Yes, but the problem is that unless you use the iCloud location data it basically kills your battery. In fact the WiKi even says: "iPhone considerations
Due to power management policies, OwnTracks on iPhone running in the background is only updating the location roughly every 10 minutes and sometimes even longer. This is blocking for many use cases that need timing wise short response."
Having a native iOS location binding would be great. @sipvoip, I would also be willing to help pay for the development.