuals. Key Points A GNSS Reflectometry setup is presented for airborne altimetry A spectral retrieval yields decimeter precision validated with in situ data Phase data is retrieved for precise resolution of residuals",
keywords = "altimetry, GNSS, interferometry, reflectometry",
author = "Semmling, {A. M.} and J. Wickert and S. Sch{\"o}n and R. Stosius and M. Markgraf and T. Gerber and M. Ge and G. Beyerle",
year = "2013",
month = jul,
day = "15",
doi = "10.1002/rds.20049",
language = "English",
volume = "48",
pages = "427--440",
journal = "Radio science",
issn = "0048-6604",
publisher = "Wiley-Blackwell",
number = "4",
}