I have added code that attempts to eliminate or handle the mysterous dropouts in bluetooth connectivity that cause Maemo Mapper to stop updating your current position while the UI continues to function. If you still experience this behavior, unfortunately resetting the bluetooth radio requires root privileges, but if you're willing, you can activate the "automatic bluetooth radio reset" functionality in Maemo Mapper by using root mode to modify the /etc/sudoers file to include the following line:

user ALL = NOPASSWD: /usr/sbin/hciconfig hci0 reset

WARNING: This is technically a security risk. Adding the above line can allow outside attackers to cause your bluetooth radio to reset without root privileges. USE AT YOUR OWN RISK.

If you do add this line to your sudoers file, please let me know if it has any effect for you. I tried for 90 minutes to reproduce the problem to see if the reset had any effect, but I couldn't reproduce it. If the behavior does occur, it may take Maemo Mapper up to 30 seconds to identify it and execute the reset.

EDIT: If you enable the bluetooth radio reset code, remember that it will cause ALL bluetooth connections to be dropped, including connections to cell phones, keyboards, etc. This will happen whenever the connection between Maemo Mapper and the GPS receiver is unexpectedly interrupted (e.g. if you walk far enough away from the receiver).