Minimizing uncertainty and improving accuracy when fusing multiple stationary GPS receivers

Low-cost GPS receivers are increasing in availability and performance, but do not provide the low-level information typically needed for more accurate positioning, which limits their use in favor of more complex and expensive commercial GPS systems. Three approaches are presented for fusing positioning data from multiple low-cost GPS receivers. One method finds a linear combination, while the remaining two attempt to reduce the uncertainty through maximum likelihood estimation and covariance trace minimization. All methods show improvements in both simulation and experiments, but trace minimization showed the most with a 23-70% reduction seen experimentally. When including uncertainty in the fusion process, the results illustrate how the fused position estimate can be improved in both accuracy and precision. With such improvements, the use of multiple, inexpensive GPS receivers may find cost effective uses in improving performance of stationary systems or lead to further research for extensions with dynamic systems.