Johannes Plendl

Johannes "Hans" Plendl (6 December 1900 – 10 May 1991), German radar pioneer, was the scientist whose airplane navigation inventions made possible the early German bombing successes in World War II. Early life Plendl was born in 1900 in Munich, German Empire to parents from Northern Bavaria. His surname is most likely a truncated Bavarian dialect form of "Plendlein." Plendl served briefly in the Imperial German Navy during World War I. Shortly thereafter, Plendl began his career as a radio and beam engineer for Telefunken corporation. His early research into meter-wave propagation and radar beams necessitated additional names for newly discovered levels of the Earth's atmosphere, and Plendl is generally credited with coining the term ionosphere. In the early 1930s, he worked on developing the radio communications used in flights by civilian aircraft and the Hindenburg Zeppelin. His research and developments with the Lorenz beam landing system gave birth to what is now known as ILS, Instrument Landing System.