sidereon-core 0.14.0

The complete Sidereon engine: numerical astrodynamics propagation core plus the GNSS domain layer (SP3, broadcast ephemeris, multi-GNSS positioning, RTK/PPP, ionosphere/troposphere, DOP) behind a default-on gnss feature
Documentation

sidereon-core

The complete engine behind sidereon: satellite propagation and observation plus GNSS positioning, in one pure-Rust crate. It is the fold of the propagation and GNSS layers. The GNSS layer sits behind a default gnss feature, so a propagation-only consumer can build with --no-default-features and never compile the SP3/RINEX/IONEX/solver code.

Propagation and observation

  • SGP4 / TLE: TLE parsing and SGP4 propagation, validated bit-exact against the Vallado reference (see Credits).
  • Numerical propagation: Cartesian state propagation under two-body and J2 gravity, with fixed-step RK4 and adaptive Dormand-Prince 5(4) integrators.
  • Frames and time: ITRS/GCRS transforms with precession, nutation, and GAST; TT/TAI/UT1 time scales backed by IERS/IAU tables.
  • Geometry and events: topocentric look angles, pass prediction, and eclipse/shadow geometry.
  • Conjunctions: close-approach screening, collision probability, and RTN-frame covariance.
  • I/O: TLE, CCSDS Orbit Mean-Elements Message / OMM (KVN, XML, and JSON; JSON behind the default-on json feature), and CCSDS Conjunction Data Message / CDM (KVN and XML). An OMM drives SGP4 bit-identically (0 ULP) to the equivalent TLE.

GNSS positioning (default gnss feature)

  • SP3 precise ephemeris and RINEX 3.x/4.x navigation (GPS, Galileo, BeiDou, GLONASS).
  • Single-point positioning, double-differenced RTK with LAMBDA ambiguity resolution, and static precise point positioning.
  • Broadcast Klobuchar ionosphere and Saastamoinen plus Niell troposphere.

Parity bar

Every independently reproducible, libm-bound component (propagation, frames, time, SGP4, ionosphere, troposphere, DOP, orbit and clock evaluation) is held to bit-exact (0 ULP) parity against pinned references, proven by committed hex-float golden vectors. Solver converged positions are sub-micron solver-agreement results, not a 0-ULP claim (the linear-algebra step is BLAS-bound). 0 ULP is certified against a pinned target (OS/arch, libm, toolchain, FMA policy); other platforms run the same algorithms but need their own fixtures. Units are SI, with frame and datum encoded in the type system.

Credits

The SGP4/SDP4 model is the public AIAA/Spacetrack theory. sidereon-core's SGP4 is a Rust port of David Vallado's reference C++ (companion code to "Fundamentals of Astrodynamics and Applications"), the same source the sgp4 Python package ports. Credit to David Vallado and the 2006 AIAA paper (Vallado, Crawford, Hujsak, Kelso). Vallado's C++ is used only as a development-time parity oracle and is not distributed with this crate.

License

MIT