An Improved Spatial Differencing Method for DOA Estimation With the Coexistence of Uncorrelated and Coherent Signals

An improved spatial differencing method for the direction of arrival estimation is proposed by constructing a spatial differencing matrix with neighboring subarrays under the coexistence of both uncorrelated and coherent signals, as well as the condition of uniform linear arrays. The color noise in the new matrix is suppressed with the property that the color noise is correlative, so the proposed method performs better in the spatial color noise environment. Then, the expression of the maximum detectable signals versus the number of sensors and subarrays is derived. Simulations show that the color noise is effectively suppressed, and the estimation accuracy is improved in the low signal noise ratio environment. The number of maximum detectable signals can be more than that of sensors, varying with the number of subarrays.