A Measurement System and the TUG-EEC-Channels Database for the Aeronautical Voice Radio

A system for measuring time-variant impulse responses and a database of such measurements for the aeronautical voice channel are presented. Maximum length sequences (MLS) are transmitted over the voice channel with a standard aeronautical radio and the received signals are recorded. For the purpose of synchronisation, both the transmitted and received signals are recorded in parallel with a GPS-based timing signal. The flight path of the aircraft is accurately tracked. A collection of recordings of MLS transmissions is generated during flights with a general aviation aircraft. The measurements cover a wide range of typical flight situations as well as static back-to-back calibrations. The resulting database is made available under a public licence free of charge. The estimated time-variant impulse responses provide a characterisation of the aeronautical voice channel. This characterisation is needed for improvements and add-ons to voice communication systems as in air traffic control, where the analogue radio will remain in use for many years to come.