Hi Benni, have you seen the new Leica Multi-station 'EDM' scanner, MS50. It would be set-up similar to a monitoring EDM and feed observations to deformation monitoring software for automatic surface difference analysis. I am using Duel and Single Frequency GNSS monitoring receivers feeding to Spider/Geomos deformation software to analyse movements in built and natural environments/structures. Power and comms are the biggest problem for 'off grid' installs, at present I am experimenting with solar panels, mini marine wind turbines to charge batteries. I use GPRS/3G data modems (low watt) to get the data off the instruments in the field. Monitoring EDMs are usually installed on a concrete pillar and surrounded by a small hut/shed with either an opening or perspex window (though I would expect the scanner will require a clean opening to insure good line of site to the target surface). Details of the MS50 system here:

http://www.leica-geosystems.co.uk/en/Leica-Nova-MS50_103592.htm

Best,

Conor.

GAP QUB.

Thanks for your reply Conor,

I was not aware of the Leica multi-station, thanks for that. Unfortunately, we won't be able to buy a new scanner. We are currently in the process of getting a new one, but we fancy the Riegl long-range scanner with up to 6 km scanning range. So, for the monitoring project we are stuck with the current Optech machine.

Some other people already suggested to use a concrete pillar for the installation. I consider this crucial to ensure the scanner does not move over the months of monitoring.

Do you know whether the huts/sheds that are normally build around the equipment are home-made? Others reminded me that if you build something like that in A-Team style Murphy's law has to be applied and there will always be something that does not work or gets stuck.

We already know that having a glass window is not really an option because it would distort the laserbeam resulting in errors. So I assume that we need to install some kind of garage door opener. I am currently in contact with some guys who probably have a complete solution for exactly the purpose that we are aiming at. They described it as a torpedo-like enclosure that opens up just like the ramps of intercontinental missiles (or at least that is how imagined it). I hope to get more info about that next week.

Hopefully energy supply and internet won't be a problem. There are a couple of houses around and we hope to be allowed to get access to their facilities.

Thanks again and kind regards,

benni

Hi Benni, we did in the past some experiences with landslide monitoring laser using scanner. In my opinion one of the most important element is to define your monitoring strategy. In my experience the use of laser scanner is good for the identification of detachments (also small ones), but it can be not easy to use if you want to monitor displacements. If I can give you a suggestion, I strongly reccomend to you to evaluate the distance of your instable area with respect to the accuracy of your laser scanner and the estimated entity of landslide's movements. The garage door solution can be a good possibility to manage the measurement sessions. If you don't have problems with power supply, I can also suggest you a little video surveillance system to remotly control your system. Another important element that you have to consider is that the DTMs comparison is a very time consuming task: your monitoring system probably will not be able to give near real time results.

If you want more information about our activities you can visit our website: http://gmg.irpi.cnr.it/

Best

Daniele

Hi Benni,

We developed an autonomously operating terrestrial laser scanner (ATLS) over the last few years that is i) weather proof (we use it for snow pack monitoring under very harsh weather conditions) and ii) can be operated with a solar panel (so there is no need to have line power).

You can find some information about the scanner on my website:

http://ecosensing.org/research/autonomously-operating-tls/

and in this publication:

Eitel, J.U.H., Vierling, L.A., Magney, T.S. 2013. A lightweight, low cost autonomously operating terrestrial laser scanner for quantifying and monitoring ecosystem structural dynamics. Agricultural and Forest Meteorology, 180, 86-96.

Depending on the laser rangefinder you use, the scanner system can be build between $6000 - $12000 (including power supply such as solar panels, and open source software (we use CloudCompare;http://www.danielgm.net/cc)

We use the ATLS mainly to look at canopy structural change of crops and to look at snow pack dynamics but we have done some preliminary work where we monitored fine scale erosion and the accuracy of the erosion estimates derived from ATLS data is very encouraging (I can sent you some of the results in you are interested).

Best,

Jan

I think you can do that with your own system if you have a laser scanner with SDK. So you can build a system to do that.

Thanks for your replies!

I am currently in South East Asia with very limited internet access, but I will get back to you once I am back home.

I am actually very curious what Jan did since I have also used CloudCompare and found it extremely useful.

Thanks a lot again,

benni

Hi guys,

thanks again for your replies. Over the weekend, I have the chance to check your suggestions in more detail.

@Daniele: Yes, displacements are definitely harder to detect. Fortunately, we will have rather short distances to the landslides (aprox. 300 m), so accuracy should be pretty good. Access to electricity and remote control are definitely planned; I assume we will be using a laptop with a remote desktop solution to be able to trouble shoot. We also want to deploy a video camera, but mostly to scare of vandals/snoopy kids. We got away from the garage door opener idea, this just might be to error prone; simply to many parts that according to Murphy's law could spoil the fun. Instead, we plan to use coated class to scan though. This should be less error-prone and also more safe. I agree on the DTM comparison issue; we have to find a way of automation. There are a couple of software solution readily available (used for mining pits) but are rather expensive.

And sure I know your working group =)

@Jan: Thanks for that. It is very helpful to see that other people were also thinking along those lines. I actually fancy your low-cost approach very much. Really incredible what you did there with only 12k $! We are in the lucky position to have an Optech ILRIS at hand for our project. I very much appreciate your paper suggestion. I have never come across that journal before (just too many others to follow) so I missed your research. I very much liked the free software tips in your paper; I will try to find out whether they could be used for our project.

@Xianfeng: Xie xie ni! I will try to get my hands on the SDK.

Thanks again and kind regards

benni

Dear Benni,

actually, we used a very similar shed with a makeshift mechanical remote controlled window opener to install the monitoring system during the Costa Concordia ship wreck recovery.The system stayed on place for nearly 2 years without problems. You could try something similar. If you need some info on the tools we used I can send you a summary.

As for the TLS monitoring in particular, we use it routinely on landslides but only with repeated field campaigns (not permanent installation) mainly because the risk of losing the TLS system is usually too high (due to theft and vandalism as you say).

The Costa Concordia case was a sort of exception in that the area was continuously surveyed by police forces and we felt safer than in the usual landslide site environment.

Let me know in case you need some other info on that,

all the best

Filippo

Dear Filippo, 

many thanks for your reply. 

By now, we have found a viable solution for the permanent laser scanning.  We decided to build a small hut to accommodate the scanner and a laptop. instead of using some mechanical window opener, we have simply used a window (special glass to not interfere with the laser, tilted for some degrees to not have 0° hits). So far, the system works great. 

We also did not have any vandalism or theft problems - also thanks to the neighbours who are all aware of what we are doing there. 

As I have left the working group in Vienna, I am not very much involved in the activities for the moment. If you are interested in the progress, please follow these links:

EGU blog entry: http://blogs.egu.eu/geolog/tag/salcher-landslide-observatory/

project website: http://noeslide.at/index.php/salcher-landslide-observatory

Many thanks again and kind regards, 

benni