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Release Notes — v0.6.8

Real-time IGS-RTS float PPP via correction = "igs-rts"

Release date: 2026-05-23 Type: Feature — new correction source (real-time RTCM-SSR / IGS-SSR float PPP) Branch: release/v0.6.8

Overview

v0.6.8 enables the correction = "igs-rts" axis: conventional float PPP driven by a real-time RTCM-SSR / IGS-SSR (MT4076) correction stream — the IGS Real-Time Service and equivalents (IGS01 / IGS03, CNES CLK9x, BKG, …).

The decode-and-apply pipeline was already present in MRTKLIB, inherited from the MADOCA-via-RTCM integration (RTCM-SSR decoders, satpos_ssr / EPHOPT_SSRAPC). v0.6.7 introduced the correction axis but kept igs-rts reserved. This release unlocks it and — importantly — routes it through the correct measurement model, then validates it end-to-end against a real RTS stream and upstream RTKLIB.

This builds on the v0.6.7 correction-axis framework (docs/design/configuration.md). The remaining real-time SSR sources gal-has and bds-b2b stay reserved.

Major changes

correction = "igs-rts" unlocked (#138)

resolve_correction() (src/pos/mrtk_opt.c):

  • Removes igs-rts from the reserved-reject (gal-has / bds-b2b stay reserved).
  • Adds it to the PPP validity matrix (ppp-static / ppp-kine / ppp-fixed).
  • Requires satellite_ephemeris = "brdc+ssrapc" (or "brdc+ssrcom").
  • Not auto-inferred — igs-rts shares brdc+ssrapc with qzs-madoca, so it must be set explicitly (omitting correction with brdc+ssrapc still infers qzs-madoca, preserving MADOCA behaviour).

Correct measurement model for RTCM-SSR

corr_meas() (src/pos/mrtk_ppp.c) now routes igs-rts through the RTKLIB float-PPP measurement model — the same branch as correction = igs — not the MADOCA SSR-bias path. The satellite orbit/clock still come from satpos_ssr (EPHOPT_SSRAPC); only the receiver-side measurement model differs.

The per-signal RTCM-SSR code/phase bias is deliberately not applied: RTCM-SSR uses a different bias convention than MADOCA-CSSR (the code bias even has the opposite sign), and applying it via the MADOCA path biases the solution by metres. The MADOCA / gal-has / bds-b2b SSR path is unchanged (bit-identical).

Validation

End-to-end against a real RTS stream captured live from the CDDIS NTRIP caster: AIRA00JPN (Aira, Japan, IGS), GPS L1/L2 + GAL E1/E5a iono-free, IGS combined RTCM-SSR (SSRA02IGS0) + broadcast ephemeris. Against the IGS final weekly SINEX coordinate (epoch-propagated), float PPP reaches 3D 1σ ≈ 0.18 m / 95% ≈ 0.33 m — the expected real-time IGS-RTS float level — and agrees with upstream RTKLIB 2.4.3 rnx2rtkp on the identical obs/nav/SSR inputs to the LAPACK-vs-embedded-LU solver level. satpos_ssr is byte-identical to upstream.

A new igsrts_setup / igsrts_ppp / igsrts_ppp_check / igsrts_cleanup regression group exercises this path (SINEX-based absolute check, tolerance 0.5 m).

Release-notes hygiene

The previously missing release-notes-v0.6.7.md was backfilled.

Files Changed

File Change
src/pos/mrtk_opt.c unlock CORR_IGS_RTS in resolve_correction() (validity matrix + sateph guard, explicit-only)
src/pos/mrtk_ppp.c route igs-rts through the RTKLIB float-PPP measurement model in corr_meas
conf/igs/rnx2rtkp_igsrts.toml igs-rts sample config
conf/igs/rnx2rtkp_igsrts_test.toml, tests/data/igs/igsrts_testdata.tar.gz, CMakeLists.txt igsrts regression test
docs/design/configuration.md, docs/reference/config-options.md igs-rts documented as implemented (float)
docs/releases/release-notes-v0.6.7.md backfilled v0.6.7 notes

Upgrade notes

  • Existing configs need no change. igs-rts is opt-in and explicit.
  • To run real-time IGS-RTS float PPP, set correction = "igs-rts" and satellite_ephemeris = "brdc+ssrapc", and feed the RTCM-SSR stream (live, or a recorded .rtcm3 log for mrtk post) alongside the rover obs and a broadcast navigation file. See conf/igs/rnx2rtkp_igsrts.toml.
  • igs-rts is float PPP. Integer PPP-AR (a phase-bias product such as CNES CLK9x) and the F9P-class GAL E5b / BDS B2I fallback are follow-ups.

Test Results

The igsrts regression group passes (AIRA, 3D 1σ ≈ 0.18 m vs SINEX). The only failures are the two known pre-existing ones on the maintainer host — rtkrcv_rt (real-time timing) and madocalib_pppar_ion_check (LAPACK vs embedded-LU numerical difference, see CLAUDE.md §7.2) — both unrelated to this release. CI build + test-regression are green. MADOCA / CLAS / IGS-files PPP paths are unchanged.

PRs

  • #146 — feat(ppp): enable IGS-RTS correction (RTCM-SSR / IGS-SSR) float PPP (#138)
  • #145 — docs(releases): backfill v0.6.7 release notes

Closes

  • #138 — feat(ppp): enable IGS-RTS correction (RTCM-SSR / IGS-SSR MT4076) — pipeline ported, unlock the axis