Nice job.
Years ago I started prototyping fully automatic self aligning coupling system. I got as far as the testing phase which went well as long as the operator could manage to back his vehicle within 3 inches left or right but he had to be reasonably straight in front of of the trailer. But this is not always possible as sometimes a trailer has to be connected at a near jack-knife angle I felt that I could have overcome that detail by adding a little more angularity movement but since the system was dependent on both the vehicle and the trailer using mated components if someone had multiple trailers all of them would have needed the came type coupler. Not very practical plus the minimum Liability insurance to put something like that on the market was in excess of 25 million, and to get DOT certification was going to be another lengthy process.So I scrapped the idea.
Now they have tailgate cams which interface with a screen on the dash even the radio I installed in my pickup has bluetooth interface capability for up to 3 cameras.
Your use of your phone is another good example of how technology has advanced since my idea back in the 80's and does not require reinventing a coupling system.
Even some new pickups and SUV's have the capability to self back a trailer down a launch ramp.