Unmanned Aerial Vehicles

Structural


Structural

UAV Benefits

  • Identify roof or gutter damage from a storm
  • Calculate surface area for materials
  • Calculate volume of structures or piles
  • Determine ground damage from construction
  • Locate hot/cold spots with proper optics
  • Inspect the top of a grain leg

Outside of agriculture, UAVs also offer many community development benefits, such as the inspection of:

  • Real estate
  • Power lines
  • Infrastructure
  • Wind turbines
  • Radio towers

UAV Challenges

Collision: When flying near structures and objects, collision is the greatest risk to a UAV.

  • Tip: Most UAVs have anti-collision features for structural inspection, but they have limitations. Know your aircraft and when to turn off those features.

Speed: Developing a stitched image of a structure requires many images, along with tight overlaps. This can be time-consuming.

  • Tip: Always capture high-resolution images for accuracy. Setting ground-control points can improve accuracy as well.

Stitching: Structures such as power lines rarely align perfectly in a stitched image. It can also be difficult when stitching images with identical, or nearly identical, structures.

  • Tip: Take additional images with tight overlaps. If it's still questionable, it may be best to forgo the stitching software and take a still image.

Examples

Solar panels in corn

Flown by John Scott, Digital Agriculture Coordinator, Purdue Extension

Solar panels were installed in at the Agronomy Center for Research and Education (ACRE) in 2019 in field planted with corn. Our project started by recording the installation of the array and track its first growing season. It became interesting by mid-August when the plant health images detected healthier, greener plants growing under the solar panels. This will be compared against yield data.

The solar array is a permanent structure; therefore, more data will be collected in subsequent years.

ACRE Solar
ACRE Solar VARI

Transmission tower footprint

Flown by Andrew Westfall, Agriculture & Natural Resources Educator, Purdue Extension - White County

The construction footprint of two newly installed power transmission towers are shown here.

TowerWaterDamage_Andrew-Westfall.jpg-e1542661262871.png

Field drainage tile was damaged during installation, and this orthomosaic map shows water damage. Using software to conduct geospatial analysis, the farmer was able to quantify the damage.

  • Orange area = 3.27 acres (too wet, not planted)
  • Purple area = 1.52 acres (plant roots too wet)
  • Total = 4.79 acres
Tower Compaction

Here, you can see the result of soil compaction during construction.

We followed up during the 2019 growing season to see if compaction was still affecting crops. This was mapped using RGB, VARI, NDVI and NDRE to compare indices.

NDRE

zarse ndre

NDVI

zarse tower ndvi

RGB

zarse tower rgb

VARI

zarse tower vari

Irrigation management

Flown by John Scott, Digital Agriculture Coordinator, Purdue Extension

UAVs can serve as a quick method to detect anomalies in irrigation systems, such as this center pivot spanning hundreds of feet. In collaboration with Michigan State Extension, we found one plugged and three malfunctioning nozzles in the line after one pass. All photographs were geotagged, so it’s possible to recheck problem areas later.

We tested the camera angle directly above, to the side and at a 45-degree angle and found:

  • The 45-degree angle (50- to 75-feet above take-off elevation) resulted in the best imagery with the most detail for maintenance purposes.
  • Water penetration in the canopy and nozzle interaction was best visible at the side angle. However, it was difficult to determine the overall spray pattern and to remain at a consistent distance, putting our UAV at risk.
  • It was more difficult to fly and we couldn’t see the entire pattern, even with a wide-angle lens, when directly above the system. Flying at a higher altitude decreased pattern visibility but did capture the entire spray area.

In this image, a clogged nozzle is identified.

Irr_PluggedNozzel

This series of images shows a malfunctioning nozzle by a fast whipping spiral of water. The first image shows the initial detection from a 45-degree angle. The second image is a top view, which shows a better view of the water pattern and a better angle to gather correct coordinates. The third image includes a geotag of the malfunctioning nozzle. Even though the pivot moves, this can be helpful to determine the span of the nozzle.

fast spin 1
fast spin 2
Irr_FastSpin_GPS

These videos reveal what the drone operator and irrigation specialist could see in real time, allowing a quick repair

Flown by Adam Shanks, Agriculture & Natural Resources Educator, Purdue Extension – Clinton County

Video was also collected on a different pivot system in Clinton County, Indiana with different nozzle placement. This video validates that the 45-degree angle view resulted in the best imagery with most detail for maintenance purposes.

Power substation maintenance and construction

Flown by Bryan Overstreet, Agriculture & Natural Resources Educator, Purdue Extension – Jasper County

Purdue Extension partnered with Newton County REMC to photograph substation renovation and infrastructure to record how the temporary substation was hooked up to the distribution lines.

power lines

Concrete pipe installation

Flown by John Scott, Digital Agriculture Coordinator, Purdue Extension

A subsurface concrete drain pipe was installed in 2019 to provide an outlet from a new retention pond to a nearby creek. The pipe was installed diagonally through the cover-crop plots and will impact soil characteristics for several years. The UAV data will determine the affected 2.3-acre area and document the damage for future uses.

DCIM100MEDIADJI_0612.JPG
pipe installation mark

Septic drain field installation

Flown by John Scott, Digital Agriculture Coordinator, Purdue Extension

Before the installation of a new septic tank and finger system, this homeowner was curious about where the existing tank and drainage tile was located in their yard. The homesite was mapped to locate the main effluent link into the tank, but due to the trees, it was not possible to locate the finger system from the air. This also is a good indicator that any existing finger system would likely be full of roots.

The second image shows lines of the homeowner’s desired placement. This took into consideration an existing drainage line and allowed the homeowner to have a meaningful conversation with the septic installer.

On site 2
On site 1

Leaky windows of courthouse

Flown by Bryan Overstreet, Agriculture & Natural Resources Educator, Purdue Extension - Jasper County

We were able to locate leaky windows on the second floor of this courthouse using a UAV. We found that a clogged gutter was the culprit. A UAV was a faster, safer, and more cost-effective alternative to human climbing in identifying this problem.

Courthouse aerial photo
Courthouse Zoomed in photo

Compost pile

Flown by Andrew Westfall, Agriculture & Natural Resources Educator, Purdue Extension - White County

UAV flights can deliver accurate stockpile information to producers. A planned flight over this compost pile generated an image, from which software then calculated length, width, and volume.

Compost Pile