Peeking underground with giant flying antennas | Hacker News Reader

Peeking underground with giant flying antennas

hackaday.com

104 pointssharpshadow29 comments

Something similar was experimented with where I live (western Sweden) to see if the technology is usable to determine the stability of soil layers against land slides. The area around the local river - Göta Älv - is known to be prone to landslides so it was deemed to be a good test subject. A helicopter carrying something which was best described as an enormous chicken run on a long line criss-crossed the area mapping it with what I assume was ground-penetrating radar. The results [1] show our farm to lie on an extremely landslide-prone part of the river valley and I know there have been landslides here in the 60's so there is something to this method. The subsoil consists of silt (the fraction over clay) on top of bedrock, as long as the water content stays below a certain percentage it has quite a high bearing capacity but once it gets over that it easily liquifies.

[1] https://ext-geodatakatalog-forv.lansstyrelsen.se/PlaneringsK...

I got to watch them operate out of a nearby airport for about a week back in 2022. Definitely an unusual sight.

I'm sure there's more data like this, but that survey seems to have produced a large amount of raw data which is publicly available.

https://www.sciencebase.gov/catalog/item/636c0b28d34ed907bf6...

The Hackaday article is referring to Geoscience Australia geophysical surveys, Helicoptor VTEM specifically.

Fixed wing surveys are also a thing and more common over ground that is relatively flat, choppers get used for ground hugging steep ground - the cost per line kilometre goes up by a factor.

All the GA data (radiometrics, EM, magnetics, gravity, DTM's, etc) is available online or by request.

Eg: https://www.ga.gov.au/about/projects/resources/geophysical-a...

describes a dataset and links to raw data sets.

I’m struck between the similarity between this and the big antenna (?) array that the ballon that went over the USA carried…

That thing flew over/near Malmstrom Air Force Base (ICBM silos.)

Using OpenStreetMap data to map stuff the balloon flew near: https://youtu.be/sQ_sEWodIrc?si=LUfvRR4kvlqQyrZ1&t=16

I had never heard of this MUNDUS tool before, but it looks like a very interesting project.

Imagine using multiple Project Loon balloons as a giant SAR.

Potentially related: https://news.ycombinator.com/item?id=30022626

Could this help detect landmines?

Yes, if you scale down the antenna/coil (and the aerial vehicle). https://www.smithsonianmag.com/innovation/a-ukrainian-teenag...

this particular rig is too lo-res for that. you need a different detector setup, and slower closer flight.

I wonder if drones could be used for this then?

A spinout from my university, UMag Solutions is detecting UXO and mines in Ukraine using special drone-mounted magnetometers.

They can and they are.

For instance:

https://sensysmagnetometer.com/products/magdrone-r4-magnetom... https://sensysmagnetometer.com/unexploded-ordnance-uxo/

You could use this: https://sensysmagnetometer.com/products/magdrone-r4-magnetom...

We have the little version of this sensor. It's quite interesting.

Can it find tunnels?

Maybe, but can you understand the data you get to realize it is a tunnel?

If not, maybe it could if you pour saltwater into the tunnels.

if so, it might be fun to fly over the US-mexican border near tijuana.

Is this used in archeology?

We have a MagDrone R3 and when researching it I saw a video showing a comparison of GPR and Mag sensors. The Mag sensor was able to detect the foundations of a buried roman structure as clearly as the GPR in that specific case. So, the answer is yes, this class of remote sensing can be used in archeology.

Did you read the article? It discusses the archaeological applications.

The article mentions the ‘traditional’ way in which magnetic surveys are carried out on the ground in archaeology. When it comes to helicopter surveys, the examples are only from geology. My question was meant to refer to helicopter surveys. I would therefore like to rephrase it: Have helicopters indeed already been used for magnetic surveys in archaeology?

From the HN guidelines[1]:

Please don't comment on whether someone read an article. "Did you even read the article? It mentions that" can be shortened to "The article mentions that".

[1]: https://news.ycombinator.com/newsguidelines.html

Do you think the spirit of that rule is to bludgeon someone with it?

You and I have different definitions of the word "bludgeon", and I see no problem with showing somebody a site rule they've broken if it's a rule you think worth encouraging people to follow (which they clearly do feel).

Did you even read that rule?

We did this for anode placement.

You put a anode x hundred yards away from a pipeline to stop it rusting. We used to send people into the field with metal spikes to measure conductivity to find the best locations. You want the anode in a place of high conductivity. This was used instead.

Personally I was dubious on the economics of a few of the things that was done on the project, doing this compared to using people was a no brainer even if it was $$$$. But all this money and as usual the SCADA was crap.

The rig was from mining if you wonder about it's everyday use.

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