This is a schematic of my wiring of the ArduIMU v3. I hope to be able to use this soon as my own personal and custom RTH and 'stabilized mode' solution with some extra benefits highlighted below. One extra analog pin will be used in the future to read out the RSSI level from the attached RC receiver.
This setup demonstrates how far you can push this remarkable board. The W5100 chip provides 30Hz telemetry over wifi to the ground (just make sure to use the sparkfun one, I've seen other implementations with a hardware bug that only allow that SPI device on the bus). It requires a wifi AP specifically designed for long-range connections that allows you to set some specific parameters for your intended range, up to 50km. I still need to see how this performs in the field though, but theoretically it should work nicely.
I'm using this setup in combination with an HD IP camera for a 720p video feed that has 150-200ms latency. The weight of that cam is 160g, so about the same as a gopro+analogcam. The two IP devices onboard are then connected to the onboard LR wifi station by a stripped down ethernet hub I found that fit the requirements. Regular, non-shielded, ethernet cables are stripped down (2x twisted pairs without grey insulation), which over these short distances and bitrate aren't any problem (20-40cm). All in all, it's about 100g heavier than a full analog setup on the same platform (2.3kg).
The benefit of digital over analog is that it's much easier to integrate both the vehicle and sensors into more complex ground station applications. The tasks for piloting, navigation and mission execution for example can be cleanly separated in either machines or persons.This opens up a range of possibilities of how people with different responsibilities interact with the platform or how they use the data that the plane is sending down at high bitrates.
I hope this ignites interest a bit in higher speed datalinks. Although I did manage to find the electronics for connecting stuff together, the hubs and other fairly simple electronics leave many things to be desired. Hopefully more people will consider adding a magjack instead of a serial port on their boards. The advantage of connecting everything on the plane on a single databus is that you can recalibrate *everything* in the air. This opens up ways to use resources more effectively and redirect resources depending on the context within which they are needed. There's something to say for one databus connection that everything is connected to. This facilitates integration and makes interoperability a lot easier.