RINEX

Receiver Independent Exchange Format

Filename extension	.rnx
Developed by	International GNSS Service (IGS) / Radio Technical Commission for Maritime Services (RTCM)
Initial release	1989; 35 years ago (1989)
Latest release	4.02 October 1, 2024; 2 months ago (2024-10-01)
Type of format	ASCII
Free format?	Yes
Website	https://igs.org/formats-and-standards/

In the field of geodesy, Receiver Independent Exchange Format (RINEX) is a data interchange format for raw satellite navigation system data. This allows the user to post-process the received data to produce a more accurate result — usually with other data unknown to the original receiver, such as better models of the atmospheric conditions at time of measurement.

The final output of a navigation receiver is usually its position, speed or other related physical quantities. However, the calculation of these quantities are based on a series of measurements from one or more satellite constellations. Although receivers calculate positions in real time, in many cases it is interesting to store intermediate measures for later use. RINEX is the standard format that allows the management and disposal of the measures generated by a receiver, as well as their off-line processing by a multitude of applications, whatever the manufacturer of both the receiver and the computer application.

The RINEX format is designed to evolve over time, adapting to new types of measurements and new satellite navigation systems. The first RINEX version was developed by W. Gurtner in 1989^[1] and published by W. Gurtner and G. Mader in the CSTG GPS Bulletin of September/October 1990. Since 1993 the RINEX 2 is available, which has been revised and adopted several times. RINEX enables storage of measurements of pseudorange, carrier-phase, Doppler and signal-to-noise from GPS (including GPS modernization signals e.g. L5 and L2C),^[2] GLONASS, Galileo, Beidou, along with data from EGNOS and WAAS satellite based augmentation systems (SBAS), QZSS, simultaneously. RINEX version 3.02 was submitted in April 2013 and contain new observation codes^[3] from GPS or Galileo systems.

Although not part of the RINEX format, the Hatanaka compression scheme is commonly used to reduce the size of RINEX files, resulting in an ASCII-based CompactRINEX or CRINEX^[4] format.^[5] It uses higher-order time differences to reduce the number of characters needed to store time data.^[6]

Ionospheric data

Ionospheric data in RINEX facilitates the exchange of information regarding the ionosphere, particularly through the IONosphere-map EXchange (IONEX) format.^[7] Developed to standardize the sharing of Total Electron Content (TEC) maps derived from Global Navigation Satellite System (GNSS) signals,^[7] IONEX files are essential for understanding the impact of ionospheric conditions on GNSS signal propagation.^[8]

As GNSS signals traverse the ionosphere, they experience distortion due to the ionised plasma present in this region.^[8] This distortion results in delays and changes in signal direction, influenced by factors such as satellite elevation and solar position.^[8] Consequently, analysis of GNSS signals at ground stations yields critical insights into the ionosphere's state, particularly the density of free electrons, which is a key parameter affecting signal quality.^[8]

IONEX files consist of an ASCII format that includes a comprehensive header with global information, followed by a data section detailing TEC maps.^[7] TEC is measured in terms of the number of free electrons per square meter in a vertical column of the ionosphere, with a standard density of 10¹⁶ electrons representing one unit of TEC.^[8]

In addition to TEC maps, IONEX files also provide Root Mean Square (RMS) error maps and height maps, enhancing the understanding of ionospheric variations.^[8]

References

1. Teunissen, Peter; Montenbruck, Oliver (2017). Springer Handbook of Global Navigation Satellite Systems. Springer. p. 1209. ISBN 9783319429281. Retrieved 30 May 2019.
2. Bossler, John D.; Campbell, James B.; McMaster, Robert B.; Rizos, Chris (2010). Manual of Geospatial Science and Technology. CRC Press. p. 231. ISBN 9781420087345. Retrieved 30 May 2019.
3. "RINEX The Receiver Independent Exchange Format Version 3.02, page 38" (PDF). International GNSS Service (IGS). 18 October 2014. Archived from the original (PDF) on 16 October 2021. Retrieved 30 May 2019.
4. El-Rabbany, Ahmed (2006). Introduction to GPS: The Global Positioning System. Artech House. p. 107. ISBN 9781596930162. Retrieved 30 May 2019.
5. "RINEX The Receiver Independent Exchange Format Version 4.02, page 55" (PDF). International GNSS Service. Retrieved 2024-10-15.
6. Hatanaka, Yuki (2008). "A Compression Format and Tools for GNSS Observation Data" (PDF). Bulletin of the Geographical Survey Institute. 55: 21–30. Retrieved 2020-09-25.
7. "Interfaces and Protocols - Navipedia". gssc.esa.int. Retrieved 2024-10-31.
8. "Standards and Data Formats | GSSC". 2021-03-01. Retrieved 2024-10-31.

External links

• RINEX: The Receiver Independent Exchange Format Version 2.11 (December 10, 2007)
• Rinex Version 2.11 (June 26, 2012, minor clarifications)
• Rinex Version 3.02 (April 3, 2013)
• Rinex Version 4.02 (October 1, 2024)
• "Observation RINEX 4.0 Format". GNSS Format Descriptions. Research group of Astronomy and GEomatics of the Polytechnic University of Catalonia. Retrieved 2024-09-05.
• "Hatanaka compression/decompression". GPS/GNSS Pre-Processing Tools. EarthScope Consortium. Retrieved 2024-09-05.
• "RINGO: RINEX pre-processing tool using Go". Geospatial Information Authority of Japan. Retrieved 2024-09-05.