eci2aer cross check against AstroPy #33
Description
Thanks for porting over these MatLab codes! I was cross checking the eci2aer function with AstroPy before incorperating it into another project I am working on, but I must be missing something or these numbers are very far off...
from pymap3d.aer import eci2aer as eci2aer
from astropy.coordinates import SkyCoord, GCRS, EarthLocation, CartesianRepresentation, AltAz
from astropy import units as u
from datetime import datetime
import numpy as np
eci = np.asarray([-34320604.87943786,2010725.129018341, 2977059.1586334566]) # units in meters
lla = np.asarray([10.0,10.0, 100]) # units in degrees, degrees, meters
t = datetime(2020, 3, 15, 0, 0, 0) # time as a datetime object
sat = SkyCoord(x=eci[0]*u.m, y=eci[1]*u.m, z=eci[2]*u.m, frame=GCRS,
representation_type=CartesianRepresentation)
origin = EarthLocation(lat=lla[0]*u.deg, lon=lla[1]*u.deg, height=lla[2]*u.m)
sataltaz = sat.transform_to(AltAz(obstime=t,location=origin))
az, el, srange = eci2aer(eci[0], eci[1], eci[2], lla[0], lla[1], lla[2],t)
np.array(sataltaz.az)-az
#array([70.90364332])
np.array(sataltaz.alt)-el
#array([-120.90947987])
np.array(sataltaz.distance)-srange
#array([1.77086727e+11])
Is ECI ~ GCRS ? Any feedback is appreciated. If this is my error vice the projects, I will gladly delete this.