A Reference Implementation is a fully functional, licensed copy of a tested, branded software that has passed the test for an associated conformance class in a version of an Implementation Standard and that is free and publicly available for testing via a web service or download (from OGC Compliance Testing Program Policies & Procedures 08-134r9).

About the duration and status of a Reference Implementation:

• The status is good for one year.
• The implementation needs to be retested every year and pass the test to maintain its status as Reference Implementation.

The Reference Implementation does not need to pass all the conformance classes within the standard. In most of the cases, the Reference Implementation will pass at least the core and possibly some number of extension conformance classes.

Multiple reference implementations can exist for an associated version of an Implementation Standard. OGC Staff after reviewing the results and checking the public interface of the software will determine if the implementation can be a reference implementation.

It is prefer that the organizations seeking reference implementation status to host the Reference Implementations on their own site.

Easy. When applying for certification, you click the option to become one

The official list of reference implementations is available at the OGC website.