System object: phased.BeamscanEstimator2D
Perform 2-D spatial spectrum estimation
Y = step(H,X)
[Y,ANG] = step(H,X)
Starting in R2016b, instead of using the
Y = step(H,X) estimates the spatial spectrum
X using the estimator
a matrix whose columns correspond to channels.
a matrix representing the magnitude of the estimated 2-D spatial spectrum.
a row dimension equal to the number of elevation angles specified
ElevationScanAngles and a column dimension
equal to the number of azimuth angles specified in
[Y,ANG] = step(H,X) returns additional
ANG as the signal's direction of
arrival (DOA) when the
ANG is a two row matrix
where the first row represents the estimated azimuth and the second
row represents the estimated elevation (in degrees).
The size of the first dimension of this input matrix can vary to simulate a changing signal length, such as a pulse waveform with variable pulse repetition frequency.
The object performs an initialization the first time the
Estimate the DOAs of two sinusoidal signals received by a 50-element URA with a rectangular lattice. The antenna operating frequency is 150 MHz. The actual direction of the first signal is -37° in azimuth and 0° in elevation. The direction of the second signal is 17° in azimuth and 20° in elevation.
Create the signals and solve for the DOA's.
fs = 8000; t = (0:1/fs:1).'; x1 = cos(2*pi*t*300); x2 = cos(2*pi*t*400); array = phased.URA('Size',[5 10],'ElementSpacing',[1 0.6]); array.Element.FrequencyRange = [100e6 300e6]; fc = 150e6; x = collectPlaneWave(array,[x1 x2],[-37 0; 17 20]',fc); noise = 0.1*(randn(size(x)) + 1i*randn(size(x))); estimator = phased.BeamscanEstimator2D('SensorArray',array, ... 'OperatingFrequency',fc, ... 'DOAOutputPort',true,'NumSignals',2, ... 'AzimuthScanAngles',-50:50, ... 'ElevationScanAngles',-30:30); [~,doas] = estimator(x + noise)
doas = -37 17 0 20
Plot the spatial spectrum.