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phased.SteeringVector System object

Package: phased

Sensor array steering vector

Description

The SteeringVector object calculates the steering vector for a sensor array.

To compute the steering vector of the array for specified directions:

  1. Define and set up your steering vector calculator. See Construction.

  2. Call step to compute the steering vector according to the properties of phased.SteeringVector. The behavior of step is specific to each object in the toolbox.

Construction

H = phased.SteeringVector creates a steering vector System object™, H. The object calculates the steering vector of the given sensor array for the specified directions.

H = phased.SteeringVector(Name,Value) creates a steering vector object, H, with each specified property Name set to the specified Value. You can specify additional name-value pair arguments in any order as (Name1,Value1,...,NameN,ValueN).

Properties

SensorArray

Handle to sensor array used to calculate steering vector

Specify the sensor array as a handle. The sensor array must be an array object in the phased package. The array can contain subarrays.

Default: phased.ULA with default property values

PropagationSpeed

Signal propagation speed

Specify the propagation speed of the signal, in meters per second, as a positive scalar.

Default: Speed of light

IncludeElementResponse

Include individual element response in the steering vector

If this property is true, the steering vector includes the individual element responses.

If this property is false, the computation of the steering vector assumes the elements are isotropic. The steering vector does not include the individual element responses. Furthermore, if the SensorArray property contains subarrays, the steering vector is the array factor among the subarrays. If SensorArray does not contain subarrays, the steering vector is the array factor among the array elements.

Default: false

EnablePolarization

Enable polarization simulation

Set to this property to true, to enable the steering vector to simulate polarization. Set this property to false to ignore polarization. This property applies only when the array specified in the SensorArray property is capable of simulating polarization and you have set the IncludeElementResponse property to true.

Default: false

Methods

cloneCreate steering vector object with same property values
getNumInputsNumber of expected inputs to step method
getNumOutputsNumber of outputs from step method
isLockedLocked status for input attributes and nontunable properties
releaseAllow property value and input characteristics changes
stepCalculate steering vector

Examples

expand all

Steering Vector for Uniform Linear Array

Calculate and display the steering vector for a 4-element uniform linear array in the direction of 30 degrees azimuth and 20 degrees elevation. Assume the array's operating frequency is 300 MHz.

hULA = phased.ULA('NumElements',4);
hsv = phased.SteeringVector('SensorArray',hULA);
Fc = 3e8;
ANG = [30; 20];
sv = step(hsv,Fc,ANG)
sv =

  -0.6011 - 0.7992i
   0.7394 - 0.6732i
   0.7394 + 0.6732i
  -0.6011 + 0.7992i

Beam Pattern With and Without Steering

Calculate the steering vector for a 4-element uniform linear array in the direction of 30 degrees azimuth and 20 degrees elevation. Assume the array's operating frequency is 300 MHz.

fc = 3e8;
ha = phased.ULA('NumElements',4);
hsv = phased.SteeringVector('SensorArray',ha);
sv = step(hsv,fc,[30; 20]);

Plot the beam patterns for the uniform linear array when no steering vector is applied (steered broadside) and when a steering vector is applied.

c = hsv.PropagationSpeed;
subplot(211)
plotResponse(ha,fc,c,'RespCut','Az');
title('Without steering');
subplot(212)
plotResponse(ha,fc,c,'RespCut','Az','Weights',sv);
title('With steering');

References

[1] Van Trees, H. Optimum Array Processing. New York: Wiley-Interscience, 2002.

See Also

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