I am trying precision landing. I tested IR-LOCK, which works great. The problem is I need to land on a plate of metal. Something like this
When in high noon, sun will create a very bright reflective light. Such strong light make pixy camera "blind", cannot detect irlock and lose landing target. And I cannot paint the metal pate to black
So I try other way. I hear some people mention RTK GPS is very accurate. I use two emlid reach RTK module, one for base station, another installed on copter. I take copter off from the metal plate, fly away and switch to RTL mode. But RTL landing is not precision enough even in RTK fixed. I set WPNAV_RADIUS to 20cm and copter hove over home position trying to reach waypoint.
So I try to feed vector from current position -> home to ardupilot precision landing code, create a virtual beacon. Because RTK GPS is cm-level accurate. This virtual beacon should be able to guide copter during landing. This is my test result
https://youtu.be/mUMjagmdYBU. I take copter off, fly away and switch to Land mode. You can see ardupilot take copter back to exactly where it take off. There is no irlock or camera installed
This is the code I changed https://github.com/chobitsfan/ardupilot/commit/b7bc7c3b1f88a85e9c13557197c70c8dd0234b18