Calculates the distance as measured over the earth's surface (the down range) for a given beam elevation and slant range.
beam_distance(range, elev, k = 4/3, lat = 35, re = 6378, rp = 6357)numeric. Slant range in m, the length of the skywave path between target and the radar antenna.
numeric. Beam elevation in degrees.
Standard refraction coefficient.
Geodetic latitude of the radar in degrees.
Earth equatorial radius in km.
Earth polar radius in km.
numeric. Beam distance (down range) in m.
depends on beam_height to calculate beam height.
# down range of the 5 degree elevation beam at a slant range of 100 km:
beam_distance(100000, 5)
#> [1] 99495.13