Object avoidance with Navio 2

Continuing the discussion from Introducing Navio2:

it’s easier if you stick to your thread;

if you wanto to detect obstacles in your way you can use an ultrasound sensor (e.g. maxbotix’s ones) and laser for greater and more precise distances;
AFAIK obstacle avoidance is not (yet) supported in APM but efforts are being made (http://ardupilot.org/copter/docs/common-lightware-sf40c-objectavoidance.html)

Thanks

In regards to this. Is it feasible to create a ROS node which utilises something like a 2d lidar to detect an obstacle and then issue commands via mavros to stop or turn 90 deg for example?

How does ArduRover deal with the fact that it is trying to do waypoint navigation while at the same time you have a mavros node telling it to stop as there is an obstacle in its path?