Beamscan spatial spectrum estimator for ULA
Phased Array System Toolbox / Direction of Arrival
The ULA Beamscan Spectrum block estimates the spatial spectrum of incoming narrowband signals by scanning a region of broadside angles using a narrowband conventional beamformer applied to a uniform linear array. The block optionally calculates the direction of arrival of a specified number of signals by estimating peaks of the spectrum.
Port 1— Received signal
Received signal, specified as an M-by-N complex-valued matrix. The quantity M is the number of sample values (snapshots) contained in the signal and N is the number of sensor elements in the array.
The size of the first dimension of the input matrix can vary to simulate a changing signal length. A size change can occur, for example, in the case of a pulse waveform with variable pulse repetition frequency.
Complex Number Support: Yes
Y— Beamscan spatial spectrum
Beamscan spatial spectrum, returned as a non-negative, real-valued column vector representing the magnitude of the estimated beamscan spatial spectrum. Each entry corresponds to an angle specified by the Scan angles (deg) parameter.
Ang— Directions of arrival
Directions of arrival of the signals, returned as a real-valued row vector. The
direction of arrival angle is the broadside angle between the source direction and the
array axis. Angle units are in degrees. The length of the vector is the number of
signals specified by the Number of signals parameter. If the
object cannot identify peaks in the spectrum, it will return
To enable this output port, select the Enable DOA output check box.
Spatial smoothing— Enable spatial smoothing
0(default) | non-negative integer
Specify the amount of averaging used by spatial smoothing to estimate the covariance matrix as a nonnegative integer. Each increase in smoothing handles one extra coherent source, but reduces the effective number of elements by one. The maximum value of this parameter is N – 2, where N is the number of sensors in the ULA.
Scan angles (deg)— Search angles for spectrum peaks
-90:90(default) | real-valued row vector
Specify the scan angles in degrees as a real-valued row vector. The angles are array broadside angles and must lie between –90° and 90°, inclusive. You must specify the angles in increasing order.