Detailed Description

Defines a base class that provide the ability to convert between time systems, using data extracted from GNSS navigation messages. The algorithm and parameters are largely the same across systems, so this is basically the TimeOffset equivalent of OrbitDataKepler, in that it contains data and algorithms to use it.

Section 20.3.3.5.2.4, paragraph b of IS-GPS-200 goes into details about how the future leap seconds (Δt_LSF) are handled. This text makes assumptions about the tying of time representation (seconds of day) and the time system (UTC) which are not true for gnsstk. Specifically, the IS allows for the leap second to be represented as 86400+ seconds of day, which the gnsstk currently rejects as an error. These leap seconds are currently not representable in the gnsstk, but the offset can still be used the rest of the time. This means that an attempt to display UTC time during the period of a leap second will be incorrect, but for now we're chosing to ignore this inconsistency rather than completely refactor the time classes again for 1 second every few years in UTC only.

Definition at line 72 of file StdNavTimeOffset.hpp.

#include <StdNavTimeOffset.hpp>

Inheritance diagram for gnsstk::StdNavTimeOffset:

[legend]

Public Member Functions
void	dump (std::ostream &s, DumpDetail dl) const override

virtual double	effEnd () const

virtual double	effStart () const

TimeCvtSet	getConversions () const override

bool	getOffset (TimeSystem fromSys, TimeSystem toSys, const CommonTime &when, double &offset) const override

	StdNavTimeOffset ()
	Initialize all data to 0. More...

Public Member Functions inherited from gnsstk::TimeOffsetData
std::list< std::string >	compare (const NavDataPtr &right) const override

CommonTime	getNearTime () const override

bool	isSameData (const NavDataPtr &right) const override

	TimeOffsetData ()
	Set the messageType. More...

virtual	~TimeOffsetData ()
	Obligatory virtual destructor. More...

Public Member Functions inherited from gnsstk::NavData
virtual NavDataPtr	clone () const =0
	Create a deep copy of this object, whatever it truly is. More...

virtual std::string	getClassName () const

std::string	getDumpTime (DumpDetail dl, const CommonTime &t) const

std::string	getDumpTimeHdr (DumpDetail dl) const

std::string	getSignalString () const

bool	getSVN (const SatID &sat, const gnsstk::CommonTime &when, std::string &svn) const

virtual CommonTime	getUserTime () const

	NavData ()
	Initialize internal data fields. More...

virtual bool	validate () const =0

Public Attributes
double	a0
	Bias coefficient of source time scale. More...

double	a1
	Drift coefficient of source time scale. More...

double	a2
	Drift rate coefficient of source time scale. More...

double	deltatLS
	Current or past leap second count (UTC only). More...

double	deltatLSF
	Current or future leap second count (UTC only). More...

unsigned	dn
	Leap second reference day number (UTC only). More...

unsigned	dnSun
	dn value for Sunday. More...

CommonTime	effTime
	Effectivity time (wnLSF,dn). More...

CommonTime	refTime
	Reference time for computation. More...

TimeSystem	src
	Source time system. More...

TimeSystem	tgt
	Target time system. More...

double	tot
	Time data reference time of week (storage only). More...

unsigned	wnLSF
	Leap second reference week number (UTC only). More...

unsigned	wnot
	Time data reference week number (storage only). More...

Public Attributes inherited from gnsstk::NavData
NavMessageID	signal
	Source signal identification for this navigation message data. More...

CommonTime	timeStamp

std::string	weekFmt

Additional Inherited Members
Static Public Member Functions inherited from gnsstk::NavData
static gnsstk::SatMetaDataStore *	getSatMetaDataStore ()
	Accessor for python. More...

static void	setSatMetaDataStore (gnsstk::SatMetaDataStore *smds)
	Accessor for python. More...

Static Public Attributes inherited from gnsstk::NavData
static const GNSSTK_EXPORT std::string	dumpTimeFmt
	Time format used for the dump method (Full). More...

static const GNSSTK_EXPORT std::string	dumpTimeFmtBrief
	Time format used for the dump method (Brief). More...

static GNSSTK_EXPORT gnsstk::SatMetaDataStore *	satMetaDataStore = nullptr
	Set this to a valid store to get PRN->SVN translations in dump(). More...

Protected Attributes inherited from gnsstk::NavData
double	msgLenSec

Constructor & Destructor Documentation

◆ StdNavTimeOffset()

gnsstk::StdNavTimeOffset::StdNavTimeOffset ( )

Initialize all data to 0.

Definition at line 47 of file StdNavTimeOffset.cpp.

Member Function Documentation

◆ dump()

void gnsstk::StdNavTimeOffset::dump	(	std::ostream &	s,
		DumpDetail	dl
	)		const

overridevirtual

Print the contents of this object in a human-readable format.

Parameters

[in,out]	s	The stream to write the data to.
[in]	dl	The level of detail the output should contain.

Todo:: maybe need to make this a dynamic label for systems that start at DN=0

Reimplemented from gnsstk::NavData.

Definition at line 97 of file StdNavTimeOffset.cpp.

◆ effEnd()

virtual double gnsstk::StdNavTimeOffset::effEnd ( ) const

inlinevirtual

Return the number of seconds after the effectivity time during which the standard delta t formula is used.

Reimplemented in gnsstk::BDSD1NavTimeOffset, and gnsstk::BDSD2NavTimeOffset.

Definition at line 108 of file StdNavTimeOffset.hpp.

◆ effStart()

virtual double gnsstk::StdNavTimeOffset::effStart ( ) const

inlinevirtual

Return the number of seconds prior to the effectivity time during which the standard delta t formula is used.

Reimplemented in gnsstk::BDSD1NavTimeOffset, and gnsstk::BDSD2NavTimeOffset.

Definition at line 104 of file StdNavTimeOffset.hpp.

◆ getConversions()

TimeCvtSet gnsstk::StdNavTimeOffset::getConversions ( ) const

overridevirtual

The set of time system conversions this class is capable of making.

Returns: a set of supported time system conversion to/from pairs.

Implements gnsstk::TimeOffsetData.

Definition at line 153 of file StdNavTimeOffset.cpp.

◆ getOffset()

bool gnsstk::StdNavTimeOffset::getOffset	(	TimeSystem	fromSys,
		TimeSystem	toSys,
		const CommonTime &	when,
		double &	offset
	)		const

overridevirtual

Get the offset, in seconds, to apply to times when converting them from fromSys to toSys.

Parameters

[in]	fromSys	The time system to convert from.
[in]	toSys	The time system to convert to.
[in]	when	The time being converted, in the same time system as fromSys.
[out]	offset	The offset in seconds where when(toSys)=when(fromSys)-offset.

Exceptions

AssertionFailure if when's time system is not fromSys.

Returns: true if an offset is available, false if not.

Implements gnsstk::TimeOffsetData.

Definition at line 56 of file StdNavTimeOffset.cpp.

Member Data Documentation

◆ a0

double gnsstk::StdNavTimeOffset::a0

Bias coefficient of source time scale.

Definition at line 122 of file StdNavTimeOffset.hpp.

◆ a1

double gnsstk::StdNavTimeOffset::a1

Drift coefficient of source time scale.

Definition at line 123 of file StdNavTimeOffset.hpp.

◆ a2

double gnsstk::StdNavTimeOffset::a2

Drift rate coefficient of source time scale.

Definition at line 124 of file StdNavTimeOffset.hpp.

◆ deltatLS

double gnsstk::StdNavTimeOffset::deltatLS

Current or past leap second count (UTC only).

Definition at line 125 of file StdNavTimeOffset.hpp.

◆ deltatLSF

double gnsstk::StdNavTimeOffset::deltatLSF

Current or future leap second count (UTC only).

Definition at line 135 of file StdNavTimeOffset.hpp.

◆ dn

unsigned gnsstk::StdNavTimeOffset::dn

Leap second reference day number (UTC only).

Definition at line 134 of file StdNavTimeOffset.hpp.

◆ dnSun

unsigned gnsstk::StdNavTimeOffset::dnSun

dn value for Sunday.

Definition at line 136 of file StdNavTimeOffset.hpp.

◆ effTime

CommonTime gnsstk::StdNavTimeOffset::effTime

Effectivity time (wnLSF,dn).

Definition at line 127 of file StdNavTimeOffset.hpp.

◆ refTime

CommonTime gnsstk::StdNavTimeOffset::refTime

Reference time for computation.

Definition at line 126 of file StdNavTimeOffset.hpp.

◆ src

TimeSystem gnsstk::StdNavTimeOffset::src

Source time system.

Definition at line 120 of file StdNavTimeOffset.hpp.

◆ tgt

TimeSystem gnsstk::StdNavTimeOffset::tgt

Target time system.

Definition at line 121 of file StdNavTimeOffset.hpp.

◆ tot

double gnsstk::StdNavTimeOffset::tot

Time data reference time of week (storage only).

Definition at line 128 of file StdNavTimeOffset.hpp.

◆ wnLSF

unsigned gnsstk::StdNavTimeOffset::wnLSF

Leap second reference week number (UTC only).

Definition at line 133 of file StdNavTimeOffset.hpp.

◆ wnot

unsigned gnsstk::StdNavTimeOffset::wnot

Time data reference week number (storage only).

Definition at line 129 of file StdNavTimeOffset.hpp.

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

Detailed Description

Public Member Functions

Public Attributes

Additional Inherited Members

Constructor & Destructor Documentation

◆ StdNavTimeOffset()

Member Function Documentation

◆ dump()

◆ effEnd()

◆ effStart()

◆ getConversions()

◆ getOffset()

Member Data Documentation

◆ a0

◆ a1

◆ a2

◆ deltatLS

◆ deltatLSF

◆ dn

◆ dnSun

◆ effTime

◆ refTime

◆ src

◆ tgt

◆ tot

◆ wnLSF

◆ wnot