Bearing Estimation of a Sensor With a Single Receiver Using Simultaneous Chirps Transmission From an Anchor Array

We propose a low sampling rate angle of arrival estimation for self-localization of a sensor with a single receiver. An anchor node array with multiple transmitters simultaneously transmit linear chirps that are observed by the receiver. Measuring the received signal strength (RSS) results in a low-frequency tonal with harmonic components. As a result, the observed signal is sampled at a significant lower rate compared to the original total bandwidth of the chirps. The angle of arrival (AOA) to the anchor node encoded in the tonal frequency is estimated by solving a nonlinear least-squares problem, which capitalizes on the harmonic structure of the received signal, and can be solved efficiently using the fast Fourier transform. Indoor acoustic channel simulations and experiments in a water tank demonstrate that the root-mean-square error of the direction estimates are close to the Cramόr-Rao lower bound (CRLB) for sufficient values of signal-to-noise ratio (SNR).