OSQZSS

x40 works fine.

Nothing can be added to the motion files during execution.

LEO BODNAR's Mini Precision GPS Reference Clock is a good and reasonable GPSDO. https://www.leobodnar.com/shop/index.php?main_page=product_info&cPath=107&products_id=301&zenid=65c5ae1b8bc80efae25c25e14c84e996

Everything you need to know is written in the ICD: https://www.unavco.org/help/glossary/docs/ICD_GLONASS_4.0_(1998)_en.pdf

Use -T option.

You might need a better clock: https://github.com/osqzss/gps-sdr-sim/issues/290

Set a proper sample rate: gps-sdr-sim -e brdc3540.14n **-s 2500000** -l 30.286502,120.032669,100

Try a good exernal clock. The frequency offset of the onboard XO could be too big.

This might help: https://nuand.com/forums/viewtopic.php?t=4984

Install PothosSDR and set the configuration properties written in limeplayer.c.