DJI Tutorial Video

This tutorial video explains how to collect LiDAR data using the XenMuse L2. It covers topics such as RTK settings, area route planning, payload settings, route parameter settings, advanced settings, waypoint route planning, live mission recording, and data collection checklist. It provides detailed instructions on how to set up and configure the equipment, plan flight routes, and optimize data collection settings for accurate and efficient LiDAR mapping. Welcome to the DGI tutorial video. In this video, you will learn how to collect LiDAR data using the XenMuse L2. XenMuse L2 supports Matrice 350 RTK and M300 RTK with RC+. Please upgrade to the latest firmware before use. RTK Settings Install the L2 onto the Matrice 350 RTK single downward gimbal connector. Turn on the remote controller and the aircraft. Open the DGI Pilot 2 app and perform a self-check. Using LiDAR requires centimeter-level positioning data and high-precision inertial navigation data. In the Flight View, General Settings, and Precise Positioning Settings, you can choose RTK or PPK to obtain centimeter-level positioning data. If the survey area has network RTK signals or you can set up a dRTK2 station on a known point, you can enable the RTK Positioning function to obtain CORS data in real-time. It is recommended to turn off Maintain Positioning Accuracy mode. RTK service types include dRTK2 Mobile Station, Network RTK, and Custom Network RTK. For example, in sequence using Custom Network RTK, fill in the nTRIP address, port, account password, and amount point information. When the status bar displays RTK Connected and the RTK Setting page shows Fix, it indicates that RTK is ready to use. You can also use PPK. Turn off the RTK function and set up the dRTK2 Mobile Station on a known point. Add the dRTK2 Mobile Station and the L2 LiDAR data to DGI Terra during data processing. Through the PPK feature, you can obtain accurate positioning data. Area Route. After completing the self-check, click Flight Route to enter the route library. Click Plus to create a new route. If you want to import a pre-planned route file, you can do so using the Import Route feature. You can also go to the camera view, click the Route icon, and click Plus to create a new route. This video uses Area Route as an example. Area Route is suitable for mapping scenarios and can obtain accurate DEM data. Click Area Route to enter the route edit page. Adjust the survey area on the map by clicking and dragging boundary points. Click Plus between the boundary points to add a new one. Click Delete to remove a selected point. Click Clear to remove all points. After planning, click the Complete button to confirm the mapping area. Choose the aircraft, select L2. For LiDAR mapping, point cloud data is collected using LiDAR sensor. For photogrammetry, photos are taken by the visible light camera. This video uses LiDAR mapping as an example. Click Payload Settings. For Return Mode, it's recommended to choose Penta Return, which means it can receive up to 5 returns for each laser pulse. Penta Return increases the point cloud density, and you can reduce it to triple due to sparse ground vegetation and low altitudes, such as 5 meters. The sampling rate should be 240 kHz, which means L2 emits 240,000 laser pulses per second. The scanning modes are non-repetitive and repetitive. For mapping users, it is recommended to choose Repetitive for higher mapping accuracy and better point cloud density. For more façade information, non-repetitive is suggested as it has a broader scanning range. Regarding dense ground vegetation or lower accuracy requirements, such as a scale of 1 to 20,000, non-repetitive is also recommended for more ground points. RGB coloring is enabled by default, and it will use a visible light camera to color the point cloud data. It should be turned off at night. The images collected by the visible light camera can also reconstruct 2D or 3D models. After completing the settings, click OK to enter the route parameter settings. Route Parameter Settings. Edit the route name, and it's recommended to select Ortho Collection. Ortho GSD refers to the GSD of the images collected by the visible light camera. Point cloud density refers to the average number of non-ground laser points theoretically present per square meter of area. For the altitude mode, you can choose from relative to takeoff point, above sea level, and above ground level. It is recommended to choose AGL, which will also enable terrain follow features. Click on the DSM files. The M350 supports both local import and download to obtain terrain data. Here, we use download as an example. Click on Download, and the app will download the terrain elevation data based on the survey area location, generating a flight route with varying heights to ensure the aircraft maintains the same altitude relative to the ground. It is recommended to set the terrain follow altitude to 150 meters. If the survey area is flat without elevation changes, you may select the altitude mode as Alt. Elevation optimization is recommended to be turned off. If tall obstacles exist between the route's takeoff and start point, you should set a safe takeoff altitude. This value should be higher than the obstacle height. The aircraft will climb vertically to this safe takeoff altitude, and then safely fly to the route's start point. It is recommended to turn on the IMU calibration. Once turned on, the aircraft will automatically decelerate and accelerate at the beginning and end during the yellow flight route part to ensure point cloud accuracy. The recommended flight speed is 15 meters per second. The course angle can be used to adjust the route direction. The default direction is parallel to the longer side of the survey area. Upon completion, it is recommended to set the action as return to home. Advanced settings. In the advanced settings, you can adjust the side overlap ratio for LIDAR and the forward overlap ratio for visible. The default side overlap of LIDAR is 20%. If you need to increase the point cloud density, or if there are significant variations in the terrain of the survey area, you can raise this value accordingly. If you need to get point cloud and ortho photo data simultaneously, setting the forward overlap ratio for visible at 70% is recommended. The side overlap ratio for visible will be adjusted based on the side overlap ratio for LIDAR. It is suggested to keep at 60%. The margins and the photo mode can remain at default settings. Turning off the custom camera angle for the LIDAR mission is recommended. You can change the starting point according to your needs. By clicking set, you can set another point as your start point. You can set the takeoff speed to maximum to improve work efficiency. Click on the save icon to save your mission. Waypoint route. Under waypoint route, you can select set waypoints or live mission recording. Set waypoints means adding and editing waypoints on the map view to create a flight route. Live mission recording automatically generates a flight route by recording the locations of the aircraft during the flight. This video will focus on using live mission recording in power line scenarios. Live mission recording. Enter the DGI Pilot 2 app camera view and click the route icon. Then click on plus waypoint route and live mission recording. Position the aircraft 50 meters away from the electrical tower at a height more significant than the top of the tower. Press the C1 button to add a waypoint at this position. To ensure the tower's visibility, it is recommended to set the waypoint height to be generally between 30 to 50 meters above the tower. This distance can be confirmed using the laser rangefinder feature. After aligning the gimbal camera with the target, press the C1 button to create a waypoint. For spans with a large sag, such as a difference of more than 50 meters, press the C1 button at about 30 meters above the maximum sag to add a waypoint. Add another waypoint 50 meters away from the final tower by pressing the C1 button. This ensures that point clouds for both the first and last hours are fully captured and that there is enough distance for the IMU calibration. After completion, click save to generate the flight route mission. Click on the flight route name, then click edit and choose add point on map to open the flight route and make any necessary edits. If additional waypoints are needed, choose edit in flight. Route parameters. Payload settings. Dual return, 240 kilohertz, non-repetitive scanning, RGB coloring enabled, altitude mode, ASL, EGM 96. Route settings. The safe takeoff altitude should be higher than any obstacles between the takeoff point and the first waypoint. If this value is less than the altitude of the first waypoint, after takeoff, the aircraft will climb to reach the first waypoint altitude before flying towards it. On the other hand, if the aircraft's altitude is higher than the first waypoint, it will maintain this height and then fly directly above the first waypoint before descending to the start waypoint. Climb to the start point. If the start point is higher than the safe takeoff altitude, the aircraft will fly straight towards the start point after reaching the safe takeoff altitude to save power and improve efficiency. If the start point is lower than the safe takeoff altitude, the aircraft will fly level and descend to the start point to ensure flight safety. Speed is inversely proportional to point cloud density. For a balance of efficiency and quality, a recommended speed is around 15 meters per second. Altitude, keep the default settings. Aircraft yaw, set to along the route. Gimbal control, set to manual and adjust the gimbal pitch angle when needed. Waypoint type, set to straight route. Aircraft stops. IMU calibration, turn it on. Upon completion, return to home is recommended. Waypoint settings. For the first waypoint, add a waypoint action for gimbal pitch rotation, which should be set to negative 90 degrees, then start point cloud modeling recording. Add a waypoint action for finish point cloud modeling recording at the final waypoint, which ends L2 data collection. Regarding speed, aircraft yaw, and waypoint type, follow route should be selected. ASL should not turn on follow route. Click save to save the mission. Data collection. Checklist before flight. In the map view, click start and go through the preflight checklist. The flight mode is in N mode. Check battery levels. RTK status is connected. Enough storage for the micro SD card. Make sure that the RTH altitude and the max altitude are set higher than the flight route altitude. For signal loss action, it's recommended to select return to home. Disable the max flight distance. The control stick mode should be set to the mode suitable to you. If the wind speed in the survey area is high or the battery is under high cycle counts, you should increase the customized battery warning values. For obstacle avoidance action, it is recommended to choose break and enable obstacle avoidance. Click next to set the signal loss action during the mission, which you can select continue or return to home as recommended. After completing the checklist, ensure the mission area is open and safe. Then upload and execute the flight mission. Data collection. Enter the flight view and monitor the point cloud and visible light view. You can switch between these views using the buttons on the edge of the screen. Pay attention to the RTK and IMU calibration status during flight. Use the laser range finder feature to check the real time distance to the ground. Press the R3 button to switch to the FPV flight view. Observe the flight environment to ensure safe operation. If a battery change is needed during the operation, it is recommended to use the battery hot swapping after landing. Click on execute and select resume. The aircraft will automatically return to the last waypoint and resume the mission. Once IMU calibration is finished, it will initiate the point cloud recording and continue the mission. Task quality report. After the mission is completed, a task quality report will be generated. Click to view the report. The quality report includes the flight route name and time of the task. The progress reflects the status when the task was completed. The point cloud data collection time is the total time from the start to the end of the point cloud capture process, excluding initial and final calibration. You can tap to switch between RTK and pause information. Click on RTK to show the RTK data collection duration and RTK statuses, which include fix, float, single, and invalid. These are represented with different colors. If the float single time is too long, you can use PPK for data processing to obtain high accuracy positioning data. Click on pause to show pause data collection duration, which is the total time from IMU calibration before point cloud collection to the end of IMU calibration after point cloud collection. Pause statuses include fix and invalid time duration. You can also go to the flight route library, click on a route, and view the task quality report. After completing the flight mission, please turn off the aircraft power, remove the micro SD card from L2, and connect it to a computer. You can check the recorded point cloud files, captured photos, and other files in the DCIM folder. Maintenance and log export. Dust and stains on the optical window can negatively affect the performance of the LIDAR sensor. If you notice any impurities on the LIDAR window, please follow these cleaning steps. A, use a compressed air cleaner. Before wiping the window with a cleaning cloth, use a compressed air cleaner to clean the targeted area on the window. Note, when particulate impurities like dust are on the window, directly wiping the window may scratch the glass and impact the LIDAR capabilities. B, wipe off stains. Use a damp lens cleaning cloth to wipe the window. A dry cloth may damage the window. If stains persist, use a mild soap solution to clean the window, then repeat step B to remove any soap residue. If the L2 shows any abnormalities during use, run the DGI Pilot 2 app and enter the health management system. Navigate to manage logs and select L2 to export logs to the micro SD card inside the L2 for subsequent analysis and processing.