Time calibration and positioning for KM3NeT

In this contribution we review the concepts put forward for the time calibration and positioning systems of the future KM3NeT neutrino telescope in the Mediterranean Sea. Even though the final layout of the detector, its mechanical structures and the light detection technologies to be used are not yet defined, much progress has been made in clarifying the possible technologies available for calibration and positioning. Concerning time calibration, we review the different concepts proposed, namely optical beacons (LED and laser), fibres or copper cables, 40K, and a pre-deployment calibration. For positioning, the use of acoustic signals with lower frequency components in combination with cheaper hydrophones than in ANTARES is being investigated. The need and use of compasses and tiltmeters is strongly correlated to the mechanical structure chosen. For absolute positioning several methods are being considered. In the following, the solutions proposed in the KM3NeT Conceptual Design Report (CDR) [2001, available at: 〈http://www.km3net.org/CDR/〉] are discussed.