def aer2ned(az: float, elev: float, slantRange: float,
            deg: bool = True) -> Tuple[float, float, float]:
    """
    converts azimuth, elevation, range to target from observer to North, East, Down

    Parameters
    -----------

    az : float or numpy.ndarray of float
         azimuth
    elev : float or numpy.ndarray of float
         elevation
    slantRange : float or numpy.ndarray of float
         slant range [meters]
    deg : bool, optional
          degrees input/output  (False: radians in/out)

    Results
    -------
    n : float or numpy.ndarray of float
        North NED coordinate (meters)
    e : float or numpy.ndarray of float
        East NED coordinate (meters)
    d : float or numpy.ndarray of float
        Down NED coordinate (meters)
    """
    e, n, u = aer2enu(az, elev, slantRange, deg=deg)

    return n, e, -u
converts azimuth, elevation, range to target from observer to North, East, Down

    Parameters
    -----------

    az : float or numpy.ndarray of float
         azimuth
    elev : float or numpy.ndarray of float
         elevation
    slantRange : float or numpy.ndarray of float
         slant range [meters]
    deg : bool, optional
          degrees input/output  (False: radians in/out)

    Results
    -------
    n : float or numpy.ndarray of float
        North NED coordinate (meters)
    e : float or numpy.ndarray of float
        East NED coordinate (meters)
    d : float or numpy.ndarray of float
        Down NED coordinate (meters)