At the moment it won’t work for remote systems without timelapse1090 installed because it just retrieves the data from that via ssh. It is relatively simple to change the script to work on remote systems and gather the aircraft.json however.
If you change line 101, which is currently this:
jq -r '.aircraft | .[] | select(.lat != null) | select (.lon !=null) | select(.rssi != -49.5) | [.lon,.lat,.rssi,.alt_baro] | @csv' /run/dump1090-fa/aircraft.json >> $wdir/heatmap
to this:
curl -sS http://$pi/dump1090-fa/data/aircraft.json | jq -r '.aircraft | .[] | select(.lat != null) | select (.lon !=null) | select(.rssi != -49.5) | [.lon,.lat,.rssi,.alt_baro] | @csv' >> $wdir/heatmap
and make sure the ip address of the remote pi is set at the top of the script. You also need to remember to change the lat/lon and heywhatsthat ID to match those for the remote receiver, and delete any existing upintheair.json file before running.
Edit - just tested it and it does work OK, so try it and see how it goes.