TLDR: You need to submit to OPUS RINEX files with observations on even 0.0000000 and 30.00000 intervals. This is a known requirement and there are a few tools to help you. I like Emlid Studio, RTKLIB/RTKCONV can take care of it with the proper options, and SparkFun has a tool also.
I ran into this a couple years back, here’s my post and @sparky 's helpful answer (ignore the screen shot the forum quoting function shows below, go click and read when you have time, it’s a long thread.)
I’ve successfully processed 100’s of RINEX files from Facets using OPUS.
OPUS needs the observations on even 30-second intervals (eg. seconds=0.0000000 and seconds=30.0000000). Open your RINEX in a text editor and check that the observations are on even 30-second intervals. I doubt that they are, because the ublox F9P in the Facets rarely output observations on exactly even 30-second intervals.
Looking in the RINEX file, each observation epoch’s data is preceded by a date time header, you need to have observations with headers on the even 0.0000000 and 30.0000000 intervals. It’s ok (but not awesome) if you have extra data, extra data just slows down the upload to OPUS and the OPUS pre-processing.
Here are headers from April 23, 2023, at 21:17:30 and 21:18:00 UTC to help you understand the RINEX files:
…
23 4 23 21 17 30.0000000
…
23 4 23 21 18 0.0000000
…
When converting from UBX to RINEX, you need to ensure the output RINEX has the observations on even 30-second intervals.
The easiest way do to this is to use Emlid Studio to convert from UBX to RINEX with the time rounding option. You can also do this with RTKLIB too, though Emild Studio is simpler to use.
You can search the internet for “ubx rinex time rounding” and you will find 100’s of posts on this topic.
The observations in the “raw” UBX files are often off the even 30-second intervals by a few milliseconds, and thus they are off by a few milliseconds in the RINEX if you don’t use the time rounding options. OPUS then rejects the file, as it finds no valid observations it can use. This is an endless source of problems for new users of devices build around ublox chips.
On the antenna topic, the last I saw, the L-Band Facet is in the queue at NGS for antenna calibration. IIRC there are a few posts in this forum on this topic. The NGS queue is long. Using the SFEFACET antenna at OPUS and correcting the vertical would be a decent workaround.
Tony.