Study on Conflict Detection Method with Downlink Aircraft Parameters

In order to keep safety of air traffic, ENRI (Electronic Navigation Research Institute) tries to improve CA (Conflict Alert) function by using airborne information via Mode S datalink. CA supports air traffic controller to keep safe separations between aircraft by predicting aircraft positions and detecting potential conflicts. Our purpose of this study is to develop the new DAPs-CDM (Conflict Detection Method using Downlink Aircraft Parameters) and evaluate the impacts of its introduction by computer simulation. Firstly, in order to understand the characteristics of the conventional CDM, we calculated horizontal and vertical prediction errors of aircraft position. The conventional CDM uses linear prediction with only radar information on the ground. We also analyzed CA occurrences by the conventional CDM. We found that both horizontal and vertical prediction errors were reduced by using airborne information in addition to radar information. We also found that it was better to smooth vertical speed for prediction and to utilize selected altitude in DAPs-CDM. Finally, the characteristics of DAPs-CDM were studied and the advantages were demonstrated. The new function of DAPsCDM is to predict aircraft positions by using aircraft velocity on the airborne side and to determine aircraft flight phases by using roll angle and selected altitude. For the purpose of comparing DAPs-CDM with the conventional CDM, ENRI developed CDES (Conflict Detection Evaluation System). It can simulate both DAPs-CDM and the conventional CDM under air traffic situations and system parameters as almost same as operational ones. As a result of computer simulation with CDES, the determination of vertical flight phases by selected altitude was most effective to reduce the number of unnecessary CA. Keywords-component; Conflict Alert; Conflict Detection Method; Downlink Aircraft Parameters