Some disjointed thoughts on UAV deployment 2

Using a Mini UAV to Support Wilderness Search and Rescue: Practices for Human Robot Teaming -Goodrich et al

Carrying on from yesterday, with the added caveat that following a meeting it seems we may be looking more into the realms of radiation leak scenarios (which actually holds a lot of overlap for this sort of thing. More on that later), this is the second paper I meant to ramble about yesterday but didn't get a chance to.

The unique perspective provided by this publication is that it uses actual search and rescue data and methods and examines how UAVs could augment these searches. The basic process is Bayesian, with an initial belief system which is then updated with various different time horizons in mind. As before there are considerations about terrain, paths, undergrowth etc which directly affect how a person might behave.

Terrain mapping

There are three methods outlined which detail how a plan of action is carried out by the various members of a search and rescue team. At this stage these are all scenarios where the UAV has a human pilot controlling it directly (albeit remotely).

Sequential:

• A search plan is designed by a mission planner or director based on initial beliefs
• This is then carried out by an overhead UAV
• Any signs of the missing person are followed up by ground crews 
• If the person isn't found, a new plan is though of and the process begins again

This method is especially useful over inaccessible terrain where a ground team can't easily move to track the missing person on foot, and where the area is very large. 

Remote-Led:

• A ground team performs a search as quickly as possible from the last known location of the missing person, following any clues of their whereabouts
• The UAV is tasked with orbiting overhead and tracking the ground team, extending their effective range of vision
• Telemetry is sent back to the mission director on the ground to further the search

A good plan for cases where the missing person has left evidence of their location or the area is quite local.

Base-Led:

• Bayesian pattern based on waypoints chosen
• UAV carries out pattern sending back data to base. Circles waypoints looking for missing person evidence.
• Ground crew then follows the UAV's search pattern ready to close in on potential signs of missing person, but otherwise remaining central to UAV circles.

Plan works well for easily mobile ground crews who don't have access to enough information to perform a remote-led search.

The paper also outlines in-brief a stochastic approach for modelling likely search positions (essentially calculating the initial probability distribution to then be updated in a Bayesian fashion) by modelling a probabilistic quasi-random walk with functions taking into account terrain direction and environment.

So- what's useful here?

Well clearly I now have a potential new context to think about (radiation or chemical leaks). It might even be worth asking the emergency services what sort of process they would carry out in this case, and then seeing whether it resembled the above at all. The initial probability distribution generation is worth considering as one might potentially have more computing power available (consider calculating it remotely and then transmitting to the UAV?). More broadly, it highlights the need for the consideration of the command structure of an operation when deciding what the UAVs need to do and who they need to report to. In any case, a Base-led or Sequential process for mapping out an emerging pollutant cloud might not be a bad starting point.

-C