Your guide to the LIDAR drone landscape: finding the perfect fit
Right now, LIDAR drone costs are driving overhead down dramatically. So if you are in a field where you need this data, getting the right system can mean big rewards. Read this guide to learn about drone LIDAR so that you can choose a system that gives you the biggest ROI possible.
What is drone LIDAR?
Drone LIDAR involves a LIDAR scanner that shoots millions of laser light pulses to the ground below its flight path. It then receives the pulse information that bounces off the surfaces below—hard ground, leaves, branches, infrastructure.
The sensor calculates the timing of all the bounces to read the distance the pulse travelled. This data offers precise horizontal and vertical insights about the surface below the flight area.
Where is LIDAR most useful?
LIDAR is useful for capturing ground, both in cases of bare Earth and in cases of lightly to densely vegetated survey areas. LIDAR pulses can reach the ground just like light would from the sky.
This is its strength over photogrammetry, because a photograph cannot capture ground-level detail in the case of vegetation, shadows or intensely homogeneous environments—like large areas of sheer white snow with no distinguishing features.
LIDAR data is often linked to vegetation, because it’s more powerful for getting the ground below trees and shrubs, but it in fact is useful at analyzing infrastructure, since the light pulses read everything they bounce off of. It’s not photorealistic, but the form and accuracy aid analytics. This Wingtra LIDAR output is of the LaFayette Geomatics lab where it underwent third-party testing.
How do you choose the best system?
As you can imagine, LIDAR for drones relies on a lot of hardware and software orchestration to deliver high quality results. Beyond this, processing data from a drone LIDAR system has required expertise.
The trick now is to find a system that is easy enough to use while still giving you data that is industry standard—the good news is, that’s finally becoming possible.
How drone LIDAR works
Before you can make an informed decision about what LIDAR drone system is best, you need to understand how it works. This way, you can assess specs and performance for yourself.
Let’s start with how LIDAR is fundamentally different from photogrammetry.
Active vs. passive surveying
A LIDAR drone represents an active sensing method. To know what that means, you can compare it to a photogrammetry drone, which carries a passive sensor. Simply put, it flies and the camera shutter opens and closes to passively capture light information in the form of pixels that make up photographs.
A LIDAR scanner actively sends out light pulses—by the hundreds per square meter—and captures them, recording how fast they return to the sensor.
LIDAR vs. photogrammetry
In a lot of ways they are completely different and in some ways the same. The take-home is that they complement each other beautifully. Explore all of this in more detail.
The anatomy of LIDAR for drones
A drone LIDAR system that does all this with precision and accuracy will require high-quality parts that work in perfect harmony.
In fact, the three critical components to a LIDAR drone sensor are the LIDAR laser scanner, which sends the light pulses; the inertial measurement unit, which measures the force and rate of movement of the sensor, and a GNSS unit, to tie the information to actual geolocations on the ground.
1. The components are so good that you don’t need to clean your data
Dependable LIDAR contains three key reputable components: a laser, an inertial measurement unit and a GNSS antenna.
Each of these is absolutely key to the quality of the LIDAR data you’re capturing and how well it aligns with reality. I.e., don’t get a sensor that skimps on these or you’ll pay more fixing all your data!
The quality of these components and how tightly they are engineered will make a difference in the quality of the data you collect.
This is especially true with LIDAR for drones, because the speed at which drones travel combined with the distance from the ground introduces more challenges to capturing accurate data.
What makes these components “high quality?
The LIDAR scanner for sure needs to be solidly built in terms of optics and the mechanics behind a powerful pulse, a reliable receiver and fine-tuned calibration.
In the industry, it’s well-known that the Hesai XT32M2X 32-Channel 360° Spinning Mid-Range LIDAR scanner is top of the range for lightweight drone LIDAR data capture.
A critical component for measuring LIDAR light pulses sent and bounced back to the drone is the inertial measurement unit (IMU). This is the component that tracks where the drone is in space and time as each pulse is sent and received. A good one operates consistently over many, many flights and is important to capturing a clean and strip-aligned point cloud.
Industry expert, Ted Strazimiri, talks about the “secret sauce” component of a good drone LIDAR payload, and what that sauce means for your results.
As for GNSS receivers, the position update rate, technology that blocks interference, the ability to receive from all major satellite systems and ability to grab a signal even in complex environments all make a huge difference in precision and the resultant accuracy of your LIDAR drone survey data.
Key applications empowered by LIDAR
Today, having a drone with a LIDAR sensor is a key asset for almost any company that needs ground truth.
Here are six industries that benefit and the ways they already employ LIDAR drones. For all of these applications, the common benefit is efficient analytics over large areas that avail insights within hours vs. days or weeks.
Surveying and mapping
Because drone LIDAR provides extremely precise vertical accuracy and surface detail, it’s excellent for creating accurate and detailed 3D models of terrain in vegetated or complex areas.
LIDAR is also useful for accurately surveying infrastructure—e.g., roads, railways, powerlines and buildings—offering accurate surface detail.
Forestry management
Since UAV LIDAR pulses can reach the ground below tree canopies, it helps to accurately assess the forest structure, biomass, tree height, and density. LIDAR.
In areas prone to wildfires, LIDAR mounted on a drone can efficiently and regularly map fuel loads and terrain features that contribute to fire spread, a huge boon for wildfire management.
Precision agriculture
LIDAR drone surveys provide precise elevation data for analyzing drainage patterns, soil health, and irrigation planning, all of which allows for more educated and precise terrain management, planting and crop maintenance.
Generally, LIDAR can also be used to measure plant growth, health and crop yields.
Environmental monitoring and conservation
LIDAR drone mapping is highly effective for providing analytics to assess changes in shorelines, riverbanks, and floodplains by comparing high-resolution terrain models over time.
LIDAR drones also expedite the mapping and identification of ecosystems, providing critical data for conservation and biodiversity protection efforts.
Construction and infrastructure development
We’ve mentioned that UAV LIDAR sensors can produce accurate terrain models, and for construction, these help in a range of ways, including providing accurate analytics on site grading, volume calculations and more. All of this optimizes planning for earth-moving activities.
Drone LIDAR is used to capture as-built conditions, creating precise building information models use in design and construction planning. The data can also be used in automation of monitoring and maintenance.
Additionally, LIDAR data can be used to comprehensively map large areas and produce maps that help predict flooding. This is useful in coastal and vulnerable areas where settlements continue.
In this free recorded webinar, experts discuss using Wingtra LIDAR for mapping through vegetation and addressing construction challenges.
Mining and resource exploration
On mine sites, LIDAR drones fetch data that provide powerful analytics for volume calculations and stockpile monitoring that empowers tighter planning and better inventory management. It’s key in restoration progress reporting and management.
Detailed LIDAR topographical models illuminate best plans for pit design, road layout and safety assessments.
LIDAR data also contributes to precisely analyzing slopes and site safety in all operational areas through landslide prevention and stability monitoring.
How do you conduct a LIDAR drone survey?
This is a multi-step process that has gotten easier as technology advances. Yet there are some things to remember. Experts agree that the biggest one is this: You really have to have a solid base station setup, because LIDAR coordinates location signals—the location of the laser itself when a signal is sent and received, along with the precise ground that that signal hits.
It’s not so easy to reconcile this after the flight, and if you do, you risk losing what you are after in the first place: ground-level information tied to a precise ground coordinate.
Check out this helpful end-to-end drone lidar survey workflow article and video.
How much does a LIDAR drone cost?
The answer to this question opens a box about the range of drone LIDAR technology available today and what exactly you need to do with it.
Basically, if you want to penetrate the most dense vegetation possible to penetrate with LIDAR, you’ll need a high-end Riegl sensor. This can cost up to 250K USD. Meanwhile a lower-end Riegl, which is smaller yet top-of-the line for quality, will run about 80K USD.
At the other end of the price spectrum, for your basic, bare Earth, or lighter vegetated areas, you can invest between 10 and 30K USD in a DJI platform.
Somewhere in between, falls Wingtra, with high-quality data capture and reliable performance.
Read this article for a deeper breakdown of cost and performance across the most popular models today.
What’s the best LIDAR software?
Unlike photogrammetry software, LIDAR software doesn’t provide much in the way of “starting out” or free versions. You need to invest. And that investment is considerable right out of the gate.
So you really need to know what kinds of projects you will be using LIDAR for, what kinds of insights you need so that you invest in the right suite.
There are two stages you will be looking at:
- You first need to classify the LIDAR point cloud based on features like ground; low, medium and high vegetation; poles; bridges; roads and 250-plus more possible categories.
- Once you classify what is in your point cloud, you need to know what you are looking for: for example, check on sagging of powerlines, check on tree heights, analyze vegetation growth and encroachment, etc.
This Wingtra LIDAR point cloud processed in LIDAR 360 would be classified as powerlines, and what you need to assess can be a range of things from vegetation encroachment to line sag in freezing temperatures.
Some LIDAR scanners come with their own software bundled in, but this software may be limited in what kinds of insights you can extract without jumping to another software.
What you need most is a software that presents minimal learning curves and doesn’t make you change to another software environment to get the insights you need once you have classified your point cloud.
For this reason, we recommend LIDAR360, which presents a relatively small learning curve along with a robust range of analytics to choose from. This is a software you can learn to use and stay in to get all your analytics in one place.
What’s the best LIDAR drone?
When investing in a LIDAR drone solution, the concept of good customer service will be more critical than with a photogrammetry project. As discussed, the orchestration of a laser, a GNSS unit and an IMU is not exactly as straightforward as a camera snapping pics at a fixed rate. You very well may need to contact someone in case of challenges, and you will want to know they are responsive and professional.
In terms of data quality, a combination of the stability of the drone in-flight and the quality of the IMU will jointly affect the quality of the point cloud you get. In other words, if the drone is unstable in the air, and the device that calculates its position based on mixed levels of acceleration or erratic motion is not so precise, of course the point cloud will be “noisy.”
Beyond flight time, field time involves many factors, and field efficiency is your big concern when taking on serious projects. Industry expert Ted Strazimiri gives a candid explanation of how three popular systems differ.
Comparison of key considerations according to testing and review of leading systems by industry expert, Ted Strazimiri
Cleaning a LIDAR point cloud is one thing. But how much does the data reflect the reality on the ground if the capture was not stable and registered precisely in the first place. In the case of DJI, industry experts, including Ted Strazimiri, have commented that the software that processes L2 data is pretty automatic, but it can introduce “fixes” that can cause doubt about what is real reflection and what is adjusted, especially in complicated terrain sections of a map.
You’ll also want to know that the system is efficient to use—not just in terms of flight time and area covered, but also in terms of setup and calibration. Calibration alone will suck some battery and time. Moreover, does the system require a lot of assembly and breakdown to travel with?
Wingtra LIDAR vs. Quantum: Data quality as captured
Common LIDAR myths dispelled
Myth: LIDAR sensors penetrate forest canopy
While it is tempting to think, since LIDAR data can reach ground beneath certain densities of vegetation, that it can go through physical objects, it cannot.
What LIDAR relies on is the passage of light beams through small open spaces, collectively diffusing and reaching the ground. Just like the sun. Rule of thumb: If you can stand in a forest, look up and see sky or light around the leaves of the canopy, you will be able to capture ground-level information from pulses of light sent from above.
There is a canopy thickness that even the highest-end LIDAR cannot deliver ground information about.
Myth: LIDAR is always better than photogrammetry
In some cases, LIDAR will outperform photogrammetry, just as in some cases photogrammetry will outperform LIDAR. The difference is what information you need and why. If you need terrestrial information from a greenfield with moderate vegetation, LIDAR drone capture will definitely work better.
If you need a detailed orthomosaic with photorealistic, high-resolution looks at the ground and features in a certain area that is not very vegetated, photogrammetry will deliver what you need.
Myth: More returns mean better outcomes
In the world of drone LIDAR this has simply not been proven to be true. If you understand what a return is and how it fits into the context of a drone survey, the reason becomes evident.
In short, drone LIDAR involves more pulses per square meter than airborne LIDAR. A return rate is the number of signals that bounce back from just one pulse. If you have three strong returns and two faint ones, you have noise in your data. Meanwhile you have enough pulses to get sufficient information.
Discrete or waveform?
Discrete returns involve a fixed number of reflected laser energy spikes recorded by the sensor. This focuses the data to reflection points according to their strength and time of impact. Discrete sensors send many pulses across small areas to get rich insights.
How many returns is optimal for lightweight drone LIDAR then?
In this free recorded webinar, experts discuss using Wingtra LIDAR for mapping through vegetation and addressing construction challenges.
FAQ
How much does a LIDAR flight cost?
The cost of a LIDAR drone flight varies based on factors such as project size, terrain complexity, equipment, and location. Flights are typically priced by the hour, per acre, or for the entire project.
Hourly rates
LIDAR drone flights generally cost between 1,000 USD and 5,000 USD per hour, including the drone, sensor, operator, and basic data processing. More complex terrains or high-end Riegl equipment push you into the higher end of this range, while simpler surveys, such as flat land mapping with light to mid levels of vegetation, are more affordable.
Cost per acre
When priced by area, costs range from 100 USD to 600 USD per acre, depending on the terrain and required data resolution. Flat, open areas are less expensive, while forested or urban areas with dense vegetation or obstacles tend to cost more due to the additional detail required.
Project-based pricing
For small projects (under 100 acres), costs typically range from 5-10K USD. Medium projects (100-1,000 acres) range from 10-50K USD, while large projects (1,000+ acres) can range from 50-100K USD, depending on complexity.
Additional costs
Post-processing fees, which convert raw LIDAR data into usable formats, range from 1-10K USD, and travel costs may apply for remote locations.
What is the lightest LIDAR drone?
At 590 grams (1.3 lbs), the Cepton Vista-P60 is currently one of the lightest LIDAR systems suitable for drone integration. However, the exact choice of system depends on the specific application and range requirements.
Where we are today, and where we are going
The above information gives you an idea of how variegated the drone LIDAR landscape has become just over the past 4-5 years. The race is now on among drone manufacturers and sensor technology firms to make everything faster, easier and more accurate.
Yet the fundamentals of how LIDAR works and what is required for it to work well will not change, so with this education, you can monitor the market like a wise owl and always make educated choices about what’s out there in a market that is constantly evolving.