Surrounded by over 8,000 foot mountains, Austria’s Innsbruck Airport posed a severe surveillance challenge to air traffic for controllers monitoring traffic arriving and departing the narrow valley airport. Conventional radar installations on the sides or on top of the mountains were impractical and several units would be required to adequately cover the necessary airspace. Austro Control’s solution was multilateration, whose small receivers could be inexpensively located in positions inaccessible to large radars to provide fully redundant signal coverage.

Innsbruck Airport