2 mil search results in Google for "drone precicion landing"
- GPS http://www.directionsmag.com/entry/finally-affordable-high-precision-gps-for-drones/470208
- IR http://diydrones.com/profiles/blogs/ir-lock-sensor-for-precision-landing-etc?page=3
- https://en.wikipedia.org/wiki/Wi-Fi_positioning_system
- http://www.scirp.org/journal/PaperInformation.aspx?paperID=378
- In this way, positioning can be achieved within a radius of 10 meters https://arxiv.org/pdf/1204.1748.pdf
- BT based http://estimote.com/
- General stuff https://locatify.com/blog/indoor-positioning-systems-ble-beacons/
- Short distance http://docs.beaconstac.com/docs/common-questions.html and long range BT based https://en.wikipedia.org/wiki/IBeacon
- https://www.quora.com/What-is-the-positioning-accuracy-of-iBeacon-and-other-BLE-technology
- Comparison Wifi-BT http://www.cl.cam.ac.uk/~rmf25/papers/BLE.pdf
- https://what3words.com/
- https://en.wikipedia.org/wiki/QR_code
- IR paint http://www.anytimesign.com/infrared_magic_black_ir_transparent_paint.htm