In this report, we present different approaches for the association of tracks for airborne sensors. The proposed approaches explore the effects of the choice of coordinate systems on the tracking filters and the association process. The performance of the association techniques is analyzed in terms of the probability of correct association (Pc) and the probability of false association (Pfa). This practical aspect of the multi-target multi-sensor tracking problem is presented for the association of radar tracks to ESM tracks in different scenarios.