Visualization of Traffic Information in Head-Mounted Displays for Helicopter Navigation

Sammanfattning: One of the major challenges for helicopter pilots are low level flights and landings in degraded visual environments (DVE). Without proper assistance systems, the pilots are prone to lose their situational awareness (SA) when fog, heavy precipitation, limited sunlight and stirred-up sand or snow degrades their view. In recent years, various synthetic and enhanced vision systems were de-veloped so as to assist the pilots in these demanding situations. This work enhances the existing sys-tems by proposing a concept for the visualization of traffic information in helmet-/head-mounted displays (HMD). The intuitive representation provides additional cues about the environment and decreases the pilots’ workload, especially during flights in offshore windparks or while search and rescue operations with many other vehicles operating within a small range.The thesis, which was created at Airbus Defence & Space Friedrichshafen, analyzes the strengths and weaknesses of conventional head-down cockpit displays of traffic information (CDTIs) and of a very basic head-up traffic cueing system. Based on the results of this assessment, a prototype implementation of an integrated traffic visualization concept is developed where both display types – HDD and HMD – complement each other in their roles. All traffic information is retrieved from the on-board ADS-B system, which provides data such as the position and velocity vector of ADS-B equipped vehicles in the vicinity.The main focus of the work is placed on the development of methods for de-cluttering the HMD and increasing the information content of the head-up symbology by coding important parame-ters visually. In order to create a de-cluttered representation, the high-dimensional traffic data is clustered with a derivation of DBSCAN so as to identify groups of traffic that can be visualized by a single symbol. Ellipsoidal shapes are applied to airborne traffic while rectangular forms high-light vehicles on ground. To avoid distraction to the pilot due to sudden symbology changes when clusters are merged or split up, a smooth transition visualization method is developed. For the graphical representation of important information on the HMD, a measure indicating the threat potential of an intruder is proposed. This parameter, which is derived from the classification ap-proach of the TCAS II, is visualized by the color of the traffic symbol. In analogy to the TCAS, it is faded from green via yellow to red when the time to a predicted conflict decreases.The realized functions are integrated into a flight simulator and tested with synthetic ADS-B data. Furthermore, the proposed algorithms are evaluated in terms of their effectiveness and run-time efficiency, and finally the advantages and limitations of the approach are discussed. Now, the application must be integrated into an operational synthetic vision system so as to conduct further tests.