Towards Wake-Resistant Aircraft through LiDAR- Based Wake Impact Alleviation

The presentation shows an approach to alleviate the impact of a wake vortex on an encountering aircraft by means of a special control system. The wake impact alleviation control system presented allows a significant reduction of the wake-induced aircraft response and thus provides the potential to achieve an appreciable safety improvement during wake vortex encounters. This could also support the reduction of wake-vortex-based separation minima for following aircraft equipped with such a controller. The presented wake vortex impact alleviation system is based on an airborne forward-looking Doppler LiDAR sensor. The basic principle of the system is to use this sensor to measure wind remotely ahead of the aircraft. On the basis of these measurements the system estimates whether a wake vortex is located in front of the aircraft. If this is the case, the wake vortex characteristics are identified and the adequate control deflections to countervail the wake-induced aircraft response are computed and applied. An integrated simulation environment comprising a full nonlinear 6-DoF A320 model (with control laws), wake vortex models, and the wake impact alleviation algorithm was developed. The LiDAR sensor subsystem has many design parameters that influence the overall wake impact alleviation performance in a complex way. This makes it particularly difficult to derive adequate requirements. The presented study provides first insights into the role of each parameter as well as some adequate parameter combinations. Based on the results of this study a wake impact alleviation performance of about 60% (in terms of maximum bank angle reduction) seems achievable with the proposed system and various sets of a priori realistic sensor characteristics.