Drone Lidar for 3D Mapping, Leading Companies, and Their Systems
Drone Lidars are the drones with a laser scanner mounted on them. These are used for 3D mapping and it is a drone service industry which has a huge commercial potential. In this article, I try to explain how a drone lidar works, how this mapping drones are used in various ways, who are the leading drone lidar system manufacturers and finally a brief introduction to their lidar systems.
Basic Principle of Operation of the Lidar:
Lidar stands for Light Detection and Ranging. The laser scanner sends a laser light (visible or non-visible) to the environment and gets the reflection from the objects in the environment onto a sensor. It measures the time of flight meaning the time taken by the light to go to the subject matter and come back to the sensor. From this period taken, it calculates the distance of the object (knowing the speed of the light). The laser scanner keeps sending the light, and the light gets reflected from objects in the environment which are infinitesimally close to each other. This way the laser scanner gathers an enormous amount of data. Now that we have many data coming back from the environment to the sensor, we can build the whole map or a full-scale 3D model of the environment! Now you know why it is called LIDAR and why it is so important because getting a full-scale 3D model of the environment is a highly valuable thing and solves many commercial issues and companies are willing to pay an enormous amount of money for that.
Use of Lidar Drones:
Lidars sensors can be considered an alternate or complementary technology to vision sensors and can be used interchangeably. Hence, we can use them in all those applications where we can use vision sensors. For example, obstacle and collision avoidance, aerial imagery, inspection. However, the extra advantage is the capability of Lidars to obtain high-precision ranging (finding the distance) and altimetry (finding the height above ground level). It is important to note that since lidar is a light sensor, Lidar data is highly accurate and precise. On the downside, it is computationally costly to analyze this data. It takes a lot of computer resources and time. However, now companies are developing very efficient software to handle this problem. These companies use cloud base data platforms to support applications demanding Realtime data analysis. The companies providing this kind of support include Precision Hawk, Airmap, DroneDeploy and Agribotix(focus on agriculture).
Drone Lidar Mapping:
Lidar mapping using drones can give very accurate mapping than any other sensors. The maps you get from Lidars are the ultimate in accuracy which cannot be achieved using any other surveying technique. It becomes critical to use the lidar drone mapping in following situations:
- In a hazardous environment, such as a disaster site or the site of a nuclear accident or the even non-accidental radioactive environment.
- When the site is hard to approach, drone lidars are at their best. It is the case for very high telecommunication poles or big tanks and vessels in an industrial environment. For some more information you may refer the article what are drones used for.
- Places where fixed-wing planes with lidar do not have a place to land, we can use drones.
- In archaeology, drone lidar mapping is used to find any patterns which could indicate something of historical
Precision agriculture or precision farming is a rapidly growing field for lidar drones. You can observe fine-scale variations in crops. From establishing highly certain paddock boundaries to terrain modeling, getting grid soil mapping, mapping for particular attributes and site-specific crop management, there are many applications in the agricultural sector. When you have the ability to map with high precision, then there are countless ways you can use it to improve the yield. For some more information you may read the article “Drones in Agriculture”.
Lidars itself can be used as a collision avoidance sensor. In fact, laser scanners are the most accurate obstacle avoidance sensors. It is not a new technology, but the highly efficient software which uses the technology in real-time are relatively new. Previously, processing of the large laser data (also called point cloud) was a challenging task because you have to process all that data in real-time to avoid obstacles (or any such task like real-time mapping!). Now many professional drones use Lidars for obstacle avoidance.
Companies Developing Drone Lidars and their Systems:
Although the company is famous for their lidars used in autonomous car development, their systems are also used by the leading drone manufacturer DJI. They have Puck series of products which are most sophisticated lidars in the market.
Their product is called UAV LidarPod. Which is a ready-to-use system for use in drones? The system is self-contained hardware, firmware, software and also workflow and can be deployed immediately. Their software is called LidarViewer. LidarPod weighs 2.8kg and can be used by any UAV which can take a payload of 3kg. According to the company, it can collect 700,000 points per second which at an altitude of 40m and flying speed of 30km/hr equates to 300 points per square meter. It has a range of 100m and an accuracy of less than 20mm. It offers a fantastic richness in the data set which greatly enhances the detail that can be collected.
It is a French company offering many aerial imaging sensors for drones. They have two products. One is called Yellowscan Mapper which weighs just 2.1 kg and has an absolute accuracy of 15cm and a battery life of 2 hrs. The other is YellowScan Surveyor which weighs 1.6kg with an absolute accuracy of 5cm.