LS Lidar LS25D 500m Railway Intrusion Detection LiDAR

High Resolution LiDAR for Railway Intrusion Detection

The LS Lidar LS25D is a long-range hybrid solid-state LiDAR developed specifically for railway monitoring and fixed-point intrusion detection. It uses a 1550 nm laser system and a wide 120° horizontal by 25° vertical field of view to monitor the track and surrounding corridor for people, animals, vehicles, debris and other objects that may create a safety risk.

Unlike a general-purpose mobile LiDAR, the LS25D is designed to be installed at a fixed position alongside or above the railway. Its strength is not high frame-rate vehicle perception, but detailed long-range scanning with very fine angular resolution. This allows the sensor to identify relatively small objects at substantial distances along the track.

200 Metre Detection at 10 Percent Reflectivity

The LS25D is specified for detection from approximately 1.5 to 200 metres at 10% target reflectivity, with a maximum detection range of up to 500 metres under suitable conditions.

The 10% reflectivity specification is particularly relevant for railway monitoring because many real-world obstacles are dark or return relatively little laser energy. Materials such as tyres, dark clothing, rocks and weathered infrastructure can be more difficult to detect than bright reflective targets. Stating the 200 m performance at 10% reflectivity therefore gives a more practical indication of what the LiDAR can do in the field than quoting maximum range alone.

Detect Small Objects at Long Distance

A defining feature of the LS25D is its ability to combine long-range detection with very fine angular resolution. LS Lidar specifically developed the sensor to identify small foreign objects within railway corridors, where early detection can give operators more time to assess and respond to hazards.

Manufacturer testing describes the LS25D as capable of detecting approximately 20 × 20 cm objects at 200 m. The sensor’s dense angular sampling can place several LiDAR measurement points on an object of this size, helping processing software distinguish it from the surrounding track environment.

120 Degree by 25 Degree Field of View

The LS25D provides a broad 120° horizontal field of view and 25° vertical coverage. This geometry is designed around railway corridors, allowing the sensor to observe a wide section of the tracks and surrounding area from one fixed mounting point.

The vertical field of view extends approximately ±12.5° around the sensor centreline. Correct mounting angle and installation height are important so the measurement area covers the intended track section while maintaining sufficient point density at the longest required distance.

Very Fine Angular Resolution

The newer LS25D specification lists horizontal angular resolution of approximately 0.0311°. Vertical resolution can be configured at approximately 0.05°, 0.025° or 0.0125° depending on the selected operating frequency.

Fine angular resolution means neighbouring measurements are positioned very close together. At long range, this helps maintain enough measurement points on smaller objects to allow them to be detected and classified by the monitoring system.

Adjustable High Density Scanning

The LS25D supports frame rates of approximately 0.25, 0.5 and 1 Hz. These values are lower than those of automotive obstacle-detection LiDAR because the sensor is optimised for extremely dense fixed-area scanning rather than rapidly refreshing a moving vehicle environment.

For a railway installation, this trade-off is practical. Trains and railway infrastructure follow a defined corridor, and a high-density point cloud can be more useful for reliably identifying smaller foreign objects than a very high refresh rate with fewer measurements per scan.

±2 cm Range Accuracy

The current LS Lidar brochure specifies ±2 cm range accuracy for the LS25D. This supports consistent positioning of detected objects within the monitored rail corridor.

Range accuracy describes the LiDAR measurement itself. The final position assigned to an obstacle will also depend on the mounting survey, sensor orientation, system calibration and any GNSS or coordinate transformation used to relate the LiDAR data to the railway infrastructure.

1550 nm Hybrid Solid State LiDAR

The LS25D uses a 1550 nm laser architecture. This wavelength allows LS Lidar to design the system around long-range detection while maintaining Class 1 eye-safety requirements under specified operating conditions.

The hybrid solid-state scanning architecture also avoids the continuously rotating external head found on many 360° mechanical LiDAR sensors. For a permanent trackside installation, the fixed 120° viewing area can be directed exactly where monitoring is required.

Railway Intrusion and Foreign Object Detection

The main purpose of the LS25D is to identify objects that should not be present within the railway corridor. Depending on the software connected to the sensor, detected objects can include pedestrians, animals, vehicles, rolling stones, fallen objects and other obstacles.

The LiDAR supplies distance and 3D contour information to the monitoring system. Detection or classification software can then determine whether an object enters a defined safety zone and generate an alert for railway operators or connected safety systems.

Industrial Ethernet Integration

The current LS25D uses Automotive Ethernet for point-cloud communication. Earlier documentation refers to Industrial Ethernet, so buyers integrating into an existing railway monitoring platform should confirm the exact interface supplied with the current hardware revision.

Ethernet output allows the dense point-cloud stream to be transferred to an industrial computer or railway monitoring controller where detection, classification and alarm logic can be performed.

12 to 36 VDC Power Input

The LS25D supports a 12–36 VDC input range and has a specified power consumption below approximately 30 W. This broad supply range simplifies integration into fixed infrastructure cabinets and railway monitoring installations using common industrial DC power systems.

For a permanent outdoor installation, power supply stability, surge protection, grounding and correct network isolation should be considered together with the LiDAR itself.

Designed for Permanent Outdoor Installation

The current LS25D specification gives an IP6K9K protection rating and an operating temperature range from approximately -40°C to +75°C. This allows the unit to be integrated into systems operating outdoors throughout the year.

The housing measures approximately 247.5 × 230.03 × 79 mm and weighs no more than around 2 kg. Its fixed installation should provide a rigid mounting point with a clear view of the monitored railway corridor.

Typical Applications

• Railway track intrusion detection
• Foreign object detection on railway lines
• Pedestrian and animal detection around tracks
• Rockfall and falling-object monitoring
• High-risk railway section monitoring
• Railway crossing and infrastructure safety systems
• Fixed long-range 3D corridor monitoring

LS25D Compared with the LS25E

The LS25D and LS25E are designed for different railway applications. The LS25D is primarily intended for fixed trackside monitoring and uses a lower frame rate with very fine resolution to detect small objects at long distances.

The LS25E is intended for vehicle or train-mounted use. It offers faster 10 or 20 Hz scanning and a longer specified 10% reflectivity range of approximately 250 m, making it better suited to continuously updating the scene ahead of a moving train.

For permanent monitoring of a high-risk section of track, the LS25D’s dense fixed-area scan is the more appropriate configuration. For onboard forward detection, the LS25E is the model designed around that workflow.

Buying the LS Lidar LS25D from Global GPS Systems

Global GPS Systems supplies professional LiDAR, GNSS and positioning equipment for infrastructure, surveying, transport and industrial monitoring projects worldwide. Our team can help evaluate the required detection distance, mounting geometry and system integration requirements for an LS25D railway monitoring installation.

For projects where the LiDAR must be tied into a surveyed coordinate system or combined with GNSS, cameras or other sensors, Global GPS Systems can also help select compatible positioning and measurement equipment for the complete installation.