ionosphere.c File Reference

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Detailed Description

GNSS core 'c' function library: GPS ionospheric calculations.

Author:

Glenn D. MacGougan (GDM)

Date:

2007-11-29

Since:

2005-08-14

Remarks:

• Get better klobuchar (alpha and beta parameters from: http://www.aiub.unibe.ch/ionosphere/
  ftp://ftp.unibe.ch/aiub/CODE/
  http://www.aiub.unibe.ch/download/CODE/
  e.g. Download CGIM3280.07N from ftp://ftp.unibe.ch/aiub/CODE/2007/ for 2007-11-29.

"LICENSE INFORMATION"
Copyright (c) 2007, refer to 'author' doxygen tags
All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided the following conditions are met:

• Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
  
• Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
  
• The name(s) of the contributor(s) may not be used to endorse or promote products derived from this software without specific prior written permission.
  

THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Definition in file ionosphere.c.

#include <math.h>
#include "ionosphere.h"
#include "constants.h"

Go to the source code of this file.

Functions
BOOL	IONOSPHERE_GetL1KlobucharCorrection (const double alpha0, const double alpha1, const double alpha2, const double alpha3, const double beta0, const double beta1, const double beta2, const double beta3, const double latitude, const double longitude, const double elevation, const double azimuth, const double gpstow, double *ionospheric_delay)
	Given the user geodetic position, GPS time of week, the azimuth and elevation to the satellite in question, and the alpha and beta Klobuchar terms, compute the ionospheric delay for this satellite.

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Function Documentation

BOOL IONOSPHERE_GetL1KlobucharCorrection	(	const double	alpha0,
		const double	alpha1,
		const double	alpha2,
		const double	alpha3,
		const double	beta0,
		const double	beta1,
		const double	beta2,
		const double	beta3,
		const double	latitude,
		const double	longitude,
		const double	elevation,
		const double	azimuth,
		const double	gpstow,
		double *	ionospheric_delay
	)

Given the user geodetic position, GPS time of week, the azimuth and elevation to the satellite in question, and the alpha and beta Klobuchar terms, compute the ionospheric delay for this satellite.

Author:

Glenn D. MacGougan (GDM)

Date:

2007-11-29

Since:

2005-08-14

Remarks:

• The ionospheric correction is referred to the L1 frequency; if the user is operating on the L2 frequency, the correction term must be multiplied by
  (f_L1/f_L2)^2 = (1575.42/1227.6)^2 = (77/60)^2 = 1.64694444...

REFERENCES

• GPS ICD 200C, pp. 126-128

Parameters:

alpha0	coefficients of a cubic equation representing the amplitude of the vertical delay [s]
alpha1	coefficients of a cubic equation representing the amplitude of the vertical delay [s/semi-circle]
alpha2	coefficients of a cubic equation representing the amplitude of the vertical delay [s/semi-circle^2]
alpha3	coefficients of a cubic equation representing the amplitude of the vertical delay [s/semi-circle^3]
beta0	coefficients of a cubic equation representing the period of the model [s]
beta1	coefficients of a cubic equation representing the period of the model [s/semi-circle]
beta2	coefficients of a cubic equation representing the period of the model [s/semi-circle^2]
beta3	coefficients of a cubic equation representing the period of the model [s/semi-circle^3]
latitude	user geodetic latitude [rad]
longitude	user geodetic longitude [rad]
elevation	elevation angle between the user and the satellite [rad]
azimuth	azimuth angle between the user and the satellite, measured clockwise positive from the true North [rad]
gpstow	receiver computed gps time of week [s]
ionospheric_delay	computed ionospheric correction [m]

Definition at line 57 of file ionosphere.c.