Collision Detection System Based on Differential Carrier-Phase Global Positioning System Broadcasts

The Global Positioning System 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. The navigation states estimated by Global Positioning System code information can be broadcast to nearby airplanes via the current traffic alert and collision avoidance system equipment. In this paper, the problem of aircraft collision detection system using Global Positioning System carrier-phase information is addressed. A new approach to the carrier-phase-based relative position estimation problem is proposed that uses particle filters in which the samples are drawn from Cartesian position space coordinates. The particle filters with position samples makes the Global Positioning System carrierphase-based position estimation algorithm robust and practical in that the algorithm is not sensitive to changes of Global Positioning System satellites and cycle slips. The same algorithm can be used to estimate the vehicle attitude if multiple Global Positioning System antennas are used. For a reliable and enhanced collision avoidance system, threedimensional trajectories are projected using relative position, velocity, and attitude estimates. It is shown that the performance of the Global Positioning System carrier-phase-based collision-detecting algorithm meets the accuracy requirements for a precise approach of flight with significantly less collision false alarms and no miss alarms. Nomenclature A = transition matrix between the body frames and inertial frames c = velocity of light Eu = attitude expressed as Euler parameters (roll, pitch, and yaw) EX Y = expectation function of Y over the probability density function X Hi0 = direction matrix to all visible Global Positioning System satellites at the linearized point Xi0 j k Hi0 to the GPS satellites l (l j;...;k) I i j = ionospheric delay error