value

Radar cross-section at specified angle and frequency

Syntax

rcsval = value(rcssig,az,el,freq)

Description

rcsval = value(rcssig,az,el,freq) returns the value, rcsval, of the radar cross-section (RCS) specified by the radar signature object, rcssig, computed at the specified azimuth az, elevation el, and frequency freq. If the specified azimuth and elevation is outside of the region in which the RCS signature is defined, the RCS value, rcsval, is returned as -Inf in dBsm.

Input Arguments

rcssig — RCS signature object

rcsSignature object

Radar cross-section signature, specified as an rcsSignature object.

az — Azimuth angle

scalar | length-M real-valued vector

Azimuth angle, specified as scalar or length-M real-valued vector. Units are in degrees. The az, el, and freq arguments must have the same size. You can, however, specify one or two arguments as scalars, in which case the arguments are expanded to length-M.

Data Types: double

el — Elevation angle

scalar | length-M real-valued vector

Elevation angle, specified as scalar or length-M real-valued vector. The az, el, and freq arguments must have the same size. You can, however, specify one or two arguments as scalars, in which case the arguments are expanded to length-M. Units are in degrees.

Data Types: double

freq — RCS frequency

positive scalar | length-M vector with positive, real elements

RCS frequency, specified as a positive scalar or length-M vector with positive, real elements. The az, el, and freq arguments must have the same size. You can, however, specify one or two arguments as scalars, in which case the arguments are expanded to length-M vectors. Units are in Hertz.

Example: 100e6

Data Types: double

Output Arguments

rcsval — Radar cross-section

scalar | real-valued length-M vector

Radar cross-section, returned as a scalar or real-valued length-M vector. Units are in dBsm.

Examples

Radar Cross-Section of Ellipsoid

Specify the radar cross-section (RCS) of a triaxial ellipsoid and plot RCS values along an azimuth cut.

Specify the lengths of the axes of the ellipsoid. Units are in meters.

a = 0.15;
b = 0.20;
c = 0.95;

Create an RCS array. Specify the range of azimuth and elevation angles over which RCS is defined. Then, use an analytical model to compute the radar cross-section of the ellipsoid. Create an image of the RCS.

az = [-180:1:180];
el = [-90:1:90];
rcs = rcs_ellipsoid(a,b,c,az,el);
rcsdb = 10*log10(rcs);
imagesc(az,el,rcsdb)
title('Radar Cross-Section')
xlabel('Azimuth (deg)')
ylabel('Elevation (deg)')
colorbar

Create an rcsSignature object and plot an elevation cut at $$30^{\circ }$$ azimuth.

rcssig = rcsSignature('Pattern',rcsdb,'Azimuth',az,'Elevation',el,'Frequency',[300e6 300e6]);
rcsdb1 = value(rcssig,30,el,300e6);
plot(el,rcsdb1)
grid
title('Elevation Profile of Radar Cross-Section')
xlabel('Elevation (deg)')
ylabel('RCS (dBsm)')

function rcs = rcs_ellipsoid(a,b,c,az,el)
sinaz = sind(az);
cosaz = cosd(az);
sintheta = sind(90 - el);
costheta = cosd(90 - el);
denom = (a^2*(sintheta'.^2)*cosaz.^2 + b^2*(sintheta'.^2)*sinaz.^2 + c^2*(costheta'.^2)*ones(size(cosaz))).^2;
rcs = (pi*a^2*b^2*c^2)./denom;
end

Extended Capabilities

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

Introduced in R2021a

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