I believe when the LAA updated their ADS-B approval process, they based the requirements on EASA CS-STAN. The lowest level of compliance (with a non-certified GPS) is configuration 3.
This is an extract from SC-STAN:
For configuration 3:
The following conditions apply to configuration 3:
— The transponder equipment and its installation are compliant with CS-SC002c or later amendments, or are otherwise approved.
— The ADS-B transmit unit (transponder) is approved in accordance with ETSO-C166b, or later revisions, or the equivalent.
— The GNSS receiver is not approved or its installation is not certified. However, the compatibility of the combination of the transponder and the GNSS receiver is explicitly stated by the manufacturer of the transponder.
— The quality indicators are configured according to the manufacturer instructions to report the lowest quality (e.g. SIL = 0 and SDA = 0, NACp = 0).
— The installation instructions from the equipment manufacturer have to be followed.When the CAA conducted a trial of non-certified ADS-B OUT several years ago in which about 12 LAA aircraft took part, the currently required ETSO wasn't available but they approved the aircraft to operate with earlier versions of C166 transponders. The problem with the Funke is that it has no ADS-B certification all all. The C112 approvals relate just to the Mode S functions.
In LAA TL3.03, the only requirement for a TSO C166b transponder is in Appendix 3 - ADS-B with SIL/SDA greater than one.
Here's the original UK trial report:
https://nats.aero/blog/wp-content/uploa ... report.pdf