Like any other field of activity, geodesy does not stand still, using modern advances in science and technology. Of course, one of the innovative solutions for surveying has become 3D laser scanning. This method of topographic surveying allows to obtain images of complex architectural and industrial objects, mine workings, quarries, etc. Laser scanning is an innovative technology of spatial data acquisition for various objects with the help of 3D scanners. Thanks to it we get an opportunity to transfer physical objects into a digital model of the highest accuracy. It is used in such areas as architecture, construction, medicine, mining, road infrastructure, linear structures, and of course, geodesy.
The principle of laser scanning
Special 3D scanners are used for laser scanning. They take up to a million measurements per second, so we get a cloud of points with spatial coordinates, which are the basis for receiving two- and three-dimensional models of the object. The data obtained are used for various measurements, analyses and calculations. There are currently three main types of laser scanners:
- pulse (TOF) scanners – calculate distance as a function of the time the laser beam travels to and from the object under study;
- Phase scanners – the method of data acquisition is based on determining the phase difference between the sent and received signals;
- triangulation 3D scanners – the principle of operation is based on solving a triangle, where in the role of spatial points: the transmitter, the object and the receiver of the signal.
Laser scanning methods
Depending on the nature of the field work and the object under study, we can distinguish 3 main methods:
- ground laser scanning – is carried out stationary for surveying complex industrial objects, open mine workings, as well as architectural structures of historical and cultural value;
- Mobile laser scanning – is applied for surveying of railways and highways, bridges and tunnels, as well as linear objects (pipelines, power lines, etc.). The essence of the method lies in the fact that the scanner is mounted on a vehicle, which allows you to scan in continuous motion;
- Airborne laser scanning – one of the varieties of aerial photography. The scanner is installed on a flying vehicle, which allows you to survey the land under the crown of trees, as well as in areas with dense buildings.
Laser Scanning Applications in Geodesy
In recent years, laser scanning has become very popular in geodesy and surveying. The main purpose of geodesic surveys is to obtain the most accurate and quick result with the highest level of detail.
The main advantages of laser scanning are:
- A three-dimensional model of the object is obtained in seconds,
- Accuracy of measurements is very high;
- Data collection is very fast – optimizing field work,
- Defects and deviations are easily detected – you only need to compare the resulting structure with the 3D design model;
- safe surveying of hazardous and hard-to-reach objects;
- topographic plans are acquired by means of virtual surveying;
- non-contact scanning method (remote sensing) enables easy work with architectural monuments;
In geodesy and surveying, 3D laser scanning is used for:
- conducting geodetic surveys;;
- drawing of topographic plans;
- performing as-built survey – control of civil and erection works, detection of deviations in accordance with design documentation
- calculating the volume of bulk material stockpiles, earthworks;
- control of stability of quarry sides, monitoring of landslide processes.
In modern geodesy laser scanning is a rapidly developing technology that allows to automate work processes, as well as to provide the most accurate results of the survey.
