Cramer-Rao Lower Bound for Direction of Arrival Estimates Using Multi-Input Interferometric Receivers in Line-of-Sight Environment

This paper deals with the computation of the closed form expression of the Cramer-Rao Lower Bound (CRLB) relative to the estimates of the direction of arrival (DOA) of an electromagnetic plane wave, using distributed multi-input interferometers that use wave correlations to discriminate the phase of an unknown signal. The CRLB bound is found to be dependent on many design parameters, including the characteristic function of power detection diodes, the signal to noise ratio (SNR), as well as the number of receiving antennas. The new CRLB expression provides intuitive insight about the performance of any unbiased DOA estimator in the case of Line-of-Sight (LOS) propagation environment.