- property damage assessment: can sUAS help document the number of houses damaged and the amount of damage in terms of height of water into the houses while there is still flooding in order to qualify the area for disaster assistance? Our experience in Louisiana suggests that UAS of any size are not a good fit because the UAS cannot see an 18 inch high water line on houses in a subdivision crowded with trees or cover much within LOS. This mission appears to be a better match for a robot boat which can zoom down the flooded streets.
- flood mapping and projection of impact: can sUAS help document the extent of the flood, the impact on residents, roads, levees, etc.? sUAS appear to have advantages over manned aircraft for forested regions where the platform can operate safely at lower altitudes and hover and stare to detect flowing water in between trees. An expert can use the sUAS in order to identify possible causes of unexpected flooding and mitigation.
- verification of flood inundation models
- flood monitoring over time: This is related to flood inundation modeling and one of the reasons why Fort Bend County had us fly multiple days.
- justification for publicly accountable decisions: The documentation of flooding is useful for future land use planning. Fort Bend County was particularly interested in capturing compelling video of the floods in the western part of the county which were severely flooded to show residents in the eastern part of the county which had not been yet been flooded so that they could see why evacuations were mandated.
- public information: Fort Bend County immediately posted the video to YouTube and began pointing citizens to the video to answer questions about their neighborhood. One of the neighborhoods filmed had an assisted living facility and relatives calling into the OEM were directed to look at the video and see that the flooding wasn’t going to impact their family member.
Choosing the type of sUAS
The majority of missions for sUAS (versus larger UAS that can fly higher and longer areas) are expert-in-the-loop missions (more formally called remote presence), where the expert wants to be able to view the video and then direct the sUAS to a better view. It is not clear that orthomosaics and digital elevation maps (DEM) are a priority. The emergency managers generally have DEM already (though they may be outdated) and the areathat they want to look at is so large that a sUAS team is unlikely to reach all of the areas if restricted to line of sight operations— this is where larger UAS or Civil Air Patrol can be of great value. Another problem is that the file size of orthomosaics is unwieldy for OEMs to handle, share, and post among themselves. Not that many mangers have laptops that can handle a 55GB file and the upload times are slow.
We have converged on quadcopters being the default platform because of expert-in-the-loop flying and because of the physical constraints of landing zones, though we don’t rule out fixed wing. In the field there is limited access to the area because of the flooding. Access points such as raised roads or levees also had high tension powerlines which can induce interference- indeed, we had one “whoa!” takeoff next to powerlines. (We won’t discuss the creepy horde of swarming insects making it unsafe to stand in one potential site, or the fire ant bites I am sporting from a misstep at another site.) Flying near rivers or from residential areas is hard because of trees and power lines. Empty lots without trees are rare, especially in older and urban parts of town, though suburban areas may have soccer fields suitable for launching and recovering fixed-wing sUAS.
Manpower: Crew Organization and CONOPS
This is my area of research, so it is always of interest to me! As noted in previous blogs, my TED talk, and papers, it’s the data that is the barrier to adoption. We’ve converged on a 4 person field team plus dedicated data management team back at the base to handle the data. Gee, that sounds like a lot, doesn’t it? Well, it is better than accidentally writing over data or taking extra hours to get data products to the OEM.
- pilot, who is in charge of the sUAS
- visual safety officer, who is not allowed to look at the pilot’s display or do anything but eyes on the sUAS and sky (and given the number of manned aircraft zipping by at low altitudes, that is an important and full time job)
- agency expert, who actually knows what to look for and to opportunistically direct the flight
- data manager, who immediately backs up the data (hard lesson learned at the 9/11 World Trade Center robot deployment) and makes sure all data is logged and stored for immediate hand-off to the OEM (want to give them that thumb drive as soon as sneaker net permits)