Module implementing refinement by iterative lateration. More...

#include <localization_iter_lateration_module.h>

Inherits wiselib::LocalizationModule< OsModel_P, Radio_P, SharedData_P >.

Public Types
typedef OsModel_P	OsModel
typedef Radio_P	Radio
typedef Distance_P	Distance
typedef Debug_P	Debug
typedef SharedData_P	SharedData
typedef LocalizationIterLaterationModule < OsModel, Radio, Distance, Debug, SharedData >	self_type
typedef LocalizationModule < OsModel, Radio, SharedData >	base_type
typedef Radio::size_t	size_t
typedef Radio::node_id_t	node_id_t
typedef Radio::block_data_t	block_data_t
typedef LocalizationIterLaterationMessage < OsModel, Radio >	IterLaterationMessage
typedef LocalizationIterLaterationSoundMessage < OsModel, Radio >	IterLaterationSoundMessage
typedef SharedData::NeighborInfoList	NeighborInfoList
typedef SharedData::Neighborhood::NeighborhoodIterator	NeighborhoodIterator
typedef SharedData::Neighborhood	Neighborhood
typedef SharedData::LocalCoordinateSystem	LocalCoordinateSystem
Public Member Functions
void	rollback (void)
void	init (Radio &radio, Debug &debug, SharedData &shared_data, Distance &distance)
construction / destruction
	LocalizationIterLaterationModule ()
	~LocalizationIterLaterationModule ()
standard methods startup/simulation steps
void	receive (node_id_t from, size_t len, block_data_t *data)
	Handling of Iter-Lateration-Messages.
void	work (void)
	Check, whether state can be set to finished or not.
module status info
bool	finished (void)
Parameter Configuration
void	set_iteration_limit (int iteration_limit)
	Maximum number of iterations in refinement phase.
void	set_min_confident_nbrs (int min_confident_nbrs)
	Minimum of confident neighbors to start refinement.
void	set_twin_measure (double twin_measure)
	Percentage of communication range.
void	set_abort_pos_update (double abort_pos_update)
	Percentage of communication range.
void	set_res_acceptance (double res_acceptance)
	If residuen check of lateration fails, there is a given chance, namely res_acceptance, to accept the result anyway.
basic access to owner, observer, neighborhood and local coordinate system
void	set_shared_data (SharedData &shared_data)
	This method sets the shared data object, which can be accessed by all available modules.
SharedData &	shared_data (void)
Neighborhood &	neighborhood (void)
LocalCoordinateSystem &	local_coord_sys (void)
Protected Member Functions
processing iterative lateration messages
bool	process_iter_lateration_sound_message (node_id_t from, size_t len, block_data_t *data)
	This method processes sound messages.
bool	process_iter_lateration_message (node_id_t from, size_t len, block_data_t *data)
	This method processes normal messages.
main refinement step
void	iter_lateration_step (void)
	This method executes the iterative lateration step.

Detailed Description

template<typename OsModel_P, typename Radio_P, typename Distance_P, typename Debug_P, typename SharedData_P>
class wiselib::LocalizationIterLaterationModule< OsModel_P, Radio_P, Distance_P, Debug_P, SharedData_P >

Module implementing refinement by iterative lateration.

This module implements refinement by iterative lateration. Idea is to take into account all neighbors, respectively their distances and positions, and start lateration with this information. After that the new position is broadcasted, so that neighbors are able to start lateration again with this new data, and so on.

The process finished, either after a given number of steps, or, if the position update becomes very small.

Main problem of this procedere are nodes with inaccurate information. To filter out most of these cases, there are different methods.

At first, there is the use of confidences. This means, that every node is associated with a special confidence level between 0 and 1. Unknowns start with a low confidence like 0.1, anchors with a high one like 1. These values are used in the lateration by a weighted least squares approach. Instead of solving $ Ax = b$ , $\omega Ax = \omega b$ is solved, where $\omega$ is the vector of confidences. After a successful lateration a node sets its confidence to the average of its neighbors confidences. This will, in general, increase the confidence level.

Second issue is filtering out ill-connected nodes.
To take part in refinement phase, a node has to be sound. This means, that there are independent references to at least three/four anchors. That is, information about anchors has to be get from different neighbors. Moreover, if a node becomes sound, it sends this out. The neighbors again receiving this information, add the sound node to an own list, so that an unsound node is able to become sound, if the size of intersection between sound and references becomes greater or equal three/four.

Third, the twin neighbors should be filtered out. This means, that one neighbor, that is very close to another, is set to be a twin and is ignored in further computation. The twin check has to be done in every iteration, because in most cases their position change.

At least, there is the residuen check to check the validity of the new position. To avoid being trapped in a local minimum, there is a given chance to accept a failed check anyway. If this happens, the confidence of affected node is reduced by 50 percent.

Member Typedef Documentation

template<typename OsModel_P , typename Radio_P , typename Distance_P , typename Debug_P , typename SharedData_P >

typedef LocalizationModule<OsModel, Radio, SharedData> wiselib::LocalizationIterLaterationModule< OsModel_P, Radio_P, Distance_P, Debug_P, SharedData_P >::base_type

template<typename OsModel_P , typename Radio_P , typename Distance_P , typename Debug_P , typename SharedData_P >

typedef Radio::block_data_t wiselib::LocalizationIterLaterationModule< OsModel_P, Radio_P, Distance_P, Debug_P, SharedData_P >::block_data_t

Reimplemented from wiselib::LocalizationModule< OsModel_P, Radio_P, SharedData_P >.

template<typename OsModel_P , typename Radio_P , typename Distance_P , typename Debug_P , typename SharedData_P >

typedef Debug_P wiselib::LocalizationIterLaterationModule< OsModel_P, Radio_P, Distance_P, Debug_P, SharedData_P >::Debug

template<typename OsModel_P , typename Radio_P , typename Distance_P , typename Debug_P , typename SharedData_P >

typedef Distance_P wiselib::LocalizationIterLaterationModule< OsModel_P, Radio_P, Distance_P, Debug_P, SharedData_P >::Distance

template<typename OsModel_P , typename Radio_P , typename Distance_P , typename Debug_P , typename SharedData_P >

typedef LocalizationIterLaterationMessage<OsModel, Radio> wiselib::LocalizationIterLaterationModule< OsModel_P, Radio_P, Distance_P, Debug_P, SharedData_P >::IterLaterationMessage

template<typename OsModel_P , typename Radio_P , typename Distance_P , typename Debug_P , typename SharedData_P >

typedef LocalizationIterLaterationSoundMessage<OsModel, Radio> wiselib::LocalizationIterLaterationModule< OsModel_P, Radio_P, Distance_P, Debug_P, SharedData_P >::IterLaterationSoundMessage

template<typename OsModel_P , typename Radio_P , typename SharedData_P >

typedef SharedData::LocalCoordinateSystem wiselib::LocalizationModule< OsModel_P, Radio_P, SharedData_P >::LocalCoordinateSystem [inherited]

Reimplemented in wiselib::LocalizationGpsFreeLcsModule< OsModel_P, Radio_P, Clock_P, Distance_P, Debug_P, SharedData_P >, and wiselib::LocalizationGpsFreeNcsModule< OsModel_P, Radio_P, Clock_P, Debug_P, SharedData_P >.

template<typename OsModel_P , typename Radio_P , typename Distance_P , typename Debug_P , typename SharedData_P >

typedef SharedData::Neighborhood wiselib::LocalizationIterLaterationModule< OsModel_P, Radio_P, Distance_P, Debug_P, SharedData_P >::Neighborhood

Reimplemented from wiselib::LocalizationModule< OsModel_P, Radio_P, SharedData_P >.

template<typename OsModel_P , typename Radio_P , typename Distance_P , typename Debug_P , typename SharedData_P >

typedef SharedData::Neighborhood::NeighborhoodIterator wiselib::LocalizationIterLaterationModule< OsModel_P, Radio_P, Distance_P, Debug_P, SharedData_P >::NeighborhoodIterator

template<typename OsModel_P , typename Radio_P , typename Distance_P , typename Debug_P , typename SharedData_P >

typedef SharedData::NeighborInfoList wiselib::LocalizationIterLaterationModule< OsModel_P, Radio_P, Distance_P, Debug_P, SharedData_P >::NeighborInfoList

template<typename OsModel_P , typename Radio_P , typename Distance_P , typename Debug_P , typename SharedData_P >

typedef Radio::node_id_t wiselib::LocalizationIterLaterationModule< OsModel_P, Radio_P, Distance_P, Debug_P, SharedData_P >::node_id_t

Reimplemented from wiselib::LocalizationModule< OsModel_P, Radio_P, SharedData_P >.

template<typename OsModel_P , typename Radio_P , typename Distance_P , typename Debug_P , typename SharedData_P >

typedef OsModel_P wiselib::LocalizationIterLaterationModule< OsModel_P, Radio_P, Distance_P, Debug_P, SharedData_P >::OsModel

Reimplemented from wiselib::LocalizationModule< OsModel_P, Radio_P, SharedData_P >.

template<typename OsModel_P , typename Radio_P , typename Distance_P , typename Debug_P , typename SharedData_P >

typedef Radio_P wiselib::LocalizationIterLaterationModule< OsModel_P, Radio_P, Distance_P, Debug_P, SharedData_P >::Radio

Reimplemented from wiselib::LocalizationModule< OsModel_P, Radio_P, SharedData_P >.

template<typename OsModel_P , typename Radio_P , typename Distance_P , typename Debug_P , typename SharedData_P >

typedef LocalizationIterLaterationModule<OsModel, Radio, Distance, Debug, SharedData> wiselib::LocalizationIterLaterationModule< OsModel_P, Radio_P, Distance_P, Debug_P, SharedData_P >::self_type

Reimplemented from wiselib::LocalizationModule< OsModel_P, Radio_P, SharedData_P >.

template<typename OsModel_P , typename Radio_P , typename Distance_P , typename Debug_P , typename SharedData_P >

typedef SharedData_P wiselib::LocalizationIterLaterationModule< OsModel_P, Radio_P, Distance_P, Debug_P, SharedData_P >::SharedData

Reimplemented from wiselib::LocalizationModule< OsModel_P, Radio_P, SharedData_P >.

template<typename OsModel_P , typename Radio_P , typename Distance_P , typename Debug_P , typename SharedData_P >

typedef Radio::size_t wiselib::LocalizationIterLaterationModule< OsModel_P, Radio_P, Distance_P, Debug_P, SharedData_P >::size_t

Reimplemented from wiselib::LocalizationModule< OsModel_P, Radio_P, SharedData_P >.

Constructor & Destructor Documentation

template<typename OsModel_P , typename Radio_P , typename Distance_P , typename Debug_P , typename SharedData_P >

wiselib::LocalizationIterLaterationModule< OsModel_P, Radio_P, Distance_P, Debug_P, SharedData_P >::LocalizationIterLaterationModule ( )

template<typename OsModel_P , typename Radio_P , typename Distance_P , typename Debug_P , typename SharedData_P >

wiselib::LocalizationIterLaterationModule< OsModel_P, Radio_P, Distance_P, Debug_P, SharedData_P >::~LocalizationIterLaterationModule ( )

Member Function Documentation

template<typename OsModel_P , typename Radio_P , typename Distance_P , typename Debug_P , typename SharedData_P >

bool wiselib::LocalizationIterLaterationModule< OsModel_P, Radio_P, Distance_P, Debug_P, SharedData_P >::finished ( void )

Returns:: true, if module is finished. false otherwise

See also:: LocalizationModule::finished()

template<typename OsModel_P , typename Radio_P , typename Distance_P , typename Debug_P , typename SharedData_P >

void wiselib::LocalizationIterLaterationModule< OsModel_P, Radio_P, Distance_P, Debug_P, SharedData_P >::init	(	Radio &	radio,
		Debug &	debug,
		SharedData &	shared_data,
		Distance &	distance
	)		`[inline]`

template<typename OsModel_P , typename Radio_P , typename Distance_P , typename Debug_P , typename SharedData_P >

void wiselib::LocalizationIterLaterationModule< OsModel_P, Radio_P, Distance_P, Debug_P, SharedData_P >::iter_lateration_step ( void ) [protected]

This method executes the iterative lateration step.

There are passed all checks mentioned in the Detailed Description above.

template<typename OsModel_P , typename Radio_P , typename SharedData_P >

LocalCoordinateSystem& wiselib::LocalizationModule< OsModel_P, Radio_P, SharedData_P >::local_coord_sys ( void ) [inline, inherited]

Returns:: Writable shared LocalizationLocalCoordinateSystem.

template<typename OsModel_P , typename Radio_P , typename SharedData_P >

Neighborhood& wiselib::LocalizationModule< OsModel_P, Radio_P, SharedData_P >::neighborhood ( void ) [inline, inherited]

Returns:: Writable shared LocalizationNeighborhood.

template<typename OsModel_P , typename Radio_P , typename Distance_P , typename Debug_P , typename SharedData_P >

bool wiselib::LocalizationIterLaterationModule< OsModel_P, Radio_P, Distance_P, Debug_P, SharedData_P >::process_iter_lateration_message	(	node_id_t	from,
		size_t	len,
		block_data_t *	data
	)		`[protected]`

This method processes normal messages.

The received information is updated in own neighborhood.

See also:: LocalizationIterLaterationMessage

template<typename OsModel_P , typename Radio_P , typename Distance_P , typename Debug_P , typename SharedData_P >

bool wiselib::LocalizationIterLaterationModule< OsModel_P, Radio_P, Distance_P, Debug_P, SharedData_P >::process_iter_lateration_sound_message	(	node_id_t	from,
		size_t	len,
		block_data_t *	data
	)		`[protected]`

This method processes sound messages.

Message source is added to sound nodes and, if necessary, the sound check is started again.

See also:: LocalizationIterLaterationSoundMessage

template<typename OsModel_P , typename Radio_P , typename Distance_P , typename Debug_P , typename SharedData_P >

void wiselib::LocalizationIterLaterationModule< OsModel_P, Radio_P, Distance_P, Debug_P, SharedData_P >::receive	(	node_id_t	from,
		size_t	len,
		block_data_t *	data
	)

Handling of Iter-Lateration-Messages.

See also:: LocalizationModule::process_message()

template<typename OsModel_P , typename Radio_P , typename Distance_P , typename Debug_P , typename SharedData_P >

void wiselib::LocalizationIterLaterationModule< OsModel_P, Radio_P, Distance_P, Debug_P, SharedData_P >::rollback ( void )

template<typename OsModel_P , typename Radio_P , typename Distance_P , typename Debug_P , typename SharedData_P >

void wiselib::LocalizationIterLaterationModule< OsModel_P, Radio_P, Distance_P, Debug_P, SharedData_P >::set_abort_pos_update ( double abort_pos_update ) [inline]

Percentage of communication range.

decides, if new position is very close to old one, whether the refinement phase is finished or not after position update. Default 0.001.

template<typename OsModel_P , typename Radio_P , typename Distance_P , typename Debug_P , typename SharedData_P >

void wiselib::LocalizationIterLaterationModule< OsModel_P, Radio_P, Distance_P, Debug_P, SharedData_P >::set_iteration_limit ( int iteration_limit ) [inline]

Maximum number of iterations in refinement phase.

Default 5.

template<typename OsModel_P , typename Radio_P , typename Distance_P , typename Debug_P , typename SharedData_P >

void wiselib::LocalizationIterLaterationModule< OsModel_P, Radio_P, Distance_P, Debug_P, SharedData_P >::set_min_confident_nbrs ( int min_confident_nbrs ) [inline]

Minimum of confident neighbors to start refinement.

Default 5.

template<typename OsModel_P , typename Radio_P , typename Distance_P , typename Debug_P , typename SharedData_P >

void wiselib::LocalizationIterLaterationModule< OsModel_P, Radio_P, Distance_P, Debug_P, SharedData_P >::set_res_acceptance ( double res_acceptance ) [inline]

If residuen check of lateration fails, there is a given chance, namely res_acceptance, to accept the result anyway.

This happens, to avoid being trapped in some local mimina. Default 0.1.

template<typename OsModel_P , typename Radio_P , typename SharedData_P >

void wiselib::LocalizationModule< OsModel_P, Radio_P, SharedData_P >::set_shared_data ( SharedData & shared_data ) [inline, inherited]

This method sets the shared data object, which can be accessed by all available modules.

Parameters:

LocalizationSharedData Shared data between all modules.

template<typename OsModel_P , typename Radio_P , typename Distance_P , typename Debug_P , typename SharedData_P >

void wiselib::LocalizationIterLaterationModule< OsModel_P, Radio_P, Distance_P, Debug_P, SharedData_P >::set_twin_measure ( double twin_measure ) [inline]

Percentage of communication range.

This parameter is taken to decide, whether a neighbor is twin or not. Default 0.1.

template<typename OsModel_P , typename Radio_P , typename SharedData_P >

SharedData& wiselib::LocalizationModule< OsModel_P, Radio_P, SharedData_P >::shared_data ( void ) [inline, inherited]

Returns:: LocalizationSharedData shared by all modules.; writable LocalizationSharedData shared by all modules.

template<typename OsModel_P , typename Radio_P , typename Distance_P , typename Debug_P , typename SharedData_P >

void wiselib::LocalizationIterLaterationModule< OsModel_P, Radio_P, Distance_P, Debug_P, SharedData_P >::work ( void )

Check, whether state can be set to finished or not.

Moreover, send initial messages and check on first pass, whether node is sound or not.

See also:: LocalizationModule::work()

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

wiselib.testing/algorithms/localization/distance_based/modules/refinement/localization_iter_lateration_module.h

Public Types

Public Member Functions

Protected Member Functions

Detailed Description

template<typename OsModel_P, typename Radio_P, typename Distance_P, typename Debug_P, typename SharedData_P> class wiselib::LocalizationIterLaterationModule< OsModel_P, Radio_P, Distance_P, Debug_P, SharedData_P >

Member Typedef Documentation

Constructor & Destructor Documentation

Member Function Documentation

template<typename OsModel_P, typename Radio_P, typename Distance_P, typename Debug_P, typename SharedData_P>
class wiselib::LocalizationIterLaterationModule< OsModel_P, Radio_P, Distance_P, Debug_P, SharedData_P >