PRSolution2 Class Reference
[GPS solution algorithms and Tropospheric]

#include <PRSolution2.hpp>

Collaboration diagram for PRSolution2:

[legend]List of all members.

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Detailed Description

This class defines an interface to routines which compute a position and time solution from pseudorange data, with a data editing algorithm based on Receiver Autonomous Integrity Monitoring (RAIM) concepts.

RAIM ref. "A Baseline GPS RAIM Scheme and a Note on the Equivalence of Three RAIM Methods," by R. Grover Brown, Journal of the Institute of Navigation, Vol. 39, No. 3, Fall 1992, pg 301.

Definition at line 55 of file PRSolution2.hpp.

Public Member Functions
	PRSolution2 () throw ()
	Constructor.
int	RAIMCompute (const CommonTime &Tr, std::vector< SatID > &Satellite, const std::vector< double > &Pseudorange, const XvtStore< SatID > &Eph, TropModel *pTropModel) throw (Exception)
	Compute a position/time solution, given satellite PRNs and pseudoranges using a RAIM algorithm.
bool	isValid () const throw ()
	Return the status of solution.
Static Public Member Functions
int	PrepareAutonomousSolution (const CommonTime &Tr, std::vector< SatID > &Sats, const std::vector< double > &Pseudorange, const XvtStore< SatID > &Eph, Matrix< double > &SVP, std::ostream *pDebug=NULL) throw ()
	-------------------------------------------------------------------------/// ----------------------PrepareAutonomousSolution--------------------------/// -------------------------------------------------------------------------///
int	AutonomousPRSolution (const CommonTime &Tr, const std::vector< bool > &Use, const Matrix< double > SVP, TropModel *pTropModel, const bool Algebraic, int &n_iterate, double &converge, Vector< double > &Sol, Matrix< double > &Cov, Vector< double > &Resid, Vector< double > &Slope, std::ostream *pDebug=NULL, Vector< int > *satSystems=NULL) throw (Exception)
	Change.
Public Attributes
double	RMSLimit
	RMS limit - either residual of fit or distance (see ResidualCriterion).
double	SlopeLimit
	Slope limit.
bool	Algebraic
	Use an algebraic (if true) or linearized least squares (if false) algorithm.
bool	ResidualCriterion
	Use a rejection criterion based on RMS residual of fit (true) or RMS distance from an a priori position.
bool	ReturnAtOnce
	Return as soon as a solution meeting the limit requirements is found (this makes it a non-RAIM algorithm).
int	NSatsReject
	Maximum number of satellites that may be rejected in the RAIM algorithm; if this = -1, as many as possible will be rejected (RAIM requires at least 5 satellites).
bool	Debug
	If true, RAIMCompute() will output solution information to *pDebugStream.
std::ostream *	pDebugStream
	Pointer to an ostream, default &std::cout; if Debug is true, RAIMCompute() will print all preliminary solutions to this stream.
int	MaxNIterations
	Maximum number of iterations allowed in the linearized least squares algorithm.
double	ConvergenceLimit
	Convergence limit (m): continue iteration loop while RSS change in solution exceeds this.
bool	Valid
	flag: output content is valid.
Vector< double >	Solution
	Vector<double> containing the computed position solution (ECEF, meter); valid only when isValid() is true.
Matrix< double >	Covariance
	4x4 Matrix<double> containing the computed solution covariance (meter); valid only when isValid() is true.
double	RMSResidual
	Root mean square residual of fit (except when RMSDistanceFlag is set, then RMS distance from apriori 4-position); in meters.
double	MaxSlope
	Slope computed in the RAIM algorithm (largest of all satellite values) for the returned solution, dimensionless ??.
int	NIterations
	the actual number of iterations used (linearized least squares algorithm)
double	Convergence
	the RSS change in solution at the end of iterations.
int	Nsvs
	the number of good satellites used in the final computation

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Constructor & Destructor Documentation

PRSolution2 (   )  throw () [inline]

Constructor. Definition at line 59 of file PRSolution2.hpp.

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Member Function Documentation

int AutonomousPRSolution (  const CommonTime &  Tr, const std::vector< bool > &  Use, const Matrix< double >  SVP, TropModel *  pTropModel, const bool  Algebraic, int &  n_iterate, double &  converge, Vector< double > &  Sol, Matrix< double > &  Cov, Vector< double > &  Resid, Vector< double > &  Slope, std::ostream *  pDebug = NULL, Vector< int > *  satSystems = NULL )  throw (Exception) [static]

Change. Input only: Parameters: Tr  Measured time of reception of the data. Use  std::vector<bool> of length N, the number of satellites; false means do not include that sat. in the computation. SVP  Matrix<double> of dimension (N,4). This Matrix must have been computed by calling PrepareAutonomousPRSolution(). Algebraic  bool flag indicating algorithm to use : algebraic (true) or linearized least squares (false). pTropModel  pointer to a gpstk::TropModel for use within the algorithm Weight matrix TD... Input and output (for least squares only; ignored if Algebraic==true): Parameters: n_iterate  integer limit on the number of iterations. On output, it is the number of iterations actually used. converge  double convergence criterion, = RSS change in solution, in meters. On output, it is the the final value. Output: (these will be resized within the function) Parameters: Sol  gpstk::Vector<double> solution (ECEF + time components; all in meters) Cov  gpstk::Matrix<double> 4X4 covariance matrix (meter*meter) Resid  gpstk::Vector<double> post-fit range residuals for each satellite (m), the length of this Vector is the number of satellites actually used (see Use). Slope  gpstk::Vector<double> slope value used in RAIM for each good satellite, length N pDebug  pointer to an ostream for debug output, NULL (the default) for no debug output. Returns: Return values: 0 ok -1 failed to converge -2 singular problem -3 not enough good data to form a solution (at least 4 satellites required) -4 ephemeris not found for one or more satellites Definition at line 667 of file PRSolution2.cpp. References GPSEllipsoid::angVelocity(), GPSEllipsoid::c(), GPSTK_RETHROW, GPSTK_THROW, gpstk::inverseSVD(), gpstk::Minkowski(), gpstk::norm(), Vector::resize(), gpstk::RSS(), SQRT, gpstk::transpose(), and Xvt::x.

bool isValid (  void   )  const throw () [inline]

Return the status of solution. Definition at line 94 of file PRSolution2.hpp.

int PrepareAutonomousSolution (  const CommonTime &  Tr, std::vector< SatID > &  Sats, const std::vector< double > &  Pseudorange, const XvtStore< SatID > &  Eph, Matrix< double > &  SVP, std::ostream *  pDebug = NULL )  throw () [static]

-------------------------------------------------------------------------/// ----------------------PrepareAutonomousSolution--------------------------/// -------------------------------------------------------------------------/// SVP is output, dimensioned (N,4) where N is the number of satellites and the length of both Satellite and Pseudorange. Data is ignored whenever Sats[i].id is < 0. NB caller should verify that the number of good entries (Satellite[.] > 0) is > 4 before proceeding. Parameters: Tr  Measured time of reception of the data. Sats  std::vector<SatID> of satellites; satellites that are to be excluded by the algorithm are marked by a negative 'prn' member. Pseudorange  std::vector<double> of raw pseudoranges (parallel to Satellite), in meters Eph  gpstk::XvtStore<SatID> to be used in the algorithm. SVP  gpstk::Matrix<double> of dimension (N,4), N is the number of unmarked satellites in Sats[], on output this contains the satellite positions at transmit time, and the corrected pseudorange. pDebug  pointer to an ostream for debug output, NULL (the default) for no debug output. Returns: Return values: 0 ok -4 ephemeris not found for all the satellites Definition at line 500 of file PRSolution2.cpp. References gpstk::C_MPS, Xvt::clkbias, Xvt::relcorr, Matrix::size(), and Xvt::x. Referenced by ModelObs::Prepare(), and ModeledPR::Prepare().

int RAIMCompute (  const CommonTime &  Tr, std::vector< SatID > &  Satellite, const std::vector< double > &  Pseudorange, const XvtStore< SatID > &  Eph, TropModel *  pTropModel )  throw (Exception)

Compute a position/time solution, given satellite PRNs and pseudoranges using a RAIM algorithm. Parameters: Tr  Measured time of reception of the data. Satellite  std::vector<SatID> of satellites; on successful return, satellites that were excluded by the algorithm are marked by a negative 'prn' member. Pseudorange  std::vector<double> of raw pseudoranges (parallel to Satellite), in meters. Eph  gpstk::EphemerisStore to be used in the algorithm. Returns: Return values: 2 solution is found, but it is not good (RMS residual exceed limits) 1 solution is found, but it is suspect (slope is large) 0 ok -1 algorithm failed to converge -2 singular problem, no solution is possible -3 not enough good data (> 4) to form a (RAIM) solution (the 4 satellite solution might be returned - check isValid()) -4 ephemeris is not found for one or more satellites Definition at line 217 of file PRSolution2.cpp. References gpstk::abs(), GPSTK_RETHROW, Combinations::isSelected(), Combinations::Next(), gpstk::RMS(), GPSWeekSecond::sow, and GPSWeek::week.

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Member Data Documentation

bool Algebraic

Use an algebraic (if true) or linearized least squares (if false) algorithm. Definition at line 106 of file PRSolution2.hpp.

double Convergence

the RSS change in solution at the end of iterations. Definition at line 172 of file PRSolution2.hpp.

double ConvergenceLimit

Convergence limit (m): continue iteration loop while RSS change in solution exceeds this. Definition at line 141 of file PRSolution2.hpp.

Matrix<double> Covariance

4x4 Matrix<double> containing the computed solution covariance (meter); valid only when isValid() is true. Definition at line 156 of file PRSolution2.hpp.

bool Debug

If true, RAIMCompute() will output solution information to *pDebugStream. Definition at line 127 of file PRSolution2.hpp.

int MaxNIterations

Maximum number of iterations allowed in the linearized least squares algorithm. Definition at line 137 of file PRSolution2.hpp.

double MaxSlope

Slope computed in the RAIM algorithm (largest of all satellite values) for the returned solution, dimensionless ??. Definition at line 166 of file PRSolution2.hpp.

int NIterations

the actual number of iterations used (linearized least squares algorithm) Definition at line 169 of file PRSolution2.hpp.

int NSatsReject

Maximum number of satellites that may be rejected in the RAIM algorithm; if this = -1, as many as possible will be rejected (RAIM requires at least 5 satellites). A (single) non-RAIM solution can be obtained by setting this to 0 before calling RAIMCompute(). Definition at line 124 of file PRSolution2.hpp.

int Nsvs

the number of good satellites used in the final computation Definition at line 175 of file PRSolution2.hpp.

std::ostream* pDebugStream

Pointer to an ostream, default &std::cout; if Debug is true, RAIMCompute() will print all preliminary solutions to this stream. Definition at line 131 of file PRSolution2.hpp.

bool ResidualCriterion

Use a rejection criterion based on RMS residual of fit (true) or RMS distance from an a priori position. If false, member Vector Solution must be defined as this a priori position when RAIMCompute() is called. Definition at line 112 of file PRSolution2.hpp.

bool ReturnAtOnce

Return as soon as a solution meeting the limit requirements is found (this makes it a non-RAIM algorithm). Definition at line 117 of file PRSolution2.hpp.

double RMSLimit

RMS limit - either residual of fit or distance (see ResidualCriterion). Definition at line 100 of file PRSolution2.hpp.

double RMSResidual

Root mean square residual of fit (except when RMSDistanceFlag is set, then RMS distance from apriori 4-position); in meters. Definition at line 161 of file PRSolution2.hpp.

double SlopeLimit

Slope limit. Definition at line 103 of file PRSolution2.hpp.

Vector<double> Solution

Vector<double> containing the computed position solution (ECEF, meter); valid only when isValid() is true. Definition at line 151 of file PRSolution2.hpp.

bool Valid

flag: output content is valid. Definition at line 146 of file PRSolution2.hpp.

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

• PRSolution2.hpp
• PRSolution2.cpp

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