I suspect that you could use a shell script to do what you want with restarting GPSapp everytime the player starts. I'm not sure if gpsapp traps any signals to 'nicely' stop, or whether the brute force approach below is the only way.

config.ini:

[hijack]
;@DC exec=/path/to/gpsapp.sh


/path/to/gpsapp.sh:

#!/bin/bash
$pid = pidof gpsapp
if [ -n $pid]; then
kill -9 $pid
usleep 10000
fi

if [ -x /path/to/gpsapp ] ; then
/path/to/gpsapp NMEA
fi

exit 0


The usleep is there to give gpsapp a chance to disappear cleanly before we restart it. The value may need to be tweaked - I have no idea. (In fact I have no idea what would happen if the second incarnation of gpsapp happened before the first disappeared anyway.)

Edit: Appended NMEA to gpsapp start line - Not sure if it's necessary anymore.