Laser Pole Detection System (LPS)

The Laser Pole Detection System (LPS) provides railroad operators with exact location information to find identified defective sections in the railroad network. The information complements GNSS (Global Navigation Satellite System) data, which can experience local coverage problems.

Locating defective sections

A defective section can be located by identifying the two poles that confine it. The LPS continuously detects the catenary wire support structure along the tracks and thus complements other measurement data with precise pole locations.

A laser distance measurement system forms the core of the LPS. The light from a high-frequency, modulated laser beam is reflected by objects and collected by a lens onto a detector. The phase of the detected signal differs from the emitted signal due to the time of flight of the light. The distance to the object is deduced from this phase shift.

The LPS consists of two acquisition units mounted side-by-side on the rooftop of the inspection car. Each unit has two distance measurement systems, with beams directed vertically upward. The system detects a pole when both laser beams from an acquisition unit are reflected simultaneously. This double reflection is caused by the pole’s anchor arms, side holders, or cantilevers. In addition, the two sensors determine the distance to distinguish such objects from others further above. The values are digitized and transmitted as a serial data flow to the data processing unit inside the car.

Optimized protective design

The LPS does not require daylight and can carry out measurements in tunnels, under bridges, and in train stations without additional lighting. The system is fully encased and actively kept at a specific temperature to minimize climatic effects. Cleaning of the glass window is controlled from inside the inspection car. The sensor is protected by a pneumatically activated cover in case of extremely rough weather or when it is parked. Thus, the system does not require any maintenance over long periods.

Operation

The LPS is available as a standalone device or as part of the Contact Wire Inspection System (CIS). The CIS multi-sensor system combines measurement technology for wire wear and wire position.

The LPS is in operation in many countries around the world, including Austria, Belgium, Brazil, Finland, Great Britain, Hong Kong, Indonesia, Malaysia, the Netherlands, and Romania.