As per the sources, Italy researchers have confirmed the possibility of quantum communications between a ground station and high orbiting worldwide navigation satellites, over a distance of twenty thousand kilometers with an exchange at a single photon level. The milestone experiment which was conducted proves the possibility of protected quantum communications using the Global Navigation Satellite System, GNSS on a global scale. Dr. Giuseppe Vallone, author from the University of Padova, Italy said that, technologies which are satellite based, enables a large variety of scientific, civil, and military applications like navigation, communications, timing, meteorology, reconnaissance, remote sensing, search and rescue, astronomy and space exploration.
The main aim of these systems is to securely transmit data and information to ground stations on Earth from orbiting satellites. A malicious advisory is very critical for the protection of these channels for both civilian and military operations. Unconditional security for the optical links is guaranteed by Space Quantum Communications, by using quantum information protocols. The first ever exchange of quite a few photons per pulse, which are between a couple of distinct satellites in the space Geodesy Centre and the Russian Glonass constellation of the Italian Space Agency, are observed by the team.
Paolo Villoresi, who is an author, said that, the experiment actually used the reactive retro-reflectors mounted over the satellites. He also added that, they can calculate the characteristics of both a receiving ground station and a dedicated quantum payload by calculating the definite losses of the channel. Their results have proved the possibility of quantum communication from GNSS in terms of attainable detection rate and signal to noise ratio. Previously, in an experiment, the longest channel length demonstrated was around 7000 km using a Medium-Earth-Orbit satellite that they reported in 2016. According to them, quantum communication can also offer many interesting solutions for GNSS for both inter-satellite and satellite-to-ground links, which can supply unconditionally safe protocols.