The OpenSky Network is a non-profit association based in Switzerland. It aims at improving the security, reliability and efficiency of the air space usage by providing open access of real-world air traffic control data to the public. The OpenSky Network consists of a multitude of sensors connected to the Internet by volunteers, industrial supporters, and academic/governmental organizations. All collected raw data is archived in a large historical database. The database is primarily used by researchers from different areas to analyze and improve air traffic control technologies and processes. The main technologies behind the OpenSky Network are the Automatic Dependent Surveillance-Broadcast (ADS-B) and Mode S. These technologies provide detailed (live) aircraft information over the publicly accessible 1090 MHz radio frequency channel.