def test_tirs_to_itrs():
"""Check the coordinate transform accuracy."""
# test_frame = "ITRS"
allowable_pos_diff = 60 * u.mm
allowable_vel_diff = 0.05 * u.mm / u.s
rv_itrs = rv_tirs_true.transform_to(ITRS(obstime=time))
r_diff = pos_err(rv_itrs, rv_itrs_true)
v_diff = vel_err(rv_itrs, rv_itrs_true)
# print(f"r {test_frame} diff : {r_diff}")
# print(f"v {test_frame} diff : {v_diff}")
assert r_diff < allowable_pos_diff
assert v_diff < allowable_vel_diff
def test_itrs_to_teme():
"""Check the coordinate transform accuracy."""
# test_frame = "TEME"
allowable_pos_diff = 300 * u.mm
allowable_vel_diff = 0.23 * u.mm / u.s
rv_teme = rv_itrs_true.transform_to(TEME(obstime=time))
r_diff = pos_err(rv_teme, rv_teme_true)
v_diff = vel_err(rv_teme, rv_teme_true)
# print(f"r {rv_teme.name} diff : {r_diff}")
# print(f"v {rv_teme.name} diff : {v_diff}")
assert r_diff < allowable_pos_diff
assert v_diff < allowable_vel_diff
def test_j2000_to_gcrs():
"""Check the coordinate transform accuracy."""
# test_frame = "GCRS"
allowable_pos_diff = 800 * u.mm
allowable_vel_diff = 0.36 * u.mm / u.s
rv_gcrs = rv_j2000_true.transform_to(GCRS(obstime=time))
r_diff = pos_err(rv_gcrs, rv_gcrs_true)
v_diff = vel_err(rv_gcrs, rv_gcrs_true)
# print(f"r {test_frame} diff : {r_diff}")
# print(f"v {test_frame} diff : {v_diff}")
assert r_diff < allowable_pos_diff
assert v_diff < allowable_vel_diff
def test_j2000_roundtrip():
"""Check whether transforming to a coord and then
transforming back yields the same output."""
# test_frame = "J2000"
allowable_pos_diff = 1.5e-6 * u.mm
allowable_vel_diff = 1.0e-9 * u.mm / u.s
rv_gcrs = rv_j2000_true.transform_to(GCRS(obstime=time))
rv_j2000_from_gcrs = rv_gcrs.transform_to(J2000(obstime=time))
r_diff = pos_err(rv_j2000_from_gcrs, rv_j2000_true)
v_diff = vel_err(rv_j2000_from_gcrs, rv_j2000_true)
# print(f"r {test_frame} diff : {r_diff}")
# print(f"v {test_frame} diff : {v_diff}")
assert r_diff < allowable_pos_diff
assert v_diff < allowable_vel_diff
def test_itrs_roundtrip():
"""Check whether transforming to a coord and then
transforming back yields the same output."""
# test_frame = "ITRS"
allowable_pos_diff = 1.5e-6 * u.mm
allowable_vel_diff = 2.8e-6 * u.mm / u.s
rv_teme = rv_itrs_true.transform_to(TEME(obstime=time))
rv_itrs_from_teme = rv_teme.transform_to(ITRS(obstime=time))
r_diff = pos_err(rv_itrs_from_teme, rv_itrs_true)
v_diff = vel_err(rv_itrs_from_teme, rv_itrs_true)
# print(f"r {rv_itrs_true.name} diff : {r_diff}")
# print(f"v {rv_itrs_true.name} diff : {v_diff}")
assert r_diff < allowable_pos_diff
assert v_diff < allowable_vel_diff
def test_cb_crs_to_icrs_earth():
"""Check the basic quasi-round-trip accuracy for the generic Central Body Celestial
Reference System, using Earth (equal to GCRS). Converts GCRS to ICRS, then ICRS to
Earth CRS. However there is a difference, possibly due to the difference between
the two transformations (`FunctionTransformWithFiniteDifference` vs
`AffineTransform`)"""
allowable_pos_diff = 800 * u.m
allowable_vel_diff = 0.510 * u.m / u.s
rv_icrs = SkyCoord(rv_gcrs_true).transform_to(ICRS)
rv_gcrs = rv_icrs.transform_to(_EarthCRS)
r_diff = pos_err(rv_gcrs, rv_gcrs_true)
v_diff = vel_err(rv_gcrs, rv_gcrs_true)
# print(f"r {rv_gcrs.name} diff : {r_diff}")
# print(f"v {rv_gcrs.name} diff : {v_diff}")
assert r_diff < allowable_pos_diff
assert v_diff < allowable_vel_diff
def test_cb_crs_to_icrs_sun():
"""Check the basic quasi-round-trip accuracy for the generic Central Body Celestial
Reference System, using Sun (equal to HCRS). Converts Sun CRS to ICRS, then ICRS to
HCRS."""
allowable_pos_diff = 5e-4 * u.mm
allowable_vel_diff = 0.0001 * u.mm / u.s
rv_suncrs_true = init_pvt(_SunCRS, time,
r_gcrs_true.with_differentials(v_gcrs_true))
rv_icrs = rv_suncrs_true.transform_to(ICRS)
rv_hcrs = rv_icrs.transform_to(HCRS)
r_diff = pos_err(rv_hcrs, rv_suncrs_true)
v_diff = vel_err(rv_hcrs, rv_suncrs_true)
# print(f"r {rv_hcrs.name} diff : {r_diff}")
# print(f"v {rv_hcrs.name} diff : {v_diff}")
assert r_diff < allowable_pos_diff
assert v_diff < allowable_vel_diff
def test_equatorial_mars():
"""NASA HORIZONS/GMAT testing between CRS and TOD & J2000 Equatorial
as well as Body Fixed (GMAT).
GMAT and HORIZONS use a different model in the IAU polar rotation parameters
(IAU 2000). Therefore test setup uses this version but not IAU 2015 versions.
Satellite orbit is taken from Mars Reconnaissance Orbiter,
using the NASA Horizons Web Interface (https://ssd.jpl.nasa.gov/horizons.cgi)."""
obstime = Time("2020-01-10T11:30:00.0003", scale="tdb")
v_eq_horz = CartesianDifferential(
[-2.061955207079347, -2.671302888480574, 0.269551765393186],
unit=u.km / u.s,
)
r_eq_horz = CartesianRepresentation(
[322.259677663235, 120.3781499221643, 3676.074343158492], unit=u.km)
rv_eq_horz = init_pvt(_MarsIAU2000TODEquatorial, obstime, r_eq_horz,
v_eq_horz)
v_inert_horz = CartesianDifferential(
[-2.062805178080304, -2.670750348642094, 0.2685217398016297],
unit=u.km / u.s,
)
r_inert_horz = CartesianRepresentation(
[321.472501283011, 119.500545946684, 3676.171898278387], unit=u.km)
rv_inert_horz = init_pvt(_MarsIAU2000J2000Equatorial, obstime,
r_inert_horz, v_inert_horz)
v_body_fixed_gmat = CartesianDifferential(
[0.622659762445902, 3.329753468204519, 0.2695517652769852],
unit=u.km / u.s,
)
r_body_fixed_gmat = CartesianRepresentation(
[-233.7124768823157, -252.4295484193542, 3676.074343157078], unit=u.km)
rv_body_fixed_gmat = init_pvt(_MarsIAU2000BodyFixed, obstime,
r_body_fixed_gmat, v_body_fixed_gmat)
allowable_pos_diff = 800 * u.mm
allowable_vel_diff = 0.35 * u.mm / u.s
# init CRS - modify frame name to point at test coords
pvt_crs = _init_orbit_mars()
pvt_crs.frame.body_name = "Mars_IAU_2000"
# Convert to TOD Equatorial
pvt_tod_eq = pvt_crs.transform_to(_MarsIAU2000TODEquatorial)
# Convert to J2000 Equatorial
pvt_j2000_eq = pvt_crs.transform_to(_MarsIAU2000J2000Equatorial)
# Convert to Body Fixed
pvt_body_fixed = pvt_crs.transform_to(_MarsIAU2000BodyFixed)
print(pvt_crs)
print(pvt_tod_eq)
print(pvt_j2000_eq)
print(pvt_body_fixed)
print(pos_err(pvt_body_fixed, rv_body_fixed_gmat))
print(vel_err(pvt_body_fixed, rv_body_fixed_gmat))
# Diff between TOD Eq values
assert pos_err(pvt_tod_eq, rv_eq_horz) < allowable_pos_diff
assert vel_err(pvt_tod_eq, rv_eq_horz) < allowable_vel_diff
# Diff between J2000 Eq (Inertial) values
assert pos_err(pvt_j2000_eq, rv_inert_horz) < allowable_pos_diff
assert vel_err(pvt_j2000_eq, rv_inert_horz) < allowable_vel_diff
# Diff between Body Fixed values
assert pos_err(pvt_body_fixed, rv_body_fixed_gmat) < allowable_pos_diff
assert vel_err(pvt_body_fixed, rv_body_fixed_gmat) < allowable_vel_diff