Given the n-vectors for positions A (n_EA_E) and B (n_EB_E), the output is the delta vector from A to B (p_AB_E).

## Usage

n_EA_E_and_n_EB_E2p_AB_E(
n_EA_E,
n_EB_E,
z_EA = 0,
z_EB = 0,
a = 6378137,
f = 1/298.257223563
)

## Arguments

n_EA_E

n-vector of position A, decomposed in E (3x1 vector) (no unit)

n_EB_E

n-vector of position B, decomposed in E (3x1 vector) (no unit)

z_EA

Depth of system A, relative to the ellipsoid (z_EA = -height) (m, default 0)

z_EB

Depth of system B, relative to the ellipsoid (z_EB = -height) (m, default 0)

a

Semi-major axis of the Earth ellipsoid (m, default [WGS-84] 6378137)

f

Flattening of the Earth ellipsoid (no unit, default [WGS-84] 1/298.257223563)

## Value

Position vector from A to B, decomposed in E (3x1 vector)

## Details

The calculation is exact, taking the ellipticity of the Earth into account. It is also nonsingular as both n-vector and p-vector are nonsingular (except for the center of the Earth). The default ellipsoid model used is WGS-84, but other ellipsoids (or spheres) might be specified via the optional parameters a and f.

## References

Kenneth Gade A Nonsingular Horizontal Position Representation. The Journal of Navigation, Volume 63, Issue 03, pp 395-417, July 2010.

n_EA_E_and_p_AB_E2n_EB_E, p_EB_E2n_EB_E and n_EB_E2p_EB_E

## Examples

lat_EA <- rad(1); lon_EA <- rad(2); z_EA   <- 3