A Two-Dimensional DOA Estimation Method Based on Virtual Extension of Sparse Array

Table 1

The explanation of variables and notations.

Variable	Meaning	Variable	Meaning
	The coprime subarray distributed in the z-axis		The virtual subarrays distributed in the z-axis
	The coprime subarray distributed in the y-axis		The virtual subarrays distributed in the y-axis
	The received signal of the y-axis real subarray		The received signal of the z-axis real subarray
	The received signal of the y-axis virtual subarray		The received signal of the z-axis virtual subarray
	The whole array received signal of the y-axis subarray		The whole array received signal of the y-axis subarray
	The y-axis real subarray steering vector		The z-axis real subarray steering vector
	The whole array steering vector of the y-axis subarray		The whole array steering vector of the z-axis subarray
	The real y-axis subarray noise		The noise of the z-axis subarray
	The whole array noises of the y-axis subarray		The whole array noises of the z-axis subarray
	The covariance matrix of the whole received data of the y-axis subarray		The covariance matrix of the whole received data of the y-axis subarray
	The vectorized data covariance matrix of the y-axis subarray		The vectorized data covariance matrix of the y-axis subarray
	The equivalent received data under the z-axis augmented array		The equivalent received data under the z-axis augmented array
	The Kronecker product operation of two y-axis steering vectors		The Kronecker product operation of two z-axis steering vectors
	The y-axis steering vectors of the uniform augmented array		The z-axis steering vectors of the uniform augmented array
	The overcomplete azimuth angle sparse dictionary		The overcomplete elevation angle sparse dictionary
	The variance of the potential azimuth angle signals		The variance of the potential azimuth angle signals
	The estimated elevation angle		The estimated azimuth angle