radar::FileTarget Class Reference

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, const SimId id=0)
	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.
SimId	getId () const noexcept
	Gets the unique ID of the target.
void	setFluctuationModel (std::unique_ptr< RcsModel > in)
	Sets the RCS fluctuation model.
const RcsModel *	getFluctuationModel () const
	Gets the RCS fluctuation model.
unsigned	getSeed () const noexcept
	Gets the initial seed used for the target's RNG.
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.
void	setName (std::string name) noexcept
	Sets 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.
unsigned	_seed
	The initial seed for the RNG.

Detailed Description

File-based radar target.

Definition at line 225 of file target.h.

Constructor & Destructor Documentation

FileTarget()

radar::FileTarget::FileTarget	(	Platform *	platform,
		std::string	name,
		const std::string &	filename,
		unsigned	seed,
		const SimId	id = 0
	)

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, id), _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().

Here is the call graph for this function:

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 265 of file target.h.

{ 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 167 of file target.h.

{ return _model.get(); }

References radar::Target::_model.

Referenced by serial::xml_serializer_utils::serializeTarget(), and radar::to_json().

Here is the caller graph for this function:

getId()

SimId radar::Target::getId ( ) const

noexceptinherited

Gets the unique ID of the target.

Returns

The target SimId.

Definition at line 153 of file target.h.

{ return Object::getId(); }

References radar::Object::getId().

Referenced by core::World::replace(), radar::to_json(), and serial::update_target_from_json().

Here is the call graph for this function:

Here is the caller graph for this function:

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 79 of file object.h.

{ return _name; }

Referenced by simulation::calculateResponse(), processing::finalizeCwReceiver(), processing::runPulsedFinalizer(), serial::xml_serializer_utils::serializeMonostatic(), serial::xml_serializer_utils::serializeReceiver(), serial::xml_serializer_utils::serializeTarget(), serial::xml_serializer_utils::serializeTransmitter(), radar::Receiver::setNoiseTemperature(), radar::to_json(), radar::to_json(), radar::to_json(), serial::update_monostatic_from_json(), serial::update_receiver_from_json(), serial::update_target_from_json(), and serial::update_transmitter_from_json().

Here is the caller graph for this function:

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 65 of file object.h.

{ return _platform; }

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

Here is the caller graph for this function:

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 50 of file object.h.

{ return _platform->getPosition(time); }

References radar::Platform::getPosition().

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

Here is the call graph for this function:

Here is the caller graph for this function:

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:

1. Calculate the bistatic angle bisector in the global simulation coordinate system.
2. Retrieve the target's own orientation (rotation) at the specified 'time'.
3. 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.
4. 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 76 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.

Here is the call graph for this function:

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 146 of file target.h.

{ return _rng; }

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 58 of file object.h.

{ return _platform->getRotation(time); }

References radar::Platform::getRotation().

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

Here is the call graph for this function:

Here is the caller graph for this function:

getSeed()

unsigned radar::Target::getSeed ( ) const

noexceptinherited

Gets the initial seed used for the target's RNG.

Returns

The initial seed value.

Definition at line 174 of file target.h.

{ return _seed; }

References radar::Target::_seed.

Referenced by serial::update_target_from_json().

Here is the caller graph for this function:

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 161 of file target.h.

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

References radar::Target::_model.

setName()

void radar::Object::setName ( std::string  name )

noexceptinherited

Sets the name of the object.

Parameters

name	The new name for the object.

Definition at line 86 of file object.h.

{ _name = std::move(name); }

Referenced by serial::update_monostatic_from_json(), serial::update_receiver_from_json(), and serial::update_transmitter_from_json().

Here is the caller graph for this function:

Member Data Documentation

_model

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

protectedinherited

The RCS fluctuation model for the target.

Definition at line 177 of file target.h.

{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 178 of file target.h.

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

_seed

unsigned radar::Target::_seed

protectedinherited

The initial seed for the RNG.

Definition at line 179 of file target.h.

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

---

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

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