Brian Davis, Associate Dir., Mobility Tech. Lab, Mechanical Engineering
Global Navigation Satellite Systems (GNSS) is a term used to collectively describe satellite-based positioning and timing systems. The Global Positioning System (GPS), operated by the United States Department of Defense, is perhaps the most well-know and widely used GNSS. The sub-meter accuracy of its position solution has revolutionized road, rail, air, and marine transportation systems worldwide. Its timing function is the de-facto "heart beat" for clocks around the globe in support of operations such as time-stamping of banking transactions and synchronizing electrical frequency on interconnected power grids. If GNSS receivers capable of generating a position solution with centimeter accuracy were widely available, they would push the GNSS-revolution in ground transportation even further as an enabler of safety enhancements such as ubiquitous lane-departure warning systems, driver-assist systems, and enhanced stability-control systems.
Centimeter-level accuracy in GNSS is achieved using a complex algorithm known as Real-Time Kinematic (RTK) processing. RTK-capable receivers require precisely calibrated antennas to receive the signals transmitted by the GNSS satellites. In addition, they must receive and process corrections from a ground network of GNSS receivers. This makes RTK-capable receivers costly (in excess of $10,000) and bulky, making them unsuitable for cost- and size-sensitive automotive applications.
GNSS equipment manufactures have started advertising inexpensive (less than $1,000) and compact RTK-capable receivers, but data supporting this claim is not publicly available. This project provided an independent performance assessment in realistic settings encountered in transportation applications.