LiDAR (Light Detection and Ranging)

The LiDAR laser system records distance measurements from the scanning laser on the aircraft to terrain features. The LiDAR system virtually paints the surface of the earth with laser pulses that record the elapsed time until the return of the pulse. When this data is combined with information about the position and attitude of the sensor the result is a dense sampling of elevation points.

LiDAR data can be collected day or night. The LiDAR system operates accurately in shadow as well as bright light. Additional benefits to nighttime data collection include fewer clouds, calmer air, and reduced air traffic over major urban areas. Because of the flexibility offered by Horizons' LIDAR system, raw data can be acquired, processed, and delivered in a matter of days or weeks instead of months.

The LiDAR instrument measures multiple echoes from a single laser pulse. Multiple echoes allow vegetation to be easily detected both for removal in the production of "bare earth" digital elevation models, and in forest structure analysis.

Other instruments involved in the collection of LiDAR elevation data are Airborne GPS (Global Positioning Systems) to derive the geographic location (latitude, longitude and ellipsoid height) of the instrument and the IMU (Inertial Measuring Unit) to derive the attitude (roll, pitch and yaw) of the instrument.

Horizontal accuracy ranges (depending on flying height) between 0.4 meter and 1.5 meter. Vertical accuracy ranges between 0.15 meter and 0.6 meter.

For many mapping applications, LiDAR offers cost savings while
maintaining accuracy and providing shorter delivery schedules