Collision Detection System Based on Differential Carrier-Phase GPS Broadcasts
Soon Sik Hwang, Jason Lee Speyer · 2009
The Global Positioning System (GPS) has great potential for the development of new collision avoidance systems and is being considered for the next generation Traffic alert and Collision Avoidance System (TCAS). The navigation states estimated by GPS code information can be broadcasted to nearby airplanes via the current TCAS equipment. In this paper, the aircraft collision detection system using GPS Carrier-Phase (CP) information is addressed. A new approach to the CP based relative position estimation problem is proposed that uses particle filters (PF) where the samples are drawn from cartesian position space coordinates. The PF with position samples makes the GPS CP based position estimation algorithm robust and practical in that the algorithm is not sensitive to changes of GPS satellites and cycle-slips. The same algorithm can be used to estimate the vehicle attitude if multiple GPS antennas are used. For a reliable and enhanced collision avoidance system, three dimensional trajectories are projected using the estimates of the relative position, velocity, and the attitude. It is shown that the performance of GPS CP based collision detecting algorithm meets the accuracy requirements for a precise approach of flight with significantly less unnecessary collision alarms.