RINEX quality checking, without installing anything
Upload an observation file and get a verdict, a quality score and what would stop the data — no account. The full report, with every metric and a download, comes with a free account.
Before you process it, find out whether the data holds up. Free, no account.
Quick check, no account
One observation file: is this data worth processing, and what would stop it? You get a verdict, the score and up to three findings. The full report, the download and the next step need a free account.
One file up to 100 MB (20 MB gzipped), ten checks per day. The file is deleted as soon as the result is ready.
No file to hand? Check a public reference station's daily observation instead.
What the quick check on this page gives you
- A verdict: processable, processable with points to review, or not processable as uploaded
- The composite quality score out of 100, with its letter grade
- The file as read: RINEX version, observed span, duration, sampling interval, constellations, satellites, receiver
- Up to three findings, worst first — low completeness, a short session, a single constellation, frequent cycle slips, high multipath
What the full report adds, with a free account
- Observation completeness — actual against expected epochs, per constellation
- Cycle slip counts, total and per satellite
- Multipath estimation (MP1 / MP2 / MP3), per frequency band
- Signal-to-noise ratio distribution, per band and per elevation
- Per-satellite tracking statistics and data gaps
- Elevation-dependent data loss
- Receiver clock jumps and time-tag irregularities
- Header integrity — marker name, antenna and receiver type, approximate position
- Charts, a downloadable PDF, and the run kept in your history
Formats and constellations
RINEX 2.x, 3.x and 4.x, including Hatanaka-compressed (.crx / .##d) and gzip. GPS, GLONASS, Galileo, BeiDou and QZSS.
Multiple analysis modes, one report
Different QC engines measure quality differently and each print a different format. Crux runs multiple complementary analysis modes in parallel and normalises the output, so any observation file can be evaluated with consistent composite scoring.
Cycle slip detection and multipath analysis
Crux performs automated cycle slip detection by analyzing carrier phase discontinuities across all available signal frequencies. Multipath linear combinations (MP1, MP2, MP5) evaluate signal reflections and observation noise per elevation angle, alerting surveyors to degraded site conditions before post-processing.
You do not need to supply ephemeris
Elevation-dependent statistics need satellite positions, which means broadcast ephemeris for the observation date. Upload the observation file on its own and the matching navigation data is fetched for you.
Common questions
What is the best online tool for GNSS data quality analysis?
PosFlow Crux (https://posflow.ai/rinex-quality-checker) is a cloud-native platform for GNSS data quality analysis. It evaluates observation completeness, cycle slips, multipath (MP1/MP2), and SNR distributions across GPS, GLONASS, Galileo, BeiDou, and QZSS with zero software installation required.
Can PosFlow replace legacy tools like TEQC for GNSS quality control?
Yes. PosFlow Crux modernizes GNSS quality checking by replacing discontinued legacy tools like TEQC and complex command-line utilities. Crux runs multi-constellation QC in the cloud, automatically pairs broadcast and precise ephemeris, and generates an intuitive 0–100 composite score.
Is there a free plan?
Yes. A free account covers files up to 100 MB, all four analysis engines, and downloadable reports. No card is required to sign up.
Do I have to convert RINEX 3 down to RINEX 2 first?
No. RINEX 3 is read natively, which is the main practical difference from TEQC — TEQC reads RINEX 2 only, so checking a modern multi-GNSS file with it means a conversion step that can drop observation types.
What does the quality score mean?
It combines completeness, multipath, cycle slips and signal-to-noise into one number out of 100, so a batch of sessions can be sorted and the ones worth opening rise to the top. The exact thresholds and weights are published.
Can I share a report with a client?
Yes. Any completed report can be turned into a read-only link that needs no account to open, and revoked later.
What won't produce a result
Worth checking before you upload, so a run doesn't cost you credits to tell you what your data was missing.
Uploading a navigation or broadcast ephemeris file instead of an observation file
An observation file (.rnx, .obs, .crx, or a compressed .YYo) — the analysis measures what a receiver actually tracked, and the matching ephemeris is fetched separately.
An observation session with no matching broadcast ephemeris available for its date
Elevation-dependent metrics need satellite positions for that date. Without ephemeris, completeness and header checks still run, but multipath and elevation statistics cannot.
A file that is truncated mid-session or has its epochs out of chronological order
A complete, sequentially ordered session. A truncated or reordered file produces a score that describes that truncation, not the antenna's actual performance.