Geosun GS 120G 120m Handheld SLAM LiDAR Scanner

Fast handheld 3D mapping with SLAM LiDAR

The Geosun GS-120G is a portable SLAM LiDAR mapping system developed for surveyors, engineers, construction teams, GIS professionals, mine operators and 3D-mapping specialists who need to capture complete environments quickly. Instead of measuring individual points or repeatedly repositioning a static laser scanner, the operator can walk through the project area while the GS-120G continuously records the surroundings and builds a three-dimensional point cloud.

The system combines LiDAR, GNSS, inertial navigation and SLAM algorithms in one unit. This allows it to work outdoors with satellite positioning as well as indoors, underground or between buildings where GNSS reception becomes unreliable.

32-channel LiDAR with 1.28 million points per second

The GS-120G uses a 32-channel laser scanner capable of recording up to 1,280,000 points per second. The high measurement rate helps create dense point clouds while the operator is moving, providing detailed geometric information for walls, floors, terrain, structures, machinery, stockpiles and other objects.

For fieldwork, the amount of detail collected depends on walking speed, distance to the surfaces and the route used through the site. Moving more slowly or passing closer to important objects generally increases the amount of usable information captured in those areas.

120 metre measuring range

The GS-120G offers a maximum LiDAR measuring range of approximately 120 m. Geosun also specifies approximately 80 m at 10% target reflectivity in its product material, illustrating how surface reflectivity influences practical working distance.

This range makes the scanner suitable for much more than room-scale scanning. It can be used in large industrial buildings, underground garages, mine workings, urban streets, outdoor terrain and other environments where surfaces may be tens of metres away from the operator.

SLAM mapping where GNSS is unavailable

A key feature of the GS-120G is its SLAM technology. SLAM, or Simultaneous Localization and Mapping, allows the system to calculate its movement by comparing the surrounding geometry between successive scans while building the point cloud at the same time.

In practical terms, this means the operator can continue surveying inside buildings, tunnels, underground garages and other GNSS-denied environments. The system does not need continuous satellite reception to maintain the local mapping trajectory, which is a major advantage compared with conventional GNSS-only surveying equipment.

SLAM RTK-SLAM and PPK-SLAM workflows

The GS-120G supports SLAM, RTK-SLAM and PPK-SLAM mapping methods. Standard SLAM is useful for fully indoor or underground work. RTK-SLAM can use real-time GNSS corrections when satellite signals and correction services are available, while PPK-SLAM allows GNSS trajectory information to be processed after data collection.

This gives survey teams flexibility on mixed projects. An operator can begin outside with GNSS positioning, walk into a building or covered environment and continue collecting data using SLAM without having to stop the survey and switch to a completely different instrument.

GNSS and INS for georeferenced surveys

The GS-120G uses the Geosun gSpin 210 GNSS/INS positioning system with a 200 Hz IMU update rate. It supports GPS, GLONASS, Galileo and BeiDou satellite signals and provides the positioning information needed to connect SLAM data to a real-world coordinate system when GNSS is available.

The published specifications list GNSS positioning accuracy of approximately 2 cm horizontally and 3 cm vertically under suitable positioning conditions, together with pitch and roll accuracy of 0.015° and heading accuracy of 0.040°. These positioning values describe the GNSS/INS unit itself; final point-cloud accuracy also depends on the survey environment, SLAM trajectory, control and processing workflow.

Up to 5 cm absolute point-cloud accuracy

The GS-120G is specified with an absolute point-cloud accuracy of ≤5 cm. This makes it suitable for many mapping, documentation, volume and spatial-analysis workflows where collecting a complete 3D representation quickly is more important than millimetre-level static scanning.

For engineering work with strict tolerances, surveyors should still use suitable control and independent checks. SLAM accuracy can be influenced by route length, environment geometry, repetitive structures, walking speed and whether the survey route contains useful loop closures.

Wide 270 by 360 degree field of view

The laser scanner provides approximately 270° vertical and 360° horizontal coverage. This wide field of view allows the GS-120G to record nearly the complete environment around the operator rather than scanning only in one direction.

For indoor surveys this means floors, ceilings, walls and structural elements can be collected during the same walking pass. In tunnels, streets or industrial spaces, the scanner can capture geometry on both sides and above the user without constant manual aiming.

Dual 20 MP cameras for coloured point clouds

The GS-120G includes two 20 MP cameras with approximately 270° horizontal image coverage. The camera data can be combined with the LiDAR geometry to create coloured point clouds and make the resulting dataset easier to interpret.

Colour is particularly useful when users need to distinguish road markings, construction materials, façade details, pipes, signs or other objects that may have similar shapes in an uncoloured point cloud.

Construction and building documentation

For construction professionals, the GS-120G provides a fast way to document existing site conditions and capture building interiors. Walking through a floor, warehouse or construction zone can produce a complete spatial record that can later be used for dimensional checks, renovation planning, progress documentation and compatible BIM or CAD workflows.

The main advantage is speed and completeness. Instead of collecting only selected survey points, the operator records the surrounding surfaces continuously, providing a richer record that can be revisited in the office.

Underground garages tunnels and mines

The GS-120G is particularly useful in underground environments because its SLAM workflow does not depend on continuous satellite visibility. Geosun lists underground garages and mine surveying among the intended applications of the system.

Operators can walk through passages, mine workings or covered structures and record the surrounding geometry as they move. This can support tunnel profiles, mine documentation, clearance checks, spatial inventories and other tasks where GNSS rovers cannot operate normally.

Stockpile and volume surveys

Stockpile measurement is another stated GS-120G application. The scanner can be walked around piles of aggregate, coal, soil or other material to produce a dense 3D representation of the surface.

Once processed in compatible software, these point clouds can be used for volume calculations, inventory records and comparison between surveys. This can be useful for construction companies, quarries, mines, recycling facilities and industrial yards where stockpile quantities change regularly.

Urban mapping and narrow spaces

The compact handheld format is also useful in urban areas where vehicle-mounted or UAV mapping systems may not have access. Geosun has demonstrated the GS-120G for mapping a narrow urban alley, capturing building façades, road surfaces and street features while GNSS visibility was partly obstructed.

For GIS and smart-city work, this type of mobile scanning can fill gaps between airborne data, vehicle mapping and traditional terrestrial surveys, especially in pedestrian zones, narrow streets, courtyards and other confined spaces.

Handheld and backpack operation

The dedicated GS-120G datasheet lists both handheld and backpack operation. This gives users different ways to carry the system depending on the length of the survey and the working environment.

The listed system weight is approximately 2.15 kg with battery. Battery capacity is 11,600 mAh, with a stated operating time of around two hours. Internal storage is 128 GB, providing space for extended point-cloud collection in the field.

Designed for real field conditions

The GS-120G is specified for operating temperatures from approximately -20°C to +55°C. Power consumption is around 25 W and the system operates from a 12–18 V supply.

For field crews, the combination of portable weight, internal storage and battery operation means the scanner can be taken through sites without needing a permanent external power connection or large supporting setup.

Point-cloud processing workflow

Geosun provides PointCloudCreater for point-cloud preprocessing. The software uses the recorded LiDAR, trajectory and positioning data to generate the finished point cloud, after which the data can be taken into compatible surveying, CAD, BIM, GIS, mining or specialist 3D-processing software depending on the required deliverable.

An optional Point Cloud Automata workflow is also available for point-cloud classification and post-processing. This can be useful where larger datasets need further separation or processing after the initial SLAM point cloud has been created.

Who is the Geosun GS-120G for?

The GS-120G is especially relevant for surveyors, construction teams, civil engineers, GIS professionals, mine operators, BIM specialists and mobile-mapping companies that need to capture large amounts of 3D information quickly. Its combination of SLAM, GNSS and high-density LiDAR makes it particularly useful for projects that move between outdoor and GNSS-denied environments.

Buying the Geosun GS-120G from Global GPS Systems

The right SLAM scanner should be selected according to the required accuracy, site dimensions, working environment, survey duration and final data format. Global GPS Systems can help determine whether the Geosun GS-120G fits your application and advise on the correct workflow for control, GNSS positioning, field collection and point-cloud processing.