gnsstk::NavOrderFilter Class Reference

Detailed Description

Order navigation message subframes by the timestamp in the NavFilterKey class. The intent is to use this when you have (near) real time navigation data arriving from multiple sites where the time of the data is not guaranteed to be completely synchronous, but the time needs to be synchronous.

The processing depth of this filter is configurable, but defaults to 3 epochs. The processing depth should be set according to how many epochs of navigation data (i.e. unique, consecutive time stamps) to collect before passing it along. The default of 3 is recommended to be the minimum as anything less would eliminate the function of this class by preventing enough accumulation of data to occur to fix an order, however if 2 is used this will behave like a filter to discard "old" navigation data.

Accepted messages are guaranteed to be in time order. Rejected messages are more than processingDepth epochs older than the most recent.

As data is added to the filter via the validate method, data older than, or the same age as procDepth epochs is accepted. This allows data to be accepted in the case where the time stamp jumps by 2 or more epochs.

Definition at line 88 of file NavOrderFilter.hpp.

#include <NavOrderFilter.hpp>

Inheritance diagram for gnsstk::NavOrderFilter:

Public Member Functions
virtual std::string	filterName () const noexcept
	Return the filter name. More...
virtual void	finalize (NavMsgList &msgBitsOut)
	NavOrderFilter (unsigned depth=3, unsigned epoch=6)
	Initialize internal structures and set the processing depth. More...
virtual unsigned	processingDepth () const noexcept
	Internal storage includes a user-specified number of epochs. More...
virtual void	validate (NavMsgList &msgBitsIn, NavMsgList &msgBitsOut)
Public Member Functions inherited from gnsstk::NavFilter
virtual void	dumpRejected (std::ostream &out) const
	Debug support. More...
	NavFilter ()
virtual std::string	reasonTerse () const noexcept
virtual std::vector< std::string >	reasonVerbose () const noexcept

Public Attributes
unsigned	epochInSeconds
unsigned	procDepth
Public Attributes inherited from gnsstk::NavFilter
NavMsgList	rejected

Protected Types
typedef std::set< NavFilterKey *, NavTimeSort >	SubframeSet

Protected Member Functions
void	examineSubframes (NavMsgList &msgBitsOut)
Protected Member Functions inherited from gnsstk::NavFilter
void	accept (const NavMsgList &valid, NavMsgList &msgBitsOut)
void	accept (NavFilterKey *data, NavMsgList &msgBitsOut)
void	reject (const NavMsgList &invalid)
void	reject (NavFilterKey *data)

Protected Attributes
SubframeSet	orderedNav
	Ordered set of nav message subframes. More...

Additional Inherited Members
Public Types inherited from gnsstk::NavFilter
typedef std::list< NavFilterKey * >	NavMsgList

Member Typedef Documentation

SubframeSet

typedef std::set<NavFilterKey*, NavTimeSort> gnsstk::NavOrderFilter::SubframeSet

protected

Definition at line 125 of file NavOrderFilter.hpp.

Constructor & Destructor Documentation

NavOrderFilter()

gnsstk::NavOrderFilter::NavOrderFilter	(	unsigned	depth = 3,
		unsigned	epoch = 6
	)

Initialize internal structures and set the processing depth.

Definition at line 46 of file NavOrderFilter.cpp.

Member Function Documentation

examineSubframes()

void gnsstk::NavOrderFilter::examineSubframes ( NavMsgList &  msgBitsOut )

protected

Filter by age.

Parameters

[out]

msgBitsOut

Nav messages passing age filter algorithm are stored here.

Definition at line 93 of file NavOrderFilter.cpp.

filterName()

virtual std::string gnsstk::NavOrderFilter::filterName ( ) const

inlinevirtualnoexcept

Return the filter name.

Implements gnsstk::NavFilter.

Definition at line 119 of file NavOrderFilter.hpp.

finalize()

void gnsstk::NavOrderFilter::finalize ( NavMsgList &  msgBitsOut )

virtual

Flush the remaining contents of orderedNav.

Parameters

[out]

msgBitsOut

Any remaining nav messages are stored here on return.

Implements gnsstk::NavFilter.

Definition at line 84 of file NavOrderFilter.cpp.

processingDepth()

virtual unsigned gnsstk::NavOrderFilter::processingDepth ( ) const

inlinevirtualnoexcept

Internal storage includes a user-specified number of epochs.

Implements gnsstk::NavFilter.

Definition at line 115 of file NavOrderFilter.hpp.

validate()

void gnsstk::NavOrderFilter::validate ( NavMsgList &  msgBitsIn, NavMsgList &  msgBitsOut  )

virtual

Add nav messages to the collection (orderedNav).

Precondition

NavFilterKey::timeStamp is set to an appropriate, consistent value for the navigation data being filtered.

Parameters

[in,out]	msgBitsIn	A list of NavFilterKey* objects containing navigation messages.
[out]	msgBitsOut	The messages successfully passing the filter.

Implements gnsstk::NavFilter.

Definition at line 54 of file NavOrderFilter.cpp.

Member Data Documentation

epochInSeconds

unsigned gnsstk::NavOrderFilter::epochInSeconds

This defaults to 6 seconds, which is the LNAV subframe period. It should be changed accordingly for other navigation message formats, either via the constructor or directly.

Definition at line 95 of file NavOrderFilter.hpp.

orderedNav

SubframeSet gnsstk::NavOrderFilter::orderedNav

protected

Ordered set of nav message subframes.

Definition at line 128 of file NavOrderFilter.hpp.

procDepth

unsigned gnsstk::NavOrderFilter::procDepth

Definition at line 122 of file NavOrderFilter.hpp.

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

• NavOrderFilter.hpp
• NavOrderFilter.cpp