ringClutterRegion
Description
creates a ring-shaped clutter region
= ringClutterRegion(cluttergen
,minrad
,maxrad
,azimuth_span
,azimuth_center
)region
in the clutter generator object
cluttergen
. The region ranges from a minimum radius
minrad
to a maximum radius maxrad
and a span of
azimuth angles azimuth_span
centered on
azimuth_center
. Clutter regions are listed in the
Regions
of ClutterGenerator
object.
Examples
Create Clutter Object with Two Clutter Regions
Generate clutter from a surface having two clutter regions. Start by creating a radarDataGenerator
. Use a radar frequency of 1 GHz, a 100 meter range resolution, a 5 kHz pulse repetition frequency (PRF), and 128 pulses. The beam is symmetric with a 4 degree two-sided beamwidth in azimuth and elevation.
fc = 1e9; rangeRes = 100; prf = 5e3; numPulses = 128; beamwidth = 4;
Use the PRF and number of pulses to calculate the nominal Doppler and range-rate resolution. The radar will update once each coherent processing interval (CPI).
dopRes = prf/numPulses; lambda = freq2wavelen(fc); rangeRateRes = dop2speed(dopRes,lambda)/2; cpiTime = numPulses/prf; rdr = radarDataGenerator(1,'No scanning','UpdateRate',1/cpiTime, ... 'DetectionMode','Monostatic','TargetReportFormat','Detections', ... 'DetectionCoordinates','Scenario', ... 'HasINS',true,'HasElevation',true,'HasFalseAlarms',false, ... 'HasNoise',false,'HasRangeRate',true, ... 'HasRangeAmbiguities',true,'HasRangeRateAmbiguities',true, ... 'CenterFrequency',fc,'FieldOfView',beamwidth, ... 'AzimuthResolution',beamwidth,'ElevationResolution', ... beamwidth,'RangeResolution', ... rangeRes,'RangeRateResolution',rangeRateRes, ... 'ReferenceRange',20e3,'ReferenceRCS',0, ... 'DetectionProbability',0.9);
Create a scenario using the radarScenario
object, setting the update rate to zero so that the update interval is derived from sensors in the scene.
scenario = radarScenario('UpdateRate',0,'IsEarthCentered',false);
Now create the scenario surface. Choose a constant-gamma reflectivity model with a gamma value appropriate for flatland. This gamma value can be found using the surfacegamma
function. Using this value, create a surfaceReflectivityLand
object to add to a LandSurface
using the RadarReflectivity
property.
gammaDB = surfacegamma('Flatland'); refl = surfaceReflectivityLand('Model','ConstantGamma', ... 'Gamma',gammaDB); landSurface(scenario,'RadarReflectivity',refl);
Add two clutter regions to the scenario. Use the clutterGenerator
object function to construct a clutter generator and enable clutter generation for the radar. The Resolution
property defines the nominal spacing of clutter patches. Set this to be 1/5th of the range resolution to get multiple clutter patches per range gate. Set the range limit to 20 km. UseBeam
indicates if clutter generation should be performed automatically for the mainlobe of the antenna pattern.
cluttergen = clutterGenerator(scenario,rdr,'Resolution', ... rangeRes/5,'RangeLimit',20e3,'UseBeam',true); rgn1 = ringClutterRegion(cluttergen,1000,10000,30,45); rgn2 = ringClutterRegion(cluttergen,1000,10000,30,105);
The getClutterGenerator
function displays the two ring-shaped clutter regions belonging to the scenario.
getClutterGenerator(scenario,rdr)
ans = ClutterGenerator with properties: ScattererDistribution: "Uniform" Resolution: 20 Regions: [1x2 radar.scenario.RingClutterRegion] UseBeam: 1 UseShadowing: 1 RangeLimit: 20000 Radar: [1x1 radarDataGenerator] SeedSource: "Auto"
Input Arguments
cluttergen
— Clutter generator
clutter generator object
Clutter generator, specified as a ClutterGenerator
object. You can create a clutter generator using the
clutterGenerator
object function.
minrad
— Minimum radius of ring clutter region
scalar
Minimum radius of ring clutter region, specified as a scalar. Range is defined with respect the surface point directly below the radar. Units are in meters.
Data Types: double
maxrad
— Maximum radius of ring clutter region
scalar
Maximum radius of ring clutter region, specified as a scalar. Range is defined with respect the surface point directly below the radar. Units are in meters.
Data Types: double
azimuth_span
— Azimuth span of ring clutter region
scalar
Azimuth span of ring clutter region, specified as a scalar. Units are in degrees.
In flat-Earth scenarios, azimuth angles are defined with respect to the global x-y coordinates system, with azimuth angle increasing counter-clockwise from the +x axis. In curved-Earth scenarios, azimuth angle is measured clockwise from North.
Data Types: double
azimuth_center
— Azimuth center of ring clutter region
scalar
Azimuth center of ring clutter region, specified as a scalar. Units are in degrees.
In flat-Earth scenarios, azimuth angles are defined with respect to the global x-y coordinates system, with azimuth angle increasing counter-clockwise from the +x axis. In curved-Earth scenarios, azimuth angle is measured clockwise from North.
Data Types: double
Output Arguments
region
— Ring clutter region
RingClutterRegion
handle to function
Ring clutter region, returned as a RingClutterRegion
handle.
Data Types: double
Version History
Introduced in R2022a
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