getElementNormal

System object: phased.URA
Package: phased

Normal vector to array elements

Syntax

normvec = getElementNormal(sURA)
normvec = getElementNormal(sURA,elemidx)

Description

normvec = getElementNormal(sURA) returns the normal vectors of the array elements of the phased.URA System object™, sURA. The output argument normvec is a 2-by-N matrix, where N is the number of elements in array, sURA. Each column of normvec defines the normal direction of an element in the local coordinate system in the form[az;el]. Units are degrees. Array elements are located in the plane selected in the ArrayNormal property. Element normal vectors are parallel to the array normal. The normal to a URA array depends upon the selected ArrayNormal property.

ArrayNormal Property ValueArray Normal DirectionArray Plane
'x'azimuth = 0°, elevation = 0° (x-axis)yz
'y'azimuth = 90°, elevation = 0° (y-axis)zx
'z'azimuth = 0°, elevation = 90° (z-axis)xy

The origin of the local coordinate system is defined by the phase center of the array.

normvec = getElementNormal(sURA,elemidx) returns only the normal vectors of the elements specified in the element index vector, elemidx. This syntax can use any of the input arguments in the previous syntax.

Input Arguments

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Uniform line array, specified as a phased.URA System object.

Example: sULA = phased.URA

Element indices , specified as a 1-by-M or M-by-1 vector. Index values lie in the range 1 to N where N is the number of elements of the array. When elemidx is specified, getElementNormal returns the normal vectors of the elements contained in elemidx.

Example: [1,5,4]

Output Arguments

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Element normal vectors, specified as a 2-by-P real-valued vector. Each column of normvec takes the form [az,el]. When elemidx is not specified, P equals the array dimension. When elemidx is specified, P equals the length of elemidx, M. You can determine element indices using the phased.URA.viewArray method.

Examples

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Construct three 2-by-2 URA's with element normals along the x-, y-, and z-axes. Obtain the element positions and normal directions.

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

sURA1 = phased.URA('Size',[2,2],'ArrayNormal','x');
pos = getElementPosition(sURA1)
pos = 3×4

         0         0         0         0
   -0.2500   -0.2500    0.2500    0.2500
    0.2500   -0.2500    0.2500   -0.2500

normvec = getElementNormal(sURA1)
normvec = 2×4

     0     0     0     0
     0     0     0     0

All elements lie in the yz-plane and the element normal vectors point along the x-axis (0°,0°).

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

sURA2 = phased.URA('Size',[2,2],'ArrayNormal','y');
pos = getElementPosition(sURA2)
pos = 3×4

   -0.2500   -0.2500    0.2500    0.2500
         0         0         0         0
    0.2500   -0.2500    0.2500   -0.2500

normvec = getElementNormal(sURA2)
normvec = 2×4

    90    90    90    90
     0     0     0     0

All elements lie in the zx-plane and the element normal vectors point along the y-axis (90°,0°).

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

sURA3 = phased.URA('Size',[2,2],'ArrayNormal','z');
pos = getElementPosition(sURA3)
pos = 3×4

   -0.2500   -0.2500    0.2500    0.2500
    0.2500   -0.2500    0.2500   -0.2500
         0         0         0         0

normvec = getElementNormal(sURA3,[1,3])
normvec = 2×2

     0     0
    90    90

All elements lie in the xy-plane and the element normal vectors point along the z-axis (0°,90°).

Introduced in R2016a