EVS BASED APPROACH PROCEDURES: IR-IMAGE ANALYSIS AND IMAGE FUSION TO SUPPORT PILOTS IN LOW VISIBILITY

摘要

Based on a recently released new flight rule by the Federal Aviation Administration (FAA) a dream of imaging technology enthusiasts becomes reality: Visual guidance (VFR) of landing aircraft in adverse weather is no longer restricted by the performance of the human eye (measured as runway visual range, R VR). Based on the output of imaging sensors it is now allowed to continue the approach beyond the classical minimum decision altitude (MDA) or decision height (DH) down to about 100 ft whenever at DH or MDA the runway can be clearly identified within the sensor image. This rule change in aircraft operation will allow to conduct bad weather landings to non-ILS- equipped airfields and without an expensive on-board ILS installation. However, after this "quantum leap in flight rule making" new questions are coming up: "How to inform the pilot what the imaging sensor just sees?" Usually, a (quite expensive) Head Up Display (HUD) is required to show the output of the sensed image, which is presented in a raster scan overlay onto the existing stroke vector image. Is this "direct overlay method", which "blocks" the transparency of the HUD, really the best way to do this, or are there other options to make-up enhanced visual aircraft guidance concepts and systems? The following contribution tries to give some hints for answering these questions and proposes a more transparent EVS display format. A new method for extracting the aircraft position relative to the runway in real-time from the on-board imaging sources is presented. Finally, some experimental results from flight trials during the US-American SE- Vision project, where the described method has been implemented and tested, are explained.