Dennis Milbert

Updated:  2006-dec-10

The program, ant2rin, takes a ".ubx" binary file from the u-blox u-center logger, and converts the LEA-4T UBX-RXM-RAW message contents into a RINEX file. Its binary in, and ASCII (RINEX) out.

There are numerous ANTARIS 4 GPS modules. Of these, only the LEA-4T outputs carrier phase in the binary UBX-RXM-RAW message. While ant2rin might operate with other versions of the UBX-RXM-RAW message, ant2rin was built to convert LEA-4T binary carrier phase and pseudorange into the RINEX format.



The program operates in the DOS window. Alternatively, you can simply run "ant2rin.exe" with a double click or with "Run..." in your "Start" menu. (I use the DOS window myself.)

One file is needed for input. One file is generated as output. The names are fixed. The files must be in the subdirectory where you are working.

Input File:

ant2rin.ubx -- Binary format. You must have enabled logging of the UBX-RXM-RAW messages in the u-center logger.

Output File:

ant2rin.obs -- ASCII, RINEX format. A RINEX observation file containing the pseudorange and carrier phase information in the UBX-RXM-RAW messages. A generic header is also constructed -- edit those elements you wish to change (like station ID and approximate position).

Command Line Options:

The following 4 options may be in any order following the "ant2rin". Options are separated by a blank. A hyphen (minus sign) is the prefix to each command line option. For example:

ant2rin -r -d
Command line options are used when you have opened a DOS window or when you use "Run..." in your "Start" menu.

-d -- "drop". Drop all weak records (QI of 6 or less). Default action is to retain all records, no matter how weak.

-r -- "rate". Decimate data to nearest epoch per 5 seconds. Default action is to retain all records.

-f -- "full". Output RINEX fields for Doppler and signal strength. Default action is to output only the L1 carrier phase and pseudorange. This option is bypassed if a "-q" option is selected.

-q -- "quality". Create a variant RINEX form, where the Message Quality Indicator (MesQI) of the UBX-RXM-RAW record is output in place of the Doppler field. This variant RINEX form is only provided for debugging purposes. Do not attempt to process the RINEX output when this option has been used.


The program generates a few lines of output in the DOS window. It echos the command line options it has detected. It lists counts of the number of binary messages it has encountered. (Note: class=2, ID=16, refers to UBX-RXM-RAW). Then, the program will list how many records were dropped due to a Message Quality Indicator (MesQI) of 4, 5, or 6. If the "-d" command line option was not invoked, then those counts will be zero.

The program will supress the records generated from WAAS/EGNOS packages in orbit.

While the u-center logger can be commanded to log data at different rates, I found it convenient to log at a 1 second rate, and then use the "-r" (decimate to 5 second) option in ant2rin. The program will track carrier loss-of-lock indicators over the skipped records when the "-r" option is selected.

For you GPS enthusiasts new to this, LEA-4T refers to the GPS module, and AEK-4T refers to an evaluation kit that contains a LEA-4T module. My experiments have been with an AEK-4T.

If you want a different (free) piece of software, check out "TEQC"

RINEX Format

The RINEX version 2.10 format (25jan2002) can be obtained from the International GPS Service and the 8jun2001 version from the National Geodetic Survey.


This is "no frills" software. There are no warranties of any sort. No Windows GUI. Just the core function.

You must have the input file with the name ant2rin.ubx. The program will overwrite any existing "ant2rin.obs" file in the working directory. The program will supress the records generated from WAAS/EGNOS packages in orbit.

Source Code and Binary Executable

The Fortran source code (2006dec08) is ant2rin.for.

The compiled executable (zipped) is ant2rin.exe.

Links to Other Pages

The links here expand on the topics above.

To Contact Me

My e-mail user name is the first initial of my first name followed by all the letters of my last name (see above). My ISP is "comcast", and it is a "dot-net", not a "dot-com". Sorry for not spelling out my e-mail address, but I try to keep the spam-bots from fingering me. But, just so the spam-bots don't feel left out, they can always go to abuse@comcast.net

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