Tracking is the most important part of high altitude ballooning, because without reliable tracking there’s no point launching in the first place.
You can either purchase a tracker kit or build your own tracker from electronic components and modules. The latter is more rewarding but not everyone has the time or requisite skills.
Here are some of the options you have:
This is my new tracker, building on experience with my previous trackers (see below). It combines the inherent reliability of a microcontroller tracker with the capabilities added by a Raspberry Pi. See this article on the new product.
FlexTrak replaces the following 2 products:
Pi In The Sky
Or you can build your own tracker, for example: