Calculating the distance between two points

GPS/GNSS Development Boards
4

I based my code using the JavaScript examples shown here:

http://www.movable-type.co.uk/scripts/latlong.html

You have to decide how often to aggregate the samples. I’m using 1/16th of a mile right now, but this might need tweaking as I get a better idea of the accuracy over time.

My code for the Arduino looks like:

#define MILES_PER_METER 0.00062137f

#define EARTH_RADIUS_METERS 6372795.0f

:

float distance = DistanceBetween2Points( latitude, longitude, f_lat, f_lon, MILES_PER_METER );

:

//************************

// Great Circle distance calculation

// Returns the distance between two lat/lon points on this great Earth

// (Note: Assumes sea level, does not take into account altitude. Close enough.)

//

float DistanceBetween2Points( float Lat1, float Lon1, float Lat2, float Lon2, float unit_conversion )

{

float dLat = radians( Lat2 - Lat1 );

float dLon = radians( Lon2 - Lon1 );

float a = sin( dLat / 2.0f ) * sin( dLat / 2.0f ) +

cos( radians( Lat1 ) ) * cos( radians( Lat2 ) ) *

sin( dLon / 2.0f ) * sin( dLon / 2.0f );

float d = 2.0f * atan2( sqrt( a ), sqrt( 1.0f - a ) );

return d * EARTH_RADIUS_METERS * unit_conversion;

}