Beamscan spatial spectrum estimator
Phased Array System Toolbox / Direction of Arrival
The Beamscan Spectrum block estimates the 2-D spatial spectrum of incoming narrowband signals by scanning a range of azimuth and elevation angles using a narrowband conventional beamformer. The block optionally calculates the direction of arrival of a specified number of signals by locating peaks of the spectrum.
X— Received signal
Received signal, specified as an M-by-N complex-valued matrix. The quantity M is the length of the signal, the number of sample values contained in the signal. The quantity 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.
Y— Beamscan 2-D spatial spectrum
2Magnitude of the estimated 2-D spatial spectrum, returned as a non-negative, returned as a real-valued P-by-Q matrix. Each entry represents the magnitude of the estimated MUSIC spatial spectrum. Each entry corresponds to an angle specified by the Azimuth scan angles (deg) and Elevation scan angles (deg) parameters. P equals the length of the vector specified in Azimuth scan angles (deg) and Q equals the length of the vector specified in Elevation scan angles (deg).
Ang— Directions of arrival
Directions of arrival of the signals, returned as a real-valued
2-by-L matrix. L is the number of signals
specified by the Number of signals parameter. The direction of
arrival angle is defined by the azimuth and elevation angles of the source with
respect to the array local coordinate system. The first row of the matrix contains the
azimuth angles and the second row contains the elevation angles. If the object cannot
identify peaks in the spectrum, it will return
NaN. Angle units are
To enable this output port, select the Enable DOA output check box.
Azimuth scan angles (deg)— Scan angles in azimuth direction
-180:180(default) | real-valued vector
Scan angles in azimuthal direction, specified as a real-valued vector. The angles must lie be between –180° and 180°, inclusive. You must specify the angles in ascending order. Units are in degrees.
Elevation scan angles (deg)— Scan angles in elevation direction
-90:90(default) | real-valued vector
Scan angles in elevation direction, specified as a real-valued vector. The angles must lie be between –90° and 90°, inclusive. You must specify the angles in ascending order. Units are in degrees.