SANTA MARIA CORE SITE

The RAEGE Station of Santa Maria station is located in Santa Maria Island (Azores) at an altitude of 247 m. The observatory site can be observed in Fig. 1.

The station has a VGOS-type radio telescope, two GNSS permanent stations, and a control building that houses an electronic laboratory, and a gravimetry room, separated from the rest of the building.

Currently, a iGRAV-051 superconductive gravimeter from GWR Instruments, a GRAVITON-EG 1183 relative gravimeter from LaCoste & Romberg, a Centaur-3/Trillium 120PA seismograph from Nanometrics, and a SILEX accelerograph built at the National geographic Institute of Spain, are installed in the gravimetry room and run continuously. The Centaur-3 seismograph is fully operational since June 2017 and is part of the International Seismological Centre (ISC) in which is known as ES.VPORT.

The VGOS 13.2m radio telescope “Colombo” (Fig. 2), was constructed in 2014, and is now part of the International VLBI Service for Geodesy and Astrometry (IVS). It is equipped with a VGOS broadband receiver developed at Yebes laboratories. The first VLBI observation was carried out on February 2018, at the time with a tri-band receiver (S, X and Ka bands), and since May 2021, it is participating routinely in R1, R4, T2 and intensive type sessions until September 2022. Currently, Santa Maria is part of the VGOS network since October 2023.

A hydrogen maser (H-MASER) atomic clock is used to synchronize all equipment involved in the VLBI observations – An iMaser from T4Science is in charge of providing the extremely stable timing signals required by the VLBI technique.

VLBI is not the only space geodetic technique implemented in Santa Maria. Two permanent GNSS stations integrated in the International (IGS), European (EUREF) and Azorean (REPRAA) regional networks are also installed at the station:

• AZSM00PRT GNSS station: Leica GRX1200GG Pro receiver and a LEIAT504 LEIS antenna and started operation in May 2017.
• RAEG00PRT GNSS station: part of the IGS network, this station is based on a Leica GR50 receiver and LEIAR20 antenna. Operational since May 2017.

At Santa Maria, there is also an auxiliary building (Fig. 3) with workshop tools and power supply.