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Release Notes — v0.7.0

Galileo HAS (High Accuracy Service) float PPP

Release date: 2026-06-12 Type: New feature (global SSR correction service: Galileo HAS) Branch: release/v0.7.0

Overview

v0.7.0 adds support for the Galileo High Accuracy Service (HAS) and opens the v0.7.x series themed around global SSR correction services (BeiDou PPP-B2b is planned next).

Galileo HAS is a free, global high-accuracy service that broadcasts SSR corrections (satellite orbit, clock, and code bias) for GPS and Galileo on the E6-B C/NAV signal — and, in parallel, over the internet. Its corrections are referenced to the GTRF/ITRF2020 frame. Combined with broadcast ephemeris, HAS enables decimeter-level global PPP without a regional service area.

MRTKLIB now decodes HAS corrections and applies them in float PPP, in both post-processing (mrtk post) and real-time (mrtk run). The HAS Initial Service broadcasts no phase biases and no ionosphere/troposphere corrections, so this release targets float PPP (analogous to the MADOCA-PPP float path); integer PPP-AR is a later phase contingent on the HAS phase-bias broadcast.

There are no positioning-algorithm or numerical changes to the existing PPP / PPP-AR / PPP-RTK engines; HAS feeds the same satpos_ssr() / corr_meas() SSR application path already used by the other correction services.

1. What's new

A new HAS decoder (src/has/)

A self-contained decoder collects HAS pages, recovers each message with a Reed–Solomon erasure decoder, and decodes the corrections:

  • Page collection — HAS pages (24-bit header + encoded payload) are grouped by Message ID and page ID; once enough distinct pages of a message are received, the message is reconstructed.
  • RS(255,32,224) erasure decoder — GF(256) Reed–Solomon decode recovers the message from the received pages. The systematic generator matrix is built at initialization by polynomial encoding (no embedded coefficient tables), and was validated against the worked example in ICD Annex C.
  • MT1 message decode — Mask, Orbit, Clock (full-set / subset), Code-bias and Phase-bias blocks are decoded into ssr_t (nav->ssr_ch[0]), with HAS masks and IOD sets cached so corrections that omit a mask reference the previous one.

The decoded corrections flow through the existing SSR machinery: satpos_ssr() applies the orbit/clock corrections to the selected broadcast ephemeris, and corr_meas() applies the code biases (via a HAS-specific bias-code selector with same-frequency fallback).

correction = "gal-has"

A new value of the correction configuration axis (introduced in v0.6.x) selects HAS for PPP modes:

TOML
[positioning]
mode = "ppp-kine"                   # or ppp-static
correction = "gal-has"
satellite_ephemeris = "brdc+ssrapc" # SSR applied to broadcast ephemeris
systems = ["GPS", "Galileo"]

.has extraction and L6E support in mrtk l6extract

  • .has extraction — mrtk l6extract extracts Galileo HAS pages from SBF GALRawCNAV (block 4024) into a fixed-record .has file, which mrtk post consumes directly (detected by extension).
  • mosaic-G5 L6E — the same tool now also extracts QZSS L6E frames from SBF block 4271 (byte-identical to the L6D block 4270 except the Source field), written per-PRN +10 above the L6D PRN to match the MADOCA .l6 convention.

2. Quick start

Capture requirements

  • A receiver that tracks and outputs Galileo E6-B C/NAV, e.g. a Septentrio mosaic-G5, configured to log SBF GALRawCNAV (and the usual MeasEpoch / raw ephemeris blocks for RINEX conversion).
  • For real-time, the same SBF stream feeds both observations/ephemeris and the HAS pages — a single stream is sufficient.

Post-processing

Bash
# 1. Extract HAS pages from the SBF capture
mrtk l6extract -i file.sbf -o file.has

# 2. Convert the SBF to RINEX obs/nav (same capture)
mrtk convert ...

# 3. Float PPP with HAS corrections
mrtk post -k conf/has/ppp_gal_has.toml obs nav file.has

mrtk post detects the .has infile by extension, feeds its records to the HAS decoder, and applies the decoded corrections through the SSR branch.

Real-time

Bash
mrtk run -o conf/has/run_gal_has.toml

The real-time path takes a single SBF stream: the Septentrio decoder gains a GALRawCNAV handler that routes HAS pages to the decoder while the same stream supplies observations and broadcast ephemeris.

Key TOML keys

TOML
[positioning]
correction = "gal-has"
satellite_ephemeris = "brdc+ssrapc"

Both conf/has/ppp_gal_has.toml (post) and conf/has/run_gal_has.toml (real-time) ship as ready-to-use starting points.

3. Validation

  • Decoder cross-validation — the MT1 decoder was cross-validated bit-exact against cssrlib over 428 MT1 messages decoded from a live mosaic-G5 capture (10 Galileo satellites, ~1 h). cssrlib (MIT License, © 2021 Rui Hirokawa, https://github.com/hirokawa/cssrlib) was used as an independent development-time cross-reference only — it is not bundled with or linked into MRTKLIB.
  • RS decoder — validated against the worked decoding example in ICD Annex C.
  • Live float PPP repeatability — over 1 h of live data the float PPP solution has a self-RMS of E 7.5 / N 7.3 / U 38 cm.
  • Real-time replay — a real-time replay of the same data produces PPP float solutions on all epochs.
  • Bundled regression dataset — tests/data/has/has_testdata.tar.gz (~2.1 MB) ships a block-filtered, 15-minute mosaic-G5 slice (G5P3162a_15m.sbf) and a has_* ctest pipeline (extract → convert → float PPP → accuracy gate). A trim-equivalence proof shows the trimmed slice is byte-identical to the corresponding full-hour window: the .has records are byte-identical (4834 records), the converted OBS records are identical (900 epochs), and the PPP solutions are bit-identical over all common epochs.

4. Known limitations

  • Float PPP only — the HAS Initial Service broadcasts no phase biases, so integer PPP-AR is not yet possible. PPP-AR is planned for when HAS reaches Full Operational Capability (FOC) with phase biases.
  • No ionosphere / troposphere corrections — HAS carries none; the iono-free combination is used and the troposphere is estimated (est-ztd), as in the MADOCA-PPP float path.
  • Absolute accuracy under investigation — the HAS float solution currently sits ~0.5–0.6 m horizontal from a cm-grade ITRF reference, larger than mature PPP would give. Candidate causes (code-bias sign/selection, orbit/clock reference-point handling, troposphere estimation over a short window) are under investigation (#215); published HAS Asia-region performance suggests 10–20 cm is attainable.
  • GPS + Galileo only — the constellations HAS corrects.

Compatibility & migration

  • No change for existing users. HAS is opt-in via correction = "gal-has"; all existing PPP / PPP-AR / PPP-RTK / VRS configurations and outputs are unchanged.
  • New HAS users: capture SBF GALRawCNAV from an E6-B-capable receiver and start from the bundled conf/has/ppp_gal_has.toml (post) or conf/has/run_gal_has.toml (real-time).

Tests

Full ctest regression: the new has_* pipeline (extract / convert / float PPP / accuracy gate) passes, and the existing suite shows only the two documented pre-existing environment/numerical failures (rtkrcv_rt headless replay, madocalib_pppar_ion_check LAPACK tolerance); no new failures. clang-format 21.1.6 / taplo 0.10.0 clean; no test tolerances changed.

Issues / PRs

  • PR #214 — Galileo HAS support (decoder, correction = "gal-has", mrtk l6extract .has / L6E extraction, bundled regression tests).
  • #215 — HAS absolute-accuracy investigation (open).

References