Replace the sat_code git submodule (lib/sat_code/) with vendored
sources in src/sgp4/. The upstream .cpp files are renamed to .c —
the code is valid C99 with zero C++ features. This eliminates the
g++ and -lstdc++ build dependencies.
Adds 518 Vallado test vectors (AIAA 2006-6753-Rev1) as a 13th
regression suite to verify byte-identical numerical output.
Updates all documentation (CLAUDE.md, DESIGN.md, 11 MDX pages,
Dockerfile) to reflect the new layout and pure-C compilation.
Clean-room DE binary reader (~400 lines C) with Chebyshev/Clenshaw
evaluation — no GPL dependency on jpl_eph. Per-backend lazy
initialization preserves PARALLEL SAFE. Existing VSOP87/ELP82B
functions stay IMMUTABLE; new _de() variants are STABLE with
automatic fallback to compiled-in ephemerides on any DE failure.
Implementation:
- de_reader.c: header parse, record seek, Clenshaw recurrence
- eph_provider.c: GUC (pg_orbit.ephemeris_path), lazy init,
ICRS-to-ecliptic frame rotation, on_proc_exit cleanup
- de_funcs.c: 11 new SQL functions (_de variants + diagnostics)
- Constant chain of custody rules 6-8 (frame rotation,
same-provider, AU consistency)
Extract observe_from_geocentric() to astro_math.h for shared use
by planet_funcs.c, moon_funcs.c, and de_funcs.c.
57 → 68 functions, 11 → 12 regression test suites, all passing.
Three-stage Dockerfile: Ubuntu 22.04 builder (glibc-matched to
TimescaleDB-HA), scratch artifact image (~748KB), and standalone
postgres:17 image. All 6 regression suites run during build.
Makefile gains docker-build, docker-push, and docker-test targets.
