High-Accuracy Indoor Ranging Using Microwave OFDM Signals

High-accuracy wireless ranging and positioning becomes necessary in many applications, and while many waveforms promise high accuracy, their performance in cluttered environments is not optimal. This article confers about the potential of high-accuracy wireless ranging using orthogonal frequency-division multiplexing (OFDM) signals. The excellent correlation properties of OFDM signals for high-accuracy ranging in real-life environments are discussed and the Cramer-Rao lower bound (CRLB) is derived for OFDM ranging independent of the transmitted information. Simulation results and experimental measurements at a carrier frequency of 1.4 GHz with 200 MHz of bandwidth are included. Range estimation is demonstrated with a standard deviation of 1.6 mm in a realistic laboratory environment with no anechoic walls.