Airborne LiDAR Technology: Precision Elevation Mapping and Real-World Coordination

Explain how LiDAR is used in airborne laser scanning for gathering elevation information data

with accurate real-world coordinates.

2. Laser Emission: The LiDAR system emits rapid laser pulses—typically in the near-infrared spectrum—from the aircraft towards the ground. The laser pulses are emitted at a high frequency (up to several hundred kHz), ensuring dense coverage of the surveyed area.

3. Pulse Propagation and Reflection: As the laser pulses travel towards the Earth's surface, they encounter various objects and terrain features such as trees, buildings, and the ground itself. Upon striking these surfaces, part of the laser light is reflected back towards the LiDAR sensor.

• GPS and IMU Integration: Aircraft carrying the LiDAR sensor are equipped with Global Positioning System (GPS) receivers and Inertial Measurement Units (IMUs). The GPS provides accurate position coordinates (latitude, longitude, altitude) of the aircraft, while the IMU measures the orientation and motion parameters (pitch, roll, yaw). Integration of GPS and IMU data with LiDAR measurements allows for precise georeferencing of each laser pulse.

• Georeferencing and Calibration: During post-processing, the collected LiDAR data is georeferenced using ground control points (GCPs) and the GPS/IMU data. GCPs are surveyed points with known coordinates on the ground, which are used to align and calibrate the LiDAR point cloud to the Earth's coordinate system (e.g., WGS84).

• Forestry and Agriculture: Assessing forest canopy structure, biomass estimation, and crop health monitoring.

• Environmental Monitoring: Mapping and monitoring changes in landscapes, vegetation cover, and coastal erosion.