ENU-ROS Transformations package

An ENU tangential plane ROS Transformations package for navigation stacks and planners utility that solves curvature and ellipsoid behavior-based inaccuracies caused by planning in linearised standard geodetic data.

This package is a geodetic conversion package created for the AUVSI SUAS navigation stack. It runs various conversions between GPS, ECEF, NED and ENU co-ordinate frames.

This linearises the co-ordinate frame of any arbitrary map or data structure used by a planner while maintaining the appropriate references to geodetic curvature with a return to the first-order model of the earth as being flat. This Local Tangent Plane(LTP) serves as a local reference direction for representing vehicle attitude and velocity for operation on or near the surface of the earth.

To change the different geodetic systems, functions in include/transforms/geodetic_conv.h can be used:

enu-ros-tf/include/transforms/geodetic_conv.h

Lines 158 to 159 in 5e9cbfe

	void geodetic2Enu(const double latitude, const double longitude, const double altitude,
	double* east, double* north, double* up)

enu-ros-tf/include/transforms/geodetic_conv.h

Lines 75 to 76 in 5e9cbfe

	void geodetic2Ecef(const double latitude, const double longitude, const double altitude, double* x,
	double* y, double* z)

Inverse Haversine functionality:

This package includes an implementation of an Inverse haversine function that provides a GPS/ENU endpoint(as an Eigen Vector2d) given a GPS/ENU start point and a bearing angle clockwise from north.

enu-ros-tf/include/enu_transforms/enu_transforms.h

Line 166 in 5e9cbfe

Eigen::Vector2d inverseHaversine(Eigen::Vector2d gps, double bearing, double dist_ft);

Results:

ENU Frame local GridMap	GPS Points generated by Path Planner

99% GPS<->ENU<->GridMap reconversion accuracy (in feet)