Improving Ranging Accuracy of OFDM Radar System Using Interpolation of DFT Samples

Orthogonal frequency division multiplexing (OFDM) waveform is being increasingly used in radar sensing because it enables joint radar-communication system on a single platform. However, the bandwidth of the OFDM radar cannot be sufficiently increased due to the given sampling requirement, which results in limited range resolution. Therefore, additional signal processing needs to be performed to enable accurate sensing of targets. This paper proposes a method for improving the ranging accuracy of the OFDM radar system using interpolation of discrete Fourier transform (DFT) samples. The DFT magnitude ratio of the two DFT samples is used to refine the coarse frequency estimate. The simulation results demonstrate that the proposed method can estimate the range of targets much more accurately than the conventional DFT-based method. In addition, the proposed method showed robust estimation performance even when the signal-to-noise ratio is low or when multiple targets exist.