Landmark Based Outdoor Robot Localization

[DonRotolo]

Ideas:
First, imagine you wanted to do this in a gym. Perfect environment, flat floor, no slippage, etc. In this case, odometry (measure wheel roaions accurately) and a gyroscope (for turns) might be enough.

Move it outdoors, with uneven and slippery terrain.

Same odometry & gyro, but you can only be assured to get to 'about' the same place (I am ssuming a series of straight lines, connected by turns). So what you need is a "waypoint": a known location that, if your robot gets near enough, it can make a correction to be in exactly the right place at each 'turn'. (for a long straight, there could be one or more in the middle too).

A waypoint can be many things: Two laser beams that cross. A buried RFID tag. A QR-Code-Like target*. A pole that lines up with another pole. A seies of flashing lights, all flashing a different code, and a camera that scans 360 degrees to find its location. You can think of others I'm sure. If the location and path are always the same, it is a lot easier than when it changes all the time.

Hope this gets you thinking down a viable path.

*Look at a modern camera-based automotive wheel-alignment machine.