Xgrid Lixel L3 Handheld LiDAR Scanner for Tunnel and Infrastructure Survey Malaysia

Xgrid Lixel L3 Handheld LiDAR Scanner for Tunnel and Infrastructure Survey Malaysia

Tunnels and infrastructure environments can be difficult to measure using conventional surveying methods alone.

They may contain restricted access, limited lighting, long corridors, irregular surfaces and areas without GNSS reception. Collecting individual points can also take considerable time when a complete three-dimensional record is required.

The Xgrid Lixel L3 Handheld LiDAR Scanner uses LiDAR and SLAM technology to capture dense 3D data while the operator walks through the site. It can support tunnel documentation, infrastructure inspection, as-built surveys and digital-twin projects in Malaysia.

Why Tunnel Surveying Is Challenging

A tunnel is a demanding environment for any mobile mapping system.

Common challenges include:

No GNSS signal

Repetitive geometry

Long distances

Limited lighting

Curved and irregular surfaces

Water and reflective materials

Moving vehicles or machinery

Restricted working periods

Dust and poor visibility

Safety and access controls

A successful tunnel survey requires suitable equipment, careful route planning and independent verification.

How the Xgrid Lixel L3 Works in a Tunnel

The Xgrid Lixel L3 uses SLAM to estimate the scanner’s position while moving through a GNSS-denied environment.

LiDAR measures the surrounding surfaces while the operator walks through the tunnel. The system combines successive measurements to create a three-dimensional point cloud.

Depending on access and visibility, the scanner may capture:

Tunnel walls

Crown and invert

Structural linings

Platforms and walkways

Pipes and cable trays

Drainage features

Equipment cabinets

Signs and safety installations

Openings and cross passages

Visible surface conditions

Only visible external surfaces can be captured. The scanner cannot see through tunnel linings, soil, rock or concealed structures.

Xgrid Lixel L3 Key Specifications

SpecificationXgrid Lixel L3Available configurations16-channel and 32-channelScanning range0.7–120 metresPoint-cloud rate320,000 or 640,000 points per secondLiDAR field of viewApproximately 360° × 270°Post-processed relative accuracyUp to 5 mm under stated test conditionsPoint-cloud thickness≤5 mmPost-processed absolute accuracyApproximately 2 cm RMSEReal-time relative accuracyApproximately 1 cmReal-time absolute accuracyApproximately 2.5 cm RMSECamera systemOne front camera and two panoramic camerasImage resolution4096 × 3072Internal storage1 TB UFSTypical operating timeApproximately 100 minutesWeightApproximately 2.5 kg including batteryProtection ratingIP54Operating temperature-20°C to 50°C

Actual performance depends on tunnel geometry, operating conditions, scan planning, survey control and processing workflow.

SLAM in GNSS-Denied Environments

GNSS and RTK normally cannot operate inside a tunnel.

The Xgrid Lixel L3 therefore relies mainly on SLAM to calculate its movement and build the point cloud.

SLAM performs best when the environment contains identifiable geometric features. Long tunnels with repeated shapes can make positioning more difficult because one section may appear similar to another.

Good tunnel scanning practice may include:

Using survey-control points

Capturing cross passages and equipment

Maintaining sufficient overlap

Moving at a controlled speed

Avoiding sudden rotations

Dividing long tunnels into manageable sections

Creating loop closures where possible

Checking alignment during processing

Control and check points are particularly important when the final data must match a project coordinate system.

Faster Mobile Data Capture

A handheld scanner allows the operator to move continuously through accessible areas instead of establishing a stationary scan position every few metres.

This can improve field efficiency for:

Preliminary tunnel documentation

Existing-condition surveys

Maintenance records

Utility-location recording

Construction progress capture

Visualisation

Digital-twin development

The actual time saving depends on access conditions, tunnel length, required accuracy and the final deliverables.

Tunnel As-Built Documentation

Construction drawings may not reflect every adjustment made during excavation, lining, M&E installation or subsequent maintenance.

The Xgrid Lixel L3 can help record visible completed conditions, including:

Tunnel geometry

Cross passages

Platforms

Equipment positions

Cable routes

Pipe routes

Safety installations

Access points

Visible structural features

The point cloud may support the preparation of sections, profiles, drawings, Mesh models or other project documentation.

A registered point cloud is not automatically a finished engineering drawing. Additional extraction and drafting work may be required.

Tunnel Cross-Sections and Profiles

A processed point cloud can be used to extract cross-sections at selected chainages.

Possible uses include:

Reviewing tunnel dimensions

Recording clearance

Comparing selected sections

Supporting lining documentation

Preparing engineering drawings

Reviewing spatial relationships with installed services

The reliability of the extracted sections depends on the scan quality, registration, control network and required project tolerance.

Clearance Assessment

Tunnel projects may require clearance information for vehicles, railway systems, equipment or maintenance access.

LiDAR data can provide a spatial reference for reviewing available space around visible objects.

However, clearance decisions must be based on:

Verified point-cloud accuracy

Correct project coordinates

Suitable control points

Approved clearance envelopes

Independent checks

Professional engineering assessment

The Xgrid Lixel L3 should not be used for a critical clearance decision without proper verification.

Infrastructure Applications Beyond Tunnels

The Xgrid Lixel L3 may also support the documentation of other infrastructure environments, including:

Underpasses

Bridges

Culverts

Utility corridors

Drainage structures

Railway facilities

Roadside structures

Underground stations

Industrial access passages

Confined infrastructure spaces

Every environment has different safety, accuracy and access requirements.

Coloured Point Clouds in Low-Light Areas

The Xgrid Lixel L3 includes HDR cameras for recording visual information together with the LiDAR data.

A coloured point cloud can help users recognise:

Pipes and cable trays

Signs

Equipment cabinets

Surface materials

Safety markings

Visible defects

Water staining

Access points

Lighting conditions may affect image quality and colour results. Additional lighting or another inspection method may be required in very dark locations.

3D Models for Infrastructure Visualisation

Depending on the selected software workflow, Xgrid Lixel L3 data can be processed into:

Standard point clouds

Coloured point clouds

Mesh models

3D Gaussian Splatting models

3D Tiles

Site images

A point cloud is appropriate for measurement and technical analysis.

Mesh and 3D Gaussian Splatting models may be useful for presentations, remote review, digital-twin visualisation and project communication.

Technical measurements should be taken from the appropriate verified dataset.

Supported Output Formats

Available output formats may include:

Point clouds: LAS, RCP, E57, PLY and iLAS

Images: JPG

Mesh models: OSGB and OBJ

3D Gaussian Splatting: LCC2, LCC and PLY

Other formats: 3D Tiles and USD

Compatibility with the customer’s CAD, BIM, GIS or infrastructure-management software should be confirmed before starting the survey.

Understanding the 5 mm Specification

The Xgrid Lixel L3 states a post-processed relative accuracy of up to 5 mm under specified test conditions in an environment of approximately 500 square metres.

A long tunnel is different from a controlled 500-square-metre test environment.

The 5 mm figure should therefore not be interpreted as a guarantee that the entire tunnel will achieve 5 mm absolute accuracy.

The stated post-processed absolute accuracy is approximately 2 cm RMSE, subject to suitable control, positioning and processing conditions.

In long GNSS-denied environments, SLAM drift can accumulate. Survey control and independent check points are essential when the project requires dependable coordinates.

Xgrid Lixel L3 and Total Station Control

The Xgrid Lixel L3 and a total station can be used together.

A possible workflow is:

Establish control points with appropriate survey equipment.

Position control targets throughout the tunnel.

Capture the visible tunnel environment with the Xgrid Lixel L3.

Process and align the point cloud.

Compare independent check points.

Confirm whether the results meet the project tolerance.

Extract the required sections, profiles or measurements.

The total station provides controlled reference points, while the Xgrid Lixel L3 captures dense surrounding geometry.

16-Channel or 32-Channel for Tunnel Surveying?

The Xgrid Lixel L3 16-channel version captures up to 320,000 points per second. It may be suitable for shorter tunnels, culverts and general infrastructure documentation.

The 32-channel version captures up to 640,000 points per second and may be more appropriate for:

Longer tunnels

Larger underground facilities

Faster mobile scanning

Complex M&E installations

Higher-density point-cloud requirements

Large infrastructure projects

The final selection should consider tunnel length, required point density, processing capacity and project budget.

Tunnel-Survey Limitations

Before selecting a handheld SLAM scanner, consider the following limitations:

GNSS is generally unavailable.

Long repetitive geometry may increase drift.

Water can affect surface returns.

Dust may create noise.

Moving vehicles can interfere with the point cloud.

Glass and reflective materials may cause irregular data.

Dark areas may reduce colour-image quality.

Restricted access may prevent full coverage.

A 100-minute operating time may require battery planning.

IP54 protection does not make the scanner waterproof.

The equipment must be used within the manufacturer’s environmental and operating limits.

Safety Requirements

Tunnel and underground surveys may involve serious hazards.

Before entering the site, confirm:

Access authorisation

Permit-to-work requirements

Traffic control

Railway or equipment shutdown procedures

Ventilation conditions

Gas-testing requirements

Lighting

Emergency communication

Personal protective equipment

Confined-space procedures

Rescue arrangements

The Xgrid Lixel L3 is a surveying and reality-capture instrument. It does not replace gas detectors, ventilation checks or other safety equipment required by the site.

Recommended Tunnel Scanning Workflow

A practical workflow may include:

Review the tunnel length and access points.

Define the required accuracy and deliverables.

Establish survey control and check points.

Divide long tunnels into manageable sections.

Plan the scanning route and overlap.

Confirm safety and access arrangements.

Capture the authorised areas.

Check data coverage.

Process and align the point cloud.

Verify independent check points.

Extract the required sections or models.

Report limitations and achieved accuracy.

The methodology should be approved before data collection begins.

Questions Before Requesting a Quotation

Before planning an Xgrid Lixel L3 tunnel or infrastructure survey, confirm:

What is the tunnel length?

What is the approximate diameter or width?

Is the tunnel operational?

What accuracy is required?

Are control points available?

What final outputs are required?

Are cross-sections or profiles required?

Is a photorealistic model needed?

What safety restrictions apply?

Are there dust, water or gas hazards?

Is the 16-channel or 32-channel version more suitable?

Which software will receive the data?

These details determine the equipment configuration, field methodology and processing scope.

Request an Xgrid Lixel L3 Infrastructure Solution in Malaysia

The Xgrid Lixel L3 offers a mobile method for capturing tunnels, underpasses, utility corridors and other infrastructure environments.

For professional projects, handheld LiDAR data should be combined with appropriate survey control, accuracy verification and site-safety procedures.

Contact MTM Precision Sdn. Bhd. to discuss the Xgrid Lixel L3 for tunnel documentation, infrastructure surveys, as-built capture and digital-twin applications in Malaysia.

Contact MTM Precision

MTM Precision Sdn. Bhd. (744811-A)

Telephone: +603-8080 7172

WhatsApp: +6016-660 7346

Email: mtmpre@yahoo.com / enquiry@mtmpre.com.my

Website: www.mtmpre.com.my

Showroom & Service Centre:

No. 29-1 & 29-2, Jalan Bandar 18,

Pusat Bandar Puchong,

47160 Puchong, Selangor, Malaysia.