How to caculate the Desired Track, DTK

GPS/GNSS Development Boards
1

Hi ,

I have the coordinates from start (origin) and destination.

I wish them calculate the Course,Desired Track(DTK).

Ssomeone knows how calculated the course or as the case may be a C-program is available.

Thanks for any help.

Willy

2 
/*-----------------------------------------------------------------------------------------------**
**  Calculate bearing to target from point.                                                      **
**  Returns: bearing in degrees,  inputs: current lat/lon, target lat/lon                        **
**  NOTE:  Math lib requires units to be in RADIANS
** Formula:                                                                                      **
** Bearing = atan2( sin(dLon).cos(lat2),cos(lat1).sin(lat2) - sin(lat1).cos(lat2).cos(d_long) )  **
**                                                                                               **
** y = sin(dLon) * cos(lat2);                                                                    **
** x = cos(lat1) * sin(lat2) - sin(lat1) * cos(lat2)* cos(dLon);                                 **
** bearing = atan2(y, x);                                                                        **
**-----------------------------------------------------------------------------------------------*/

                                                                                                                         
double calcBearing(double CurrentLatitude, double CurrentLongitude, double SavedLatitude, double SavedLongitude)        
 {                                                                                                                       
     double RadToDegrees =  57.2957795;                                                                                  
     double DegToRadians = 0.017453293;         // (PI/180)  0.017453293                                                 
     double DeltaLongitude, x, y, Bearing;   //                                                                          
                                                                                                                         
     // degrees to radians                                                                                               
     CurrentLatitude = (CurrentLatitude + 180) * DegToRadians;     // Remove negative offset (0-360), convert to RADS    
     CurrentLongitude = (CurrentLongitude + 180) * DegToRadians;                                                         
     SavedLatitude = (SavedLatitude + 180) * DegToRadians;                                                               
     SavedLongitude = (SavedLongitude + 180) * DegToRadians;                                                             
                                                                                                                         
     //CurrentLatitude = CurrentLatitude  * DegToRadians;     // convert to RADS                                         
     //CurrentLongitude = CurrentLongitude * DegToRadians;                                                               
     //SavedLatitude = SavedLatitude * DegToRadians;                                                                     
     //SavedLongitude = SavedLongitude * DegToRadians;                                                                   
                                                                                                                         
     DeltaLongitude = SavedLongitude - CurrentLongitude;                                                                 
                                                                                                                         
     y = sin(DeltaLongitude) * cos(SavedLatitude);                                                                       
     x = (cos(CurrentLatitude) * sin(SavedLatitude)) - (sin(CurrentLatitude) * cos(SavedLatitude)* cos(DeltaLongitude)); 
     Bearing = atan2(y, x);                                                                                              
     Bearing = Bearing + RadToDegrees;                                                                                   
                                                                                                                         
     return(Bearing);                                                                                                    
 }

*/