People post on facebook assuming the privacy model of facebook, where they have revokable control of who sees what they share. What do you think your friends would say if you told them you're keeping a personal copy of their photos even if they try to delete them?
Please stop this. This is a huge violation of your friend's privacy. Just because a friend has shared something with you on facebook doesn't mean they expect it to be in someone's personal cambridge analytica forever.
That's similar performance to NASA's Gipsy solver and a couple other PPP solutions.
The practical problem is PPP falls apart when there's any sort of multipath or noise, with will be the case for any receiver not in a completely open field. A single nearby tree is often the difference between 4cm accuracy and a meter.