Function ecef_to_enu 

pub fn ecef_to_enu(
    x: f64,
    y: f64,
    z: f64,
    ref_lat_deg: f64,
    ref_lon_deg: f64,
    ref_alt_m: f64,
) -> (f64, f64, f64)

Converts a position in ECEF to Local Tangent Plane (ENU) relative to a reference point.