Fast Real Time Positioning using GNSS

A well-established method of differential GNSS corrections, referred to as real time kinematic (RTK), is applied to raw signals which can be obtained for inexpensive automotive grade GNSS designs. This technical approach to position determination is historically found only in higher cost survey grade devices. Today’s automotive class designs can achieve positional accuracies of slightly over one meter when using satellite-based augmentation system (SBAS) corrections, and require 25 seconds or more to begin operating. With local differential corrections (DGPS) they can achieve sub meter accuracies. Using these RTK methods we proved in Phase I that such devices can achieve positional accuracies of centimeters when operating in a fixed ambiguity mode, while sub-meter accuracies are obtained when in a floating mode – both were achieved while operating in moving vehicles in typical urban environments. Hence decimeter accuracy performance levels for a moving vehicle become both achievable and cost effective. Startup times to initial first fix are also sharply reduced due to the ready availability of local data for use. In Phase II we will add additional robustness to the developed algorithms moving towards a commercial product in the form of a reference design which others can readily adopt for their own needs.