Abstract
This paper proposes an improved spatial differencing (ISD) scheme for two-dimensional direction of arrival (2-D DOA) estimation of coherent signals with uniform rectangular arrays (URAs). We first divide the URA into a number of row rectangular subarrays. Then, by extracting all the data information of each subarray, we only perform difference-operation on the auto-correlations, while the cross-correlations are kept unchanged. Using the reconstructed submatrices, both the forward only ISD (FO-ISD) and forward backward ISD (FB-ISD) methods are developed under the proposed scheme. Compared with the existing spatial smoothing techniques, the proposed scheme can use more data information of the sample covariance matrix and also suppress the effect of additive noise more effectively. Simulation results show that both FO-ISD and FB-ISD can improve the estimation performance largely as compared to the others, in white or colored noise conditions.
Highlights
Two-dimensional direction of arrival (2-D DOA) estimation of multiple signals with different array geometries is an important problem in many practical applications such as radars and wireless communications
The 2-D spatial smoothing methods were applied for DOA estimation [19] or joint DOA and direction of departure (DOD) estimation [20] with multi-input multi-output (MIMO) radar, where the transmission and reception diversity smoothing is derived by constructing a new covariance matrix with decorrelated signal subspace
The wavelength of transmitted signals is set as 1m and the estimation performance is examined over 500 Monte Carlo trials
Summary
Two-dimensional direction of arrival (2-D DOA) (i.e., elevation and azimuth angles) estimation of multiple signals with different array geometries is an important problem in many practical applications such as radars and wireless communications. Liu et al [26] developed a generalized covariance differencing algorithm by using the difference between the FB smoothing matrix and its complex conjugation. These methods [23,24,25,26] cannot be directly applied for 2-D DOA estimation. The classical spatial differencing methods only focus on the suppression of additive noise and few ones consider the information loss caused by the difference-operation. In this paper, we propose an improved spatial differencing (ISD) scheme for 2-D DOA estimation of coherent signals with URAs, where both the forward only ISD (FO-ISD) and forward backward ISD (FB-ISD) methods are developed.
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