Recursive Phase Extraction for Holographic Localization of Incoherent FMCW Beacons

Radio-based localization systems are a vibrant field of scientific research with various use-cases in indoor environments. Particularly, the live tracking of freely moving objects offers significant value; however, such tracking requires high update rates and precise localization. An advanced approach with low computational effort is the holographic extended Kalman filter (HEKF), which has already achieved accuracy in the cm-range even with a moderate bandwidth. Hereby, the phase value is extracted from the peak of the spectrum requiring a maximum-search in the full spectrum. The computational effort in frequency-modulated-continuous-wave systems can be reduced by replacing the maximum search by calculating the evaluation bin. In this paper, a recursive method for the phase extraction for HEKFs in secondary radar systems with an incoherent beacon is presented and evaluated using a 24 GHz frequency-modulated-continuous-wave system.