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Short answer
RINEX (Receiver Independent Exchange Format) is the open text format used to exchange raw GNSS data between receivers and processing software. An observation file stores the code, carrier-phase, Doppler and signal-strength measurements a receiver recorded, with a header describing the marker, receiver, antenna and observation types. Before processing, we check that header against the field record and review the data for gaps, missing frequencies and short sessions.
- The observation file holds measurements, not coordinates. The position in the header is only approximate.
- A wrong antenna type or antenna height in the header moves the result while every processing diagnostic still looks normal.
- Keep the receiver-native file as well. A RINEX conversion can drop signals or metadata that the original contains.
Who this is for: Surveyors, GNSS field teams and engineers who receive or hand over raw GNSS observations.
What does a RINEX file contain?
RINEX separates GNSS data by purpose. The observation file is the one a processing engine needs from your receiver. Navigation files carry the broadcast orbit and clock messages, and meteorological files carry weather sensor readings where a station records them. Each file starts with a labelled header and continues with time-tagged records.
The header is where most handover problems begin. It names the marker, the receiver and antenna models and serial numbers, the antenna offset from the marker, the observation types and the first observation time. Processing software reads these fields literally, so an empty or default value becomes part of the solution.
| File type | What it stores | Why you need it |
|---|---|---|
| Observation | Code, carrier-phase, Doppler and signal-strength measurements per satellite and epoch | The raw measurements for baseline, network or PPP processing |
| Navigation | Broadcast ephemeris and clock messages from the satellites | Satellite positions for real-time-style or quick solutions; precise products usually replace them in final processing |
| Meteorological | Pressure, temperature and humidity from a station sensor | Optional input for troposphere modelling at reference stations |
Technical references: IGS: formats and standards; IGS/RTCM: RINEX version 4.02 specification.
RINEX 2, 3 and 4: which version do you have?
The first header line states the format version. RINEX 2 was designed around GPS and later extended; its observation codes are two characters, such as L1 or P2, and its short file names follow the pattern station, day of year, session and year. RINEX 3 introduced three-character observation codes that identify the frequency band and the tracking channel, and long file names that state the station, start time, duration and sampling interval.
RINEX 4 keeps the version 3 observation structure and revises the navigation file so that newer message types can be carried. The International GNSS Service publishes the current specification and lists the supported constellations and signals. Check which versions your processing software and any online service accept before converting, and record the converter and its version with the file.
- Multi-constellation data (GPS, GLONASS, Galileo, BeiDou, QZSS, NavIC) is better described in RINEX 3 or 4 than in RINEX 2.
- Converting from version 3 to version 2 can discard signals that have no version 2 code.
- Hatanaka-compressed observation files are a compact form of the same data and must be decompressed with the matching tool before most software can read them.
Technical references: IGS/RTCM: RINEX version 4.02 specification; IGS: formats and standards; GSI Japan: RNXCMP Hatanaka compression tools.
Which header fields should you check first?
We compare the header with the field sheet before looking at any data record. The antenna entry deserves the most attention. Processing software applies phase-centre corrections by antenna model name, so the name must match the calibration file exactly, including the radome code. The height entry must state what was measured: vertical height to the antenna reference point, or a slant height that still needs reduction.
- Marker name and number: do they identify the point that was occupied?
- Receiver and antenna type and serial number: do they match the equipment record?
- Antenna delta height, east and north: is the height vertical to the antenna reference point, in metres?
- Observation types: are both frequencies and the expected constellations listed?
- Sampling interval and first and last observation times: do they match the planned session?
- Approximate position: is it near the site? A zero or distant value can slow or break processing.
Technical references: IGS/RTCM: RINEX version 4.02 specification; NOAA NGS: antenna calibrations.
What quality checks can you run on the observations?
A quality-check run summarises what the file contains without computing a final coordinate. Typical outputs are the number of epochs and satellites, the share of expected observations actually recorded, data gaps, cycle-slip counts, code multipath indicators and signal-strength statistics. These describe the observing conditions. They do not state the accuracy of the position you will compute.
Read the summary against the site. Frequent slips and high multipath on low satellites near a building or tree line are expected; the same pattern in open sky suggests a cable, antenna or receiver problem. A session that is shorter than planned, or that crosses a receiver restart, should be recorded in the processing notes rather than silently merged.
- Confirm the session length and sampling interval meet the requirement of the processing method or service.
- Look for gaps and receiver resets, and decide whether to split the session.
- Check that the second frequency is present for the whole session, not only part of it.
- Compare cycle slips and multipath between sessions at the same point.
- Keep the quality summary with the processing record.
Technical references: GFZ: gfzrnx RINEX toolbox; UNAVCO: teqc translation, editing and quality check.
Which tools read, convert and check RINEX?
Receiver manufacturers supply converters from their native formats, and those are usually the first choice because they understand the receiver's own records. GFZ's gfzrnx toolbox handles RINEX 2, 3 and 4 for checking, editing, splitting, merging and version conversion; check its licence terms for your use. UNAVCO's teqc was the long-standing tool for translation, editing and quality checks. Its publisher lists it as end-of-life after a final release in February 2019, so we would treat it as a legacy option for older RINEX 2 data.
For a transparent, scriptable check, our open-source geodesy-toolkit includes RINEX quality checks written in Python. Whichever tool you use, record its name and version. A conversion or edit is a processing step and belongs in the audit trail.
Technical references: GFZ: gfzrnx RINEX toolbox; UNAVCO: teqc translation, editing and quality check.
What should accompany a RINEX file at handover?
A reviewer can then repeat the processing and see why a session was accepted, split or rejected. That is the difference between a coordinate you can defend and a number in a spreadsheet.
- The receiver-native file and the RINEX file, with the converter name and version.
- A field sheet: point identifier, antenna model, how the height was measured, start and end times and the observer.
- A photograph or sketch of the setup where obstructions matter.
- The quality-check summary and any edits made to the file.
- The intended reference frame, epoch and height system for the result.
Technical references: IGS/RTCM: RINEX version 4.02 specification.
Common questions
Can I open a RINEX file in a text editor?
Yes. RINEX is plain text, so any text editor shows the header and records. Hatanaka-compressed or zipped files must be decompressed first. Avoid saving changes from an editor that alters line endings or column positions, because the format is column-sensitive.
Does a RINEX observation file contain my surveyed coordinates?
No. It contains raw measurements. The header may hold an approximate position, which is only a starting value. Coordinates come from processing the observations with reference data or precise products.
Is RINEX 2 still acceptable?
Many tools and services still read RINEX 2, and it can be adequate for GPS-only work. It cannot describe every modern signal, so multi-constellation observations are better exchanged in RINEX 3 or 4. Check what the receiving software or service accepts.
Official references
Sources checked 12 November 2026. The linked publishers remain the authority for their specifications and services.
- IGS: formats and standards
Authoritative index of RINEX and related GNSS exchange formats maintained by the International GNSS Service.
- IGS/RTCM: RINEX version 4.02 specification
File types, header labels, observation codes and file naming; the specification remains the authority for any field definition.
- GFZ: gfzrnx RINEX toolbox
Tool capabilities and licence terms for RINEX checking, editing and version conversion.
- UNAVCO: teqc translation, editing and quality check
End-of-life status after the 2019 final release; used here for quality-check concepts, not as a current recommendation.
- NOAA NGS: antenna calibrations
Antenna naming, antenna reference point and phase-centre calibration context.
- GSI Japan: RNXCMP Hatanaka compression tools
Source of the compression and decompression tools for Hatanaka-compressed observation files.