Selecting the Right Drone for Your Construction Business

Selecting the Right Drone for Your Construction Business

Douglas Spotted Eagle and Brady Reisch headed into the field to collect aerial construction data over fourteen weeks with three different drones.  Their goal was to determine which drone was best for the construction job site.

They used three popular aircraft for the comparisons and the results were pretty surprising.   

Drones Compared:

Unmanned Aircraft (UA/Drones) have rapidly become a significant component of the modern construction industry workflow whether it’s for progress reporting, site planning, BIM, inventory control, safety awareness, structure inspection, topo’s, or other purposes. Site supervisors, architects, and stakeholders all benefit from the rapid output of accurate 2D/Ortho, or 3D models that may be used for purposes ranging from simple visualizations, progress reporting, stockpile calculations, DSM, contours, to more complex overlaying blue-prints in the As-Designed/As-Built or BIM process.

Choosing the right aerial asset/UA may be challenging, particularly as the marketing of many UA is focused on RTK built in (rarely accurate) PPK solutions and a many component workflow versus others that are single-step workflows. Decisions on aircraft choices will be made based on budget, accuracy requirements, speed to result, and overall reporting requirements.

On any site flown for BIM, input to AutoDesk or similar tools, having accurate ground control points (GCP) is required. GCP’s may be obtained from the site surveyor, county plat, or other official sources, and this is often the best method assuming that the ground control points may be identified via UA flight-captured images. Site supervisors may also capture their own points using common survey tools. Devices such as the DTResearch 301 RTK tablet may be used to augment accuracy, combining GPC location points from the air and on the ground. Failing these methods, site supervisors can capture their own points based on the specific needs of the site. These points may be calculated via traditional rover/base RTK systems, or using PPK, RTK, or PPP solutions, again being budget and time dependent. If centimeter (vs decimeter) accuracy is required, RTK or PPK are necessary.

Putting accuracy aside, image quality is gaining importance as stakeholders have become accustomed to photo-grade ortho or models. Oftentimes, these models are used to share growth with inspectors as well, which means having presentation-grade images may be critical. Image quality is high priority when generating pre-development topos, or simply illustrating a tract of land from all directions. In other words, a high-quality imaging sensor (camera) is a necessity. Some aircraft allow user-choice cameras, while many UA manufacturers are creating cameras specific to their aircraft design.

Turning to aircraft, we chose three popular aircraft for the comparisons:

Flying the site several times in various conditions, the same RTK capture points are used in all three mapping projects. The DTResearch 301 RTK system is used to capture GCP on-location, with Hoodman GCP kit as the on-ground GCP. The Hoodman SkyRuler system was also captured as a scale-constraint checkpoint.

This commercial site is small in size (1.64 acres), and one we were able to begin capturing prior to forms being laid, all the way to vertical installation.

Accuracy varied greatly with each aircraft system, particularly in elevation calculations. Deviations are from projected points vs the GCP points obtained through a surveyor’s RTK system.
Overall (and to our surprise), the Autel EVO was most accurate with a deviation of:

  • x-5.112ft
  • y-47.827ft
  • z-16.541ft 

The Yuneec H520/E90 combo was not far behind with a deviation of:

  • X-10.323ft
  • y-44.225ft
  • z-92.788ft

Finally, the DJI Phantom 4 presented deviations of:

  • x-1.95ft
  • y-45.565ft
  • z-140.626ft 

All of these deviations are calculated and compensated for in Pix4DMapper, which is used to assemble all of these week-to-week projects.
As 3D modelling was part of the comparison/goal, obliques were flown in addition to nadir captures. While manual settings are often essential for high quality maps and models, in the following images cameras were all set to automatic exposure, shutter, ISO.

It is important to remember that these are NOT corrected via network nor base station. This is autonomous flight, localized in Pix4D.

MODELS

AUTEL EVO (Original version)
YUNEEC H520/E90
PHANTOM 4 PRO

All aircraft models work well with Pix4DMapper, although at the time of this writing, Pix4D has not created lens profiles for the Autel EVO (they have indicated this feature should be available “soon”). We custom-sized the lens profile ourselves, based on information provided by Autel’s product managers. *as of 2.1.22, Pix4D has generated lens profiles for both Autel EVO and EVO II aircraft.

Orthos

AUTEL EVO
YUNEEC H520/E90
PHANTOM 4 PRO

Although image quality is subjective, our client and our team all agree the Autel EVO provides the best image quality and color of all aircraft, with all aircraft set to automatic exposure, shutters peed, and ISO of 100. This is a surprise, given the Autel is a ½.3 imager, vs the 1” rolling shutter of Yuneec and global shutter of the DJI aircraft. Based on internet forums, Autel is very well known for their camera parameters being impressive.

All flights are single-battery flights. This is important, as changing batteries offers different functions for the various aircraft. Using Yuneec and DJI products and their respective software applications, we are able to fly larger sites with proper battery management with the aircraft returning to launch point when a battery is depleted and resume a mission where it left off once a fresh/charged battery is inserted. The Autel mission planner currently does not support multi-battery missions (although we’re told it will soon do so).

There are a few aspects to this workflow that are appreciated and some that are not. For example, when flying Autel and Yuneec products, we’re able to act as responsible pilots operating under our area wide Class B authorization provided by the FAA. To fly the DJI Phantom, the aircraft requires a DJI-provided unlock that permits flights. It’s a small annoyance, yet if one shows up on a jobsite not anticipating an unlock, it can be tedious. In some instances, we are just on the edge and outside controlled airspace, yet DJI’s extremely conservative system still requires an unlock. Most times, the unlock is very fast; other times, it doesn’t happen at all.

All three aircraft are reasonably fast to deploy, and this is important when a LAANC request for a zero-altitude grid is a short window. Autel clearly wins the prize for rapid deployment, with the EVO taking approximately 30 seconds to launch from case-open to in-the-air. Mission planning may be managed prior to flight and uploaded once the UA has left the ground. We are experiencing much the same with the latest release of the EVO II 1” camera as well. We also appreciated the lack of drift and angle in relatively high winds (26mph+).

DJI is next fastest at approximately three minutes, (assuming propellers remain attached in the case), while the mission planning aspect is a bit slower than the Autel system. DJI uploads the mission to the aircraft prior to launch. Of course, this is assuming we’ve already achieved an approval from DJI to fly in the restricted airspace, on top of the FAA blanket approval. If we don’t, we may find (and have found) ourselves unable to fly once on-site, due to glitches or slow response from DJI.

Yuneec is the slowest to deploy, given six props that must be detached for transport. Powering the ST16 Controller, attaching props, and waiting for GPS lock often requires up to five minutes. The mission planning tool (DataPilot) is significantly more robust than DJI’s GSPro, third party Litchi or other planning apps, and is far more robust than Autel Explorer’s mission planner. DataPilot also essentially ensures the mission will fly correctly, as it auto-sets the camera angle for different types of flight, reducing the margin for pilot error. The Yuneec H520 is superior in high winds, holding accurate position in reasonably high winds nearing 30mph.

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All three aircraft turn out very usable models. All aircraft capture very usable, high-quality images. All of the aircraft are, within reason, accurate to ground points prior to being tied to GCP.

We were surprised to find we prefer the Autel EVO and are now completing this project after having acquired an Autel EVO II Pro with a 1” camera and 6K video.

Why?

Foremost, the Autel EVO family offered the most accurate positioning compared to the other aircraft in the many, many missions flown over this site. With dozens of comparison datasets, the Autel also offered the fastest deployment, and ability to fly well in high winds when necessary. The cost of the Autel EVO and EVO II Pro make this an exceptionally accessible tool and entirely reliable. That the Autel EVO requires no authorization from an overseas company, particularly in areas where we already have authorizations from the FAA, is significant to us, and the image quality is superior to either of the other aircraft.

We also greatly appreciate the small size of the aircraft, as it takes little space in our work truck, and our clients appreciate that we’re not invasive when working residential areas for them. The aircraft isn’t nearly as noisy as other aircraft, resulting in fewer people paying attention to the UA on the jobsite. The bright orange color, coupled with our FoxFury D3060 light kit (used even in daylight) assists in being able to see the aircraft quite easily, even when up against a white sky or dark building background.

We also of course, appreciate the speed in deployment. With safety checks, LAANC authorizations, planning a mission, and powering on remote and aircraft, the Autel EVO is deployable in under two minutes. When flying in G airspace, from case to airborne can be accomplished in under 30 seconds.

Battery life on the EVO 1 is substantial at 25 minutes, while our newly acquired EVO II Pro offers 40 minutes of flight time with incredible images to feed into Pix4D or other post-flight analytics software.

Of greatest importance, the EVO provides the most accurate XYZ location in-flight compared to the other aircraft. For those not using GPS systems such as the DTResearch 301 that we’re using on this project, accuracy is critical, and being able to ensure clean capture with accurate metadata is the key to successful mapping for input to Autocad applications.

WHERE TO LEARN MORE:

www.autel.com (UA, mission planning)

www.dtresearch.com (RTK Tablet with hyper-accurate antenna system)

www.dji.com (UA, mission planning)

www.foxfury.com (Lighting system for visualization)

www.hoodman.com (GCP, LaunchPad, SkyRuler)

www.Pix4D.com (Post-flight mapping/modelling software)

www.sundancemediagroup.com (training for mapping, Pix4D, public safety forensic capture)

www.yuneec.com/commercial (UA, mission planning)

With thanks to AutelHoodmanDTResearch, and Pix4D.

Part 91, 101, 103, 105, 107, 137: WHAT’S THE DIFFERENCE?

All these FARs, what’s a drone pilot to do in order to understand them? Do they matter?

YES!

In virtually every aviation pursuit except for sUAS, an understanding of regulations is requisite and part of most testing mechanisms.  As a result, many sUAS pilots holding 

a Remote Pilot Certificate under Part §107 are woefully uninformed, to the detriment of the industry.

Therefore, sUAS pilots would be well-served to inform themselves of how each section of relevant FARs regulate components of aviation.

Let’s start by digging into the intent of each Part.

  • §Part 91 regulates General Operating and Flight Rules.
  • §Part 101 regulates Moored Balloons, Kites, Amateur Rockets, Unmanned Free Balloons, and some types of Model Aircraft.
  • §Public Law Section 336 regulates hobby drones as an addendum to Part 101.
  • §Part 103 regulates Ultra-Light Vehicles, or manned, unpowered aviation.
  • §Part 105 regulates Skydiving.
  • §Part 107 regulates sUAS
  • §Part 137 regulates agricultural aircraft

RELEVANT PARTS (Chapters):

Part §91

This portion of the FARs is barely recognized, although certain sections of Part 91 may come into play in the event of an action by the FAA against an sUAS pilot. For example, the most concerning portion of Part 91 is  91.13, or “Careless or Reckless Operation.” Nearly every action taken against sUAS pilots have included a charge of 91.13 in the past (prior to 107).

Specific to drone actions, The vast majority of individuals charged have also included the specific of a 91.13 charge.

sUAS pilots whether recreational or commercial pilots may be charged with a §91.13 or the more relevant §107.23 (reckless)

It’s pretty simple; if there are consequences to a pilot’s choices and actions, it’s likely those consequences also included a disregard for safety or planning, ergo; careless/reckless. The FAA has recently initiated actions against Masih Mozayan for flying his aircraft near a helicopter and taking no avoidance action. They’ve also taken action against Vyacheslav Tantashov for his actions that resulted in damage to a military helicopter (without seeing the actual action, it’s a reasonable assumption that the action will be a §91.13 or a §107.23 (hazardous operation).

Other parts of Part 91 are relevant as well. For example;

  • §91.1   Applicability.

(a) Except as provided in paragraphs (b), (c), (e), and (f) of this section and §§91.701 and 91.703, this part prescribes rules governing the operation of aircraft within the United States, including the waters within 3 nautical miles of the U.S. coast.

The above paragraph includes sUAS.  Additionally, Part 107 does not exclude Part 91. Airmen (including sUAS pilots) should be aware of the freedoms and restrictions granted in Part 91.

§91.3   Responsibility and authority of the pilot in command.

(a) The pilot in command of an aircraft is directly responsible for, and is the final authority as to, the operation of that aircraft.

(b) In an in-flight emergency requiring immediate action, the pilot in command may deviate from any rule of this part to the extent required to meet that emergency.

(c) Each pilot in command who deviates from a rule under paragraph (b) of this section shall, upon the request of the Administrator, send a written report of that deviation to the Administrator.

§91.7   Civil aircraft airworthiness.

(a) No person may operate a civil aircraft unless it is in an airworthy condition.

(b) The pilot in command of a civil aircraft is responsible for determining whether that aircraft is in condition for safe flight. The pilot in command shall discontinue the flight when unairworthy mechanical, electrical, or structural conditions occur.

§91.15   Dropping objects.

No pilot in command of a civil aircraft may allow any object to be dropped from that aircraft in flight that creates a hazard to persons or property. However, this section does not prohibit the dropping of any object if reasonable precautions are taken to avoid injury or damage to persons or property.

§91.17   Alcohol or drugs.

(a) No person may act or attempt to act as a crewmember of a civil aircraft—

(1) Within 8 hours after the consumption of any alcoholic beverage;

(2) While under the influence of alcohol;

(3) While using any drug that affects the person’s faculties in any way contrary to safety; or

Sound familiar?

SubPart B also carries relevant information/regulation with regard to operation in controlled airspace, operations in areas under TFR ((§91.133), operations in disaster/hazard areas, flights during national events, lighting (§91.209)

PART 101

Part §101 has a few applicable sections.

Subpart (a) under §101.1 restricts model aircraft and tethered aircraft (balloons). Although subpart (a.4. iiv) is applicable to balloon tethers, there is argument that it also applies to sUAS. Subpart (a.5.iii) defines recreational flight for sUAS/model aircraft.

Finally, §101.7 re-emphasizes §91.15 with regard to dropping objects (may not be performed without taking precautions to prevent injury or damage to persons or property).  Public Law 112-95 Section 336 (which may be folded into a “107 lite” version), clarifies sections not added to Part 101.

Bear in mind that unless the pilot follows the rules and guidelines of a NCBO such as the AMA, AND the requirements of that NCBO are met, the flight requirements default to Part 107 requirements.

PART §103

Part §103 regulates Ultralight vehicles (Non powered, manned aviation)

Although no component of Part §103 specifically regulates UAV, it’s a good read as Part 103 contains components of regulation found in Part 107.

PART §105

Part §105 regulates Skydiving.

Part §105 carries no specific regulation to sUAS, an understanding of Part 105 provides great insight to components of Part 107. Part 107 has very few “new” components; most of its components are clipped out of other FAR sections.

PART §107

Although many sUAS pilots “have their 107,” very few have actually absorbed the FAR beyond a rapid read-through. Without a thorough understanding of the FAR, it’s difficult to comprehend the foundation of many rules.

PART §137

Part 137 applies specifically to spraying crops via aerial vehicles.

Those looking into crop spraying via sUAS should be familiar with Part 137, particularly with the limitations on who can fly, where they can fly, and how crops may be sprayed.
One area every ag drone pilot should look at is §137.35 §137.55 regarding limitations and business licenses.

The bottom line is that the more informed a pilot is, the better pilot they can be.  While there are many online experts purporting deep knowledge of aviation regulations and how they specifically apply to sUAS, very few are familiar with the regulations in specific, and even less informed as to how those regulations are interpreted and enforced by ASI’s. We’ve even had Part 61 pilots insist that the FSDO is a “who” and not a “what/where.” Even fewer are aware of an ASI and how they relate to the world of sUAS.

FSIM Volume 16

It is reasonably safe to say that most sUAS pilots are entirely unaware of the Flight Standards Information Management System, aka “FSIMS.” I’ve yet to run across a 107 pilot familiar with the FSIMS, and recently was vehemently informed that “there is nothing beyond FAR Part 107 relative to sUAS. Au contraire…

Familiarity with the FSIMS may enlighten sUAS operator/pilots in how the FAA examines, investigates, and enforces relevant FARs.

Chapter 1 Sections 1, 2  and 4 are a brief, but important read, as is Chapter 2, Section 2.

Chapter 3 Section 1 is informational for those looking to apply for their RPC Part 107 Certificate.

Chapter 4 Sections 2, 5, 7, 8 are of particular value for commercial pilots operating under Part 107.

Volume 17, although related only to manned aviation, also has components related to 107, and should be read through (Chapters 3 & 4) by 107 pilots who want to be informed.

Gaining new information is always beneficial, and even better if the new information is implemented in your workflow and program. Become informed, be the best pilot you can be, and encourage others to recognize the value in being a true professional, informed and aware.

 

Six ways drones have proven themselves as a tool for the AEC, Surveying, and mapping industries.

Drones and unmanned aircraft in AEC scanning and construction

Six ways drones have proven themselves as a tool for the AEC, Surveying, and mapping industries

Drones and unmanned aircraft in AEC scanning and construction process are becoming more common.  Unmanned aircraft, or drones are becoming much more common on today’s project sites. many companies in the AEC, Surveying and mapping industries are utilizing these aircraft daily. So how do drones capture data? What are professionals getting out of said data? What makes a drone into a valuable tool versus a toy?

UAS technology has advanced to a point where the aircraft; while still very sophisticated, are quite simple to operate. They utilize; altimeter’s, magnetometers, inertial measurement units, GNSS (GPS) and radio transmitters to control the flight operations, but the end-user would never know it. These sensors and more are all managed behind the scenes so well that an operator can takeoff from any point, fly a “mission” which involves several tasks collecting data, avoid collisions from unexpected obstacles, know when they have just enough battery to return home safely and land all in a constantly changing environment, 100% autonomously starting from a single tap for initiation. Flying a drone is fun but unless you’re collecting data it brings no value. There are many sensors that can be attached to unmanned aircraft such as LiDAR and Gravitometers but in this article we are primarily going to address cameras and their use in Photogrammetry.

Photogrammetry

When you photograph an object from two different angles and add some Trigonometry, three dimensional measurements can be calculated.  The entire process is simple and automated.  A 3D model from aerial imagery is nothing new. Photogrammetry can be summarized as; the art, science and technology of making precise measurements from photos, and has been around since the mid 1800’s.

The whole process works like this: The distance (f) from a Camera Lens to its sensor is proportional to the distance (h) from said camera lens to objects being photographed. This property is written into several equations that photogrammetrists use to calculate things such as the scale of a photo and even the elevation of specific points or pixels in aerial photographs.

When two overlapping photographs are in correct orientation relative to each other, a Stereopair or Stereoscopic Imagery exists.  This imagery creates perspective on objects within the overlap of the photographs and is the principle behind all forms of 3D viewing.

Stereoscopic Imagery drones and unmanned aircraft in AEC scanning and construction

As mentioned above, drone users can pre-program routes to fly over their intended mapping area. Photos are taken with specific overlap which is computed based on altitude, speed, and the resolution of their camera sensor. Drones use the onboard sensors like GNSS or even real time corrected positioning (RTK) to both georeference the photos taken, control the flight of the by changing the RPM’s of the individual motors. This data is all carried over in the image files where they are further processed.

Today’s Photogrammetry softwares use these mathematical principles to orient, scale and combine photographs and data. The software will ultimately generate Point Clouds, Orthorectified (measurable) photos and 3D models with varying output types.

Project Output drones and unmanned aircraft in AEC scanning and construction

Drones and unmanned aircraft in AEC and Construction:  Valuable Applications for AEC, Surveying, and mapping.

Surveying and Mapping. The use of drones and unmanned vehicles in surveying and mapping is almost self-evident. Surveyors and Cartographers have used Aerial Photography dating back about as far as the invention of the airplane. What may not be immediately apparent are the costs to purchase a survey-quality UAS and required software is a small investment in comparison to traditions surveying equipment and the man hours saved easily pays for itself.   Point Clouds and Orthometric photos are great for drafting planimetric features and generating TIN surfaces to represent topography. Whether you’re mapping for design data, a feasibility study, GIS, or performing an ALTA/ACSM survey, using unmanned vehicle to capture data may be significantly more efficient than traditional means.

Reality Capture, which is just that; capturing the reality of the current conditions of a project site. This is a great practice for design, bidding, marketing and simply helping clients “capture the vision.” This may be as simple as viewing an oblique photograph or as complicated as combining a designed structure with a 3D mesh and viewing it in VR. I personally get a kick whenever I see a IFC model inserted in a point cloud.

Building Information modeling (BIM). It would be hard to mention reality capture without mentioning BIM. While flying a drone indoors is doable its not very practical so this is not what we are referring to here. Many companies today, especially in the design-build world are utilizing BIM for much more than building modeling. They are integrating models in all their civil design as well.  These departments are already using laser scanning and are familiar with point clouds so adding a UAS into their tool chest is a natural move. Drones are great for capturing data that can be used for clash detection, QC, and as-built drawings.

Pre-Construction and Takeoffs are a major part of heavy civil construction. When it comes to moving dirt, knowing exactly what must be done can make all the difference in winning a bid, making a profit or losing your shorts. This is done when companies are bidding on projects, but the same process occurs over often in design builds and any time a RFI or change order comes up. Capturing data to that represent the existing site condition is key when building a model and matching existing roadway and other civil tie-in points. Using a drone is a great way to make this happen.

Project Output2 drones and unmanned aircraft in AEC scanning and construction

Project Management. Unmanned Aircraft may be utilized for many processes in project management. Creating progress reports and viewing current conditions may be the most basic use and might just be the most beneficial when it comes to decision making. Billing on some projects is solely based on materials moved and/or installed. This makes tracking linear feet, area, and volumes the bottom line. Some other overlooked uses may include, creating safety plans and incident reports, public involvement, and training. There are also various other project management uses above.

Inspections. Drones are one of the best tools utilized in inspections. Often an environment is not safe for a person such as inspecting a high wall in an open pit mine; or the situation may not be as efficient for an individual such as climbing versus flying to inspect bolts on a suspension bridge. When we apply the use of Infrared /thermals sensors to unmanned aircraft they are capably much more. Infrared light is absorbed by water making it possible to discover moisture that may be invisible to the naked eye. This is great for leak detection among other things. Thermal makes it possible to view and analyze heat signatures. This is often used to find areas of heat loss in anything from mechanical to thermal applications.

One of the biggest challenges today’s companies in the AEC, Surveying and Mapping industry face is a shortage of manpower. The only way to overcome a shortage in manpower is to innovate. Many choosing to innovate are looking to drone to solve their problems. Two trends I’ve noticed in helping companies develop their UAS applications is that they may start with a particular expectation in mind and one drone, but they always utilize their UAS data more than they anticipated and want to expand their drone fleet. I believe UAS technology is one of the best investments for a company in these industries to make. It is very apparent to me that Unmanned Aircraft are a major focus in developing technology. They are a powerful tool and not a toy.

By Bryan Worthen Kuker-Ranken SLC

Examples:
https://cloud.pix4d.com/dataset/812780/map?shareToken=30b94ff7-79a2-46e9-822e-0a97dbd26408

https://cloud.pix4d.com/dataset/788626/map?shareToken=38540ee0-e5a4-47e4-ab1a-6fb57ac48142
https://cloud.pix4d.com/dataset/665273/model?shareToken=612c5c7f-e47c-4721-8c2f-53ba80a6e544

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