PT  - JOURNAL ARTICLE
AU  - Shehaj, Endrit
AU  - Wilgan, Karina
AU  - Frey, Othmar
AU  - Geiger, Alain
TI  - A collocation framework to retrieve tropospheric delays from a combination of GNSS and InSAR
AID  - 10.1002/navi.398
DP  - 2020 Dec 21
TA  - NAVIGATION: Journal of the Institute of Navigation
PG  - 823--842
VI  - 67
IP  - 4
4099  - https://navi.ion.org/content/67/4/823.short
4100  - https://navi.ion.org/content/67/4/823.full
SO  - NAVIGATION2020 Dec 21; 67
AB  - High spatio-temporal variability of atmospheric water vapor affects microwave signals of Global Navigation Satellite Systems (GNSS) and Interferometric Synthetic Aperture Radar (InSAR). A better knowledge of the distribution of water vapor improves both GNSS- and InSAR-derived data products. In this work, we present a collocation framework to combine and retrieve zenith and (relative) slant tropospheric delays. GNSS and InSAR meteorological products are combined aiming at a better retrieval of the atmospheric water vapor. We investigate the combination approach with synthetic and real data acquired in the Alpine region of Switzerland. Based on a closed-loop validation with simulated delays, a few mm accuracy is achieved for the GNSS-InSAR combination in terms of retrieved ZTDs. Furthermore, when real delays are collocated, the combination results are more congruent with InSAR computed products. This research is a contribution to improve the spatio-temporal mapping of tropospheric delays by combining GNSS-derived and InSAR-derived delays.