If BurtBackgroundMonitor doesn't receive odometry for 60 seconds it assumes that the subscription has been lost (e.g. the mainboard has been restarted) and resubscribes to observables.
To test: Make sure BurtBackgroundMonitor is not already running (ps -ef | grep BurtBackgroundMonitor). Run BurtBackground monitor. It will log to a file in /opt/barrett/burt/odometry/ and also print to the terminal. Confirm that it is receiving odometry messages. Then restart the mainboard firmware. (Methods of restarting are power cycling the robot, pressing the restart button on the mainboard itself, or running the BurtSharp program RestartFirmware.exe.) Confirm that BurtBackgroundMonitor resubscribes after 60 seconds.