Function navtk::navutils::transverse_radius

Function Documentation

double navtk::navutils::transverse_radius(double latitude)

Calculate the transverse radius of curvature (termed \(R_E\) in Titterton and Weston, sometimes called \(R_N\)).

This is the radius of curvature in the east-west direction (i.e., normal to a meridian), which varies according to latitude. The radius of curvature can be used to relate change in longitude ( \(d\lambda\)) to change in the east direction in a local-level frame expressed in meters ( \(d\text{East}\)):

\( d\text{East} = R_N \cos\phi d\lambda \)

where \(\phi\) is the latitude.

REFERENCES:

See also

meridian_radius()

Strapdown Inertial Navigation Technology 2nd ed, Titterton and Weston, eq. 3.84

WGS-84 Reference System (NIMA report TR 8350.2), page 7-5.

Parameters

latitude – WGS-84 latitude (radians)

Returns

Radius of curvature in north/south direction (along a meridian) (meters).