Function navtk::navutils::delta_lat_to_north

Function Documentation

double navtk::navutils::delta_lat_to_north(double delta_lat, double approx_lat, double altitude = 0.0)

Converts small changes of latitude (radians) into distance in meters along the North axis of the local level NED frame.

Input parameters are with respect to the WGS-84 ellipsoid.

This conversion is approximate, and the error grows as the delta_lat grows.

Example:

delta_lat = \(Lat_1 - Lat_0\) (radians)

approx_lat = \((Lat_1 + Lat_0)/2\) (or just \(Lat_0\) or \(Lat_1\)) (radians)

altitude = approximate WGS-84 altitude (meters)

The function will return the approximate distance, in meters, between the points ( \(Lat_1\), \(Lon\), altitude) and ( \(Lat_0\), \(Lon\), altitude) for any longitude \(Lon\). The sign of the output matches the sign of the delta_lat input.

See also

delta_lon_to_east()

See also

north_to_delta_lat() for the companion function that converts in the opposite direction.

See also

east_to_delta_lon()

Parameters

  • delta_lat – Small distance in latitude to convert (radians)

  • approx_lat – Approximate latitude (radians)

  • altitude – WGS-84 altitude (ellipsoidal) (meters)

Returns

Equivalent distance in the north direction (meters).