Detailed Description

Base class for ICD-GPS-200 navigation messages. This class provides functions for decoding the bits in navigation message, and is the base class for all "engineering units" types.

Definition at line 69 of file EngNav.hpp.

#include <EngNav.hpp>

Inheritance diagram for gnsstk::EngNav:

[legend]

Public Types
enum	BitConvertType { BITS8 = 0, BITS10 = 1 }
	This enumeration is used by the convertXBit() method. More...

Public Member Functions
	EngNav () noexcept
	default constructor More...

virtual	~EngNav ()
	destructor More...

Static Public Member Functions
static bool	checkParity (const std::vector< uint32_t > &v, bool knownUpright=true)

static bool	checkParity (const uint32_t input[10], bool knownUpright=true)

static uint32_t	computeParity (uint32_t sfword, uint32_t psfword, bool knownUpright=true)

static bool	convert10bit (int gpsWeek, double *out) noexcept

static bool	convert8bit (int gpsWeek, double *out) noexcept

static short	convertXBit (short fullGPSWeek, short incompleteGPSWeek, BitConvertType type)

static void	dump (std::ostream &s=std::cout)

static uint32_t	fixParity (uint32_t sfword, uint32_t psfword, bool nib, bool knownUpright=true)

static uint32_t	getd29 (uint32_t sfword)
	Get bit 29 from the given subframe word. More...

static uint32_t	getd30 (uint32_t sfword)

static unsigned long	getHOWTime (uint32_t word2)
	Get the HOW time from the provided HOW. More...

static bool	getNMCTValidity (const uint32_t sf2[10], unsigned howWeek, NMCTMeta &meta)

static bool	getNMCTValidity (const uint32_t sf2[10], unsigned howWeek, uint32_t &aodo, CommonTime &tnmct, CommonTime &toe, CommonTime &tot)

static short	getSFID (uint32_t word2)
	Get the subframe ID from the provided HOW. More...

static short	getSubframePattern (const long input[10]) noexcept

static short	getSubframePattern (const uint32_t input[10]) noexcept

static unsigned long	getTOW (uint32_t word2)
	Get the TOW count from the provided HOW. More...

static bool	sfpage2svid (short subframe, short page, short &svpgid) noexcept

static bool	subframeConvert (const long input[10], int gpsWeek, double output[60]) noexcept

static bool	subframeConvert (const uint32_t input[10], short gpsWeek, double output[60]) noexcept

static bool	subframeParity (const long input[10])
	This is the old routine only left around for compatibility. More...

static bool	sv2page (short svpgid, short &subframe, short &page) noexcept

static bool	zcount2page (unsigned long zcount, short &subframe, short &page) noexcept

Static Private Member Functions
static void	convertQuant (const uint32_t input[10], double output[60], const DecodeQuant &dq) noexcept

Member Enumeration Documentation

◆ BitConvertType

enum gnsstk::EngNav::BitConvertType

This enumeration is used by the convertXBit() method.

Enumerator
BITS8
BITS10

Definition at line 73 of file EngNav.hpp.

Constructor & Destructor Documentation

◆ EngNav()

gnsstk::EngNav::EngNav ( )

noexcept

default constructor

Definition at line 369 of file EngNav.cpp.

◆ ~EngNav()

virtual gnsstk::EngNav::~EngNav ( )

inlinevirtual

destructor

Definition at line 83 of file EngNav.hpp.

Member Function Documentation

◆ checkParity() [1/2]

bool gnsstk::EngNav::checkParity	(	const std::vector< uint32_t > &	v,
		bool	knownUpright = `true`
	)

static

Definition at line 722 of file EngNav.cpp.

◆ checkParity() [2/2]

bool gnsstk::EngNav::checkParity	(	const uint32_t	input[10],
		bool	knownUpright = `true`
	)

static

Perform a parity check on a navigation message subframe.

Returns: true if the parity check is successful.

Definition at line 727 of file EngNav.cpp.

◆ computeParity()

uint32_t gnsstk::EngNav::computeParity	(	uint32_t	sfword,
		uint32_t	psfword,
		bool	knownUpright = `true`
	)

static

Compute and return the parity of the given subframe word, based on the algorihm defined in Section 20.3.5 of IS-GPS-200D.

Parameters

sfword	The subframe word to compute the parity of.
psfword	The previous word in the subframe (use 0 when sfword is word 1)
knownUpright	When this is set, the data is assumed to be upright and no D30 inversion is performed

Returns: the 6-bit parity (or, if zeroBits is set, the 6-bit parity along with the two t-bits, the non-information bits used for parity computation).

Definition at line 637 of file EngNav.cpp.

◆ convert10bit()

bool gnsstk::EngNav::convert10bit	(	int	gpsWeek,
		double *	out
	)

staticnoexcept

Convert the week number in out from 10-bit to full using the full week number gpsWeek.

Parameters

gpsWeek	source full week number.
out	10-bit week number to convert to full

Returns: true if source and target are within 511 weeks of each other.

Definition at line 448 of file EngNav.cpp.

◆ convert8bit()

bool gnsstk::EngNav::convert8bit	(	int	gpsWeek,
		double *	out
	)

staticnoexcept

Convert the week number in out from 8-bit to full using the full week number gpsWeek.

Parameters

gpsWeek	source full week number.
out	8-bit week number to convert to full

Returns: true if source and target are within 127 weeks of each other.

Definition at line 436 of file EngNav.cpp.

◆ convertQuant()

void gnsstk::EngNav::convertQuant	(	const uint32_t	input[10],
		double	output[60],
		const DecodeQuant &	dq
	)

staticprivatenoexcept

Given 10 words of a navigation message subframe, in, and a structure, p, defining a particular conversion, perform the conversion and store the results in the appropriate location in the output array.

Parameters

[in]	input	words of navigation message subframe. Each nav message word is in the 30 lsbs of the corresponding input[i].
[out]	output	array of 60 doubles. The converted output will be placed in the output array at the location specified in the conversion specification.
[in]	dq	structure defining conversion to be performed.

Note: While convertQuant specifies an array of 60 doubles for output, not all of these are always used. The actual number of data that are in output is dependent on the input message format. The indices are defined in the formats array in EngNav.cpp.

Definition at line 742 of file EngNav.cpp.

◆ convertXBit()

short gnsstk::EngNav::convertXBit	(	short	fullGPSWeek,
		short	incompleteGPSWeek,
		BitConvertType	type
	)

static

Convert the week number in out from 8 or 10-bit to full using the full week number fullGPSWeek.

Parameters

fullGPSWeek	source full week number.
incompleteGPSWeek	week number to convert to full
type	BITS8 (0) or BITS10 (1)

Returns: Full GPS week corresponding to incompleteGPSWeek assuming incompleteGPSWeek is within half the 8/10 bit distance from fullGPSWeek.

Definition at line 461 of file EngNav.cpp.

◆ dump()

void gnsstk::EngNav::dump ( std::ostream & s = std::cout )

static

Emit human-readable instance data to the specified stream.

Parameters

s	stream to which data will be written

Definition at line 800 of file EngNav.cpp.

◆ fixParity()

uint32_t gnsstk::EngNav::fixParity	(	uint32_t	sfword,
		uint32_t	psfword,
		bool	nib,
		bool	knownUpright = `true`
	)

static

Compute the parity for the given subframe using the prior subframe and a flag to handle the "non-information bits" that appear in certain words of each subframe.

Parameters

sfword	The subframe word to compute the parity of.
psfword	The previous word in the subframe (use 0 when sfword is word 1)
nib	if true, sfword is one of the words with the non-information bearing bits (word 2 or 10), and the parity will be computed as appropriate for that situation.

Returns: sfword with the proper parity bits.

Definition at line 685 of file EngNav.cpp.

◆ getd29()

static uint32_t gnsstk::EngNav::getd29 ( uint32_t sfword )

inlinestatic

Get bit 29 from the given subframe word.

Definition at line 140 of file EngNav.hpp.

◆ getd30()

static uint32_t gnsstk::EngNav::getd30 ( uint32_t sfword )

inlinestatic

Following two used by checkParity Get bit 30 from the given subframe word

Definition at line 134 of file EngNav.hpp.

◆ getHOWTime()

static unsigned long gnsstk::EngNav::getHOWTime ( uint32_t word2 )

inlinestatic

Get the HOW time from the provided HOW.

Definition at line 146 of file EngNav.hpp.

◆ getNMCTValidity() [1/2]

static bool gnsstk::EngNav::getNMCTValidity	(	const uint32_t	sf2[10],
		unsigned	howWeek,
		NMCTMeta &	meta
	)

inlinestatic

Get the NMCT validity time from subframe 2. Refer to IS-GPS-200 section 2.3.3.4.4.

Parameters

[in]	sf2	The 10 words of subframe 2.
[in]	howWeek	the GPS full week for the HOW time in sf2.
[in]	meta	Other metadata pertaining to the NMCT.

Returns: true if the AODO is something other than 27900, which indicates that the NMCT is invalid (i.e. a return value of false means that the other output data is invalid as is the NMCT itself).

Exceptions

InvalidParameter if sf2 is not subframe 2.

Definition at line 361 of file EngNav.hpp.

◆ getNMCTValidity() [2/2]

bool gnsstk::EngNav::getNMCTValidity	(	const uint32_t	sf2[10],
		unsigned	howWeek,
		uint32_t &	aodo,
		CommonTime &	tnmct,
		CommonTime &	toe,
		CommonTime &	tot
	)

static

Get the NMCT validity time from subframe 2. Refer to IS-GPS-200 section 2.3.3.4.4.

Parameters

[in]	sf2	The 10 words of subframe 2.
[in]	howWeek	the GPS full week for the HOW time in sf2.
[out]	aodo	Age of data offset in seconds.
[out]	tnmct	The NMCT validity time.
[out]	toe	Time of ephemeris.

Returns: true if the AODO is something other than 27900, which indicates that the NMCT is invalid (i.e. a return value of false means that the other output data is invalid as is the NMCT itself).

Exceptions

InvalidParameter if sf2 is not subframe 2.

Definition at line 851 of file EngNav.cpp.

◆ getSFID()

static short gnsstk::EngNav::getSFID ( uint32_t word2 )

inlinestatic

Get the subframe ID from the provided HOW.

Definition at line 163 of file EngNav.hpp.

◆ getSubframePattern() [1/2]

short gnsstk::EngNav::getSubframePattern ( const long input[10] )

staticnoexcept

Given a navigation message subframe, return the pattern number to be used in converting the subframe to engineering units. The patterns are defined in the following table. The numbers correspond to the ordering of the bit definitions in ICD-GPS-200 Figure 20-1.

Subframe # SV_id Pattern # 1 n/a 1 2 n/a 2 3 n/a 3 4 1-24 4 4 25 5 5 57 6 5 58-62 7 5 56 8 5 63 9 5 52-55 10

Parameters

input 10 long integers containing the ten words of the navigation message subframe.

Returns: the pattern ID as defined in the above table.

Definition at line 478 of file EngNav.cpp.

◆ getSubframePattern() [2/2]

short gnsstk::EngNav::getSubframePattern ( const uint32_t input[10] )

staticnoexcept

Definition at line 487 of file EngNav.cpp.

◆ getTOW()

static unsigned long gnsstk::EngNav::getTOW ( uint32_t word2 )

inlinestatic

Get the TOW count from the provided HOW.

Definition at line 154 of file EngNav.hpp.

◆ sfpage2svid()

bool gnsstk::EngNav::sfpage2svid	(	short	subframe,
		short	page,
		short &	svpgid
	)

staticnoexcept

Given an SV/Page ID (1-63), set the subframe ID and page passed to the function.

Parameters

subframe	(input) the subframe ID of svpgid (4,5)
page	(input) the page number of svpgid (1-25)
svpgid	(output) the SV/Page ID translated from subframe/page

Returns: false if svpgid was invalid

Note: Some SV/Page IDs are redundant, so the result will be one of the possible pages for that SV/Page ID.

Definition at line 583 of file EngNav.cpp.

◆ subframeConvert() [1/2]

bool gnsstk::EngNav::subframeConvert	(	const long	input[10],
		int	gpsWeek,
		double	output[60]
	)

staticnoexcept

Given 10 words of a navigation message subframe (as defined in ICD-GPS-200), convert to the "appropriate" 60 floating point values.

Parameters

[in]	input	array of ten 30-bit words (stored in the 30 least-significant bits of each long.
[in]	gpsWeek	full (>10 bits) GPS week number associated with almanac reference time.
[out]	output	60 floating point values as defined in the formats array in EngNav.cpp.

Note: While subframeConvert specifies an array of 60 doubles for output, not all of these are always used. The actual number of data that are in output is dependent on the input message format. The indices are defined in the formats array in EngNav.cpp.

Returns: true if successful.

Definition at line 375 of file EngNav.cpp.

◆ subframeConvert() [2/2]

bool gnsstk::EngNav::subframeConvert	(	const uint32_t	input[10],
		short	gpsWeek,
		double	output[60]
	)

staticnoexcept

Given 10 words of a navigation message subframe (as defined in ICD-GPS-200), convert to the "appropriate" 60 floating point values.

Parameters

[in]	input	array of ten 30-bit words (stored in the 30 least-significant bits of each long.
[in]	gpsWeek	full (>10 bits) GPS week number associated with almanac reference time.
[out]	output	60 floating point values as defined in the formats array in EngNav.cpp.

Note: While subframeConvert specifies an array of 60 doubles for output, not all of these are always used. The actual number of data that are in output is dependent on the input message format. The indices are defined in the formats array in EngNav.cpp.

Returns: true if successful.

Definition at line 387 of file EngNav.cpp.

◆ subframeParity()

bool gnsstk::EngNav::subframeParity ( const long input[10] )

static

This is the old routine only left around for compatibility.

This is the OLD GNSSTk method, left here for compatibility.

Definition at line 714 of file EngNav.cpp.

◆ sv2page()

bool gnsstk::EngNav::sv2page	(	short	svpgid,
		short &	subframe,
		short &	page
	)

staticnoexcept

Given an SV/Page ID (1-63), set the subframe ID and page passed to the function.

Parameters

svpgid	(input) the SV/Page ID to be translated (typically extracted from subframe 4/5, word 3, bits 3-8 (bit 1=MSB).
subframe	(output) the subframe ID of svpgid (4,5)
page	(output) the page number of svpgid (1-25)

Returns: false if svpgid was invalid

Note: Some SV/Page IDs are redundant, so the result will be one of the possible pages for that SV/Page ID.

Definition at line 524 of file EngNav.cpp.

◆ zcount2page()

bool gnsstk::EngNav::zcount2page	(	unsigned long	zcount,
		short &	subframe,
		short &	page
	)

staticnoexcept

Given a Z-count representing the TOW in the HOW of a navigation subframe (i.e. TOW * 4), set the subframe ID and page passed to the function.

Parameters

zcount	(input) the TOW count, in z-counts, of a nav subframe
subframe	(output) the subframe ID of svpgid (4,5)
page	(output) the page number of svpgid (1-25)

Returns: false if zcount was invalid

Definition at line 608 of file EngNav.cpp.

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

Detailed Description

Public Types

Public Member Functions

Static Public Member Functions

Static Private Member Functions

Member Enumeration Documentation

◆ BitConvertType

Constructor & Destructor Documentation

◆ EngNav()

◆ ~EngNav()

Member Function Documentation

◆ checkParity() [1/2]

◆ checkParity() [2/2]

◆ computeParity()

◆ convert10bit()

◆ convert8bit()

◆ convertQuant()

◆ convertXBit()

◆ dump()

◆ fixParity()

◆ getd29()

◆ getd30()

◆ getHOWTime()

◆ getNMCTValidity() [1/2]

◆ getNMCTValidity() [2/2]

◆ getSFID()

◆ getSubframePattern() [1/2]

◆ getSubframePattern() [2/2]

◆ getTOW()

◆ sfpage2svid()

◆ subframeConvert() [1/2]

◆ subframeConvert() [2/2]

◆ subframeParity()

◆ sv2page()

◆ zcount2page()