With the increasing flight flow of aircraft

the probability of collision during free flying is becoming larger. A collision detection algorithm based onADS-B spherical model is put forward via reasonably divide surrounding area of aircraft. Combine with the theory and feature of ADS-B

this method establishes spherical model instead of cylindrical model

then implement the pre-selecting of collision objects

calculate the possible collision position

track-crossing point and distance. It estimates the arriving time and compare with threshold value to detect whether a collision can happen. Simulation result shows this algorithm can realize collision detection more quickly and accurately

which can be advantageous to avoid flight collision by sending collision alert to the pilot.