code: def aer2ecef(
      az,
      el,
      srange,
      lat0,
      lon0,
      alt0,
      ell: Ellipsoid = None,
      deg: bool = True,
  ) -> tuple:
      """
      converts target azimuth, elevation, range from observer at lat0,lon0,alt0 to ECEF coordinates.
  
      Parameters
      ----------
      az : float
           azimuth to target
      el : float
           elevation to target
      srange : float
           slant range [meters]
      lat0 : float
             Observer geodetic latitude
      lon0 : float
             Observer geodetic longitude
      alt0 : float
           observer altitude above geodetic ellipsoid (meters)
      ell : Ellipsoid, optional
            reference ellipsoid
      deg : bool, optional
            degrees input/output  (False: radians in/out)
  
      Returns
      -------
  
      ECEF (Earth centered, Earth fixed)  x,y,z
  
      x : float
          ECEF x coordinate (meters)
      y : float
          ECEF y coordinate (meters)
      z : float
          ECEF z coordinate (meters)
  
  
      Notes
      ------
      if srange==NaN, z=NaN
      """
      # Origin of the local system in geocentric coordinates.
      x0, y0, z0 = geodetic2ecef(lat0, lon0, alt0, ell, deg=deg)
      # Convert Local Spherical AER to ENU
      e1, n1, u1 = aer2enu(az, el, srange, deg=deg)
      # Rotating ENU to ECEF
      dx, dy, dz = enu2uvw(e1, n1, u1, lat0, lon0, deg=deg)
      # Origin + offset from origin equals position in ECEF
      return x0 + dx, y0 + dy, z0 + dz
  
file_path: pymap3d/src/pymap3d/aer.py
imports: from __future__ import annotations
  from datetime import datetime
  from .ecef import ecef2enu, ecef2geodetic, enu2uvw, geodetic2ecef
  from .ellipsoid import Ellipsoid
  from .enu import aer2enu, enu2aer, geodetic2enu
label_desc: Use image node_id 6 for calling a global function with example usage: aer2ecef(az, el, srange, lat0, lon0, alt0, ell, deg) and returns: unknown,  unknown,  unknown