The goal of this project is to update and widen the presently available Sapienza Geodetic Infrastructure. This infrastructure, consisting in a Global Navigation Satellite System (GNSS) permanent station, equipped with meteo station and atomic clock, was installed about 20 years ago, in the early 2000's, thanks to a dedicated fund for University infrastructure granted to a project leaded by Prof. Mattia Crespi. The proposed improvements are related: to the update of the GNSS receiver to the state-of-the-art; to add two more space geodesy techniques, Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS) and Geodetic Synthetic Aperture Radar (G-SAR) with active reflectors on the ground, both not installed in Italy yet; to add a second GNSS permanent receiver dedicated to ionosphere sounding; to install an ad hoc device dedicated to high accuracy simulations of long term displacements, to understand the true accuracy potential of each installed space geodesy technique. The achievement of this goal will enable Sapienza to strengthen the participation to international initiatives for Earth observation, sustainability monitoring, and anthropic and natural hazards prevention and management, naturally including the realization and maintenance of the global and national reference frames, in the line of the activities promoted by the United Nations Subcommittee on Geodesy, established within the United Nations Initiative on Global Geospatial Information Management in 2017.
The most relevant innovations brought by the requested instruments are hereafter summarized:
- GNSS permanent station (update) -It will guarantee the fulfillment of the standards requested in 2022 at international level to contribute to the worldwide IGS permanent network. Two options are possible, in this respect: substantial upgrade of the present GNSS receiver to the last-generation one of the same manufacturer or complete replacement with a last-generation GNSS receiver from a different manufacturer. To avoid as much as possible the well-known problems related to receiver/antenna replacement, the first option is preferred, also considering it is the cheapest.
[NOTE - This is the unique difference between the two attached quotations. The extra budget eventually requested by the second option will be guaranteed by other already available free funds]
- Active SAR reflector (ECR) (new installation) - It is a new instrument not yet installed in Italy in an IGS site. It will realize a tie between SAR satellites and ITRF, enabling a more optimal use of the wide/long stripmap imagery acquired by Sentinel-1, both for linking the deformation maps coming from SAR interferometry (InSAR) directly to the global reference frame ITRF, and for improving the estimation of the height variation of the M0SE station, introducing a constrain on the coordinate which is worst estimated from GNSS. At present there is a unique manufacturer for such a device (Metasensing Group - https://www.metasensing-group.com/)
- GNSS permanent station for ionosphere monitoring (new installation). It is a unique instrument dedicated to ionosphere monitoring in the panorama of GNSS receiver. The installation of this special GNSS receiver will also let deeper comparisons with ionosphere monitoring based on the ionosonde already installed at the Istituto Nazionale di Geofisica premises in Rome. At present there is a unique manufacturer for such a device (Septentrio - https://www.septentrio.com/en)
- High precision device to simulate three dimensional displacements (new installation). It will be an ad hoc instrument which will enable to assess the accuracy of different space geodesy instruments (different kinds of GNSS receivers, active SAR reflector) in detecting displacements. This device will be o realize this reference, an ad hoc high precision device will be designed and build by a high-specialized manufacturer, properly selected due to the long experience in high-precision geodetic installations (Idrogeotec - http://www.idrogeotec.it/index.php).
- DORIS instrument (new installation). It is an instrument used to realize and maintain the global reference frame ITRF, but not yet installed in Italy. It will let to improve the tie between DORIS and GNSS. This instrument will be supplied by CNES for free, according to the standard international regulation concerning DORIS (International DORIS Service - https://ids-doris.org/doris-system/tracking-network/doris-station.html).