Questions regarding BDS IODE matching and epoch start time in MADOCA L6 decoding

[221zzl]

2026001.txt

Hello,

I have some questions regarding the decoding of MADOCA L6 files. Recently, I have been using your tools to process the file 2026001C.204.l6. I performed the decoding using the following commands:
cat 2026001C.204.l6 | python3 qzsl6read.py > 2026001C.rtcm
cat 2026001C.rtcm | python3 rtcmread.py -t 2 > 2026001.txt

I have encountered the following two issues:

1. Confusion about the Epoch Start Time in ST2 As shown in the attached screenshot, the epoch timestamps for the ST2 messages do not start from 00:00:00 (HH:MM:SS). Instead, they begin at 00:00:05. Could you please explain why there is a 5-second offset at the beginning of the file?

2. BDS ST2 IODE Matching Issue In the decoded ST2 messages for BDS, the IODE is shown as 130. However, when I check the corresponding CNAV broadcast ephemeris, I cannot find an entry with a matching IODE. Does MADOCA use a specific convention or algorithm to calculate/map the IODE for Beidou (BDS) messages?

I would appreciate any insights or guidance you could provide on these matters. Thank you for your time and for sharing these tools!

Best regards