Short answer
The standard text-based file format for storing raw GNSS observations (.YYo files), navigation messages (.YYn), and meteorological data (.YYm). All survey-grade receivers can write RINEX, and all post-processing software can read it. Versions 2.11 and 3.05 are the most common.
Detailed explanation
RINEX is the universal exchange format for raw GNSS data. A daily observation file from a receiver typically contains 86,400 epochs (1 Hz sampling) of pseudorange, carrier phase, Doppler, and C/N₀ measurements for every satellite tracked, formatted as ASCII columns with a structured header.
Two versions dominate the field. RINEX 2.11 uses short file names of the form ssssDDDs.YYo where ssss is a 4-character site code, DDD is day-of-year (1–366), s is the session letter (0 for full-day files, a–x for hourly files), YY is the two-digit year, and 'o' identifies observation files. Daily example: WUHA0150.24o.
RINEX 3.05 (and later) uses longer file names of the form ssss00CCC_R_YYYYDDDHHMM_PP_FF_TT.rnx that encode the country code, sampling interval, file period, and observation type explicitly. Necessary for multi-constellation, multi-frequency data because the short form runs out of room.
RINEX is generated by every survey-grade receiver (Trimble, NovAtel, Septentrio, ublox ZED-F9P, Topcon, etc.) and consumed by every PPP / post-processing service (CSRS-PPP, AUSPOS, OPUS, magicGNSS). The GPS Time Converter tool helps you build the time-dependent portion of the filename for the current epoch.
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Open the toolRelated terms
NMEA
A serial-line ASCII protocol for marine and consumer GNSS receivers. Sentences like $GPGGA (fix), $GPRMC (recommended minimum), $GPGSV (satellites in view) are broadcast at ~1 Hz. The dominant output format for low-cost receivers; survey receivers also use binary formats like RTCM and proprietary streams.
Ephemeris & Almanac
Two related types of orbital data broadcast by GNSS satellites. Ephemeris gives precise (cm-class) satellite positions, validity 4 hours. Almanac gives coarse (km-class) positions for the entire constellation, validity weeks. Receivers need both for cold start.
GPS
United States DoD-operated GNSS, fully operational since 1995. Broadcasts civil signals on L1 (1575.42 MHz), L2 (1227.6 MHz), and L5 (1176.45 MHz), plus restricted military M-code on L1 and L2.
CORS
A permanently-installed GNSS receiver streaming raw measurements 24/7. CORS networks are the backbone of RTK and network-RTK services, geodetic monitoring, and post-processed precise positioning. Typical inter-station spacing is 50–100 km for regional RTK, 200–300 km for national geodetic networks.