Comparison of two-way ranging with FMCW and UWB radar systems

Abstract

In this work, two positioning systems based on the two-way ranging synchronization-protocol, are discussed and compared. A frequency modulated continuous wave (FMCW), and a ultra wide band (UWB) radio detection and ranging (Radar) setup are used for this comparison. Indoor and outdoor ranging measurements between one host and one tag node were performed and evaluated. These radar systems present an alternative to global positioning system (GPS) tracking, especially for indoor use, where GPS does not work reliably or at all. This is due to the requirement of GPS of a perfect line Of sight (LOS) connection between satellites and the object to be tracked. The FMCW system was superior in raw measurement quality with accuracy below 25 cm, as well as measured maximum range with 70 m (FMCW) against 30 m (UWB). Worst-case precision was measured to be 2.3 cm (FMCW) against 2.8 cm (UWB). The UWB system allows for very high update rates of 400 Hz with low computational effort.