Low-Complexity Spatial Parameter Estimation for Coherently Distributed Linear Chirp Source

In this paper, the problem of estimating the spatial parameters of multiple coherently distributed linear chirp sources is considered. In the fractional Fourier domain, a novel low-complexity algorithm based on the MUSIC criterion is proposed to estimate the central angle and the extension width. For small extension width scenarios, the 2-D spatial angle search in traditional estimators for the distributed sources estimation is replaced by a two-step 1-D MUSIC search which dramatically decreases the computational complexity. In the case of chirp signals with different frequency parameters, sources can be separated, and the spatial parameters of each source can be estimated individually. When sources cannot be separated, this problem can be considered as a classical direction-of-arrival estimation of multiple signals. In addition, the central angle estimation does not require any assumption on the distribution of angular spread. Simulation results show that the proposed algorithm obtains comparable performance in the parameters estimation accuracy for small extension width scenarios with the reduced complexity compared with our previous work.