Found a Mavic Mini in North London near Trent Park, [...] I'm desperately trying to find the owner.
When you say "
nothing on the SD card", is it truly blank? Or is there just nothing in the DCIM folder?
If there
is a DCIM folder (even empty), then there should also be a
hidden MISC folder. These folders are created automatically on any brand new card, or a recently formatted card, whenever the Mini is powered up. Recorded photos and videos go into the DCIM folder, and log files go under the MISC folder.
In the Windows File Explorer menu, click View, then check the boxes to show "File name extensions" and "Hidden items". Then restart File Explorer.
On the SD card you now should see the DCIM folder and a pale (no longer hidden) MISC folder. Open that folder down to MISC/LOG/flylog and you'll find a 512MB file named "fc_log.log"
If the Mini has ever been powered up and flown, there will a ton of information logged in that file. You need a program called
DatCon (
datfile.net/DatCon/downloads.html) in order to decrypt and view the log file.
[Edit] I forgot to mention one important detail. You need to change the file extension on fc_log.log to fc_log.DAT in order to open it with DatCon.
On my slow computer, DatCon takes a looong time to chew through the file. Be patient. Eventually DatCon creates a CSV spreadsheet file which can be opened in Excel, again taking a very long time. It's a HUGE file, in my case going across to column-LL and down 174,944 rows!
The third and fourth column contain GPS coordinates, IMU_ATTI(0):Longitude & IMU_ATTI(0):Latitude, tracking the Mini's flight path. Scroll all the way across to (again in my case) columns
BV &
BW, which are again
GPS:Long and
GPS:Lat, and two more columns to the right to column
BZ which is
GPS:dateTimeStamp.
If you are clever at using Excel, you can strip out just the Lat/Long and dateTime columns, then sort by unique dates and start times. Maybe you will only find multiple flights starting every time from the same flying park location. But hopefully there will also be unique log entries from the Mini being started up long enough to record the GPS location of the owner's home.
It's worth a try unless of course, as you say, the SD card truly is empty. ?