Compressive Measurements Exploiting Coprime Frequencies for Direction Finding

Sparse arrays are considered as an effective solution to reduce the system complexity for direction-of-arrival (DOA) estimation as they can resolve more sources than the number of sensors. Inspired by such techniques, the coprime frequency-based array structure was recently proposed to further reduce the number of required sensors. Multiple sensing signals with mutually coprime carrier frequencies are transmitted, and the reflected signals are used to estimate the target DOAs. The cross-correlation obtained from each pair of frequencies provides additional degrees of freedom (DOFs). On the other hand, a compression matrix can be designed to reduce the dimension of the received signal vector, thereby effectively reducing the number of front-end circuit chains. In this paper, we use the compressive measurements of the received signal vector obtained from a coprime frequency-based array structure to estimate the signal DOAs. The proposed scheme can obtain an increased number of DOFs and high estimation accuracy because of the coarray operation and the large array aperture of the coprime frequency-based array structure. Meanwhile, the system complexity is also significantly reduced. The effectiveness of the proposed scheme is validated using simulation results.