# Changelog
All notable changes to this project are documented here. The format is based on
[Keep a Changelog](https://keepachangelog.com/en/1.1.0/), and this project
adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
## [0.9.0] - 2026-06-05
A large GNSS expansion — signal generation, measurement modelling, velocity,
quality control, and differential positioning — alongside a consolidation of
the whole GNSS surface under the `Orbis.GNSS.*` namespace.
### Added
- **`Orbis.GNSS.Signal.CA`** — GPS L1 C/A Gold-code generation, chip indexing,
and auto/cross-correlation (IS-GPS-200 G1/G2 generators and per-PRN taps).
- **`Orbis.GNSS.Signal.Correlator`** — C/A code+carrier replica, coherent
correlation, a 2-D code-phase/Doppler acquisition search, and the
coherent-integration (sinc²) loss model.
- **`Orbis.GNSS.Navigation.LNAV`** — GPS LNAV subframe synthesis and decoding:
TLM/HOW, time-of-week, subframe parity (IS-GPS-200 Table 20-XIV), and
ephemeris bit-packing.
- **`Orbis.GNSS.Observables`** — predicted geometric range, range-rate, Doppler,
satellite clock, elevation, and azimuth from a receiver position and an SP3
ephemeris, with light-time (transmit-time) and Sagnac corrections.
- **`Orbis.GNSS.Geometry`** — satellite visibility above an elevation mask,
dilution of precision (GDOP/PDOP/HDOP/VDOP/TDOP), DOP/visibility time series,
and rise/set passes.
- **`Orbis.GNSS.Velocity`** — receiver velocity and clock drift from Doppler or
pseudorange-rate measurements by least squares over the line-of-sight geometry.
- **`Orbis.GNSS.QC`** — measurement quality control: residual-based RAIM fault
detection, leave-one-out fault detection and exclusion (FDE), and
elevation/C-N₀ measurement weighting.
- **`Orbis.GNSS.IonosphereFree`** — the dual-frequency ionosphere-free
pseudorange combination, with standard per-system frequency pairs
(GPS L1/L2, Galileo E1/E5a, BeiDou B1I/B3I).
- **`Orbis.GNSS.DGNSS`** — code-differential positioning: base-station
pseudorange corrections and corrected rover solves that cancel the errors
common to both receivers (satellite clock, ephemeris, short-baseline
atmosphere).
- **`Orbis.GNSS.SolutionReport`** — a per-satellite and summary diagnostic over
a position solution: elevation/azimuth, post-fit and RAIM-normalized
residuals, DOP, residual RMS, and the integrity verdict.
- **`Orbis.GNSS.ReducedOrbit.Piecewise`** — a piecewise (segmented)
reduced-orbit model that tiles a span into contiguous fitted segments for
tighter caching/transport accuracy than a single mean-element fit.
### Changed
- **Breaking:** GNSS modules now live under the `Orbis.GNSS.*` namespace. The
old top-level GNSS names (`Orbis.SP3`, `Orbis.PointPositioning`,
`Orbis.GnssData`, etc.) were removed instead of retained as aliases, matching
the library's current single-client / pre-broad-adoption status. Examples:
`Orbis.GNSS.SP3`, `Orbis.GNSS.Positioning`, `Orbis.GNSS.Data`,
`Orbis.GNSS.RINEX.Observations`, `Orbis.GNSS.ReducedOrbit`,
`Orbis.GNSS.Signal.CA`, and `Orbis.GNSS.Navigation.LNAV`.
- Internal GNSS implementation helpers were consolidated under
`Orbis.GNSS.Core` for shared constants, ECEF input normalization,
epoch/window handling, validation, source sampling, and versioned-map guards.
- Hardened public-API input validation across the GNSS modules: malformed
receiver/base positions, out-of-range RAIM options, sub-second piecewise
segment lengths, out-of-range LNAV flags, and duplicate observations now
return tagged errors (or raise a clear `ArgumentError` for invalid options)
instead of crashing, looping, or silently truncating.
## [0.8.0] - 2026-06-05
Observation parsing and a compact orbit model. Orbis can now read a station's
RINEX observation file end-to-end into pseudoranges, and distill a position
track into a tiny, transportable mean-element model.
### Added
- **`Orbis.GNSS.RINEX.Observations`** — RINEX 3 observation parsing with Hatanaka (CRINEX 1.0
and 3.0) decoding. Decodes `.crx`/`.rnx`, exposes the header (incl. the
surveyed `APPROX POSITION`), observation codes, and epochs, and extracts
single-frequency pseudoranges (`pseudoranges/3`) in the
`[{satellite_id, range_m}]` shape `Orbis.GNSS.Positioning.solve/4` consumes —
closing the loop from a station's observation file to a recovered position.
`Orbis.GNSS.Data` gains a station observation product fetch and an
`observations/2` loader. CRINEX decoding is verified byte-for-byte against
`crx2rnx`; an end-to-end test recovers a surveyed station position to metre
level from real GPS observations.
- **`Orbis.GNSS.ReducedOrbit`** — a compact, fitted mean-element approximation of an
orbit for caching, transport, and quick visibility math (not orbit
determination). Fits from an `Orbis.GNSS.SP3` track or a list of ECEF samples;
evaluates position/velocity (ECEF by default, GCRS on request); reports a
source-backed `drift/3` against the source ephemeris; and serialises to a
stable, versioned map (`to_map/1`/`from_map/1`). Two models: `:circular_secular`
(default) and `:eccentric_secular` (nonsingular `h = e·sin ω`, `k = e·cos ω`),
the latter recovering the radial `a·e` signal that the circular model discards —
cutting full-day extrapolation error by one-to-three orders of magnitude for
GPS and BeiDou while matching the circular model on near-circular Galileo.
## [0.7.0] - 2026-06-04
GNSS positioning. Orbis can now recover a receiver position from pseudoranges
against precise or broadcast ephemeris, with the supporting ephemeris,
correction, time, and data-fetch layers.
### Added
- **`Orbis.GNSS.Positioning`** — single-point positioning (SPP). Solves a
receiver position, clock, and geometry diagnostics from one epoch of
pseudoranges against either an `Orbis.GNSS.SP3` precise product or an
`Orbis.GNSS.Broadcast` handle. Multi-constellation
(GPS / Galileo / BeiDou / GLONASS) solves carry one receiver clock per system;
the solution reports position, geodetic position, per-system clocks, DOP,
residuals, used/rejected satellites, and solver metadata.
- **`Orbis.GNSS.SP3`** — SP3-c/SP3-d precise orbit/clock loading and arbitrary-epoch
satellite position/clock interpolation, plus `satellite_ids/1` to read the
product's declared satellite set.
- **`Orbis.GNSS.Constellation`** — a GPS constellation catalog built from
CelesTrak `gps-ops` OMM identity and an optional NAVCEN status/SVN overlay
(PRN ↔ SVN ↔ NORAD ↔ SP3 id, active/usable flags). Merges sources only when
the block type matches, recording PRN-transition disagreements as conflicts
rather than corrupting identity; exports the compact mapping CSV and validates
a catalog (duplicate PRNs/NORAD ids, inactive/unusable PRNs, and missing/extra
satellites against a loaded `Orbis.GNSS.SP3` product).
- **`Orbis.GNSS.Broadcast`** — RINEX 3.x and 4.xx navigation parsing and
broadcast orbit/clock evaluation: GPS LNAV, Galileo I/NAV and F/NAV, BeiDou
D1/D2 (including geostationary satellites), and GLONASS (PZ-90.11 state-vector
propagation by Runge–Kutta integration).
- **`Orbis.GNSS.Ionosphere`** (broadcast Klobuchar, frequency-aware across L1/E1/B1I)
and **`Orbis.GNSS.Troposphere`** (Saastamoinen zenith delay + Niell mapping)
correction models.
- **`Orbis.GNSS.Data`** — an optional product fetch/cache layer: a catalog over
public archives, HTTPS (`Req`) and FTP downloads, an atomic on-disk cache with
SHA-256 integrity and provenance sidecars, a gzip-bomb guard, and an offline
mode. Includes convenience loaders that return `Orbis.GNSS.SP3` /
`Orbis.GNSS.Broadcast` handles. `Req` is an optional dependency.
- **`Orbis.GNSS.Time`** — GNSS epoch/seconds-of-week and day-of-year helpers.
### Notes
- The GNSS numerical core lives in the Rust `astrodynamics` / `astrodynamics-gnss`
crate layer. Its libm-bound components (orbit and clock evaluation, ionosphere,
troposphere, dilution of precision) are held to bit-exact (0 ULP) parity
against pinned Python references; broadcast orbits are additionally validated
against precise SP3 products. The least-squares solver's final position is a
sub-micron solver-agreement result, not a 0-ULP claim.
---
Releases before 0.7.0 predate this changelog.