Directional Finding for Sources with Unknown Bandwidths and Center Frequencies

Signal direction of arrival (DOA) estimation is a classical problem that exists in a wide range of military applications such as radar, sonar, COMINT, as well as civilian applications such as emergency/disaster response, search and rescue, and the cellular telephone industry. In many of these applications, key parameters of the signals impinging on the array, such as bandwidth and center frequency, may not be known in advance. In these cases, we require a precision DOA estimator that can operate on these signals with arbitrary, but unknown, bandwidth and center frequency. There are many classical DOA estimation algorithms that can be used to estimate the DOAs of ideal narrowband sources with known center frequencies. Unfortunately, the problem of unknown center frequency and arbitrary bandwidth presents a substantial challenge to classical DOA estimation approaches. During Phase I, GIRD Systems focused on an innovative DOA estimation algorithm and have investigated computationally efficient methods for digital processing of the algorithm, in order to operate over the largest bandwidth possible. The GIRD solution offers an achievable approach for accurately estimating the DOAs of signals in a relatively “blind” manner, i.e., without advanced knowledge of signal types, bandwidths, and carrier frequencies. The Phase II effort is focused towards an implementation and demonstration of the DOA algorithm on a hardware prototype.