convbin does not generate Galileo NAV records from u-blox RXM-SFRBX although Galileo SFRBX messages are present

[MarcosDuo]

Hi,

I am using convbin to convert a u-blox ZED-F9P UBX raw log into RINEX 3.04. The UBX file contains RXM-RAWX and RXM-SFRBX messages.

The conversion successfully generates:

• RINEX observation file .obs
• RINEX navigation file .nav

The observation file contains GPS, Galileo and BeiDou observations, but the navigation file only contains GPS and BeiDou ephemerides. No Galileo E## navigation records are written.

Receiver / input data

• Receiver: u-blox ZED-F9P
• Input format: u-blox UBX
• Messages enabled:
  • UBX-RXM-RAWX
  • UBX-RXM-SFRBX
• Log duration: 39 min 17 s
• Observation interval: 1 Hz
• Number of observation epochs in RINEX OBS: 2358

convbin version is the one downloaded from CONVBIN demo5 b34d

The help output shows support for: u-blox LEA-4T/5T/6T/8/9 : RXM-RAW, RXM-RAWX, RXM-SFRB

Command used:
convbin.exe -r ubx -v 3.04 -od -os -oi -ot -ol -d ./rinex ./raw/ublox_base_raw_20260524.ubx
I also tried with the "EPHALL" AND "GALINAV" options, but no Galileo navigation record were generated.

The .obs file contains Galileo observations:
3.04 OBSERVATION DATA M: Mixed RINEX VERSION / TYPE
G 8 C1C L1C D1C S1C C2X L2X D2X S2X SYS / # / OBS TYPES
E 8 C1X L1X D1X S1X C7X L7X D7X S7X SYS / # / OBS TYPES
C 7 C2I L2I D2I S2I C7I D7I S7I SYS / # / OBS TYPES

And Galileo satellites are also present in the observation epochs.

The .nav file contains GPS and BeiDou ephemerides, however, o Galileo records are present.

I parsed the UBX file directly and counted RXM-SFRBX messages by constellation. Galileo SFRBX messages are present in large numbers:

SFRBX messages by constellation:
0: GPS -> 3439 messages
2: Galileo -> 15277 messages
3: BeiDou -> 2252 messages

The Galileo SFRBX messages are present on these signal IDs:
Galileo sigId=1 -> present
Galileo sigId=5 -> present

In summary, no Galileo navigation records are generated in the RINEX NAV file, even though Galileo RXM-SFRBX messages are present in the UBX log. Is this expected behavior for this convbin build, or could this be a bug/limitation in the u-blox RXM-SFRBX Galileo I/NAV decoding path?

[ourairquality]

Try running it at trace level 3 and look for any relevant messages, any error or 'unsupported' trace messages.

Btw could I ask the extent of coverage on BeiDou with this ublox now, is it just C09 and C10 that have the 7I observation with all the rest, BDS3 satellites, having only 2I?

[MarcosDuo]

I looked at the trace, and I dont see any relevant Galileo-related errors.

Regarding BeiDou coverage, the RINEX OBS header generated by convbin contains:
C 7 C2I L2I D2I S2I C7I D7I S7I

So for BeiDou, the file contains full 2I observables including carrier phase (C2I/L2I/D2I/S2I), but for 7I it only contains code, Doppler and SNR (C7I/D7I/S7I). There is no L7I in the RINEX output.

I checked the BeiDou observation coverage per satellite/epoch. It is not only C09/C10. In this particular log, C09 was not present, while C10 was almost entirely 7I. However, most of the other BeiDou satellites also have some 7I observations, although usually only for a small fraction of their epochs.

[ourairquality]

Tried with some f9p data from the last 24hr and it did decode the nav data for Galileo. Tested using the 'main' branch code.

Checked the BDS signals and can confirm that 7I is only reported on the two remaining BDS2 satellites, C09 C10, and not on the BDS3 satellites. Do see those spots of 7I on BDS3 and guess that is some glitch as they have no 7I signal. Also for BDS2 it did include L7I.

Perhaps check the SNR of the signals and try getting some cleaner data and retry. Otherwise can you make some raw data available to check.

Alternatively might a RTCM stream with the nav data be an option. Also there is some code being tested that allows downloaded predicted nav and clock data to be used so that the receiver works without and broadcast data. If post processing then it is possible to download the broadcast nav data, e.g. see the IGS data.

[MarcosDuo]

You were right. The issue was the converter version.

I was using CONVBIN demo5 b34d. With that build, the same UBX file generated GPS and BeiDou NAV records but no Galileo E## records, even though Galileo RXM-SFRBX messages were present.

I retried using the current main branch code and Galileo NAV records are now decoded correctly.

So this seems to have been a build/version-specific issue rather than a problem with the receiver configuration or the raw UBX data.

Thanks for the help.