Rinex Observation File

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The RinexObsFile object provides functionalities for reading and writing Global Navigation Satellite System (GNSS) Observation data to and from a Rinex Observation file. This is an ASCII file of Pseudorange data conforming to the RINEX standard. The time system is GPS Time, and the scalar data is reference frame independent. FreeFlyer supports the RINEX 2 and RINEX 3 formats.

 

•For information on how to simulate GNSS Pseudorange data, see Simulating Tracking Data.

•For information on how to generate RINEX Observation files, see Generating Tracking Data Files.

•For information on viewing and editing data in a RINEX Observation file, see Using the Tracking Data Editor.

•For information on including a RINEX Observation file in a Kalman Filter, Unscented Kalman Filter, or Batch Least Squares OD process, see Including Tracking Data in an Estimation Process.

 

More information on the RINEX format can be found in several locations. Two example references are provided below:

 

•http://en.wikipedia.org/wiki/RINEX

•https://files.igs.org/pub/data/format/rinex305.pdf

 

Occasionally, GNSS Observation data is provided either in receiver dependent formats, or in a "compact" RINEX format, known as the Hatanaka format. Several conversion utilities are freely available from:

 

•https://www.unavco.org/software/software.html

•ftp://terras.gsi.go.jp/software/RNXCMP/

 

Examples of the format of a RINEX Observation file (version 2 and 3) are given below. The header includes information on:

 

•The RINEX version and type

•The program used to create the data

•The types of observations

•The time of the first observation

 

After the header, data is divided into sections, grouping measurements taken at the same time together. Multiple measurements may exist for the same epoch due to visibility to multiple GPS satellites. The lines indicating the date include this information:

 

•Year

•Month

•Day

•Hour

•Minute

•Second

•Epoch Flag record

o0 is "OK - No events occurred"

oValues greater than 0 indicate that an event occurred. See the links above for more details.

•Number of visible satellites

•Identifiers for each of the visible satellites

 

After the line indicating the date, the columns contain measurement data. The data types for each column are indicated in the header.  For RINEX 3, the three-character codes are used to indicate the following:

 

•Measurement Type

oC - Code phase

oL - Carrier phase

oD - Doppler

oS - Signal strength

•Frequency Band

o1-9

•Channel or Code

oC, S, L, X, Y, M, etc.

 

The RINEX 2 format only supports GPS, while the RINEX 3 format supports GPS, Galileo, and other navigation constellations. All GPS measurements supported in RINEX 2 are also supported in RINEX 3. Possible data types include:

 

•RINEX 2 (GPS-specific)

oL1

oL2

oC1

oC2

oP1

oP2

oD1

oD2

oS1

oS2

 

•RINEX 3

oSee https://files.igs.org/pub/data/format/rinex305.pdf for a complete list of available measurement codes. Codes available for pseudorange measurement processing in FreeFlyer are listed explicitly below.

oGPS Measurements

▪C1C (analagous to C1 in RINEX 2)

▪C1S

▪C1L

▪C1X

▪C1P (analagous to P1 in RINEX 2)

▪C1W

▪C1Y

▪C1M

▪C2C (analagous to C2 in RINEX 2)

▪C2D

▪C2S

▪C2L

▪C2X

▪C2P (analagous to P2 in RINEX 2)

▪C2W

▪C2Y

▪C2M

▪C5I

▪C5Q

▪C5X

oGalileo Measurements

▪C1A

▪C1B

▪C1C

▪C1X

▪C1Z

▪C5I

▪C5Q

▪C5X

▪C7I

▪C7Q

▪C7X

▪C8I

▪C8Q

▪C8X

▪C6A

▪C6B

▪C6C

▪C6X

▪C6Z

 

Note: FreeFlyer GNSS Pseudorange Observations may include the IonoFree Measurement type; these measurements will not be written out to file.

 

Example of RINEX 2 format:

 

 

Example of RINEX 3 format:

 

 

 

See Also

•RinexObsFile Properties and Methods