LiDAR (LIght Detection And Ranging) in a nutshell
LiDAR is a remote sensing technology that measures distance by illuminating a target with a laser beam from a transmitting device and analyzing the reflected (returned) light.
If the exact position of the transmitter is known at the exact moment of the transmission of the pulse (done by way of high-end GPS technology), the position of the reflected surface (a laser point) can be accurately plotted in space, subject to the angular correction of the transmitter, also referred to as the IMU (inertial measurement unit).
If a pulse is repeatedly transmitted (frequency of transmission), a point cloud is created from which 3D image may be drawn of the surface that was illuminated. The higher the frequency that the surface is “painted” by the transmitter (referred to as the scanner), the more accurately the surface may be plotted. Accuracy of the 3D model all depends on the distance of the transmitter (called the scanner) from the target, the frequency of scanner, accuracy of the IMU, movement of the scanner through the air etc.
LiDAR surveys and more specifically helicopter-based corridor surveys are carried out by GeoM, our sister company based in Tswane, South Africa. By utilizing the aerial resources of Chopper Worx and the technology skills of 3DLM, highly accurate and cost effective survey data is provided.
- LiDAR point density at the tower structures in excess of 60 points/m2.
- The LiDAR point density between towers in excess of 20 points/m2.
- LiDAR point absolute accuracy better than 10cm.
- Ortho Photos better than 5cm GSD (Ground Sample Distance) are supplied to a minimum servitude width of 100 m.
- The minimum LiDAR swath width is 50 m either side of the power line centerline.
- Ortho Photos better than 15cm resolution.
- A 1.5 cm pixel resolution oblique imagery of tower hardware, taken from a stabilized aerial platform.
- High definition video of entire servitude, as well as of all defects.
- All data is geo-referenced and integrated into spatial multimedia software, compatible with ESRI GIS platform.
- Vegetation clearance modeling.
- Fully PLS CADD line models, accurate to engineering standards.
- We do in-field 1st stage processing, allowing us to check for consistency in the data and validation of coverage and quality.
- Data can be stored off-site on encrypted servers, allowing access to authorized personnel only.
- Weather stations are deployed together with the GPS base stations in the immediate survey area, recording low and high velocity wind vectors, ambient temperature, humidity, UV radiation etc.