163 lines
4.7 KiB
C++
163 lines
4.7 KiB
C++
// fg_geodesy.hxx -- routines to convert between geodetic and geocentric
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// coordinate systems.
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//
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// Copied and adapted directly from LaRCsim/ls_geodesy.c
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//
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// See below for the complete original LaRCsim comments.
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//
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// $Id$
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#ifndef _FG_GEODESY_HXX
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#define _FG_GEODESY_HXX
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#ifndef __cplusplus
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# error This library requires C++
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#endif
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#include <Math/point3d.hxx>
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#include <Math/polar3d.hxx>
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// fgGeocToGeod(lat_geoc, radius, *lat_geod, *alt, *sea_level_r)
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// INPUTS:
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// lat_geoc Geocentric latitude, radians, + = North
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// radius C.G. radius to earth center (meters)
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//
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// OUTPUTS:
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// lat_geod Geodetic latitude, radians, + = North
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// alt C.G. altitude above mean sea level (meters)
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// sea_level_r radius from earth center to sea level at
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// local vertical (surface normal) of C.G. (meters)
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void fgGeocToGeod( double lat_geoc, double radius, double
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*lat_geod, double *alt, double *sea_level_r );
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// fgGeodToGeoc( lat_geod, alt, *sl_radius, *lat_geoc )
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// INPUTS:
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// lat_geod Geodetic latitude, radians, + = North
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// alt C.G. altitude above mean sea level (meters)
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//
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// OUTPUTS:
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// sl_radius SEA LEVEL radius to earth center (meters)
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// (add Altitude to get true distance from earth center.
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// lat_geoc Geocentric latitude, radians, + = North
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//
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void fgGeodToGeoc( double lat_geod, double alt, double *sl_radius,
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double *lat_geoc );
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// convert a geodetic point lon(radians), lat(radians), elev(meter) to
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// a cartesian point
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inline Point3D fgGeodToCart(const Point3D& geod) {
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double gc_lon, gc_lat, sl_radius;
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// printf("A geodetic point is (%.2f, %.2f, %.2f)\n",
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// geod[0], geod[1], geod[2]);
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gc_lon = geod.lon();
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fgGeodToGeoc(geod.lat(), geod.radius(), &sl_radius, &gc_lat);
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// printf("A geocentric point is (%.2f, %.2f, %.2f)\n", gc_lon,
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// gc_lat, sl_radius+geod[2]);
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Point3D pp = Point3D( gc_lon, gc_lat, sl_radius + geod.radius());
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return fgPolarToCart3d(pp);
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}
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/***************************************************************************
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TITLE: ls_geodesy
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----------------------------------------------------------------------------
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FUNCTION: Converts geocentric coordinates to geodetic positions
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----------------------------------------------------------------------------
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MODULE STATUS: developmental
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----------------------------------------------------------------------------
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GENEALOGY: Written as part of LaRCSim project by E. B. Jackson
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----------------------------------------------------------------------------
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DESIGNED BY: E. B. Jackson
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CODED BY: E. B. Jackson
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MAINTAINED BY: E. B. Jackson
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----------------------------------------------------------------------------
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MODIFICATION HISTORY:
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DATE PURPOSE BY
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930208 Modified to avoid singularity near polar region. EBJ
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930602 Moved backwards calcs here from ls_step. EBJ
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931214 Changed erroneous Latitude and Altitude variables to
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*lat_geod and *alt in routine ls_geoc_to_geod. EBJ
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940111 Changed header files from old ls_eom.h style to ls_types,
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and ls_constants. Also replaced old DATA type with new
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SCALAR type. EBJ
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CURRENT RCS HEADER:
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$Header$
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* Revision 1.5 1994/01/11 18:47:05 bjax
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* Changed include files to use types and constants, not ls_eom.h
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* Also changed DATA type to SCALAR type.
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*
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* Revision 1.4 1993/12/14 21:06:47 bjax
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* Removed global variable references Altitude and Latitude. EBJ
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*
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* Revision 1.3 1993/06/02 15:03:40 bjax
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* Made new subroutine for calculating geodetic to geocentric; changed name
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* of forward conversion routine from ls_geodesy to ls_geoc_to_geod.
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*
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----------------------------------------------------------------------------
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REFERENCES:
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[ 1] Stevens, Brian L.; and Lewis, Frank L.: "Aircraft
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Control and Simulation", Wiley and Sons, 1992.
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ISBN 0-471-61397-5
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----------------------------------------------------------------------------
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CALLED BY: ls_aux
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----------------------------------------------------------------------------
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CALLS TO:
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----------------------------------------------------------------------------
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INPUTS:
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lat_geoc Geocentric latitude, radians, + = North
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radius C.G. radius to earth center, ft
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----------------------------------------------------------------------------
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OUTPUTS:
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lat_geod Geodetic latitude, radians, + = North
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alt C.G. altitude above mean sea level, ft
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sea_level_r radius from earth center to sea level at
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local vertical (surface normal) of C.G.
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--------------------------------------------------------------------------*/
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#endif // _FG_GEODESY_HXX
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