A Particle Swarm Optimization Based Algorithm for the Calculation of User Differential Range Error

To enhance the integrity and safety of the flight, the User differential range error (UDRE) must bound the maximum residual error in the service volume with the probability of 99.9%. The most important thing of computing the UDRE is how to find the Worst user location (WUL) in the service volume. Then, a UDRE algorithm using PSO is described to solve this problem. To avoid falling in local optimum, the proposed algorithm generates a group of particles with uniform spacing in the service volume. Experiments were made to compare the performance of the proposed PSO algorithm, the original PSO algorithm and the exhaustive grid search method. The related results show that the proposed PSO algorithm can find the WUL precisely and increase the accuracy of UDRE and this algorithm is suitable for computing UDRE at the master station.