vision system error

[laserdoc85]

flying out front this morning. Was up about 300 feet and i got the low battery warning. So I started to bring it down and I lost gps. I stopped and it wanted to climb and drift even tho I had my left stick pulled back. It climbed to 400 and said maximum reached. I could here it but not see it. I finally saw it and was able to bring it down as it was saying that it would return to home with 10% left. I was able to land it in front of me on the street as the home point was behind me in the driveway. KP index is 2 so I dont know why I lost gps or the vision system error