you can use the tracker unit in standalone or connected mode.
in standalone mode you use the mobile app to configure and/or start single user races.
in connected mode the tracker unit connects to the host system via wifi. there you can run multiple participant races with different race modes.
tbd
you can run the host software on any computer and operating system that has java se support.
setup for raspberry pi setup is described here raspberry pi tutorial
just run the jar file from a command line (using java -jar fpvlaptracker-1.0.jar).
the host software can be configured using a config file.