Global Positioning System (GPS) technology is used worldwide in everyday life. Lesser-known systems, referred to as GNSS RTK, which make carrier phase measurements on multiple satellite systems and achieve sub-centimeter accuracy, now at prices affordable even by a maker.

Early real-time kinematic (RTK) receivers were intended exclusively for professional uses, such as topographic measurements. Professional receivers still have costs of several thousands of euro. For the past few years, modules featuring many applications and a significantly lower cost have been found on the market: In addition to traditional applications such as geographic information systems (GIS), these RTK receivers are particularly suitable for controlling aircraft and other vehicles, such as unmanned aerial vehicles (UAV) and unmanned ground vehicles (UGV) utilized as agricultural tractors and drones.

An interesting application is by using two RTK receivers linked together to measure not only position, b...