Demonstration of Inter-Vehicle UWB Ranging to Augment DGPS for Improved Relative Positioning

Vehicle-to-vehicle (V2V) navigation is reviewed and the concept of differential GPS relative navigation augmented with ultra-wideband (UWB) and bearing measurements is introduced theoretically. Filtering software is developed and tested using a data set collected between three moving vehicles in a test in Calgary. Initial results combining GPS pseudorange, UWB range and bearing measurements show that the additional measurements can significantly improve horizontal positioning accuracy, particularly in environments where GPS availability is poor. The UWB measurements generally contributed to an improved along-track relative position while the bearing measurements improved the across-track position. Data from the three vehicle test was also used to characterize UWB systematic errors in the V2V environment. Correcting for a scale factor and bias in each UWB range measurement reduced the UWB errors from decimeter to centimeter magnitude and allowed for an improved carrier-phase DGPS float solution augmented with UWB ranges to be calculated.