Range rate: topocentric residuals now include an optional 4th component
(dot(Δr, v_ecef) / |Δr|) with OD_RR_SCALE=10.0 for unit balancing.
Controlled via fit_range_rate parameter on tle_from_topocentric().
Weighted observations: per-observation weights applied as √w scaling
to both residuals and Jacobian rows, producing the weighted normal
equations H'WH without explicit W construction. Weights parameter
added to tle_from_eci, tle_from_topocentric, and tle_from_angles.
Gauss angles-only IOD: Vallado Algorithm 52 implementation for
seed-free orbit recovery from 3+ RA/Dec observations. New RA/Dec
residual function with cos(dec) scaling and wrap-around handling.
New tle_from_angles() and tle_from_angles_multi() SQL functions
accepting RA in hours [0,24), Dec in degrees [-90,90].
New standalone test suite: test_od_gauss (17 assertions).
New regression tests: Tests 18-25 covering range rate, weights,
angles-only with/without seed, and error cases.
Batch weighted least-squares differential correction using equinoctial
elements, LAPACK dgelss_() for SVD solve, vendored SGP4/SDP4 as the
propagation engine. Per Vallado & Crawford (2008) AIAA 2008-6770.
New SQL functions:
- tle_from_eci(): fit TLE from ECI position/velocity ephemeris
- tle_from_topocentric(): fit TLE from az/el/range observations
- tle_fit_residuals(): per-observation position residuals diagnostic
Solver features: 6-state (orbital) or 7-state (+ B*) fitting,
equinoctial elements for singularity-free optimization, tiered step
limiting, Brouwer/Kozai Newton-Raphson conversion, auto initial guess
from first ECI observation when no seed TLE provided.
Tested: 8 regression tests (LEO/MEO/near-circular round-trips,
B* recovery, topocentric, seedless, error handling, diagnostics),
67 standalone math unit tests, all 14 suites pass.
