What data does a lidar point cloud contain?

The emergence of UAV lidar has changed the way of traditional surveying and mapping, and greatly improved operational efficiency. UAV lidar point cloud contains rich data information. What do these data information mean? Let's take a look.

XYZ coordinate information

According to the obtained XYZ coordinates, the three-dimensional structure information of the measured object can be directly obtained. The three-dimensional structure information is the carrier of other geographic information, and based on this, the processing and processing of the later data results can be carried out.

Echo times

The number of echoes is the total number of echoes for a given pulse. Laser pulses emitted from lidar systems are reflected off the ground and objects on the ground: vegetation, buildings, bridges, and more. An emitted laser pulse may return to the lidar sensor in the form of one or more echoes. Any emitted laser pulse traveling toward the ground that encounters multiple reflective surfaces will be split into as many echoes as there are reflective surfaces.
 
Most current commercial LiDARs can provide multiple echo data, even infinite echoes. The echo characteristic enables LiDAR to penetrate vegetation and acquire more ground points, so it is more suitable for areas with dense vegetation.

Strength information

Intensity is a measure (collected for each point) that reflects the strength of the lidar pulse echo that generated a point. Different ground objects have different degrees of reflection to lidar, and different ground objects are distinguished by intensity signals. For example, power lines, towers, and vegetation can be distinguished by their intensity. In addition, since the intensity of noise also has characteristics, it is very effective for noise removal during scanning.

Category

Each post-processed lidar point may have a classification that defines the type of object that reflects the lidar pulse. Lidar points can be classified into many categories, including ground, bare surface, top of canopy, and water.
RGB (red, green, blue) bands can be used as attributes of lidar data. This property typically comes from imagery acquired during lidar measurements.

GPS time

GPS timestamp of the laser point emitted from the aircraft. This time is expressed in seconds of a GPS week.

Scanning angle

The scan angle is a value between -90 degrees and +90 degrees. At 0 degrees, the laser pulse is nadir directly below the aircraft. At -90 degrees, the laser pulses are on the left side of the aircraft; at +90 degrees, the laser pulses are on the right side of the aircraft, in the same direction as the flight.

Scanning direction

The scanning direction is the travel direction of the laser scanning mirror when the laser pulses are emitted outward. A value of 1 represents a positive scan direction, while a value of 0 represents a negative scan direction. Positive values indicate that the scanner is moving from the left to the right of the trajectory flight direction, while negative values do the opposite.

FDG-260X has a maximum measuring range of 300m, and the product weight is only 0.99kg, which maximizes the operation time. The maximum laser point frequency is 1920000pts/s, three echoes, and strong penetrability. At the same time, the camera is deeply integrated, and the point cloud and image are collected simultaneously. . FDG-260X is widely used in terrain mapping, power channel inspection, forestry survey, digital city and other industries, and is suitable for large-scale data collection.

System parameters

Point cloud accuracy: 10cm@150m
Point cloud density: 42pts/m²@100m@10m/s
Equipment weight: 0.99Kg
System power consumption: 20W
Storage space: Internal flash memory 64G+128G SD card
Power Range: 12-24V
Appearance size: 11.8cm*11.5cm*11cm
Working temperature: -20℃-55℃
Platform: Airborne, Vehicle

POS performance

Model: gSpin310
Data update frequency: 200Hz
GNSS signal type: GPS L1/L2; GLO L1/L2; GAL E1/E5b; BDS B1/B2a/B3
Positioning accuracy: horizontal 0.02m, elevation 0.03m
Pitch angle accuracy: 0.005°
Roll angle accuracy: 0.005°
Heading angle accuracy: 0.017°

Laser performance

Range: maximum range 300m
Ranging accuracy: ±2cm
Number of lines: 32 lines
Horizontal field of view: 360°
Vertical field of view: 40.3°
Dot frequency: 1.92 million dots/second (three echoes)

camera

Pixels: 26 million
Field of view: 83°

Shooting Mode: Isochronous/Isometric