Best drone for measuring accuracy of steel beams on construction site?

[PHZ]

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[DARKSeifer]

LiDAR is the most accurate in any case. Photos will give better results for rendering the textures(for now) what you do not need in your case.

The only advantage of laser or SLS (which could also be a solution) vs photogrammetry is that it's faster on producing the 3D model, as it's basically on the fly.

Both commercial LIDAR and SLS solutions are heavy dependent on the calibration and resolution, which won't fit all scenarios, while photogrammetry can be calibrated for every single possible scenario with no limitation both on accuracy and resolution.

Camera alignment can be performed in subpixel accuracy and depending on the magnification you are working, you can have any three-dimensional resolution you want. The only limitation is the time you want to spend on each project.

Photogrammetry will beat any other solution on both quality, accuracy and gear price anytime; but not on speed.

Another downside of photogrammetry is that it needs an expert "photgrameter" to get the best results, while any dummie can scan with a comercial SLS or LIDAR solution and get a decent result.

In the end the trigonometry process is basically the same, but LIDAR/SLS come with the calibration and calculations "prebaked" and on photogrammetry are calculated afterward.

PS: So in resume, if you want a fast and accurate measurement basically on the spot, laser or sls would be the best options. If time is not critical, photogrammetry is cheaper and has no resolution or accuracy limitations.

 

[MNewman]

Try DJI Matrice Drone Forum

Yes, it's a separate entity, not part of mavicpilots.com.

Thank you!

 

[JC in New Hampshire]

that the elevator company wants to make sure that the parts they are going to install for the elevator shaft are the right size, so they want to make sure they have the absolute precise measurements for the steel beams and frames that have already been constructed so as not to insert a part that is either too long or too short -- even by 1 inch.

Are you SURE you want to accept that kind of liability? If your answer is wrong, a lot of angry people will come after you like a swarm of hornets!

 

[Etbrown4]

There's a standard solution for this that doesn't include drones. It's called an approved set of building drawings stamped by engineers and architects, and site visits.

Engineers and architects routinely make site visits while jobs are underway to assure conformity to plans. It's their job.

Elevator companies order their components based on plans. If they want to verify clearances in the field, that's up to them.

It seems that OP has been asked to do something that's far outside any ordinary construction process.

Not that it's recommended for checking structural steel, it is however, common for architects to photograph buildings they plan to renovate. Those pics are converted into autocad and can be coordinated with architectural drawings. I don't know the degree of accuracy, nor the format or required camera specifications, but most architects would.

 

[MNewman]

I think there's been some confusion about what I'm asking, so I'll try again:

My brother in-law is a very experienced project manager for an elevator company. He asked me if drones can be used to take extremely accurate measurements of elevator shafts on construction sites, as he would prefer to pay me to measure the beams inside the shafts with a drone instead of paying one of the construction people to do it by hand.

If you're going to post, please don't ask about liability, or provide some engineering answer, or offer an easier way of doing it -- that is not what I'm asking. I'm simply asking: "Yes or no -- can a drone do this?" If the answer is yes:

1) Which drone can do this?
2) How does the drone do this? (i.e. Lidar, Photogrammetry, something else...)?
3) How accurate would it be? Would it be accurate up to less than 1 cm?

 

[MARK (LI)]

On a whim I googled the subject and got this...the answer is yes
, drones equipped with advanced sensors and software, especially those with RTK (Real-Time Kinematic) capabilities, can achieve very accurate measurements, with some achieving centimeter-level accuracy for surveying and mapping.

Here's a breakdown of how drones can achieve accurate measurements:

• Advanced Sensors:
  Drones utilize high-resolution cameras, LiDAR (Light Detection and Ranging), and GPS/GNSS (Global Navigation Satellite System) technology for data capture.
  

• RTK Technology:
  RTK systems provide precise positioning data, significantly improving accuracy compared to standard GPS.
  
  
• Photogrammetry and 3D Modeling:
  Drones capture multiple images and use software to create 3D models, allowing for accurate measurements of objects and areas.
  
  
• Ground Control Points (GCPs):
  GCPs are strategically placed markers on the ground that are used to georeference drone imagery, further enhancing accuracy.
  
  
• Software and Post-Processing:
  Specialized software is used to process drone data, generate accurate maps, and extract measurements.
  

Examples of drones known for their accuracy:

• DJI Matrice 350 RTK: A state-of-the-art drone designed for precision and efficiency in aerial operations.
  

• DJI Mavic 3 Enterprise: A compact, cost-effective drone with RTK capabilities, offering survey-grade data.
  
  
• Wingtra One: A drone designed for large-scale mapping and surveying projects.
  

Applications of accurate drone measurements:

• Surveying and Mapping:
  Creating accurate maps, measuring land areas, and monitoring infrastructure.
  

• Construction:
  Tracking project progress, measuring stockpiles, and creating 3D models of construction sites.
  
  
• Environmental Monitoring:
  Assessing forest cover, monitoring wildlife populations, and measuring changes in landscapes over time.
  
  
• Roof Measurements:
  Measuring roof areas and slopes for roofing projects.
  

 

[Meta4]

On a whim I googled the subject and got this...the answer is yes
, drones equipped with advanced sensors and software, especially those with RTK (Real-Time Kinematic) capabilities, can achieve very accurate measurements, with some achieving centimeter-level accuracy for surveying and mapping.

Here's a breakdown of how drones can achieve accurate measurements:

• Advanced Sensors:
  Drones utilize high-resolution cameras, LiDAR (Light Detection and Ranging), and GPS/GNSS (Global Navigation Satellite System) technology for data capture.
• 
  
• RTK Technology:
  RTK systems provide precise positioning data, significantly improving accuracy compared to standard GPS.
  
  
• 
  
• Photogrammetry and 3D Modeling:
  Drones capture multiple images and use software to create 3D models, allowing for accurate measurements of objects and areas.
  
  
• 
  
• Ground Control Points (GCPs):
  GCPs are strategically placed markers on the ground that are used to georeference drone imagery, further enhancing accuracy.
  
  
• 
  
• Software and Post-Processing:
  Specialized software is used to process drone data, generate accurate maps, and extract measurements.

Examples of drones known for their accuracy:

• DJI Matrice 350 RTK: A state-of-the-art drone designed for precision and efficiency in aerial operations.
• 
  
• DJI Mavic 3 Enterprise: A compact, cost-effective drone with RTK capabilities, offering survey-grade data.
  
  
• 
  
• Wingtra One: A drone designed for large-scale mapping and surveying projects.

Applications of accurate drone measurements:

• Surveying and Mapping:
  Creating accurate maps, measuring land areas, and monitoring infrastructure.
• 
  
• Construction:
  Tracking project progress, measuring stockpiles, and creating 3D models of construction sites.
  
  
• 
  
• Environmental Monitoring:
  Assessing forest cover, monitoring wildlife populations, and measuring changes in landscapes over time.
  
  
• 
  
• Roof Measurements:
  Measuring roof areas and slopes for roofing projects.

All of those are about mapping or surveying large areas.
None of those relate to what the OP was asking.

 

[MARK (LI)]

All of those are about mapping or surveying large areas.
None of those relate to what the OP was asking.

I guess you didn't bother reading this part

Or this part
Roof Measurements:
Measuring roof areas and slopes for roofing projects.

Not that this is a roof job....just demonstrating that it is not a particularly large area

I believe that if the pieces of steel were already in place they would know if they were the right size....hence they must still be part of the stockpile

 

[Cafguy]

If the OP is working with an experienced Project Manager for an Elevator company then I would think that the Manager would know that the engineers would not "rely" on anyone to "drive out there and measure beams". There are just too many things to consider in Building construction and design.
Engineering changes cost Time and Money I would think any Engineer that stamped final construction prints for a buildings elevator or its replacement, would want to see the old erection Drawings and past calculations the original engineers made.
If you are say measuring the whole roof or maybe even simple lengths and widths then Maybe, but Exact beam sizes and lengths are not gonna be possible. My 2 cents..'Sorry bout the engineering talk lol.
The last elevator I added to a building was designed with no connections to the old structure and we even had to dig new piles in the basement of the building for the new structure.

 

[Meta4]

I guess you didn't bother reading this part

I read everything carefully.
It looks like you didn't take any notice of this:

I'm not an engineer. I'm a drone pilot. An engineer who works as a project manager for an elevator company asked me the above, so I'm going to assume that he already has the blueprints necessary and all that stuff. Sometimes, parts are cut incorrectly -- by as little as an inch or less.

He's looking for precision measurement, not gross measurement of stockpiles or any of the other things you included.

 

[MARK (LI)]

I read everything carefully.
It looks like you didn't take any notice of this:

He's looking for precision measurement, not gross measurement of stockpiles or any of the other things you included.

You musta missed this:

drones equipped with advanced sensors and software, especially those with RTK (Real-Time Kinematic) capabilities, can achieve very accurate measurements, with some achieving centimeter-level accuracy for surveying and mapping.

 

[Meta4]

You musta missed this:
with some achieving centimeter-level accuracy for surveying and mapping.

I didn't miss it.
But I do understand what surveying and mapping are.
And they are very, very different from what the OP is asking about.

 

[Felix le Chat]

I was recently asked what drone one should use for the highest accuracy to measure steel beams on a construction sight as it would save a company quite a lot of money from sending a person up there to measure it themselves. I figured I would forward that question here.

The research I have found has unearthed things like LiDAR and Photogrammetry. One website says they're equally accurate. Another says that LiDAR is better. And then ChatGPT says Photogrammetry is better.

That said, are they referring to accuracy when mapping an entire region or accuracy when photographing steel beams up close?
And any recommendations for what drone/drone package would do the trick for accomplishing this task?

Regularly end up being tasked with taking metric photographs (study, comparison & analysis) and with a standard digital camera: I am only aware of two ways of producing high accuracy images that can stand up to hostile scrutiny.
#1 - include a centimetre accurate scale on or very near the object.
#2 - for oblique shots: use a perspective square placed on the plane you want to measure.

Then you have to factor in distortion from the wide angle lens. The Matrices can carry the P1 camera which is custom designed for metric/orthophotography.

 

[jaja6009]

OP, post this question to the Reddit UAV Mapping subforum. Some of their answers on similar questions have been very good and sometimes downright creative.


I have way to many questions to ask but here is my opinion trying to stick to your requests.

1) Which drone can do this?
2) How does the drone do this? (i.e. Lidar, Photogrammetry, something else...)?
3) How accurate would it be? Would it be accurate up to less than 1 cm?

1. Many different drones could do this. A lot will depend on the building. Is this a skeletal structure, a complete building.

If the drone must fly inside a skeletal structure to obtain the images, then a Skydio X10 could be good with its obstalce avoidance. There are plenty of videos of this drone flying inside of a skeletal tower to obtain images.

Skydio X10

Skydio X10

Skydio X10 autonomous drones deliver the best sensors for a drone this small, piloted by the most advanced AI in the sky.

www.skydio.com

Leica has a laser scanning drone

Leica Drone Scanner

https://shop.leica-geosystems.com/leica-blk/blk2fly/overview?srsltid=AfmBOoqr_OJh3-YDfGrvbEV0k6FUwhBZdtCscu9tSNds7rMykVCYQsj1

Not too sure if this drone would far well inside a skeletal structure.


2. Both could work, but photogrammetry will be much lower cost and this again depends on the building and the ability of the drone to see as much as possible.

3. Accuracy can be in the cm range. I can't speak for Lidar and laser scanning as I have never used them persoannly , but photogrammetry can be as accurate as 1 to 3x the GSD. GSD is simply the resolution of your images, the distance from the center of a pixel to the center of the pixel next to it. The lower the GSD, the higher resolution your spatial product.


I can provide a link and you can assess some of it your self.

Here is a 3D model of a building, collected using RTK. Use the tools on the right to measure lines, areas etc.
Just remember, photogrammetry can only create what it has multiple images of. You could end up missing various sides of said steel beams introducing problems.

Some software will allow you to further reinforce your relative (scale) accuracy by introducing scale constraints - telling it how long something is that you know. Then it could also use a scale check by seeing the length of something as compared to its known length.

Notice you can only see and measure what was created and only the outside and small portions of the inside were created due to no images taken of those areas and this includes the back sides of items.

Up top right you have tools: Ruler - measure a line, point - get coordinates, line - draw a line and then see the length, slope on the right. area - draw a shape and then get perimeter, area, volume

https://cloud.agisoft.com/shared/projects/a5ec5888-c04b-4b4f-adb5-368ffd324e5a?position=-74.634533,39.402227,11.724422&orientation=93.518,-26.22,0

I actually love it when people think outside of the box and create yet another drone use case.

I wish you luck.

 

[Etbrown4]

I admire the op's interest in looking into all of the possibilities. Precise drone taken measurements almost has to be possible if you are willing to invest a lot of time and money.

Let's say you invest a few $ thousand on the low side, or more, and actually come up with measurements.

Who then will pay the additional experts to field check all of your dimensions?

So it seems pretty clear that some reliable folks taking traditional field measurements is going to occur anyway.