ADS-B tracking with an off grid Raspberry Pi

I have been looking for a solution to do ADS-B tracking off grid for quite a while. I have several Piaware trackers in different setup (fixed one at home, mobile one with GPS in the car, mobile one that I take with me when I travel abroad), and I wanted to add some in places where I don’t have power or wifi. After some research I decided to use a solar panel for power and a SigFox hat for connection. The SigFox hat has limited data throughput (6 messages per hour in uplink), but it is enough to report new or interesting aircraft to my server.

There is a lot of literature on solar power for the Pi, but I still ended up underestimating the size of the panel. 20W just gives me 6h per day in average. I will need to upgrade to 120W to make sure I run 24/24 7/7 365/365. The BIG power consumption comes from the RTL-SDR dongle, and you can not toggle it on and off to save power as it needs to be on for an extended period of time to do its job. Having my tracker going on and off created an unexpected issue that I didn’t see during my debug session with wifi: as the Pi does not have a RTC, the Pi time is losing 16h per day in average.

Rapidly, my timestamp for the planes detected were off. Hopefully, as SigFox allows also 4 downlink messages per day, I am able to request a time update through this channel. With some adjustment to make sure I don’t use my downlink messages budget when the Pi powers up just for few minutes when battery is low but sun is high, I was able to make that work. Next step is to work on improvements for the battery management and I will have a fully independent solution. I now have a Piaware tracker running fully off grid!

You can find more details on my setup and the data reported by my trackers on https://www.foxtrotcharlie.ovh

When I started this project I didn’t know how far it would bring me! My long term goal is still to share all my software on Github, but that will need some cleaning!

Also published on www.raspberrypi.org