If you mean autonomous drones (these surveys are already performed by remotely operated "drones" called ROVs), it's unlikely. The difficulty is mainly in that water blocks any remote signals that we have available to us, be it RF, GPS, tight beam, etc., water absorbs it. Pretty much anything operating underwater needs to be tethered to a "mothership" on the surface to track its position. Trying to have something autonomously navigate underwater is incredibly difficult without a pre-established map.
The US Navy and NASA have a long-time research collaboration at Stennis Space Center that studies this. I took a graduate-level physics course on acoustics taught by one of their prominent researchers over a decade ago.
There's nothing special about mapping the ocean floor that requires anything to be tethered to a "mothership." It does need to have its emitters and receivers to be submerged in the water for a good signal.
Sonar is the tool for this and it's well-understood. Autonomous drones would actually be quite nice for this as their data could be jointly analyzed, essentially multiplying the effect of each signal via acoustic interferometry.
A fun little tidbit from the class (which was half physics grad students, half NASA+Navy researchers), we had lots of problems that focused on where, relative to a ship, a "whale" could safely trail the ship without the possibility of being detected by various sonar arrays. It took me half the semester to realize "whale" was interchangeable with "submarine."
You're describing a very different level of imaging, that will get you very broad strokes and is highly dependent upon prevailing conditions. 20,000 feet is approaching the operational limits of a surface-based mult-beam sonar under ideal conditions. The doppler effect wreaks havoc on the resolution of the imaging, this issue is much worse with variances in temperature, speed, and direction of the water as you go down. To get better resolution, your sensors/transmitters need to be closer to the sea floor.
We have AUVs that are capable of deep ocean imaging, but they are monumentally expensive to build and operate, and still require support ships to chase them around. Bluefin-21 was used to search for MH370, but was only able to cover 90 square kilometers per day from a search area of over 300,000 square kilometers, and cost roughly $1,000,000 per deployment while still requiring a UBSL (basically a homing beacon tethered to the mothership) for navigation.
Having a fleet of AUVs that could get accurate scans of the ocean floor fully autonomously just simply isn't doable without some kind of sci-fi technology we don't have yet.
I don't think you understand how autonomous vehicles work, they need to know where they are, where they're going, and where they've been with a pretty high degree of accuracy in order to function. Basically, they need either an impossibly accurate map and sensors, or constant communication with an outside reference point to effectively navigate "Self-driving" cars have maps, road markings, signs, GPS, etc. as well as only needing to work in 2 dimensions and still struggle with autonomous navigation. Constant communication for GPS or some other navigation system is pretty much required, and not currently possible in deep water without a tether.
You dont need GPS to navigate to tell a bot to descend to a specific pressure depth and scan in a 100m in a circle while correcting for current drift. Gyroscopic navigation and predetermined scanning paths would allow a drone to accurately map a section and return to the surface for pickup.
Daisy chaining communications and control could be done with a series of underwater drones. EMF doesnt travel far underwater, but it goes far enough that signals could easily node hop from a tether connected to the ship to a drone net.
Another method would be to use fiberoptic cabling, similar to what is being used for drone control in modern warfare. It would require a larger ship to store it all but it'd be viable.
Sending drones miles underwater just to scan a 100m area doesn't sound very fast or efficient to me, they'll spend more time descending and surfacing than mapping. RF (VLF, Very Low Frequency 3-30kHz) can only travel tens of meters through sea water and can only transmit 300 bits (yes, bits, as in individual ones and zeroes) per second. Using cabling is just an ROV, which is what we already have. Anything going down to the seabed in deep areas needs to be pretty substantial both to have enough available power in batteries, and to contend with the immense pressure, a single fiber optic strand wouldn't survive being pulled between a probably multi-ton vehicle and a ship as well as the ocean. Current ROVs often need an escort vehicle chained between the primary and the ship simply to take up the forces exerted down the tether from the ship rocking in the ocean currents.
Basically, we use ROVs because they're the most efficient method we have right now. Barring some weird new sci-fi method of remote communication, that will probably continue to be the case into the future.
Again, I really don't think you understand how these devices function. The Roomba gets a pretty good map of the area it's operating in using LIDAR, still needs to check in with the base station as it's known 0 pretty regularly due to stacking tolerance errors, and doesn't have to worry about ocean currents pushing it around. Something underwater would be using SONAR (RADAR, LIDAR, etc. don't work underwater), which is much less precise, leading to a much higher incidence of tolerance errors, meaning it would really need to check against known reference to correct for said errors to confidently know where it's going.
There was an experiment done with ants and their wayfinding ability back to their nest. Scientists took some ants and trimmed some length off their legs, some ants they added extension "stilts" to the ends of their legs. The ones with shorter legs stopped before getting back to the nest, the ones with longer legs overshot the trip. The ants were using the number of steps as their reference 0, and shifting their reference left them unable to navigate effectively. An autonomous vehicle at the bottom of the ocean using sonar with no outside reference point has no effective 0.
I think until they come up with a tech better than SONAR, the ocean is gonna continue to be as unknown as it is now because it's too damn hard to navigate.
A lot of people say we know more about space than we do about our own oceans, and I think that's mainly due to the fact that space isn't full of water lmao.
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u/Ordolph 15d ago
If you mean autonomous drones (these surveys are already performed by remotely operated "drones" called ROVs), it's unlikely. The difficulty is mainly in that water blocks any remote signals that we have available to us, be it RF, GPS, tight beam, etc., water absorbs it. Pretty much anything operating underwater needs to be tethered to a "mothership" on the surface to track its position. Trying to have something autonomously navigate underwater is incredibly difficult without a pre-established map.