getElementNormal

Normal vectors for array elements

Since R2021a

Syntax

normvec = getElementNormal(array)

normvec = getElementNormal(array,elemidx)

Description

normvec = getElementNormal(array) returns the normal vectors normvec to the array.

normvec = getElementNormal(array,elemidx) returns only the normals of the elements that are specified in the element index vector elemidx.

Examples

ULA Element Normals

Construct three ULAs with elements along the x-, y-, and z-axes. Obtain the element normals.

First, choose the array axis along the x-axis.

sULA1 = phased.ULA('NumElements',5,'ArrayAxis','x');
norm = getElementNormal(sULA1)

norm = 2×5

    90    90    90    90    90
     0     0     0     0     0

The element normal vectors point along the y-axis.

Next, choose the array axis along the y-axis.

sULA2 = phased.ULA('NumElements',5,'ArrayAxis','y');
norm = getElementNormal(sULA2)

norm = 2×5

     0     0     0     0     0
     0     0     0     0     0

The element normal vectors point along the x-axis.

Finally, set the array axis along the z-axis. Obtain the normal vectors of the odd-numbered elements.

sULA3 = phased.ULA('NumElements',5,'ArrayAxis','z');
norm = getElementNormal(sULA3,[1,3,5])

norm = 2×3

     0     0     0
     0     0     0

The element normal vectors also point along the x-axis.

Input Arguments

array — Phased array System object

System object™

Phased array, specified as a System object.

elemidx — Element index vector

all element indexes (default) | vector of positive integers

Element index vector, specified as a vector of positive integers each of which takes a value from 1 to N. The dimension N is the number of elements of the array.

Example: [1,2,3]

Output Arguments

normvec — Normal vector

2-by-M real-valued matrix

Normal vector of array elements, returned as a 2-by-M real matrix. Each column of normvec specifies the normal direction of the corresponding element in the local coordinate system in the form [azimuth;elevation]. If the input argument elemidx is not specified, M is the number of elements of the array, N. If elemidx is specified, M is the size of elemidx. You can determine element indices using the viewArray object function. The azimuth angle is defined as the angle from x-axis toward y axis. The elevation angle is defined as the angle from xy-plane toward z-axis. Units are in degrees.

For uniform linear arrays, the normal vector depends upon the value of the ArrayAxis property.

ArrayAxis Property Value	Array Normal Direction
'x'	azimuth = 90°, elevation = 0° (y-axis)
'y'	azimuth = 0°, elevation = 0° (x-axis)
'z'	azimuth = 0°, elevation = 0° (x-axis)

• For a conformal array, the origin of the local coordinate system, i.e., the phase center of the array, is defined at an arbitrary point. In local coordinate system, x, y, and z axes are three orthogonal axes with x axis defines the normal direction of the conformal array. The elements are located in the 3D space.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

Version History

Introduced in R2021a