Recent Upgrades of the EOLE and AIAS Lidar Systems of the National Technical University of Athens Operating Since 2000 in Athens, GreeceA. Papayannis, P. Kokkalis, M. Mylonaki, R. Soupiona, C. A. Papanikolaou, R. Foskinis and A. GiakoumakiEPJ Web Conf., 237 (2020) 02030DOI: https://doi.org/10.1051/epjconf/202023702030