coordframe.go

package nvector

var (
	// ZAxisNorth defines the axes of the coordinate frame E (Earth-Centred,
	// Earth-Fixed, ECEF) when the z-axis points to the North Pole.
	//
	// The z-axis points to the North Pole and x-axis points to the point where
	// latitude = longitude = 0. This choice is very common in many fields.
	//
	// See: https://github.com/FFI-no/n-vector/blob/f77f43d18ddb6b8ea4e1a8bb23a53700af965abb/nvector/R_Ee.m#L48
	ZAxisNorth = Matrix{
		0, 0, 1,
		0, 1, 0,
		-1, 0, 0,
	}

	// XAxisNorth defines the axes of the coordinate frame E (Earth-Centred,
	// Earth-Fixed, ECEF) when the x-axis points to the North Pole.
	//
	// The x-axis points to the North Pole, y-axis points towards longitude +90deg
	// (east) and latitude = 0. This choice of axis directions ensures that at
	// zero latitude and longitude, N (North-East-Down) has the same orientation
	// as E. If roll/pitch/yaw are zero, also B (Body, forward, starboard, down)
	// has this orientation. In this manner, the axes of E is chosen to correspond
	// with the axes of N and B.
	//
	// See: https://github.com/FFI-no/n-vector/blob/f77f43d18ddb6b8ea4e1a8bb23a53700af965abb/nvector/R_Ee.m#L55
	XAxisNorth = Matrix{
		1, 0, 0,
		0, 1, 0,
		0, 0, 1,
	}
)