GNSS Format Descriptions

Obs Rinex



GNSS data sets follow a well defined set of standards. These standard formats provide many advantages, the most obvious being it is easy to exchange. ASCII and binary formats both satisfy this function, but ASCII does it with greater generality because binary formats are computer operating system dependent. These formats have evolved to satisfy growing requirements, satellite systems, capabilities, etc.

But reading a standard format description is a tough task. This section aims to provide the community a reliable and powerful tool which explains these necessary standards in a very easy and friendly way, aided with explanatory tooltips. These tooltips will be triggered automatically when the mouse is hovered over a field. These explanations include the standard description of the field, the format in which is written and, if applicable, its units.

Get familiar with the different format standard(s) involved in the GNSS data sets, take your time to analyse in detail particularities and characteristics of the GNSS systems, observables, versions, models through the different data sets provided. Please email any suggestions, comments or requests to gAGE:


gFD Quiz

New to GNSS field? How much do you master the different GNSS standards? Do you think you know all the particularities of your daily used format standard? Discover it through the GNSS Format Descriptions (gFD) Quiz prepared by gAGE. The proposed Quiz is based on the explained GNSS formats gathered here. There are no complicated questions to answer, the test guides your mouse through the different formats involved. Click here to take the gFD Quiz now!

This quiz is based on the work of Adria Rovira-Garcia. The gFD Quiz is intentend to be used worldwide: not only by student of professionals starting in the GNSS field, but also to senior researches that need to refresh their knowledge on some particular standard, or need to move to a new format.


Explained Formats

File Type Version Version Date File Name Description
Observation 2.10 10 December 2007 Observation Rinex v2.10.html RINEX format for GPS and GLONASS observations.
2.11 10 December 2007 Observation Rinex v2.11.html RINEX format for GPS and GLONASS observations.
3.01 22 June 2009 Observation Rinex v3.01.html RINEX format for GPS and GLONASS observations.
Navigation 2.11 10 December 2007 GLONASS Navigation Rinex v2.11.html RINEX format for GLONASS Navigation Message File.
2.11 10 December 2007 GPS Navigation Rinex v2.11.html RINEX format for GPS Navigation Message File.
3.01 22 June 2009 SBAS Navigation Rinex v3.01.html RINEX format for the complete broadcast data of Space-Based Augmentation Systems (SBAS).
Ionospheric 1.00 25 February 1998 IONEX v1.0.html IONEX format for ionosphere models determined by processing data of a GNSS tracking network.
Clocks 3.00 14 November 2006 RINEX CLOCKS v3.00.html RINEX format for satellite and receiver clock offsets determined by processing data of a GNSS tracking network.
Antenna 1.3 20 September 2006 ANTEX v1.3.html ANTEX format for Phase Center Offsets (PCOs) and Phase Center Variations (PCVs) of geodetic GNSS antennae.
Precise Products C 12 February 2007 SP3 Version C.html SP3 format for GNSS orbit and clock solutions.



About the Data

Variable Type

FORTRAN Format Example Description
Integer In I4 : '2010' A 'n' position integer.
Note it can be specified the minimum lenght of the integer by including a number after the floating point symbol. This forces the number to be padded, even with zeros.
I5 : ' 2010'
I3.3 : '010'
Float Fn.m F8.2 : '-1402.50' A 'n' position double with 'm' decimal positions.
Note 'n' includes sign space and the floating point symbol.
F8.2 : ' 1402.50'
F7.3 : ' 44.000'
Exponential Dn.m D12.2 : '-1402.50D+02' A 'n' position exponential double with 'm' decimal positions.
Note 'n' is the total lenght of the exponential number, this includes sign space, the floating point symbol and the exponent itself.
In order to account for the various compilers, E,e,D, and d are allowed letters between the fraction and exponent of all floating point numbers in the navigation message files of RINEX v3.01. Zero-padded two-digit exponents are required, however.
D12.4 : '-0.1966D+06'
E12.3 : '44.000E+006'
e12.3 : '-44.000E+006'
Characters An A7 : 'GLONASS' A 'n' position character.
Note this includes empty characters.
A2: ' E'
Empty Fields nX 1X : ' ' A 'n' empty characters.
The fields that are defined as blanks are reserved fields which must remain blank as may be used in future versions.