View of the corner reflector in the Montsec Observatory. © isardSAT.
The first measurement campaign of the corner reflector at the Montsec Observatory, which took place between September 2021 and April 2022 shows promsing results (F. Gibert et al., 2023).
After being processed with a FF-SAR algorihtm, the values obtained are comparable to what is currently achieved by means of active transponders, and therefore, it is demonstrated that passive reflectors may be of interest to support radar altimeter regular calibration.
Impulse response functions for the Sentinel-6A passes over the corner reflector (blue) and the Crete transponder (red) measured on 22 and 29 March 2022, respectively. Overall agreement is found in both facilities, except for some asymmetries in the secondary lobes.
The success of this campaign confirms their utility in some radar altimeter key calibration aspects that need to be regularly monitored. The results highlighted the need to equip the facility with a permanent GNSS monitoring system, as the analysis presented was done assuming only the ETRS89 drift with respect to the ITRS system, therefore neglecting eventual residual displacement due to local tectonic activity.
Centered radargram with the 2-D impulse response function of the corner from the pass on October 25, 2021. © isardSAT.