There are other ways to get even greater accuracy than an applanix. But they require pre-indexing the surroundings and using a lidar to position yourself within the "virtual" world.
Also the error grows with distance. So if your bot is navigating off of objects 200 meters away, yeah you'll be more off. But you can use points closer to it and you'll get better results. Look around and you'll see that the velodyne has been made to work. Nobody loves it though.
The riegl has very low beam divergence, is beautiful, survey accurate, not waterproof and $300k+.
Don't forget the workhorse SICK scanners. They are cheap and have their pros and cons.