Model radar gains and losses and assess performance in different environments

## Description

The Radar Designer app is an interactive tool that assists engineers and system analysts with high-level design and assessment of radar systems at the early stage of radar development. Using the app, you can:

• Assess and compare multiple radar designs in a single session

• Incorporate environmental effects due to Earth's curvature, atmosphere, terrain, and precipitation

• Add custom target radar cross-sections, antenna/array models, and both range-independent and range-dependent losses

• Export and save results, sessions, models, and plots to continue your analysis

## Open the Radar Designer App

• MATLAB® Toolstrip: On the Apps tab, under Signal Processing and Communications, click the app icon.

• MATLAB command prompt: Enter radarDesigner.

## Examples

expand all

Design a radar to install on top of a truck. Adjust the design parameters so the radar can work in foggy conditions and still make the objective range. Export the design session to the MATLAB Workspace.

Open Radar Designer. At the command line, type

Start a radar design session. On the toolstrip, click New Session and select the Automotive Radar option. The app specifies typical radar design, target, and environment parameters.

The radar you are designing must be set 3 meters above the ground. On the Radar tab, in the Antenna and Scanning section, change the Antenna Height from 1 meter to 3 meters.

On the Environment tab, in the Precipitation section, specify the Precipitation Type as Fog and set the Fog Density to Heavy.

As the SNR vs Range plot and Metrics and Requirements table show, the radar satisfies the threshold maximum range but falls short of the desired maximum range of 300 meters.

Increase the transmitted power to attain a higher maximum range. On the Radar tab, in the Main section, increase the Peak Power to 4e-05 kW. The plot and table show that the radar satisfies the requirement with the new power value.

Export the radar design to the MATLAB Workspace. On the toolstrip, click Export and select Generate Metrics Report to generate a formatted report of numeric metrics.

## Parameters

To enable the Radar parameters, click New Session on the app toolstrip to load one of the built-in Radar Designer Configurations. Use the Radars section of the app toolstrip to add, duplicate, or delete radar designs during a session.

• Use the Current Radar list to switch between different radar designs within a single session.

• Use the Name box to change the name of the currently selected radar.

Use these parameters to specify pulse and carrier settings, such as the carrier frequency and the transmitted power.

ParameterDescription
Carrier wave Frequency (default) or Wavelength

Carrier frequency or carrier wavelength, specified as a scalar.

• Specify Frequency as a scalar in Hz, kHz, MHz, or GHz.

• Specify Wavelength as a scalar in m, cm, or mm.

Pulse BandwidthBandwidth of the transmitted pulse, specified as a scalar in Hz, kHz, MHz, or GHz.
Average Power (default) or Peak Power

Average transmitted power or peak transmitted power, specified as a scalar.

• Specify Average Power as a scalar in W, kW, MW, dBw, or dBm.

• Specify Peak Power as a scalar in W, kW, MW, dBw, or dBm.

Pulse Width (default) or Duty Cycle

• Specify Pulse Width, the duration of the transmitted pulse, as a scalar in s, ms, or μs.

• Specify Duty Cycle, fraction of the time the radar is transmitting, as a dimensionless scalar from 0 to 1.

PRF (default) or PRI

Pulse repetition frequency (PRF) or pulse repetition interval (PRI), specified as a scalar.

• Specify PRF, the number of pulses transmitted per second, as a scalar in Hz, kHz, or MHz.

• Specify PRI, the time between two consecutive transmitted pulses, as a scalar in s, ms, or μs.

Use these parameters to specify noise settings, such as noise temperature or dynamic range.

ParameterDescription
Noise Temperature or Noise Figure

System noise temperature or noise figure, specified as a scalar.

• Specify Noise Temperature as a scalar in K.

• Specify Noise Figure as a scalar in dB or in linear units.

Reference Noise TemperatureReference noise temperature, specified as a scalar in K.
Quantization NoiseSelect Quantization Noise to include quantization noise.
Number of Bits

Number of bits in the analog-to-digital (A/D) converter, specified as a dimensionless scalar.

This parameter applies only if Quantization Noise is selected.

Dynamic Range

Dynamic range of the A/D converter, specified as a scalar in dB or in linear units.

This parameter applies only if Quantization Noise is selected.

Use these parameters to specify position, beamwidth, and gain settings, such as antenna height, antenna polarization, or azimuth beamwidth.

ParameterDescription
Antenna Height

Height of the antenna above the surface, specified as a scalar in m, km, ft, or kft.

This parameter applies to both the transmit antenna and the receive antenna.

Antenna Tilt Angle

Angle between the electric axis of the antenna and the ground plane, specified as a scalar in deg, rad, or mrad.

This parameter applies to both the transmit antenna and the receive antenna.

Antenna Polarization

Specify the antenna polarization as Horizontal or Vertical.

This parameter applies to both the transmit antenna and the receive antenna.

Specify the Transmit Antenna Gain Input as one of these:

• Manual — Use the Gain box to enter a custom value for the transmit antenna in dBi.

• From Beamwidth — Compute the transmit antenna gain from the beamwidths assuming an ideal Gaussian beam pattern with no sidelobes. You can set these parameters.

ParameterDescription
Azimuth BeamwidthAzimuth beamwidth of the transmit antenna, specified as a scalar in deg, rad, or mrad.
Elevation BeamwidthElevation beamwidth of the transmit antenna, specified as a scalar in deg, rad, or mrad.

Select Use Different Antenna for Receive to indicate that the receive and transmit antennas have different gains. If you use a different antenna for receive, you can specify the Receive Antenna Gain Input as one of these:

• Manual — Use the Gain box to enter a custom value for the receive antenna in dBi.

• From Beamwidth — Compute the receive antenna gain from the beamwidths assuming an ideal Gaussian beam pattern with no sidelobes. You can set these parameters.

ParameterDescription

Specify the scan mode for your design as one of these:

• None — The radar performs no scanning. Radar Designer does not incorporate scanning-related losses into the analysis.

• Mechanical — The radar performs mechanical scanning. Radar Designer incorporates beam shape loss and beam-dwell factor (range-dependent loss for rapidly scanning beam) into the analysis.

• Electronic — The radar uses a phased array to perform electronic scanning. Radar Designer incorporates beam shape loss and scan sector loss into the analysis.

If you specify Scan Mode as Mechanical or Electronic, you can set these parameters.

ParameterDescription
Azimuth Scan Sector SizeAzimuth span of the search volume, specified as a scalar in deg, rad, or mrad.
Elevation Scan LimitsInitial and final elevations of the scan volume, specified as two scalars in deg, rad, or mrad.

Based on the chosen parameters, Radar Designer computes and displays these settings:

• Max Scan Rate, the maximum scan rate in degrees per second given the selected PRF, the number of transmitted pulses, and the antenna beamwidth. This setting is displayed if Scan Mode is specified as Mechanical.

• Search Volume Size, the size of the solid angular search volume in steradians.

• Search Time, the time in seconds it takes to scan the search volume given the selected PRF, the number of transmitted pulses, and the antenna beamwidth.

Use these parameters to specify Pfa, CPI, and M-of-N settings, such as probability of false alarm or track confirmation logic threshold.

ParameterDescription
Probability of False Alarm

Desired probability of false alarm (Pfa) at the output of the detector, specified as a dimensionless scalar. The default value is 10–6 (1e-06).

Number of Pulses

Number of pulses within a coherent processing interval (CPI), specified as a positive integer scalar.

Pulse Integration

Pulse integration, specified as Coherent or Noncoherent.

Select Moving Target Indicator (MTI) to include moving target indicator processing in your design. If you enable moving target indicator processing, you can set these parameters.

ParameterDescription
Canceler

Canceler, specified as one of these:

• Two-pulse — First-order canceler

• Three-pulse — Second-order canceler

• Four-pulse — Third-order canceler

Null VelocityClutter velocity to which the MTI filter is adjusted, specified as a scalar in m/s, km/hr, mi/hr, or kts.
Method

Method to perform MTI processing, specified as one of these:

• SequentialRadar Designer processes pulses sequentially.

• BatchRadar Designer processes pulses in batches.

This option is available if Pulse Integration is set to Noncoherent.

Specify how to perform binary (M-of-N) pulse integration as one of these:

• NoneRadar Designer does not apply binary integration.

• AutomaticRadar Designer applies binary integration and computes the optimal number of detected pulses (M) out of the total number of pulses (N).

• CustomRadar Designer applies binary integration with a manually specified number of detected pulses. If you choose this option, specify the Number of Detected Pulses (M) out of the total number of pulses (N) as a positive integer.

This option is available if Pulse Integration is set to Noncoherent.

Select Constant False Alarm Rate (CFAR) to enable constant false alarm rate (CFAR) detection. If you enable CFAR detection, you can set these parameters.

ParameterDescription
Number of Reference CellsTotal number of CFAR reference (training) cells, specified as a positive integer scalar.
Method

CFAR detection method, specified as one of these:

• Cell AveragingRadar Designer sets the detection threshold by computing the average output of the surrounding range and Doppler cells.

• Greatest-of Cell AveragingRadar Designer sets the detection threshold by computing separate averages for leading and lagging cells and choosing the greatest value.

Specify the number of coherent processing intervals (CPIs) as a positive integer scalar.

Select M-of-N CPI Integration to enable M-of-N integration of coherent processing intervals (CPIs). If you enable M-of-N integration of CPIs, you can set this parameter.

ParameterDescription
Number of CPIs with DetectionNumber of coherent processing intervals with a declared detection (M) out of the total number of CPIs (N), specified as a dimensionless scalar.

Select Sensitivity Time Control to enable sensitivity time control in your design. If you enable sensitivity time control, you can set these parameters.

ParameterDescription
Cutoff RangeCutoff range beyond which the full receiver gain is used, specified as a scalar in m, km, nmi, ft, or kft. Default: 50 km.
ExponentExponent selected to maintain target detectability for ranges inside the cutoff range. Default: 3.5.

Use the Common Gate History Algorithm to compute track confirmation probabilities. You can set these parameters.

ParameterDescription
Confirmation ThresholdConfirmation threshold, specified as two positive integer scalars that represent an M-of-N or M/N confirmation logic. Default: 2/3.
Update Rate or Update Time

Update rate or update time:

• Specify Update Rate, the number of track updates per second, as a scalar in Hz.

• Specify Update Time, the time interval between two consecutive track updates, as a scalar in seconds.

Default: 1 Hz or 1 s.

Use these parameters to specify loss factors.

ParameterDescription
EclipsingEclipsing loss, specified as None (default), Range-Dependent Factor, or Statistical Loss.
Custom LossCustom loss, specified as a scalar in dB or linear units. Default: 4 dB.

To enable the Target parameters, add at least one radar to the app.

ParameterDescription
Radar Cross SectionRadar cross section, specified as a scalar in m2 or dBsm.
Swerling ModelSwerling model, specified as Swerling 0/5, Swerling 1, Swerling 2, Swerling 3, or Swerling 4.
Height or Elevation Angle

Height or elevation angle, specified as a scalar.

• Specify Height in m, km, nmi, ft, or kft.

Max AccelerationMaximum acceleration, specified as a scalar in m2 or in units of g.

Use the Environment tab to incorporate effects due to earth's curvature, atmosphere, terrain, and precipitation.

Specify atmosphere and surface characteristics to use seasonal latitude models, surface, and surface clutter settings.

By default. Radar Designer has the Free Space parameter selected. This option corresponds to propagation in a vacuum, and the only variable you can control is the Precipitation. To access other options, clear the box.

Specify the Earth Model as Curved or Flat. Using a curved Earth model gives access to more atmosphere models and enables you to control the Effective Earth Radius.

Specify the type of atmosphere through which the radar signal propagates as No Atmosphere, Uniform, Standard, Low Latitude, Mid Latitude, or High Latitude.

Specify No Atmosphere to use a constant index of refraction of 1. This model does not incorporate atmospheric gas loss or lens effect loss.

Specify Uniform for an atmosphere with uniform temperature, pressure, and water vapor density. This model can incorporate atmospheric gas loss but not lens effect loss. You can set these parameters.

ParameterDescription
Ambient TemperatureTemperature of uniform atmosphere, specified as a scalar in C or K. Default: 15 °C.
Dry Air PressureDry air pressure of uniform atmosphere, specified as a scalar in hPa, Pa, or mbar. Default: 1013 hPa.
Water Vapor DensityWater vapor density of uniform atmosphere, specified as a scalar in g/m3 or g/cm3. Default: 7.5 g/m3.
Include Atmospheric Gases LossSelect to incorporate the path loss due to atmosphere gaseous absorption.

Specify Standard to use the ITU Mean Annual Global Reference Atmosphere (MAGRA) recommended in ITU-R P.835-6 [1]. This option applies only if Earth Model is specified as Curved. You can set these parameters.

ParameterDescription
Water Vapor Density ProfileWater vapor density profile, specified as Automatic or Custom. Use this parameter to use the settings recommended in ITU-R P.835-6 or to use your own settings of water vapor density and scale height.
Surface Water Vapor Density

Surface water vapor density, specified as a scalar in g/m3 or g/cm3.

This parameter applies only if Water Vapor Density Profile is specified as Custom. The recommended value is 7.5 g/m3.

Scale Height

Scale height, specified as a scalar in m, km, nmi, ft, or kft.

This parameter applies only if Water Vapor Density Profile is specified as Custom. The recommended value is 2 km for typical atmospheric conditions and 6 km for dry atmospheric conditions.

Include Atmospheric Gases LossSelect to incorporate the path loss due to atmosphere gaseous absorption.
Include Lens Effect LossSelect to incorporate the lens effect loss due to the changing index of refraction in the atmosphere. This effect is significant only at small grazing angles.

Specify Low Latitude to use the ITU atmosphere model for latitudes less than 22° recommended in ITU-R P.835-6 [1]. This option applies only if Earth Model is specified as Curved. You can set these parameters.

ParameterDescription
Include Atmospheric Gases LossSelect to incorporate the path loss due to atmosphere gaseous absorption.
Include Lens Effect LossSelect to incorporate the lens effect loss due to the changing index of refraction in the atmosphere. This effect is significant only at small grazing angles.

Specify Mid Latitude to use the ITU atmosphere model for latitudes from 22° to 45° recommended in ITU-R P.835-6 [1]. This option applies only if Earth Model is specified as Curved. You can set these parameters.

ParameterDescription
SeasonSeason, specified as Summer or Winter.
Include Atmospheric Gases LossSelect to incorporate the path loss due to atmosphere gaseous absorption.
Include Lens Effect LossSelect to incorporate the lens effect loss due to the changing index of refraction in the atmosphere. This effect is significant only at small grazing angles.

Specify High Latitude to use the ITU atmosphere model for latitudes greater than 45° recommended in ITU-R P.835-6 [1]. This option applies only if Earth Model is specified as Curved. You can set these parameters.

ParameterDescription
SeasonSeason, specified as Summer or Winter.
Include Atmospheric Gases LossSelect to incorporate the path loss due to atmosphere gaseous absorption.
Include Lens Effect LossSelect to incorporate the lens effect loss due to the changing index of refraction in the atmosphere. This effect is significant only at small grazing angles.

Specify Effective Earth Radius as one of these:

• AutomaticRadar Designer computes the radius automatically based on the reference atmosphere.

No Atmosphere6371 km
Uniform6371 km
Standard8719 km
Low Latitude9540 km
Mid Latitude8262 km
High Latitude8308 km

• Custom — This option is recommended for high-altitude geometries. Specify the effective radius of the Earth as a scalar in m, km, nmi, ft, or kft. This parameter is often set to 4/3 of the Earth's actual radius.

Specify the type of surface on which the radar signal propagates as Featureless, Sea, Land, or Custom.

If you specify the Surface Type as Featureless, you can set the Propagation Factor parameter, which is available only if you set Earth Model to Curved. Propagation Factor is off by default.

If you specify the Surface Type as Sea, you can set these parameters.

ParameterDescription
Sea State Number

Sea state number, specified as one of these:

• 0 - Glassy (Default) — Calm, glassy sea surface. No waves.

• 1 - Ripples — Calm, rippled sea surface. Wave heights from 0 to 0.1 m.

• 2 - Smooth — Smooth sea surface. Wave heights from 0.1 m to 0.5 m.

• 3 - Slight — Slight waves. Wave heights from 0.5 m to 1.25 m.

• 4 - Moderate — Moderate waves. Wave heights from 1.25 m to 2.5 m.

• 5 - Rough — Rough waves. Wave heights from 2.5 m to 4 m.

• 6 - Very Rough — Very rough waves. Wave heights from 4 m to 6 m.

• 7 - High — High waves. Wave heights from 6 m to 9 m.

• 8 - Very High — Very high waves. Wave heights from 9 m to 14 m.

The radar propagation factor is the ratio of the magnitude of the actual magnetic field at a point in space to the magnitude of the magnetic field at the same point in free space.

This parameter is available only if you set Earth Model to Curved. The parameter is off by default.

Permittivity Model

Permittivity model, specified as one of these:

• Blake's Model (Default) — Blake's model is applicable in the frequency range from 100 MHz to 10 GHz.

• Sea Water — ITU seawater permittivity model. Uses a temperature of 20 °C and a salinity of 35 g/kg.

• Pure Water — ITU pure water permittivity model. Uses a temperature of 20 °C.

• Wet Ice — ITU wet ice permittivity model. Uses a liquid water fraction of 0.5.

• Dry Ice — ITU dry ice permittivity model. Uses a temperature of –10 °C

• Custom — Specify a frequency-independent custom sea surface permittivity.

This parameter applies only if Include Radar Propagation Factor is selected.

If you specify the Surface Type as Land, you can set these parameters.

Land Type

Land type, specified as one of these:

• SmoothVegetation Type set to None.

• Flatland (Default) — Vegetation Type set to Thin Grass.

• DesertVegetation Type set to Thin Grass.

• FarmVegetation Type set to Thin Grass.

• Rolling HillsVegetation Type set to Dense Brush.

• Wooded HillsVegetation Type set to Dense Trees.

• UrbanVegetation Type set to None.

• MetropolitanVegetation Type set to None.

• MountainsVegetation Type set to Dense Trees.

• Rugged MountainsVegetation Type set to Dense Trees.

The radar propagation factor is the ratio of the magnitude of the actual magnetic field at a point in space to the magnitude of the magnetic field at the same point in free space.

This parameter is available only if you set Earth Model to Curved. The parameter is off by default.

Vegetation Type

Vegetation type, specified as one of these:

• None

• Thin Grass

• Dense Weeds

• Dense Brush

• Dense Trees

This parameter applies only if Include Radar Propagation Factor is selected.

Permittivity Model

Permittivity model, specified as one of these:

• Sandy Loam (Default) — Uses a default temperature of 20 °C and a water content of 0.5. Specify the temperature as a scalar in C or K and the water content as a dimensionless scalar.

• Loam — Uses a default temperature of 20 °C and a water content of 0.5. Specify the temperature as a scalar in C or K and the water content as a dimensionless scalar.

• Silty Loam — Uses a default temperature of 20 °C and a water content of 0.5. Specify the temperature as a scalar in C or K and the water content as a dimensionless scalar.

• Silty Clay — Uses a temperature of 20 °C and a water content of 0.5. Specify the temperature as a scalar in C or K and the water content as a dimensionless scalar.

• Custom Soil — Uses a default temperature of 20 °C and a water content of 0.5, and specifies these additional parameters:

• Temperature — Specify the temperature as a scalar in C or K. Default: 20 °C.

• Sand Percentage — Specify the sand percentage as a dimensionless scalar from 0 to 100. Default: 51.52.

• Clay Percentage — Specify the clay percentage as a dimensionless scalar from 0 to 100. Default: 13.42.

• Specific Gravity — Specify the specific gravity as a dimensionless scalar. Default: 2.66.

• Bulk Density Model — Specify Automatic to use the value chosen by Radar Designer or Custom to use your own value.

• Bulk Density — Specify the bulk density as a scalar in g/m3 or g/cm3. Default: 1.601 g/cm3.

This parameter applies only if Bulk Density Model is specified as Custom.

• Vegetation — Uses a default temperature of 20 °C and a water content of 0.5. Specify the temperature as a scalar in C or K and the water content as a dimensionless scalar.

• Custom — Uses a default permittivity of (28.5 – j11.5) F/m. Specify the permittivity as a complex-valued scalar in F/m.

This parameter applies only if Include Radar Propagation Factor is selected.

If you specify the Surface Type as Custom, you can set these parameters.

ParameterDescription
Height Standard DeviationSurface height standard deviation, specified as a scalar in m, km, nmi, ft, or kft.

The radar propagation factor is the ratio of the magnitude of the actual magnetic field at a point in space to the magnitude of the magnetic field at the same point in free space.

This parameter is available only if you set Earth Model to Curved. The parameter is off by default.

Slope

Surface slope, specified as a scalar in deg, rad, or mrad. Default: 3.151°.

This parameter applies only if Include Radar Propagation Factor is selected.

PermittivitySurface permittivity, specified as a complex-valued scalar in F/m. Default: (28.5 – j11.5) F/m.

The properties of the Custom Surface Type have no dependence on frequency.

You can specify these clutter properties.

ParameterDescription
Gamma

Surface gamma (γ) parameter, specified as a scalar in dB or linear units.

The γ value for a system operating at a frequency f is

γ = γ0 + 5 log10(f/f0),

where γ0 is the value of γ at f0 = 10 GHz and is determined by measurement.

This parameter applies only if Surface Type is specified as Custom.

Clutter Velocity Specification

Clutter velocity, specified as one of these:

• AutomaticRadar Designer chooses values for the other parameters in this table.

• Custom — You can specify the other parameters in this table.

This parameter applies only if Surface Type is specified as Sea.

Polarization Dependence

Polarization dependence, specified as Dependent or Independent.

This parameter applies only if Surface Type is specified as Sea and Clutter Velocity Specification is specified as Custom, or if Surface Type is specified as Custom.

Clutter Velocity

Clutter velocity, specified as a scalar in m/s, km/hr, mi/hr, or kts.

This parameter applies only if Polarization Dependence is specified as Independent.

H-pol Clutter Velocity

Clutter velocity for horizontal polarization, specified as a scalar in m/s, km/hr, mi/hr, or kts.

This parameter applies only if Polarization Dependence is specified as Dependent.

V-pol Clutter Velocity

Clutter velocity for vertical polarization, specified as a scalar in m/s, km/hr, mi/hr, or kts.

This parameter applies only if Polarization Dependence is specified as Dependent.

Clutter Velocity Standard DeviationClutter velocity standard deviation (clutter velocity spread), specified as a scalar in m/s, km/hr, mi/hr, or kts.

Specify the Precipitation Type during the propagation of the radar signal as None, Rain, Snow, Fog, or Clouds to use rain, snow, fog, and cloud models with range settings.

If you specify the Precipitation Type as Rain, you can set these parameters.

ParameterDescription
Model

Rain model, specified as one of these:

• ITU — Compute the path loss due to rain using the model from ITU-R P.530-17.

• Crane — Compute the path loss due to rain using the Crane rain model.

Precipitation Start RangeStart range of the precipitation patch, specified as a scalar in m, km, nmi, ft, or kft.
Precipitation Range ExtentRange extent of the precipitation patch, specified as a positive scalar in m, km, nmi, ft, or kft.
Rain RateLong-term statistical rain rate, specified as a scalar in mm/hr.
Statistical PercentageStatistical Percentage, specified as a dimensionless scalar no smaller than 0.001 and no larger than 1. This parameter returns the attenuation for the specified percentage of time and applies only if Model is specified as ITU.

If you specify the Precipitation Type as Snow, you can set these parameters.

ParameterDescription
Precipitation Start RangeStart range of the precipitation patch, specified as a scalar in m, km, nmi, ft, or kft.
Precipitation Range ExtentRange extent of the precipitation patch, specified as a positive scalar in m, km, nmi, ft, or kft.
Snow Rate

Snow rate, specified as:

• Light — Light snow with an equivalent liquid water content of 0.5 mm/hr

• Moderate — Moderate snow with an equivalent liquid water content of 2 mm/hr

• Heavy — Heavy snow with an equivalent liquid water content of 3 mm/hr

• Custom — Your own equivalent liquid water content

Liquid Water ContentLiquid water content, specified as a scalar in mm/hr. This parameter applies only if Snow Rate is specified as Custom. A moderate snow rate is from 1 mm/hr to 2.5 mm/hr.

Radar Designer uses the Gunn-East model [3] to compute snow loss.

If you specify the Precipitation Type as Fog, you can set these parameters.

ParameterDescription
Precipitation Start RangeStart range of the precipitation patch, specified as a scalar in m, km, nmi, ft, or kft.
Precipitation Range ExtentRange extent of the precipitation patch, specified as a positive scalar in m, km, nmi, ft, or kft.
TemperatureFog ambient temperature, specified as a scalar in C or K.
Fog Density

Fog liquid water density, specified one of these:

• Moderate — Moderate fog with a liquid water density of 0.5 g/m3, corresponding to a visibility of about 300 m

• Heavy — Heavy fog with a liquid water density of 0.05 g/m3, corresponding to a visibility of about 50 m

• Custom — Your own liquid water density

Liquid Water DensityLiquid water density, specified as a scalar in g/m3 or g/cm3. This parameter applies only if Fog Density is specified as Custom.

Radar Designer uses the ITU fog/cloud model from ITU-R P.840-6. The model is not recommended for slant path propagation.

If you specify the Precipitation Type as Clouds, you can set these parameters.

ParameterDescription
Precipitation Start RangeStart range of the precipitation patch, specified as a scalar in m, km, nmi, ft, or kft.
Precipitation Range ExtentRange extent of the precipitation patch, specified as a positive scalar in m, km, nmi, ft, or kft.
Cloud Type

Type of clouds, specified as one of these:

• Cumulus (default) — Liquid water density of 1 g/m3 at an altitude of 3000 ft, with average heights in the range from 1000 ft to 5000 ft

• Stratus — Liquid water density of 0.29 g/m3 at an altitude of 1000 ft, with average heights in the range from 0 to 2000 ft

• Stratocumulus — Liquid water density of 0.15 g/m3 at an altitude of 2500 ft, with average heights in the range from 1000 ft to 4000 ft

• Altostratus — Liquid water density of 0.41 g/m3 at an altitude of 15,000 ft, with average heights in the range from 10,000 ft to 20,000 ft

• Nimbostratus — Liquid water density of 0.65 g/m3 at an altitude of 5000 ft, with average heights in the range from 0 to 10,000 ft

• Cirrus — Liquid water density of 0.06405 g/m3 at an altitude of 30,000 ft, with average heights in the range from 20,000 ft to 40,000 ft

• Custom — Liquid water density of 1 g/m3 and a temperature of 9 °C

Liquid Water DensityLiquid water density, specified as a scalar in g/m3 or g/cm3. This parameter applies only if Fog Density is specified as Custom.

Radar Designer uses the ITU fog/cloud model from ITU-R P.840-6. The model is not recommended for slant path propagation.

Performance Metrics

Specify the quantity for which to solve the radar equation and the quantity to keep fixed when solving.

• Probability of Detection — Compute probability of detection (Pd) and other metrics with a maximum range constraint. Specify the maximum range as a scalar in m, km, nmi, ft, or kft.

• Maximum Range — Compute maximum range and other metrics with a probability-of-detection (Pd) constraint. Specify the probability of detection as a scalar in decimal units.

The chosen constraint appears at the top of the table in the Metrics and Requirements tab.

Use the Metrics and Requirements tab to adjust and modify the metrics required for the tradeoff analysis to obtain the desired performance and satisfy your radar design requirements. The tab uses the same color coding as a Stoplight Chart and shows the metrics in the table.

To generate a formatted report of numeric metrics, click on the toolstrip and select Generate Metrics Report.

MetricDescription
Probability of Detection

Probability of detection, specified as a dimensionless scalar. This is the first entry in the table if you specify Metric as Probability of Detection.

Given the maximum range Rmax specified in Metric, the probability of detection is the value Pd such that

SNRav(Rmax) = Dx(Pd,Pfa,N,SW),

where SNRav is the Available Signal-to-Noise Ratio, Dx is the effective Detectability Factor, Pfa is the chosen probability of false alarm, N is the number of received pulses, and SW is the Swerling signal model.

Max Range

Maximum range, specified as a scalar in m, km, nmi, ft, or kft. This is the first entry in the table if you specify Metric as Maximum Range.

Given the desired probability of detection Pd specified in Metric, the radar maximum range is the value Rmax such that

SNRav(Rmax) = Dx(Pd,Pfa,N,SW),

where SNRav is the Available Signal-to-Noise Ratio, Dx is the effective Detectability Factor, Pfa is the chosen probability of false alarm, N is the number of received pulses, and SW is the Swerling signal model.

Min Detectable Signal

Minimum detectable signal, specified as a scalar in W, kW, MW, dBw, or dBm.

The minimum detectable signal is computed using

MDS = kTsBDx,

where k is Boltzmann's constant, Ts is the system noise temperature, B is the bandwidth, and Dx is the detectability factor.

Min Range

Minimum range, specified as a scalar in m, km, nmi, ft, or kft.

The minimum range is computed using

Rmin = cτ/2,

where c is the speed of light and τ is the pulse duration.

Unambiguous Range

Unambiguous range, specified as a scalar in m, km, nmi, ft, or kft.

The unambiguous range is computed using

Rua = c × PRI/2 = c/(2 × PRF),

where c is the speed of light, PRI is the pulse repetition interval, and PRF is the pulse repetition frequency.

Range Resolution

Range resolution, specified as a scalar in m or ft.

The range resolution is computed using

δR = c/(2 × B),

where c is the speed of light and B is the pulse bandwidth.

First Blind Speed

First blind speed, specified as a scalar in m/s.

The maximum unambiguous radial velocity (unambiguous Doppler) is computed using

Vrmax = λ × PRF/4,

where λ is the radar wavelength and PRF is the pulse repetition frequency.

Range Rate Resolution

Range rate resolution, specified as a scalar in m/s.

The range rate resolution is computed using

δVr = λ × PRF/(2N),

where λ is the radar wavelength, PRF is the pulse repetition frequency, and N is the number of received pulses.

Range Accuracy

Range accuracy, specified as a scalar in m or ft.

The range accuracy for a linear frequency modulated (LFM) pulse is computed using

${e}_{\text{r}}=\sqrt{\frac{3{c}^{2}}{8{\pi }^{2}×\text{SNR}×{B}^{2}}+{b}_{\text{r}}^{2}},$

where c is the speed of light, SNR is the available signal-to-noise ratio, B is the pulse bandwidth, and br2 is the range bias.

Azimuth Accuracy

The azimuth accuracy for an M-element uniform linear array (ULA) is computed using

${e}_{\theta }=\sqrt{\frac{6{\theta }_{\text{e}}^{2}}{4{\pi }^{2}×\text{SNR}×M{k}^{2}}+{b}_{\theta }^{2}},$

where θe is the azimuth beamwidth, SNR is the available signal-to-noise ratio, k is the beamwidth factor (k = 0.89 for a ULA), and bθ is the azimuth bias.

Elevation Accuracy

The elevation accuracy for an M-element uniform linear array (ULA) is computed using

${e}_{\theta }=\sqrt{\frac{6{\theta }_{\text{e}}^{2}}{4{\pi }^{2}×\text{SNR}×M{k}^{2}}+{b}_{\theta }^{2}},$

where θe is the elevation beamwidth, SNR is the available signal-to-noise ratio, k is the beamwidth factor (k = 0.89 for a ULA), and bθ is the elevation bias.

Range Rate Accuracy

Range rate accuracy, specified as a scalar in m/s.

The range rate accuracy for N pulses coherently processed during a coherent processing interval is computed using

${e}_{\text{rr}}=\sqrt{\frac{6×{\text{PRF}}^{2}×{\lambda }^{2}}{4{\pi }^{2}×\text{SNR}×4{N}^{3}}+{b}_{\text{rr}}^{2}},$

where PRF is the pulse repetition frequency, λ is the radar wavelength, SNR is the available signal-to-noise ratio, B is the pulse bandwidth, and brr is the range rate bias.

Probability of True Track

Probability of true track, specified as a dimensionless scalar.

The probability of true track is computed using the common gate history algorithm. For more details, see toccgh.

Probability of False Track

Probability of false track, specified as a dimensionless scalar.

The probability of false track is computed using the common gate history algorithm. For more details, see toccgh.

Effective isotropic radiated power, specified as a scalar in W, kW, MW, dBw, or dBm.

The effective radiated power is computed using

ERP = PtGtx,

where Pt is the peak transmitted power and Gtx is the transmitter antenna gain.

Power-Aperture Product

Power-aperture product, specified as a scalar in W·m2, kW·m2, or MW·m2.

Visualization

For every radar design session, Radar Designer displays the Available Signal-to-Noise Ratio (SNR) at the receiver input as a function of the target range. The plot shows the maximum range requirements and a Stoplight Chart based on the detectability factor (required SNR) values.

To generate a script to recreate the signal-to-noise ratio plot for the currently selected radar, click on the toolstrip and select Export SNR vs Range MATLAB Script.

For every radar design session, Radar Designer displays a Scenario Geometry tab that shows this information:

• Environment (curved Earth, flat Earth, free space)

• Target height and position at various ranges (constant elevation or constant height)

• Radar antenna pattern demonstrating the applied tilt angle

This plot shows the scenario geometry plot for one weather radar with the default settings on a curved Earth. For more information, see Radar Designer Configurations.

Specify the plots to use to visualize and analyze your radar design.

• — View clutter-to-noise ratio versus range for all designs

To visualize the clutter-to-noise ratio (CNR) as a function of range for your radar designs, click on the toolstrip.

Radar Designer displays the CNR in dB and shows the horizon range.

• — Inspect gains and losses of the currently selected radar

To visualize the gains and losses for your radar designs, click on the toolstrip.

Radar Designer models several components of the radar signal processing chain that affect the resulting Detectability Factor. The app displays a waterfall chart that shows the individual losses and gains that contribute to increasing the required signal energy.

• The losses, represented in red, increase the required SNR threshold.

• The gains, represented in green, decrease the required SNR threshold.

Scan the plot left to right to see how the detectability factor changes as these components are added:

• Integration gain

• Fluctuation loss

• Binary integration loss

• CFAR loss

• Eclipsing loss

• MTI loss

• Beam shape loss

• Scan sector loss

• — View environmental losses for the currently selected radar

To visualize the range-dependent loss components for your radar designs in their operation environments, click on the toolstrip.

Radar Designer displays four range-dependent loss components that correspond to different atmospheric and propagation effects:

• Precipitation loss

• Atmospheric gas loss

• Lens-effect loss

This plot shows the environmental losses plot for one airport radar with the default settings using a high-latitude atmosphere model. For more information, see Radar Designer Configurations.

• — Show probability of detection (Pd) versus range for all designs

To visualize the probability of detection as a function of range for your radar designs, click on the toolstrip.

Radar Designer displays the probability of detection at the output of the receiver (effective Pd) as a function of the target range. The plot shows the maximum range requirements and a Stoplight Chart based on the desired Pd values.

This plot shows the probability of detection versus range plot for one tracking radar with the default settings. For more information, see Radar Designer Configurations.

• — Explore range/Doppler space for the currently selected radar

To visualize the ambiguity-free range/Doppler coverage regions for your radar designs, click on the toolstrip.

Radar Designer displays a log-log plot of first blind speed as a function of unambiguous range (lower x-axis) and PRF (upper x-axis). Each solid line on the plot represents a radar design. Designs with different carrier frequencies appear as parallel lines.

• — Plot Blake chart for the currently selected radar

To visualize the range-height-angle relationships for your radar designs, click on the toolstrip.

Radar Designer displays a vertical coverage diagram of the selected radar. Vertical coverage diagrams, also known as range-height-angle charts or Blake charts, show the relationship between the range to a target, the height of the target, and the initial elevation angle of the transmitted rays for the sensor.

To generate a script to recreate the vertical coverage plot for the currently selected radar, click on the toolstrip and select Export Vertical Coverage MATLAB Script.

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## Tips

• Use Ctrl+Z to undo a modification. Use Ctrl+Y to redo an undone modification.

## References

[1] Recommendation ITU-R P.835-6 (12/2017). "Reference Standard Atmospheres." Geneva: International Telecommunication Union, 2017, https://www.itu.int/dms_pubrec/itu-r/rec/p/R-REC-P.835-6-201712-I!!PDF-E.pdf.

[2] Barton, David K. Radar Equations for Modern Radar. Norwood, MA: Artech House, 2013.

[3] Gunn, K. L. S., and T. W. R. East. “The Microwave Properties of Precipitation Particles.” Quarterly Journal of the Royal Meteorological Society 80, no. 346 (October 1954): 522–45. https://doi.org/10.1002/qj.49708034603.

[4] O'Donnell, R. M. "Radar Systems Engineering." IEEE AES Society, IEEE New Hampshire Section, Radar Systems Course, January 2010.

[5] Ward, J. "Space-Time Adaptive Processing for Airborne Radar." TR-1015, MIT Lincoln Laboratory, December 1994. https://apps.dtic.mil/dtic/tr/fulltext/u2/a293032.pdf

[6] Wasson, Charles S. System Engineering Analysis, Design, and Development: Concepts, Principles, and Practices. Second edition. Wiley Series in Systems Engineering and Management. Hoboken, New Jersey: John Wiley & Sons Inc, 2016.

## Version History

Introduced in R2021a