def test_teme_loopback():
from_coo = TEME(1 * u.AU, 2 * u.AU, 3 * u.AU, obstime='2001-01-01')
to_frame = TEME(obstime='2001-06-30')
explicit_coo = from_coo.transform_to(ICRS()).transform_to(to_frame)
implicit_coo = from_coo.transform_to(to_frame)
# Confirm that the explicit transformation changes the coordinate
assert not allclose(
explicit_coo.cartesian.xyz, from_coo.cartesian.xyz, rtol=1e-10)
# Confirm that the loopback matches the explicit transformation
assert_allclose(explicit_coo.cartesian.xyz,
implicit_coo.cartesian.xyz,
rtol=1e-10)
def el2rv(inc, raan, ecc, argp, mean_anomaly, mean_motion, epoch):
"""
Converts mean orbital elements to state vector
"""
time_tle = epoch.jd - 2433281.5
sat = Satrec()
sat.sgp4init(
WGS84,
"i",
0,
time_tle,
0.0,
0.0,
0.0,
ecc,
argp,
inc,
mean_anomaly,
mean_motion,
raan,
)
errorCode, rTEME, vTEME = sat.sgp4(epoch.jd1, epoch.jd2)
if errorCode != 0:
raise RuntimeError(SGP4_ERRORS[errorCode])
pTEME = coord.CartesianRepresentation(rTEME * u.km)
vTEME = coord.CartesianDifferential(vTEME * u.km / u.s)
svTEME = TEME(pTEME.with_differentials(vTEME), obstime=epoch)
svITRS = svTEME.transform_to(coord.ITRS(obstime=epoch))
orb = Orbit.from_coords(Earth, svITRS)
return orb.r, orb.v
def test_teme_to_tirs_no_vel():
"""Check whether coord transform without velocity is possible."""
rv_teme_no_vel = TEME(r_teme_true,
obstime=time,
representation_type="cartesian")
rv_teme_no_vel.transform_to(TIRS(obstime=time))
0.0,
0.0,
ecc,
argp,
inc,
m_ano,
m_mot,
raan,
)
errorCode, rTEME, vTEME = sat.sgp4(epoch.jd1, epoch.jd2)
if errorCode != 0:
raise RuntimeError(SGP4_ERRORS[errorCode])
# Convert state vector from TEME (True Equator Mean Equinox) to ITRS
pTEME = coord.CartesianRepresentation(rTEME * u.km)
vTEME = coord.CartesianDifferential(vTEME * u.km / u.s)
svTEME = TEME(pTEME.with_differentials(vTEME), obstime=iss.epoch)
svITRS = svTEME.transform_to(coord.ITRS(obstime=iss.epoch))
sv = Orbit.from_coords(Earth, svITRS)
# Display results
print("State vector [rv2el]")
print(f" r = {sv.r}")
print(f" v = {sv.v}")
print()
print("State vector differences [poliastro - rv2el]")
print(f" dr = {iss.r - sv.r}")
print(f" dv = {iss.v - sv.v}")
print()
raise RuntimeError(SGP4_ERRORS[error_code])
# Convert SGP4 TEME to Astropy native TEME
teme_p = CartesianRepresentation(teme_p*u.km)
teme_v = CartesianDifferential(teme_v*u.km/u.s)
teme = TEME(teme_p.with_differentials(teme_v), obstime=t)
'''
itrs = teme.transform_to(ITRS(obstime=t))
location = itrs.earth_location
print(location.geodetic)
'''
# Lat/Lon/Alt of the Washington Monumnet
monumentLat = 38.889484
monumentLon = -77.035278
monumnetAlt = 169 # meters
# get the locations into similar coordinate system objects
#satellilteEarthLocation = ?.from_geocentric(xSat,ySat,zSat)
monumentEarthLocation = EarthLocation.from_geodetic(monumentLon,monumentLat,monumnetAlt)
aa = teme.transform_to(AltAz(obstime=t, location=monumentEarthLocation))
print('Altitude: ', aa.alt.degree)
print('Azimuth: ', aa.az.degree)
# Range is hyp of ground distance and sat geodetic altitude-monument altitude
# file, lat, lon, alt, heading, tilt, range, url
MakeKML('outFile.kml', monumentLat, monumentLon, monumnetAlt, aa.az.degree-180.0, 90.0-aa.alt.degree, 609374.8, url)