What are the SBP/RTCP/UBC protocols in the DGPS module?

Hi,

the module_DGPS mentions "DGPS injection support for SBP/RTCP/UBC"

What are these protocols?

Is "SBP" like SBAS? Is "RTCP" a typo of RTCM? And is "UBC" the U-blox UBX protocol?

Thanks in advance for clarification.....

Start by reading the module_DGPS implementation and its references to SBP, RTCP, and UBC. Determine what each protocol means and whether the names or suspected typo are correct, then document the clarification where module_DGPS users will find it.

Written by the indexing model from the issue text.