Geodetic, Gravity & Magnetics

[GM-01] Atmospheric noise mitigation in SAR interferometry: current state of progress

★ Invited

*Yohei Kinoshita¹ (1. University of Tsukuba (Japan))

The synthetic aperture radar interferometry (InSAR) is a powerful space geodetic tool to observe surface displacement with a wide spatial coverage and high spatial resolution. However, InSAR often suffer from the atmospheric noise due to the microwave propagation delay effect. The atmospheric delay in InSAR can be divided into contributions from the ionosphere and the neutral atmosphere. Because the ionospheric delay effect has a frequency-dispersive nature, the range-split spectrum method that uses two band-splitted SAR data was recently shown as an effective correction method for the ionospheric delay noise. On the other hand, the neutral atmospheric delay has a non-dispersive nature and is mainly caused by the spatial heterogeneity of atmospheric water vapor that shows high variability in space and time, resulting the difficulty to be precisely modeled. For more than two decades, although numbers of studies proposed and applied atmosoheric noise corrections, there has been no decisive methods for InSAR atmospheric noise correction until now. Mainstreams of the InSAR neutral atmospheric delay correction are the timeseries approach (such as PS-InSAR and SBAS) and the use of external data like numerical weather model outputs. GNSS atmospheric observation data can also be used for the InSAR delay correction because the GNSS is also affected by the atmospheric delay same as InSAR. The author is now developing a new InSAR delay correction model based on GNSS data, whose preliminary result showed a better correction than numerical weather model approaches.
In the presentation I will introduce the current state with regard to the InSAR atmospheric noise correction and show a progress of my research.