All posts by Juha Kallunki

CRAF studies the aggregate interference from automotive radars at 77 GHz 

Vehicle radars equipped in modern self-driving cars can no longer use the 24 GHz band and will be switching to the 76−81 GHz band. Radio Astronomy detections of molecules in the interstellar medium are performed in the band with several first-class radio telescopes in Europe such as the 30-m radio telescope (IRAM Pico Veleta, Spain), the NOEMA interferometer (IRAM Plateau de Bure, France), the Onsala 20 m radio telescope (OSO, Sweden) and the 40m radio telescope (IGN-Yebes Observatory, Spain) in the 76−81 GHz range.

To understand the future impact of the adoption of this band by cars for radio astronomy, CRAF proposed an aggregate study for 10 radiotelescopes: NOEMA (France), SRT (Italy), Yebes (Spain), Best (Hungary), Onsala (Sweden), Effelsberg (Germany) Noto (Italy), Metsähovi (Finland), IRAM (Spain), and Medicina (Italy). Studies were conducted by simulating the car distribution around the radio telescope according to road classification given by Open Street Map. Furthermore, the car density was varied with the aim of emulating traffic fluctuations between day and night and throughout the year. The results show variations between locations because of the high dependence on terrain attenuation around the site. Excluding Effelsberg located in a valley well shielded by mountains, the rest of the studied radio telescopes will require at least an exclusion zone of a radius of 10 km. This study was proposed to CEPT-ECC project team SE24 at the September 2022 meeting.

New IAU Centre – Protection of the Dark and Quiet Sky from Satellite Constellation Interference

The International Astronomical Union (IAU) held a press briefing on Thursday, February 3 to announce the establishment of the new IAU Centre for the Protection of the Dark and Quiet Sky from Satellite Constellation Interference. The Centre will be international, interdisciplinary, and work across multiple jurisdictions to help mitigate the impact of satellite constellations on astronomy at optical through radio wavelengths. The scope should include technical as well as regulatory work.

The Centre will be co-hosted by National Science Foundation’s (NSF’s) National Optical-Infrared Astronomy Research Laboratory (NOIRLab) and the Square Kilometre Array Observatory (SKAO), alongside a wide collaboration with several institutions and individuals. CRAF is one of the bodies that will collaborate with the Centre in the area of radio astronomy protection.

Compatibility studies initiated for the Radio Astronomy 6.6 GHz band at ITU-R Working Party 7D

With an increased pressure on the important radio astronomy band 6650 – 6675.2 MHz used for observations of methanol spectral lines, CRAF proposed to initiate compatibility studies at ITU-R Working Party 7D (WP7D) during its last meeting in September 2021. The studies aims at radio astronomy protection from existing active services in the 6-7 GHz band such as the Fixed services and Fixed Satellite Services, as well as the potential allocation to new services such as the International Mobile Telecommunication (IMT) services. CRAF has also provided compatibility studies for the RAS-IMT section. WP7D approved the studies scope and a new working document towards a preliminary draft new Report [RAS 6-7 GHz] was initiated.