Our precision landing Solo is flying great! :) This test rig has an IR-LOCK sensor (via I2C), an SF/10A rangefinder (via Serial), and is running a customized precision landing firmware based on APM:Copter (solo-rebase). The video above shows two vision-guided landings. The full 10-landing test sequence is shown below. The typical landing accuracy ranges from 0-10cm, even in moderate/gusty wind.
One of the primary challenges of designing a precision landing UAV system is the controls tuning. Every UAV has different flight characteristics, and finding the right PID (+EKF) parameters can be a painstaking process. So it is very helpful to have a popular, consistent hardware platform (e.g., Solo) to develop on. Solo flies nicely out of the box without significant parameter modifications. The precision landing performance is noticeably better than our IRIS+ platform, and our previous Solo test platform (w/out a laser rangefinder). In the 10-landing test sequence, the typical landing accuracy ranged from ~0-10cm. There was only one ‘failure’ (landing #5 out of 10), in which the copter landed far outside of the specified bounds. This will be analyzed and corrected via the controls code.
This test platform is running a customized precision landing firmware, which uses the vision-based localization data to actively manage the landing accuracy. You can read more about the code, and see previous testing here. USER BEWARE: this code is experimental, and it assumes that you have a reliable rangefinder connected.
Customized Firmware: ArduCopter-v2.px4
Github: http://bit.ly/1q3fIvS
Connecting IR-LOCK to Solo: Hackster.io article