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Quick Start: Galileo HAS PPP

This guide walks you through running Galileo High Accuracy Service (HAS) float PPP with MRTKLIB, in both post-processing and real-time.

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 over the internet). Corrections are referenced to the GTRF/ITRF2020 frame. Combined with broadcast ephemeris, HAS enables decimeter-level global PPP without a regional service area.

Float PPP only (HAS Initial Service)

The HAS Initial Service broadcasts no phase biases and no ionosphere/troposphere corrections, so MRTKLIB runs HAS as float PPP (no ambiguity resolution), analogous to the MADOCA-PPP float path. Integer PPP-AR is planned for when HAS reaches Full Operational Capability (FOC) with phase biases.

Prerequisites

  • MRTKLIB built successfully (cmake --build build)
  • A receiver that tracks and outputs Galileo E6-B C/NAV, e.g. a Septentrio mosaic-G5, configured to log SBF GALRawCNAV (block 4024) alongside the usual measurement and raw-ephemeris blocks needed for RINEX conversion.

Required Files

File TOML Key Purpose
RINEX observation (.obs) positional arg GNSS observations from the receiver
RINEX navigation (.nav / .rnx) positional arg Broadcast ephemeris (GPS + Galileo)
HAS corrections (.has) positional arg Galileo HAS SSR (orbit, clock, code bias)

The .has file is produced from the SBF capture by mrtk l6extract (see below). For post-processing, the observations and navigation come from the same SBF capture converted with mrtk convert.

Bundled Configuration Files

File Mode Use
conf/has/ppp_gal_has.toml Float PPP (ppp-kine) Post-processing
conf/has/run_gal_has.toml Float PPP Real-time (mrtk run)

Both set correction = "gal-has" and satellite_ephemeris = "brdc+ssrapc" (HAS SSR applied to broadcast ephemeris) and restrict systems to GPS and Galileo — the constellations HAS corrects.

Post-Processing

Bash
# 1. Extract HAS pages from the SBF capture
mrtk l6extract -i G5P3162a.sbf -o G5P3162a.has

# 2. Convert the SBF to RINEX obs/nav (same capture)
mrtk convert ... -o G5P3162a.obs -n G5P3162a.nav G5P3162a.sbf

# 3. Float PPP with HAS corrections
mrtk post -k conf/has/ppp_gal_has.toml \
  G5P3162a.obs G5P3162a.nav G5P3162a.has

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

Expected output: float PPP solutions (Q=6) on every epoch once HAS corrections are available.

Real-Time

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

The real-time path takes a single SBF stream: the Septentrio decoder routes GALRawCNAV pages to the HAS decoder while the same stream supplies observations and broadcast ephemeris. No separate correction stream is required.

Key Configuration Points

Correction Source

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

gal-has routes corrections through the SSR branch; brdc+ssrapc applies the HAS orbit/clock SSR to broadcast ephemeris (antenna-phase-center convention).

gal-has requires brdc+ssrapc

correction = "gal-has" must be paired with satellite_ephemeris = "brdc+ssrapc". With any other ephemeris source the SSR corrections are not applied and you will get no usable HAS solution.

Constellations and Signals

TOML
[positioning]
systems = ["GPS", "Galileo"]

HAS corrects GPS and Galileo only. The iono-free combination is used for the ionosphere (dual-freq) and the troposphere is estimated (est-ztd); HAS carries neither correction itself.

What Accuracy to Expect

Metric Result
Repeatability (1 h self-RMS) E 7.5 / N 7.3 / U 38 cm
Absolute (vs cm-grade ITRF reference) ~0.5–0.6 m horizontal (investigation open)
Convergence decimeter-level after the float filter settles

Absolute accuracy is 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. The accuracy investigation is open (#215); published HAS Asia-region performance suggests 10–20 cm is attainable, so day-to-day repeatability (above) is the more representative figure for now.

Limitations

  • Float PPP only — no phase biases in the Initial Service, so no PPP-AR yet.
  • No ionosphere / troposphere corrections in HAS (estimated locally instead).
  • GPS + Galileo only.

Troubleshooting

correction = "gal-has" rejected / no corrections applied

Ensure satellite_ephemeris = "brdc+ssrapc". HAS is an SSR service applied to broadcast ephemeris; another ephemeris source disables the SSR application.

No solutions (stuck at Single / no fix in PPP)

  1. No HAS pages in the capture — confirm the receiver was logging SBF GALRawCNAV (block 4024). Run mrtk l6extract and check that the .has file contains records; an empty or tiny .has means E6-B was not being tracked/decoded.
  2. E6-B not tracked — verify the receiver is configured to track Galileo E6 and output C/NAV. mosaic-G5 must have E6-B enabled.
  3. Missing GPS/Galileo broadcast ephemeris — the converted .nav must contain GPS and Galileo ephemerides; HAS corrects orbit/clock relative to broadcast ephemeris.

Larger-than-expected position offset

This is the known absolute-accuracy offset (~0.5–0.6 m horizontal) under investigation in #215. Repeatability is good; absolute accuracy is expected to improve.

Next Steps