sgp4: reject SGP4-XP element sets (ephemeris type 4) with a clear error - #174
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sgp4: reject SGP4-XP element sets (ephemeris type 4) with a clear error#174ssmichael1 wants to merge 1 commit into
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An SGP4-XP line 1 stores agom and a B term in the columns a classic TLE uses for nddot and B*. satkit parsed those as nddot/bstar and ran classic SGP4 on them, returning a plausible but wrong state. The TLE and OMM SGP4 sources now return an UnsupportedEphemerisType error for type 4; parsing is unchanged so mixed catalogs still load. The Python dict-to-OMM converter never copied EPHEMERIS_TYPE, so the guard could not see it from that path; it now carries the field through (top level and tleParameters, int or numeric string). Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01QpWfy5Nh7LVU531hD5Lkwv
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Summary
sgp4()now refuses SGP4-XP element sets instead of silently propagating them, for TLE and OMM inputs, in Rust and Python.An SGP4-XP line 1 (ephemeris type 4, column 63) stores agom and a B term in the columns a classic TLE uses for nddot and B*. satkit parsed those as nddot/bstar and ran classic SGP4 on them, returning a plausible but wrong state.
Changes
tle::Error::UnsupportedEphemerisType(u8); theSGP4Sourceimpl returns it for type 4. Parsing is unchanged, so catalog files mixing types still load.EPHEMERIS_TYPE == 4with a matchingomm::Error::UnsupportedEphemerisType.omm_from_pydictnever copiedEPHEMERIS_TYPE, so the Rust guard could not see it. It now carries the field through (top level and nestedtleParameters, int or numeric string). Python raisesRuntimeErrormentioning SGP4-XP.ephem_type(Rust + stub), a paragraph in the SGP4 guide, changelog line.Not in scope: any SGP4-XP support. The reference implementation is distributed by USSF as Fortran binaries only; examined and dropped.
Tests
test_sgp4.py. Full suite minus GMAT: 169 passed.🤖 Generated with Claude Code
https://claude.ai/code/session_01QpWfy5Nh7LVU531hD5Lkwv