Initial revision.

1997-07-31 23:13:14 +00:00
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+/**************************************************************************
+ * fg_geodesy.h -- routines to convert between geodetic and geocentric 
+ *                 coordinate systems.
+ *
+ * Copied and adapted directly from LaRCsim/ls_geodesy.c
+ *
+ * See below for the complete original LaRCsim comments.
+ *
+ * $Id$
+ * (Log is kept at end of this file)
+ **************************************************************************/
+
+
+#ifndef FG_GEODESY_H
+#define FG_GEODESY_H
+
+
+/* fgGeocToGeod(lat_geoc, radius, *lat_geod, *alt, *sea_level_r)
+ *     INPUTS:	
+ *         lat_geoc	Geocentric latitude, radians, + = North
+ *         radius	C.G. radius to earth center, ft
+ *
+ *     OUTPUTS:
+ *         lat_geod	Geodetic latitude, radians, + = North
+ *         alt		C.G. altitude above mean sea level, ft
+ *         sea_level_r	radius from earth center to sea level at
+ *                      local vertical (surface normal) of C.G.
+ */
+
+void fgGeocToGeod( double lat_geoc, double radius, double
+		   *lat_geod, double *alt, double *sea_level_r );
+
+/* fgGeodToGeoc( lat_geod, alt, *sl_radius, *lat_geoc )
+ *     INPUTS:	
+ *         lat_geod	Geodetic latitude, radians, + = North
+ *         alt		C.G. altitude above mean sea level, ft
+ *
+ *     OUTPUTS:
+ *         sl_radius	SEA LEVEL radius to earth center, ft (add Altitude to
+ *                      get true distance from earth center.
+ *         lat_geoc	Geocentric latitude, radians, + = North
+ *
+ */
+
+void fgGeodToGeoc( double lat_geod, double alt, double *sl_radius,
+		   double *lat_geoc );
+
+
+
+/***************************************************************************
+
+	TITLE:	ls_geodesy
+	
+----------------------------------------------------------------------------
+
+	FUNCTION:	Converts geocentric coordinates to geodetic positions
+
+----------------------------------------------------------------------------
+
+	MODULE STATUS:	developmental
+
+----------------------------------------------------------------------------
+
+	GENEALOGY:	Written as part of LaRCSim project by E. B. Jackson
+
+----------------------------------------------------------------------------
+
+	DESIGNED BY:	E. B. Jackson
+	
+	CODED BY:	E. B. Jackson
+	
+	MAINTAINED BY:	E. B. Jackson
+
+----------------------------------------------------------------------------
+
+	MODIFICATION HISTORY:
+	
+	DATE	PURPOSE						BY
+	
+	930208	Modified to avoid singularity near polar region.	EBJ
+	930602	Moved backwards calcs here from ls_step.		EBJ
+	931214	Changed erroneous Latitude and Altitude variables to 
+		*lat_geod and *alt in routine ls_geoc_to_geod.		EBJ
+	940111	Changed header files from old ls_eom.h style to ls_types, 
+		and ls_constants.  Also replaced old DATA type with new
+		SCALAR type.						EBJ
+
+	CURRENT RCS HEADER:
+
+$Header$
+$Log$
+Revision 1.1  1997/07/31 23:13:14  curt
+Initial revision.
+
+Revision 1.1  1997/05/29 00:09:56  curt
+Initial Flight Gear revision.
+
+ * Revision 1.5  1994/01/11  18:47:05  bjax
+ * Changed include files to use types and constants, not ls_eom.h
+ * Also changed DATA type to SCALAR type.
+ *
+ * Revision 1.4  1993/12/14  21:06:47  bjax
+ * Removed global variable references Altitude and Latitude.   EBJ
+ *
+ * Revision 1.3  1993/06/02  15:03:40  bjax
+ * Made new subroutine for calculating geodetic to geocentric; changed name
+ * of forward conversion routine from ls_geodesy to ls_geoc_to_geod.
+ *
+
+----------------------------------------------------------------------------
+
+	REFERENCES:
+
+		[ 1]	Stevens, Brian L.; and Lewis, Frank L.: "Aircraft 
+			Control and Simulation", Wiley and Sons, 1992.
+			ISBN 0-471-61397-5		      
+
+
+----------------------------------------------------------------------------
+
+	CALLED BY:	ls_aux
+
+----------------------------------------------------------------------------
+
+	CALLS TO:
+
+----------------------------------------------------------------------------
+
+	INPUTS:	
+		lat_geoc	Geocentric latitude, radians, + = North
+		radius		C.G. radius to earth center, ft
+
+----------------------------------------------------------------------------
+
+	OUTPUTS:
+		lat_geod	Geodetic latitude, radians, + = North
+		alt		C.G. altitude above mean sea level, ft
+		sea_level_r	radius from earth center to sea level at
+				local vertical (surface normal) of C.G.
+
+--------------------------------------------------------------------------*/
+
+
+#endif /* FG_GEODESY_H */
+
+
+/* $Log$
+/* Revision 1.1  1997/07/31 23:13:14  curt
+/* Initial revision.
+/*
+ */