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odm/tests/test_formats.py
ThePetrovich 5303986377 Initial commit
2026-08-18 22:03:52 +08:00

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"""TLE / OMM format conversion tests.
Round-trip checks: ``parse_tle -> tle_from_gp`` should reproduce the underlying
orbit (compared via sgp4) to within float tolerance. OMM XML rendering must
emit every CCSDS-mandatory field, and the parser must handle the real-world
``<ndm>`` wrapper Space-Track ships in its archive exports.
"""
from __future__ import annotations
import math
import pytest
from sgp4.api import Satrec
from odm import (
OmmRecord,
as_omm_xml,
as_txt_txt,
as_plaintext,
omm_xml_to_records,
parse_tle,
tle_from_gp,
)
ISS = (
"ISS (ZARYA)",
"1 25544U 98067A 24070.50000000 .00012345 00000-0 22000-3 0 9991",
"2 25544 51.6400 200.0000 0001234 90.0000 270.0000 15.50000000400000",
)
NOAA15 = (
"NOAA 15",
"1 25338U 98030A 24070.20000000 .00000050 00000-0 31000-4 0 9990",
"2 25338 98.7000 100.0000 0010000 10.0000 350.0000 14.26000000900000",
)
# Real-world Space-Track archive sample (verbatim from user-supplied issue),
# trimmed to two records to keep the test fast.
SPACETRACK_ARCHIVE_XML = """\
<ndm xsi:noNamespaceSchemaLocation="https://sanaregistry.org/r/ndmxml_unqualified/ndmxml-3.0.0-master-3.0.xsd">
<omm id="CCSDS_OMM_VERS" version="3.0">
<header>
<COMMENT>GENERATED VIA SPACE-TRACK.ORG API</COMMENT>
<CREATION_DATE>2026-01-08T05:20:27</CREATION_DATE>
<ORIGINATOR>18 SPCS</ORIGINATOR>
</header>
<body>
<segment>
<metadata>
<OBJECT_NAME>TBA - TO BE ASSIGNED</OBJECT_NAME>
<OBJECT_ID>2025-313AU</OBJECT_ID>
<CENTER_NAME>EARTH</CENTER_NAME>
<REF_FRAME>TEME</REF_FRAME>
<TIME_SYSTEM>UTC</TIME_SYSTEM>
<MEAN_ELEMENT_THEORY>SGP4</MEAN_ELEMENT_THEORY>
</metadata>
<data>
<meanElements>
<EPOCH>2026-01-06T22:50:56.049504</EPOCH>
<MEAN_MOTION>15.21286088</MEAN_MOTION>
<ECCENTRICITY>0.00095778</ECCENTRICITY>
<INCLINATION>97.4119</INCLINATION>
<RA_OF_ASC_NODE>84.2715</RA_OF_ASC_NODE>
<ARG_OF_PERICENTER>195.9225</ARG_OF_PERICENTER>
<MEAN_ANOMALY>164.1711</MEAN_ANOMALY>
</meanElements>
<tleParameters>
<EPHEMERIS_TYPE>0</EPHEMERIS_TYPE>
<CLASSIFICATION_TYPE>U</CLASSIFICATION_TYPE>
<NORAD_CAT_ID>67290</NORAD_CAT_ID>
<ELEMENT_SET_NO>999</ELEMENT_SET_NO>
<REV_AT_EPOCH>143</REV_AT_EPOCH>
<BSTAR>0.00053078883000</BSTAR>
<MEAN_MOTION_DOT>0.00011823</MEAN_MOTION_DOT>
<MEAN_MOTION_DDOT>0.0000000000000</MEAN_MOTION_DDOT>
</tleParameters>
<userDefinedParameters>
<USER_DEFINED parameter="SEMIMAJOR_AXIS">6880.097</USER_DEFINED>
<USER_DEFINED parameter="PERIOD">94.657</USER_DEFINED>
<USER_DEFINED parameter="APOAPSIS">508.552</USER_DEFINED>
<USER_DEFINED parameter="PERIAPSIS">495.373</USER_DEFINED>
<USER_DEFINED parameter="OBJECT_TYPE">UNKNOWN</USER_DEFINED>
<USER_DEFINED parameter="RCS_SIZE"/>
<USER_DEFINED parameter="COUNTRY_CODE"/>
<USER_DEFINED parameter="LAUNCH_DATE"/>
<USER_DEFINED parameter="SITE"/>
<USER_DEFINED parameter="DECAY_DATE"/>
<USER_DEFINED parameter="FILE">4962752</USER_DEFINED>
<USER_DEFINED parameter="GP_ID">308346717</USER_DEFINED>
</userDefinedParameters>
</data>
</segment>
</body>
</omm>
<omm id="CCSDS_OMM_VERS" version="3.0">
<header>
<COMMENT>GENERATED VIA SPACE-TRACK.ORG API</COMMENT>
<CREATION_DATE>2026-01-08T15:46:24</CREATION_DATE>
<ORIGINATOR>18 SPCS</ORIGINATOR>
</header>
<body>
<segment>
<metadata>
<OBJECT_NAME>TBA - TO BE ASSIGNED</OBJECT_NAME>
<OBJECT_ID>2025-313AU</OBJECT_ID>
<CENTER_NAME>EARTH</CENTER_NAME>
<REF_FRAME>TEME</REF_FRAME>
<TIME_SYSTEM>UTC</TIME_SYSTEM>
<MEAN_ELEMENT_THEORY>SGP4</MEAN_ELEMENT_THEORY>
</metadata>
<data>
<meanElements>
<EPOCH>2026-01-08T11:09:24.647040</EPOCH>
<MEAN_MOTION>15.21321390</MEAN_MOTION>
<ECCENTRICITY>0.00096980</ECCENTRICITY>
<INCLINATION>97.4116</INCLINATION>
<RA_OF_ASC_NODE>85.7604</RA_OF_ASC_NODE>
<ARG_OF_PERICENTER>190.1005</ARG_OF_PERICENTER>
<MEAN_ANOMALY>170.0038</MEAN_ANOMALY>
</meanElements>
<tleParameters>
<EPHEMERIS_TYPE>0</EPHEMERIS_TYPE>
<CLASSIFICATION_TYPE>U</CLASSIFICATION_TYPE>
<NORAD_CAT_ID>67290</NORAD_CAT_ID>
<ELEMENT_SET_NO>999</ELEMENT_SET_NO>
<REV_AT_EPOCH>166</REV_AT_EPOCH>
<BSTAR>0.00055242000000</BSTAR>
<MEAN_MOTION_DOT>0.00012321</MEAN_MOTION_DOT>
<MEAN_MOTION_DDOT>0.0000000000000</MEAN_MOTION_DDOT>
</tleParameters>
</data>
</segment>
</body>
</omm>
</ndm>
"""
@pytest.mark.parametrize("name,l1,l2", [ISS, NOAA15])
def test_parse_tle_yields_expected_omm(name, l1, l2):
parsed = parse_tle(name, l1, l2)
assert parsed.omm["NORAD_CAT_ID"] == int(l1[2:7])
assert math.isclose(parsed.omm["INCLINATION"], float(l2[8:16]), abs_tol=1e-4)
@pytest.mark.parametrize("name,l1,l2", [ISS, NOAA15])
def test_round_trip_preserves_orbit(name, l1, l2):
parsed = parse_tle(name, l1, l2)
name_out, l1_out, l2_out = tle_from_gp(parsed.omm)
assert l1_out.startswith("1 ")
assert l2_out.startswith("2 ")
assert len(l1_out) == 69
assert len(l2_out) == 69
sat_a = Satrec.twoline2rv(l1, l2)
sat_b = Satrec.twoline2rv(l1_out, l2_out)
assert sat_a.satnum == sat_b.satnum
assert math.isclose(sat_a.inclo, sat_b.inclo, abs_tol=1e-5)
assert math.isclose(sat_a.nodeo, sat_b.nodeo, abs_tol=1e-5)
assert math.isclose(sat_a.ecco, sat_b.ecco, abs_tol=1e-7)
assert math.isclose(sat_a.argpo, sat_b.argpo, abs_tol=1e-5)
assert math.isclose(sat_a.mo, sat_b.mo, abs_tol=1e-5)
assert math.isclose(sat_a.no_kozai, sat_b.no_kozai, abs_tol=1e-7)
def test_txt_txt_format():
name, l1, l2 = ISS
parsed = parse_tle(name, l1, l2)
out = as_txt_txt([(parsed.name, parsed.line1, parsed.line2)])
lines = out.split("\r\n")
assert lines[0] == parsed.name[:24].ljust(24)
assert lines[1] == parsed.line1
assert lines[2] == parsed.line2
assert lines[3] == ""
def test_plaintext_format_has_trailing_newline():
out = as_plaintext(*ISS)
assert out.endswith("\n")
assert out.count("\n") == 3
def test_omm_xml_contains_all_mandatory_fields():
parsed = parse_tle(*ISS)
rec = OmmRecord(
omm=parsed.omm,
object_name=parsed.name,
object_id=parsed.omm["OBJECT_ID"],
originator="YKSA",
mean_element_theory="SGP4",
)
xml = as_omm_xml([rec], originator="YKSA")
assert xml.startswith("<?xml")
assert "<omm" in xml and 'id="CCSDS_OMM_VERS"' in xml and 'version="3.0"' in xml
assert "<CREATION_DATE>" in xml
assert "<ORIGINATOR>YKSA</ORIGINATOR>" in xml
for field in (
"OBJECT_NAME", "OBJECT_ID", "CENTER_NAME", "REF_FRAME",
"TIME_SYSTEM", "MEAN_ELEMENT_THEORY",
):
assert f"<{field}>" in xml, f"missing mandatory metadata field {field}"
for field in (
"EPOCH", "MEAN_MOTION", "ECCENTRICITY", "INCLINATION",
"RA_OF_ASC_NODE", "ARG_OF_PERICENTER", "MEAN_ANOMALY",
):
assert f"<{field}>" in xml, f"missing mandatory meanElements field {field}"
assert "<tleParameters>" in xml
for field in ("NORAD_CAT_ID", "BSTAR", "MEAN_MOTION_DOT"):
assert f"<{field}>" in xml
def test_omm_xml_round_trip_preserves_orbit():
parsed = parse_tle(*ISS)
rec = OmmRecord(
omm=parsed.omm,
object_name=parsed.name,
object_id=parsed.omm["OBJECT_ID"],
mean_element_theory="SGP4",
)
xml = as_omm_xml([rec])
parsed_back = list(omm_xml_to_records(xml))
assert len(parsed_back) == 1
rt = parsed_back[0]
assert rt.object_name == parsed.name
assert rt.mean_element_theory == "SGP4"
assert rt.ref_frame == "TEME"
assert math.isclose(rt.omm["INCLINATION"], parsed.omm["INCLINATION"], abs_tol=1e-9)
assert math.isclose(rt.omm["MEAN_MOTION"], parsed.omm["MEAN_MOTION"], abs_tol=1e-12)
# NORAD_CAT_ID round-trips through OMM XML as a string (to accommodate the
# future alphanumeric Space-Track catalog IDs).
assert str(rt.omm["NORAD_CAT_ID"]) == str(parsed.omm["NORAD_CAT_ID"])
def test_omm_xml_omits_tle_params_for_non_sgp_theories():
parsed = parse_tle(*ISS)
rec = OmmRecord(
omm=parsed.omm,
object_name=parsed.name,
object_id=parsed.omm["OBJECT_ID"],
mean_element_theory="DSST",
)
xml = as_omm_xml([rec])
assert "<tleParameters>" not in xml
assert "<MEAN_ELEMENT_THEORY>DSST</MEAN_ELEMENT_THEORY>" in xml
def test_omm_xml_parses_spacetrack_archive_format():
"""The Space-Track archive ships <ndm>-wrapped multi-document OMM with an
undeclared xsi: prefix and a vendor-specific <userDefinedParameters> block.
All three must be tolerated without losing structured data.
"""
records = list(omm_xml_to_records(SPACETRACK_ARCHIVE_XML))
assert len(records) == 2
a, b = records
# First record's precise numeric fields must survive verbatim -- this is
# the exact reason we treat OMM as canonical instead of round-tripping
# through TLE line 1.
assert a.omm["NORAD_CAT_ID"] == "67290"
assert math.isclose(a.omm["MEAN_MOTION_DOT"], 0.00011823, abs_tol=1e-12)
assert math.isclose(a.omm["BSTAR"], 0.00053078883, abs_tol=1e-14)
assert math.isclose(a.omm["MEAN_MOTION"], 15.21286088, abs_tol=1e-12)
# Second record carries its own creation date -- header context must be
# per-OMM, not shared across the whole <ndm>.
assert b.omm["NORAD_CAT_ID"] == "67290"
assert math.isclose(b.omm["BSTAR"], 0.00055242, abs_tol=1e-14)
# Metadata from the segment must be threaded through correctly.
assert a.mean_element_theory == "SGP4"
assert a.ref_frame == "TEME"
assert a.originator == "18 SPCS"
assert a.object_id == "2025-313AU"
# The original <omm> chunk must be preserved verbatim so we can hand it
# back to API consumers unchanged. The userDefinedParameters block must
# still be present in the stored XML even though we discard it from the
# structured dict.
assert "<omm" in a.omm_xml and "</omm>" in a.omm_xml
assert "userDefinedParameters" in a.omm_xml
assert "SEMIMAJOR_AXIS" in a.omm_xml
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