Embedded LiDAR technology on drones
LiDAR technology is a laser remote sensing technique that maps a 3D environment using accurate direct georeferencing.
It is used in many applications: precision agriculture, forestry, mining and quarrying, roads and railways, infrastructure and power lines inspection, and archeology.
The LiDAR POD compatible aerial, bathymetric and terrestrial drone
Hélicéo develops its own LiDAR system
Our geomatic experts have joined forces to offer you a turnkey and efficient LiDAR system.
The development of this solution was notably supported by the research work of the ESGT (School of Surveyors and Topographers) with its GeF laboratory (Geomatic and Land).
The LiDAR POD integrates the best components of the market in terms of direct georeferencing and data processing with the Trimble Applanix card and the POSPac and Trimble RealWorks software suite. We are today a partner with the leading suppliers of LiDAR heads worldwide.
Structured around a carbon chassis, the LiDAR POD guarantees a small footprint and a longer mission time. With the universal connectivity “HConnect” development, it embarks very easily on all the drones Hélicéo and on the bathymetry. It is also compatible with the DJI Matrix 600 range. In addition, its clever “Quick Attach” 4-point fixing system “Press & Record” technology make it operational in a few seconds. This LiDAR system is guaranteed IP67 since it is perfectly waterproof against splashing water and dust.
Mounted on anti-vibration dampers, the LiDAR POD brings you a point cloud of quality, free from spurious noise generated by the drone. Its association with the SuperFox6 or the SuperBathy makes it possible to obtain a very precise calculation of the lever of the GNSS antenna. As a result, it improves the georeferencing of your point cloud.
Thanks to the “external storage” waterproof function, your data is stored on a memory stick supplied with the system. This reduces the risks associated with drone manipulations such as sensor scratches or falls. As soon as the landing is over, your data is ready for operation.
Lynx16: one of the most economical LiDAR PODs on the market
The Lynx16 LiDAR POD is recognized as one of the most economical solutions on the market. Indeed, it is aimed at teams who want to scan urban or extra-urban areas with a limited budget. It is compatible with most drones on the market like the DJI Matrix 600 Pro.
Particularly user-friendly, with its “press & record, ” the Lynx16 guarantees you an implementation in seconds. Immediately after landing, a USB key allows you to recover your entire mission.
On the other hand, the Lynx16 has 16 beams and a maximum range of 75 m. Thanks to its double echo, it can capture up to 600,000 points per second. Its horizontal field of view is 360 ° and its vertical field of view is 30 °. Powerful and smart, it is the ideal solution for any type of mission.
Puma32: the versatile LiDAR solution for a high-density point cloud
Designed by our teams for increased precision requirements, the Puma32 provides point clouds with a density doubled. It uses the same technology “press & record ” than his brother the Lynx16.
The Puma32 has 32 beams and a maximum range of 200 m. Thanks to its double echo mode, it can generate around 1.2 million points per second. The denser implantation of the beams thus allows a higher resolution over longer distances. Its horizontal field of view is 360 ° and its vertical field of view at 40 °.
The characteristics of Hélicéo LiDAR systems
|Number of beams||16 beams||32 beams|
|Range||100 m||200 m|
|Precision||+ or – 3 cm||+ or – 3 cm|
|Vertical FOV||+15,0° to -15,0° (30°)||-25° to +15° (40°)|
|Angular resolution (vertical)||2,0°||0,33°|
|Angular resolution (horizontal)||0,1° – 0,4°||0,1° – 0,4°|
|Rotation rate||5KHz – 20 KHz||5KHz – 20 KHz|
|Laser product classification||
(safe for the eyes according to
|Wave length||903 nm||903 nm|
|MECHANICAL, ELECTRICAL & OPERATIONAL SPECIFICATIONS|
(protection against dust and
the effects of temporary immersion)
(protection against dust and
the effects of temporary immersion)
|Output||– Simple echo: ~300,000 points per sec
– Double echoes: ~600,000 points per sec
|– Simple echo: ~600,000 points per sec
– Double echoes: ~1,200,000 points per sec
|Number of antennas||1||2|
|IMU data rate||200 Hz||200 Hz|
How does LiDAR work?
What is a LiDAR?
LiDAR (Light detection and ranging) is a remote light measurement tool. Therefore, this device is based on the principle of remote sensing laser telemetry. Lasers are sent in different directions over 360 °. Each beam of light is reflected on one or more objects, then returns to the receiver. By calculating the time elapsed between the emission of the pulse and its reception and knowing the speed of light, the LiDAR system can thus measure the distance between the source and the target.
Your LiDAR POD consists of five elements:
First of all, the sensor emits and receives the laser pulses. It sends light beams in all directions and can thus cover the environment on 360 °. LiDAR also includes a GPS positioning system which retrieves GNSS data. With this device, you can determine the POD position in the space in x, y and z to a few centimeters. The inertial unit or IMU measures the precise orientation of the drone for each point surveyed. It records all the movements of the drone and can correct the data acquired for more precision.
Embedded computing and electronics allow to store the acquired data during the flight through algorithms developed by Hélicéo. They also provide inertial data (IMU), GNSS, and LiDAR fusion to produce a consistent and accurate point cloud. Inheritance of the photogrammetric HASK version developed by Hélicéo since 2014, the HASK LiDAR software ensures the LiDAR data fusion but especially the integration of mechanical lever arms GNSS and IMU to obtain an absolute precision of + – 3cm. The HASK integrates a real-time visualizer during the processing of the point cloud.
To understand how LiDAR works in 5 steps
1) The laser pulse emission: LiDAR emits a laser pulse on a target.
2) The backscattered signal recording: the laser is reflected by the target object and returns to the LiDAR pulse source. This process is repeated continuously to produce a complete 3D map of the study area.
3) The distance measurement: the laser travel time is measured and more precisely the time elapsed between the emission and the reception of the laser wave by LiDAR. The calculation to be performed is as follows: distance = travel time x light speed.
4) Recovery of the drone position and altitude: the GNSS navigation and positioning system provides accurate geographic information about the sensor position (latitude, longitude, height) and the inertial measurement unit (IMU) defines its precise orientation.
The recorded data thus makes it possible to generate the base of the point cloud.
5) Data processing: the data collected by LiDAR can be viewed and processed in software such as Trimble RealWorks.
What are the 6 advantages of LiDAR on photogrammetry?
1# Get a geometrically perfect point cloud and 100% reliable
Dark point of the photogrammetric missions, geometric reconstruction is frequently defeated. This causes problems when restoring the orthophoto (For example: problem of alignment or superposition of aberrant point clouds).
Due to the accuracy of the LiDAR data, geometric distortions are totally eliminated. As a result, it ensures consistent accuracy across the entire mission area.
On the other hand, LiDAR has a higher sampling density than photogrammetry, which greatly improves the results.
2# Remove ground support points
Thanks to the very high precision inertial unit and GNSS RTK / PPK navigation system, you can avoid the stereo preparation. This consists of putting targets on the ground and measuring them on the GNSS rod. In photogrammetry, this operation can take several hours whereas it is useless for LiDAR missions. This greatly increases your productivity.
3# Multiply your market opportunities with LiDAR
UAVs can now ship high-performance LiDAR systems, which opens up multiple mission opportunities. You can capture new markets where photogrammetry was totally ineffective.
Civil engineering and building:
With LiDAR, you can acquire high-quality digital elevation models (DEM) or digital terrain models (DTM) very quickly. It is particularly effective for scanning buildings with complex geometries with smooth surfaces. Indeed, LiDAR will be perfectly at ease on concrete walls, metal bridges, glass walls, where traditionally photogrammetry is defeated.
Thanks to LiDAR, you are less dependent on poor sunlight conditions than with photogrammetry. So you can go on a mission more often. In addition, the results obtained by the lasergrammetry are of higher quality. You measure your stocks more precisely with increased periodicity.
LiDAR is the only technology that provides canopy layer modeling and soil topography under vegetation. The points density recorded is greater than with photogrammetry. The results are more accurate and improve the estimation of biomass and tree classification.
LiDAR can provide enhanced infrastructure information to operators who need to ensure the maintenance of transport networks.
LiDAR systems provide detailed information about the environment and help operators make decisions. Embedded on a drone, they make it possible to raise difficult areas like the coasts, the forests or even the agricultural zones.
LiDAR drones facilitate the inspection and monitoring of industrial sites and oil and gas networks. Indeed, LiDAR is very useful for complex and reflective objects such as pipes or industrial parks.
In the field of architecture, the surfaces to be taken up are often complex and very detailed. However, LiDAR can measure them faster than with photogrammetry.
LiDAR is proving to be very useful in archeology because it allows you to explore previously inaccessible areas because of the density of vegetation. Recently, pre-Columbian remains were discovered using LiDAR technology while they were totally invisible under the forest cover.
Farmers are increasingly using LiDAR to monitor their farms and collect information on soil quality. They can determine how resources should be used to increase productivity.
4# Classify your data accurately with multi-echo
LiDAR is used to represent the elevation of several objects in a very dense point cloud. Thanks to the multi echo principle, it can collect several points for the same beam. In other words, a single laser pulse can reverberate on several reflecting surfaces before returning to LiDAR. A beam is divided into as many echoes as there are reflection surfaces. The first impulse is the most significant echo. It represents the highest object such as the top of a building for example. If the first object corresponds directly to the ground, only one return will be detected by the device. On the other hand, the intermediate echoes characterize the structure of the vegetation.
With the multi echo principle, you can classify very simply the various elements found despite the density of vegetation. For example, the points belonging to the buildings will be separated from the points belonging to the forest cover.
5# Earn twice as much time for your LiDAR missions
With LiDAR, the data acquisition time is halved compared to photogrammetry. Indeed, at equal altitude the LiDAR requires a recovery of only 20% for the majority of the missions between the flight lines while in photogrammetry, it is 60 to 80%. For a photogrammetric swath of 73 m to 50 m of altitude, the LiDAR will realize a swath of 160 m wide (Example of a flight at 50m on the basis of an APCS matrix in photogrammetry against a Lynx16 LiDAR flight). LiDAR brings you a real time saving and especially a significant money gain.
6# Save 10 times more time when calculating the point cloud
LiDAR allows you to divide your treatment time by ten. Indeed, you can generate a dense 3D point cloud after only a few minutes of process. While in photogrammetry, the calculation time is several hours or ten hours for major missions. The point cloud requires long hours of cleaning to ensure quality rendering. The sunshine and flight conditions impact heavily the result. Major advantage of LiDAR, these parameters do not interfere on the quality of the cloud of points. You get a very clean and exploitable cloud with little noise. This production gain is therefore a guarantee of record profitability for your projects.
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