Hello Avenza Support
The only reliable way we have found to connect a Bad Elf Bluetooth GPS to the Avenza app is to set up your Android phone as a developer’s phone and then load the Bluetooth GPS app (by GG MobLab) to act as the mock GPS location app. Then when you open the Bluetooth GPS app select the Bad Elf GPS. This will give a stable accuracy of 1.7m on the Avenza app using the Bad Elf Pro +. It can be a bit fiddly at times but luckily the Bluetooth GPS app has various work-a-rounds you can select to get a stable connection.
Ideally, it would be simpler if the Avenza app had an option to select a Bluetooth GPS rather than phone’s integrated receiver – you can do this within Collector for ArcGIS app.
We use the Avenza app (search area track logging), Collector for ArcGIS app (polygon mapping of invasive plants) and iNaturalist app (photo point and id of invasive plants) simultaneously, so we use the mock location app method above to force the three apps to use the Bad Elf Pro + location.