Re the radar’s input to object avoidance, simple avoidance only makes use of 45degree sectors but BendyRuler has a 2D object database where it stores the locations of objects that have been sensed by the lidar. To get the radar’s input into AP’s object avoidance we’d probably need a new driver or you could send in the data over malink using the obstacle-distance message.
If you’re looking to write your own obstacle avoidance library you could extend the AC_Avoidance library to add a 3rd path planning method (the 1st and 2nd methods being BendyRuler and Dijkstra’s).
Doing obstacle avoidance is quite difficult but if you’re interested in contributing to AP’s avoidance features there are a number of ways that we know we can improve it and these are in the issues list. Coincidentally I’ve added links to some of them from our GSoC page. I’m not suggesting you’re a GSoC student of course but it’s just one place that I’ve listed up some of the top priority items.