The video below shows the results from a test flight of the drone using a custom built application. This is NOT testing the accuracy of the drone to land on the red X but to check the agreement of the virtual drones position with the real drones position. The virtual drone says its position is at X: -0.18m Y: 0.98m from the origin (take-off position). The real drones results were close at X: -0.15m Y: 1.01m. The difference is 3cms in each axis. Of course these flights were short and the margin of error will increase over time.
Red X = desired position to land
Red dotted line = flight path
The flowery duvet cover helps the drone stabilise using the vertical camera because it has diverse colours and shapes.