Constants

Constants used in the processing can be found in the source files constants.h and refsystems.h. The main parameters in constants.h are:

 const real8     SOL        = 299792458.;   // speed of light in m/s
 const real8     EPS        = 1e-13;        // small number
 const int32     NaN        = -999;         // Not a Number
 const real8     PI         = 4.*atan(1.);

The main parameters in refsystems.h are (actually only WGS is used for now):

 const   real8   WGS84_A=6378137.0;              // semimajor axis wgs84
 const   real8   WGS84_B=6356752.3;              // semiminor axis wgs84
 const   real8   GRS80_A=6378137.0;              // semimajor axis grs80
 const   real8   GRS80_B=6356752.3;              // semiminor axis grs80
 const   real8   BESSEL_A=6377397.155;           // semimajor axis bessel
 const   real8   BESSEL_B=6356078.963;           // semiminor axis bessel
 const   real8   RADIUS=.5*(WGS84_A+WGS84_B);    // for sphere pol2car