LiDAR system for surveying land and in shallow water
In fact, there is no other
Green laser light For drone laser surveying
It is an irreplaceable and important light.
Performance Improvement
Fastter and More Efficient
Laser Power: 2x, Concentration: 1.9x, Light Sensitivity: 2x
We have upgraded the performance by doubling the laser power, increasing the concentration by 1.9 times, and doubling the light sensitivity from previous models.
Measurement Speed Improved by 167%
The measurement speed has been improved by 167%, with a pulse rate of 160,000 pulses per second and a scan rate of 80 lines per second.
This significant speed increase dramatically enhances operational efficiency.
TDOT 3 GREEN
| Pulse Rate | 60,000Hz |
|---|---|
| Scan Rate | 30 lines/second |
| FOV | 90° |
| Number of Returns | 4 |
| Laser Wavelength | Green (532 nm) |
| Compatible Drone | MATRICE 350 RTK |
TDOT 7 GREEN
| Pulse Rate | 160,000Hz |
|---|---|
| Scan Rate | 80 lines/second |
| FOV | 120° |
| Number of Returns | 6 |
| Laser Wavelength | Green (532 nm) |
| Compatible Drone | GLOW.H |
Range Performance
Accurately Capturing Targets
The measurement distance has improved by 172% from previous models, achieving ≥10% at 430 meters. With excellent distance measurement performance that allows measurement from an altitude of 430 meters even for objects with only 10% light intensity, targets can be reliably captured within the normal operating altitude of 150 meters or less.
In land area, it is advantageous for capturing the ground surface beneath trees, and in water areas, it allows for deeper measurements.
Depth Measurement Performance
Capturing deeper waterbeds
The depth measurement capabilities have improved compared to previous models.
The depth measurement capability is 13.5 meters from an altitude of 50 meters and 16.8 meters from an altitude of 15 meters, both exceeding 10 meters depth.
The extended laser reach underwater allows for more in-depth measurements of aquatic areas.
Depth Measurement Ability
| TDOT 3 GREEN | TDOT 7 GREEN | |
|---|---|---|
| Clear Water R＝0.40 @ Altitude 50m | 1.13 Secchi | 1.43 Secchi |
| Turbid Water R＝0.40 @ Altitude 50m | 0.47 Secchi | 0.60 Secchi |
| Clear Water C＝0.22 @ Altitude 50m | 10.7m | 13.5m |
| Clear Water C＝0.22 @ Altitude 50m | 14.2m | 16.8m |
R=Reflectivity C=Beam attenuation coefficient
Clear Water
Detecting the Waterbed
A single laser reflects off both the water surface and the waterbed. The reflected waves received are distinguished based on their reflection intensity, allowing high-precision topography measurements even underwater.
Turbid Water
In Turbid Water
Impurities can cause multiple reflections (noise), making it difficult to identify the clear reflection surface of the target, which may reduce depth measurement performance. The feasibility of measurements can be predicted in advance based on information about the transparency of the target area.
Too Shallow Water
Where the Water is Too Shallow
The two waveforms reflected from the water surface and the waterbed overlap, making it impossible to distinguish between them from the reflected waves, potentially causing measurement errors. However, it may still be possible to measure with laser incidence at an angle.
Close Range and Strong Reflections from Frontal Surface/ Directly Below
Where Reflections are Too Strong
It may exceed the sensor’s sensitivity limit, preventing accurate readings. Attention is required for measurements from low altitudes and at points where the laser enters the water surface perpendicularly, due to the strong reflection from the water surface.
Capturing a Wide Area
Field of View 120°
The Field of View (FOV) has increased from 90° to 120°. This wider FOV allows for safe and accurate measurement of areas that were previously difficult to capture with a narrower FOV, such as steep slopes and the sides of structures.
Capturing Underwater Topography
Able to obtain data from land, water’s edge, water surface, and waterbed
Ability to Measure Wet Objects
Conventional NIR laser is absorbed by water, making surveying difficult immediately after rain. Green light, which is less absorbed by water, is effective not only for surveying the waterbed but also for measuring wet surfaces.
Improved Number of Returns
The number of returns refers to the number of echoes received from objects that the emitted laser beam encounters on its way to the farthest target. Therefore, it is also called the number of echoes. The first object hit by the laser is called the first pulse, and the last object is called the last pulse. In areas with dense vegetation, the first pulse typically captures the tree canopy, while the last pulse captures the ground surface, depending on the conditions. The more returns there are, the greater the number of middle pulses between the first and last pulses, resulting in a clearer representation of the tree structure.
Eye safety for eye-protection
In the case of drone laser surveying, the operator and people in the vicinity are required to keep eyes on the drone. Also, because the laser beams over a wide area, it can have an impact on people in the vicinity, and it is necessary to ensure safety for their eyes. Therefore, it is necessary to pay close attention to eye safety. International safety standards have been established for laser products to prevent eye injury.
The green laser in TDOT 7 GREEN is classified as “Class 3R”. To avoid the risk of instantaneous exposure to the naked eye, TDOT 7 GREEN is equipped with an eye-safe function.
Precision of Position and Attitude Measurement of the Laser System
Equipped with a high-performance INS that improves data output rate
In laser surveying, it is necessary to calculate how long it takes for the laser light to return from the target object hundreds of thousands of times per second. While the position where the laser light is emitted is measured by GNSS, it can only measure a few dozen times per second, causing significant errors in the position of the target object. Additionally, the measurement error in the laser light’s emission angle results in a positional deviation proportional to the distance to the target object. Therefore, the further the target object is, even a small error in the laser light’s emission angle can prevent obtaining accurate coordinates of the target object.
To address this, accelerometers capture the drone’s movements, and gyroscopes detect the drone’s continuously changing attitude. Combining these IMUs (Inertial Measurement Units) with GNSS forms what is known as an INS combined navigation (inertial navigation) system. By leveraging the strengths of both systems, a high-precision surveying system is achieved.
The INS in TDOT 7 GREEN is designed to provide high-precision surveying with an accuracy of several tens of millimeters, even while emitting laser light tens of thousands of times per second.
Real-Time Processing and Remote Transmission
In recent years, the frequency of earthquakes and heavy rain disasters has been increasing. To prepare for such urgent surveying needs, the TDOT 7 GREEN is equipped with real-time processing of survey results and real-time remote transmission capabilities.
The TDOT 7 GREEN features an LTE module, allowing it to obtain data from GNSS reference stations during survey flights and maintain an RTK (Real Time Kinematic) state. By performing real-time calculations with its built-in computer, the collected data can be transferred to remote servers or PCs as point cloud data. This functionality is highly effective for initial survey tasks that require immediate response.
*To use this feature, a separate SIM card capable of aerial mobile communication is required.
Equipped with Visible Camera / Thermal camera (Optional)
Images captured by the visible light camera can provide color information to the point cloud.
Additionally, since the images contain coordinate information, it is possible to create orthophotos with coordinates. By equipping the optional thermal camera, temperature information can be added to the point cloud, allowing for the visualization and understanding of conditions such as groundwater seepage from slopes. Various data embedded in the point cloud can enhance the visualization of relationships, characteristics, and trends of different phenomena.
*Separate SfM (Structure from Motion) software is required to create orthophotos.
Updated TDOT 7 Dedicated Application
You can access TDOT 7 GREEN by using WiFi communication on devices that support browsers, such as tablets and smartphones. The application allows you to check status information, set laser emission speed and scan rate, display real-time cross-sections, configure various settings for the visible light camera and thermal camera, and manage RTK usage. This enables more detailed settings and viewing capabilities.
Real-Time Display of Survey Data
You can check the measurement data in real-time during the survey. For example, by displaying cross-sections of the target objects, you can confirm the acquisition status of ground surface data beneath vegetation in areas with dense tree cover, or the reach of the laser light to the waterbed in aquatic areas, all in real-time during the flight. This allows you to verify on-site whether the survey is proceeding as planned, enabling efficient surveying operations without the need for rework.
*To view cross-sectional data during the flight, the drone must be equipped with an image transmission device that can connect to HDMI.
An Integrated Platform to Realize the Concept of Easy Surveying for Everyone
The laser scanner system is composed of number of precision devices, and setting each of them to optimal conditions is not an easy task. For those without specialized knowledge, it takes significant effort to master the procedures, often through many trials and errors, to achieve high-precision outputs. These complex operations required of the operators have been an obstacle to the widespread adoption of drone laser surveying.
TDOT 7 GREEN offers a platform that enables anyone to maximize its performance. It includes features such as performing alignment flights before and after the survey while entering the flight route, and downloading corresponding GNSS Reference station data with simple drag-and-drop operations to immediately combine with INS data for automatic optimal trajectory analysis. By using our platform, which incorporates our surveying service expertise, anyone can easily conduct accurate laser surveys.
Scanning and Preview Display
Verify scan data on-site through preview.
Supports efficient surveying without rework.
Optimal Trajectory Analysis with Cloud Services
Simply upload the necessary data to the cloud service for automatic trajectory analysis (optimal trajectory analysis) using INS data.
Linking Analysis Results and Data Output by PC
Integrate optimal trajectory analysis with scan data to output high-precision point cloud data.