Effects of lidar location on retrieval of aircraft wake vortex characteristic parameter

To improve the accuracies of wake vortex detection and retrieval of lidar in range height indicator mode, an algorithm for solving the optimal location of airport lidar based on the vortex core region segmentation was proposed. The influence of the lidar lateral and longitudinal installation positions on the accuracy of wake vortex retrieval was studied. Considering the effects of wake vortex dissipation and descent, a simulation model of lidar dynamic echo data was established. The radial distance formula of the wake vortex region segmentation was deduced, and the wake vortex core positions were determined according to the velocity extreme points after the region segmentation. After the detection time difference was corrected, the vortex core positions were substituted into the induced velocity equation. The simultaneous equations were constructed using the radial velocity of the characteristic point near the vortex core, and the relative error of the wake vortex circulations was solved. The calculation process for the lidar optimal location was designed based on the porportion of aircraft types at the airport. According to the operational data at a domestic airport for one week, data of five typical aircraft types were extracted to analyze the impact of airport lidar location, and the optimal lidar location of the airport was determined. Research results show that the lateral distance of the lidar location has a great influence on the retrieval accuracy, and there is an optimal lateral distance, which is about 10 times the aircraft wingspan. Approximately 200 m near the optimal lateral distance is a pretty good selection range, and the detection accuracy within this range does not change much. There is a minimum value for the selection of longitudinal distance, which is positively correlated with the descent speed of the wake vortex. For the typical large civil aviation aircraft, the value is about 800 m. When the longitudinal distance is greater than the minimum value, its change basically does not affect the wake vortex detection accuracy. The best location area for the airport lidar is a long strip area where the lateral position is near the optimal lateral distance, and the longitudinal distance is greater than the minimum value. It can be seen that the algorithm for solving the optimal location of the airport lidar is effective, and can be applied to the wake vortex detection experiment or the lidar location decision analysis of the dynamic wake separation system. 2 tabs, 11 figs, 31 refs.