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, i.e. the length of the skywave path between target and the radar antenna, in m.
Numeric. Beam elevation, in degrees.
Numeric. Standard refraction coefficient.
Numeric. Geodetic latitude of the radar, in degrees.
Numeric. Earth equatorial radius, in km.
Numeric. Earth polar radius, in km.
Beam distance (down range), in m.
depends on beam_height to calculate beam height.
Other beam_functions:
beam_height(),
beam_profile(),
beam_profile_overlap(),
beam_range(),
beam_width(),
gaussian_beam_profile()
# Down range of the 5 degree elevation beam at a slant range of 100 km:
beam_distance(100000, 5)
#> [1] 99495.13