File-based radar target. More...

#include "target.h"

Inheritance diagram for radar::FileTarget:

Collaboration diagram for radar::FileTarget:

Public Member Functions
	FileTarget (Platform *platform, std::string name, const std::string &filename, unsigned seed)
	Constructs a file-based radar target.

RealType	getRcs (math::SVec3 &inAngle, math::SVec3 &outAngle, RealType time) const override
	Gets the RCS value from file-based data for a specific bistatic geometry and time.

const std::string &	getFilename () const noexcept
	Gets the filename associated with this target's RCS data.

std::mt19937 &	getRngEngine () noexcept
	Gets the target's internal random number generator engine.

void	setFluctuationModel (std::unique_ptr< RcsModel > in)
	Sets the RCS fluctuation model.

const RcsModel *	getFluctuationModel () const
	Gets the RCS fluctuation model.

math::Vec3	getPosition (const RealType time) const
	Retrieves the position of the object.

math::SVec3	getRotation (const RealType time) const
	Retrieves the rotation of the object.

Platform *	getPlatform () const noexcept
	Retrieves the associated platform of the object.

const std::string &	getName () const noexcept
	Retrieves the name of the object.

Protected Attributes
std::unique_ptr< RcsModel >	_model {nullptr}
	The RCS fluctuation model for the target.

std::mt19937	_rng
	Per-object random number generator for statistical independence.

Detailed Description

File-based radar target.

Definition at line 209 of file target.h.

Constructor & Destructor Documentation

◆ FileTarget()

radar::FileTarget::FileTarget	(	Platform *	platform,
		std::string	name,
		const std::string &	filename,
		unsigned	seed
	)

Constructs a file-based radar target.

Parameters

platform	Pointer to the platform associated with the target.
name	The name of the target.
filename	The name of the file containing RCS data.
seed	The seed for the target's internal random number generator.

Exceptions

std::runtime_error If the file cannot be loaded or parsed.

Definition at line 59 of file target.cpp.

                                                                                                             :
        Target(platform, std::move(name), seed), _azi_samples(std::make_unique_for_overwrite<interp::InterpSet>()),
        _elev_samples(std::make_unique_for_overwrite<interp::InterpSet>()), _filename(filename)
    {
        XmlDocument doc;
        if (!doc.loadFile(filename))
        {
            throw std::runtime_error("Could not load target description from " + filename);
        }
 
        const XmlElement root(doc.getRootElement());
 
        loadTargetGainAxis(_elev_samples.get(), root.childElement("elevation", 0));
        loadTargetGainAxis(_azi_samples.get(), root.childElement("azimuth", 0));
    }

References XmlElement::childElement(), XmlDocument::getRootElement(), and XmlDocument::loadFile().

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Member Function Documentation

◆ getFilename()

const std::string & radar::FileTarget::getFilename ( ) const

noexcept

Gets the filename associated with this target's RCS data.

Returns: The source filename.

Definition at line 248 of file target.h.

248{ return _filename; }

◆ getFluctuationModel()

const RcsModel * radar::Target::getFluctuationModel ( ) const

inherited

Gets the RCS fluctuation model.

Returns: A const pointer to the RcsModel.

Definition at line 159 of file target.h.

159{ return _model.get(); }

radar::Target::_model

std::unique_ptr< RcsModel > _model

The RCS fluctuation model for the target.

Definition target.h:162

References radar::Target::_model.

Referenced by radar::to_json().

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◆ getName()

const std::string & radar::Object::getName ( ) const

noexceptinherited

Retrieves the name of the object.

Returns: A const reference to the string representing the object's name.

Definition at line 68 of file object.h.

68{ return _name; }

Referenced by simulation::calculatePreviewLinks(), simulation::calculateResponse(), processing::finalizeCwReceiver(), serial::Response::getTransmitterName(), processing::runPulsedFinalizer(), radar::Receiver::setNoiseTemperature(), radar::to_json(), radar::to_json(), and radar::to_json().

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◆ getPlatform()

Platform * radar::Object::getPlatform ( ) const

noexceptinherited

Retrieves the associated platform of the object.

Returns: A pointer to the Platform object associated with this object.

Definition at line 61 of file object.h.

61{ return _platform; }

Referenced by simulation::calculateDirectPathContribution(), simulation::calculateReflectedPathContribution(), and simulation::calculateResponse().

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◆ getPosition()

math::Vec3 radar::Object::getPosition ( const RealType time ) const

inherited

Retrieves the position of the object.

Parameters

time	The time at which to get the position of the object.

Returns: A math::Vec3 representing the position of the object.

Definition at line 46 of file object.h.

46{ return _platform->getPosition(time); }

radar::Platform::getPosition

math::Vec3 getPosition(const RealType time) const

Gets the position of the platform at a specific time.

Definition platform.h:74

References radar::Platform::getPosition().

Referenced by simulation::calculatePreviewLinks(), simulation::solveRe(), and simulation::solveReDirect().

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◆ getRcs()

RealType radar::FileTarget::getRcs	(	math::SVec3 &	inAngle,
		math::SVec3 &	outAngle,
		RealType	time
	)		const

overridevirtual

Gets the RCS value from file-based data for a specific bistatic geometry and time.

Parameters

inAngle	The incoming angle of the radar wave in the global frame.
outAngle	The outgoing angle of the reflected radar wave in the global frame.
time	The simulation time at which the interaction occurs.

Returns: The Radar Cross Section (RCS) value in meters squared (m²).

Exceptions

std::runtime_error If RCS data cannot be retrieved.

This function calculates the target's aspect-dependent RCS. The key steps are:

Calculate the bistatic angle bisector in the global simulation coordinate system.
Retrieve the target's own orientation (rotation) at the specified 'time'.
Transform the global bistatic angle into the target's local, body-fixed frame by subtracting the target's rotation. This is critical, as RCS patterns are defined relative to the target itself.
Use this local aspect angle to look up the azimuthal and elevation RCS values from the loaded data.

NOTE: This function returns the raw RCS value (σ), which is linearly proportional to scattered power. The calling physics engine is responsible for converting this to a signal amplitude by taking the square root.

Implements radar::Target.

Definition at line 75 of file target.cpp.

    {
        // TODO: the handling of arbitrary rcs models needs to be validated and expanded to cover edge cases.
        // 1. Calculate the bistatic angle bisector in the GLOBAL frame.
        const SVec3 global_bisector_angle = inAngle + outAngle;
 
        // 2. Get the target's own rotation at the current time.
        const SVec3 target_rotation = getRotation(time);
 
        // 3. Transform the global angle into the target's LOCAL frame for lookup.
        const SVec3 local_aspect_angle = global_bisector_angle - target_rotation;
 
        // 4. Use the local aspect angle (bisector is halved) to look up RCS.
        const auto azi_value = _azi_samples->getValueAt(local_aspect_angle.azimuth / 2.0);
 
        if (const auto elev_value = _elev_samples->getValueAt(local_aspect_angle.elevation / 2.0);
            azi_value && elev_value)
        {
            // Return the raw RCS value (proportional to power), not its square root.
            const RealType rcs = *azi_value * *elev_value;
            return _model ? rcs * _model->sampleModel() : rcs;
        }
 
        LOG(logging::Level::FATAL, "Could not get RCS value for target");
        throw std::runtime_error("Could not get RCS value for target");
    }

References radar::Target::_model, math::SVec3::azimuth, math::SVec3::elevation, logging::FATAL, radar::Object::getRotation(), and LOG.

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◆ getRngEngine()

std::mt19937 & radar::Target::getRngEngine ( )

noexceptinherited

Gets the target's internal random number generator engine.

Returns: A mutable reference to the RNG engine.

Definition at line 145 of file target.h.

145{ return _rng; }

radar::Target::_rng

std::mt19937 _rng

Per-object random number generator for statistical independence.

Definition target.h:163

References radar::Target::_rng.

◆ getRotation()

math::SVec3 radar::Object::getRotation ( const RealType time ) const

inherited

Retrieves the rotation of the object.

Parameters

time	The time at which to get the rotation of the object.

Returns: A math::SVec3 representing the rotation of the object.

Definition at line 54 of file object.h.

54{ return _platform->getRotation(time); }

radar::Platform::getRotation

math::SVec3 getRotation(const RealType time) const

Gets the rotation of the platform at a specific time.

Definition platform.h:82

References radar::Platform::getRotation().

Referenced by getRcs(), and processing::runPulsedFinalizer().

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◆ setFluctuationModel()

void radar::Target::setFluctuationModel ( std::unique_ptr< RcsModel > in )

inherited

Sets the RCS fluctuation model.

Assigns a new RCS fluctuation model to the target.

Parameters

in	Unique pointer to the new RCS fluctuation model.

Definition at line 153 of file target.h.

153{ _model = std::move(in); }

References radar::Target::_model.

Member Data Documentation

◆ _model

std::unique_ptr<RcsModel> radar::Target::_model {nullptr}

protectedinherited

The RCS fluctuation model for the target.

Definition at line 162 of file target.h.

162{nullptr}; ///< The RCS fluctuation model for the target.

Referenced by radar::Target::getFluctuationModel(), getRcs(), and radar::Target::setFluctuationModel().

◆ _rng

std::mt19937 radar::Target::_rng

protectedinherited

Per-object random number generator for statistical independence.

Definition at line 163 of file target.h.

Referenced by radar::Target::getRngEngine().

The documentation for this class was generated from the following files:

packages/libfers/src/radar/target.h
packages/libfers/src/radar/target.cpp

Public Member Functions

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

◆ FileTarget()

Member Function Documentation

◆ getFilename()

◆ getFluctuationModel()

◆ getName()

◆ getPlatform()

◆ getPosition()

◆ getRcs()

◆ getRngEngine()

◆ getRotation()

◆ setFluctuationModel()

Member Data Documentation

◆ _model

◆ _rng