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)

Arguments

range

Numeric. Slant range, i.e. the length of the skywave path between target and the radar antenna, in m.

elev

Numeric. Beam elevation, in degrees.

k

Numeric. Standard refraction coefficient.

lat

Numeric. Geodetic latitude of the radar, in degrees.

re

Numeric. Earth equatorial radius, in km.

rp

Numeric. Earth polar radius, in km.

Value

Beam distance (down range), in m.

Details

depends on beam_height to calculate beam height.

Examples

# Down range of the 5 degree elevation beam at a slant range of 100 km:
beam_distance(100000, 5)
#> [1] 99495.13