UBX2RINEX

ubx2rinex is a small command line utility to deserialize a U-Blox data stream into standardized RINEX file(s).

⚠️ this tool is work in progress.

Licensing

This application is part of the RTK-rs framework which is delivered under the Mozilla V2 Public license.

Install from Cargo

You can directly install the tool from Cargo with internet access:

cargo install ubx2rinex

Build from sources

Download the version you are interested in:

git clone https://github.com/rtk-rs/ubx2rinex

And build it using cargo:

cargo build -r

The application uses the latest UBX protocol supported. This may unlock full potential of modern devices, and does not cause issues with older firmwares, simply restricted applications.

Getting started

To deploy, you must at least select one Constellation and one signal.
We propose one flag per constellation, modern UBlox supports tracking of up to 3 constellations. We offer one flag per signal.

The default opmode is Observation RINEX collection. In the following example, we will collect all L1 observations for GPS

RUST_LOG=trace ubx2rinex -p /dev/ttyUSB1 --gps --l1
[2025-02-23T10:48:22Z INFO  ubx2rinex] Connected to U-Blox
[2025-02-23T10:48:22Z DEBUG ubx2rinex] Software version: EXT CORE 3.01 (111141)
[2025-02-23T10:48:22Z DEBUG ubx2rinex] Firmware version: 00080000

Not defining a baud rate value means you are using our 115_200 default value.

In summary, the mandatory flags are:

• -p,--port to define your serial port
• at least one constellation activation flags, like --gps
• define a specific baud rate if you want

To determine your U-Blox port on linux, for example:

dmesg | tail -n 20

Follow through this tutorial to understand all the options we offer, especially:

• the application default behavior
• U-Blox configuration options
• select your constellation
• Observation RINEX collection

⚠️ M8 Series usage

⚠️ Until further notice ⚠️

This application is compatible with M8 series device but does not offer any option (as of today) to reprogram the Constellation / Signal settings. You will have to use a third party tool to actually reconfigure your device.

For example, M8T factory settings are GPS (L1) and GLO (L1). We would deploy like this:

ubx2rinex -p /dev/ttyUSB1 --gps --glonass --l1

Any other constellation flags has no effect. Selecting other signals has no effect. Removing L1 signal would create invalid RINEX.

Application logs

ubx2rinex uses the Rust logger for tracing events in real-time and not disturb the collection process.
To activate the application logs, simply define the $RUST_LOG variable:

export RUST_LOG=info

Several sensitivity options exist:

• info
• error
• debug
• trace

U-Blox configuration

U-Blox receivers are very user friendly yet still require a little knowledge to operate.
That is especially true to advanced use cases.

The most basic configuration your need to understand, is how to parametrize the streaming options of your U-Blox device. ubx2rinex allows partial reconfiguration of the U-Blox receiver:

(1) Define the streaming interface(s) and options (2) Customize the receiver for this application's need

(1): means you can actually use ubx2rinex to parametrize how your U-Blox streams. It is also necessary to activate streaming on at least the USB/UART port that you intend to use.

(2): configuring the receiver, in particular what frames it will transmit, will modify the RINEX content we are able to collect obviously.

USB/UART port setup

TODO

UBX streaming setup

TODO

RINEX Collection

ubx2rinex is a collecter, in the sense that it gathers a real-time stream from your u-Blox, and dumps it into supported RINEX formats. It is important to keep in mind that, in order to format a meaningful (and correct) RINEX header, we can only redact it after completion of a first entire epoch, every time a new gathering period starts.

File name conventions

ubx2rinex follows and uses RINEX standard conventions. By default we will generate RINEX V2 (short) filenames, as it only requires one field to be complete. By default, this field is set to UBX, but you can change that with --name:

RUST_LOG=trace ubx2rinex -p /dev/ttyUSB1 --gps --name M8T

Signal Collection

The default ubx2rinex collection mode is Observation RINEX collection.

Using this mode, you can use your U-Blox as a real-time signal source (sampler) which is then collected as Receiver Independent EXchange for distribution, post processing and much more. The default RINEX format garantees 17 digits of precision on sampled signal and 14 digits on the local clock state.

Observation RINEX collection is the default mode and deploys at all-times, unless you use the --no-obs flag, which will disable this mode:

./target/release/ubx2rinex \
        -p /dev/ttyACM0 \
        -b 115200 \
        --gps \
        --l1 \
        --rx-clock \
        -m "M8T u-Blox"

[2025-02-25T20:30:01Z DEBUG ubx2rinex::device] U-Blox Software version: EXT CORE 3.01 (111141)
[2025-02-25T20:30:01Z DEBUG ubx2rinex::device] U-Blox Firmware version: 00080000
[2025-02-25T20:30:01Z INFO  ubx2rinex::device] Enabled constellations: GPS, Glonass, 
[2025-02-25T20:30:01Z INFO  ubx2rinex::device] Supported constellations: GPS, Galileo, BeiDou, Glonass, 
[2025-02-25T20:30:01Z DEBUG ubx2rinex] UBX-NAV-EOE enabled
[2025-02-25T20:30:02Z DEBUG ubx2rinex] UBX-NAV-PVT enabled
[2025-02-25T20:30:02Z DEBUG ubx2rinex] UBX-NAV-CLK enabled
[2025-02-25T20:30:02Z DEBUG ubx2rinex] UBX-NAV-PVT enabled
[2025-02-25T20:30:02Z DEBUG ubx2rinex] Measurement rate is 30 s (Gps)
[2025-02-25T20:30:03Z INFO  ubx2rinex] Observation RINEX mode deployed
[2025-02-25T20:30:03Z INFO  ubx2rinex] 2025-02-25T20:30:18.313672551 GPST - program deployed
[2025-02-25T20:30:12Z TRACE ubx2rinex::collecter] 2025-02-25T20:30:30.006000000 GPST - (G02 RAWX) - pr=2.2654484E7 cp=1.1905012E8 dop=-1.1215144E3 cno=25
[2025-02-25T20:30:12Z TRACE ubx2rinex::collecter] 2025-02-25T20:30:30.006000000 GPST - (G03 RAWX) - pr=2.1846652E7 cp=1.1480491E8 dop=6.1150366E2 cno=37
[2025-02-25T20:30:12Z TRACE ubx2rinex::collecter] 2025-02-25T20:30:30.006000000 GPST - (R19 RAWX) - pr=2.4613278E7 cp=1.3166441E8 dop=-3.8444370E3 cno=23
[2025-02-25T20:30:12Z DEBUG ubx2rinex] NAV PVT: NavPvt { itow: 246630000, year: 2025, month: 2, day: 25, hour: 20, min: 30, sec: 12, valid: 55, time_accuracy: 50, nanosecond: 371019, fix_type: Fix3D, flags: NavPvtFlags(GPS_FIX_OK), flags2: NavPvtFlags2(RESERVED1 | RESERVED3 | CONFIRMED_AVAI | CONFIRMED_DATE | CONFIRMED_TIME), num_satellites: 8, lon: 4.635316899999999, lat: 43.6876077, height_meters: 65.992, height_msl: 18.155, horiz_accuracy: 21079, vert_accuracy: 24241, vel_north: 0.081, vel_east: 0.092, vel_down: -0.129, ground_speed: 0.123, heading: 0.0, speed_accuracy_estimate: 0.20400000000000001, heading_accuracy_estimate: 162.7699, pdop: 204, reserved1: [0, 0, 74, 100, 35, 0], heading_of_vehicle: 0.0, magnetic_declination: 0.0, magnetic_declination_accuracy: 0.0 }
[2025-02-25T20:30:12Z DEBUG ubx2rinex] nav-sat: NavSat { itow: 246630000, version: 1, num_svs: 21, reserved: [0, 0], [...] }
[2025-02-25T20:30:12Z DEBUG ubx2rinex] NAV CLK: NavClock { itow: 246630000, clk_b: 628984, clk_d: 187, t_acc: 50, f_acc: 736 }
[...]

Observation RINEX Timescale

⚠️ Observation RINEX express timestamps and clock states in a specific GNSS Timescale, not UTC.

ubx2rinex is smart, it will adapt the main Timescale to your Constellation choices.

Receiver clock state collection

Observation RINEX allows describing the receiver clock state with 14 digits precision.
This is optional and disabled by default. If you are interested in capturing and distributing your local clock state, you should turn activate this option with --rx-clock.

Sampling period

When collecting signal observations, it is important to define your sampling period. The default sampling period is set to 30s, which is compatible with standard Observation RINEX publications.

You can use any custom value above 50ms.

In this example, we reduce the sampling period to 1s:

ubx2rinex -p /dev/ttyACM0 \
          --gps \
          -s "1 s"

Snapshot period

The snapshot period defines how often we release a RINEX of each kind. When the snapshot is being released, the file handled is released and the file is ready to be distributed or post processed.

By default, the snapshot period is set to Daily, which is compatible with standard RINEX publications.

Several options exist (you can only select one at once):

• --hourly for Hourly RINEX publication
• --quarterly for one publication every 6 hours
• --noon for one publication every 12 hours
• --custom $dt for custom publication period. Every valid Duration description may apply. For example, these are all valid durations: `--period

NB:

• the first signal observation is released everyday at midnight 00:00:00 in the main Timescale
• the last signal observation is released everyday at 23:59:30 in the main Timescale

File rotation and descriptors

ubx2rinex owns the File descriptor with write access (only) until the end of this period.
That means you can only read the file until the end of the period. Deleting the file descriptor while the program is actively collecting will the program to panic.

At the end of each period, the file descriptor is released and you can fully process it.
The file pointer is then incremented, using standard naming conventions.

ubx2rinex will provide content "as soon as" it exists (+/- some file descriptor access, that we try to keep efficient). This means that exploitation of this program is compatible with real-time watching of the file being produced and each new symbol is published fairly quickly.

Program interruption and release

ubx2rinex does not support Ctrl+C interruption cleanly as of today.

Other customizations

• Define your name as Operator`` in RINEX terminology, with --operator myself`
• Define your name as Observer`` in RINEX terminology, with --observer myself`
• Define your agency (publisher) with --agency myagency
• Define the country code (3 letter) of your agency with --country ABC

no-std

This program relies on both the ubx parser and the rinex library.
The first one supports no-std, but it is unfortunately not true for the latter.
We will see if we can provide some very reduced, no-std compatible portions of the rinex library in the future, especially the file production side. This is not scheduled work as of today. Feel free to join in if you want to see this happen sooner.