Conversion of Non-Contact LIDAR Velocity Measurements to Spatial Markings and Indication Signals for Commercial Train Systems

Abstract

The primary purpose of this study is to develop a foot pulse electrical circuit that can be integrated into a LIDAR system used for measuring track speed and curvature. LIght Detection And Ranging (LIDAR) technology is used in a wide variety of applications because it is capable of reliably producing accurate and precise measurements. While application of LIDAR technology is vast, this particular study focuses on its ability to accurately measure velocity and track geometry of rail tracks. A research team at Virginia Tech (VT) has already developed, tested, and proven the capability of LIDAR technology to be used for railway applications [1,2]. Their analysis shows that a railcar-mounted LIDAR system can accurately measure track geometry, centerline velocity, car body dynamics, and several other useful parameters. While this system is reliable and multifunctional, the prototype used for testing is not easily upgraded to include additional features without augmenting the software currently used to analyze and record the LIDAR signal. However, the prototype LIDAR system lacks several capabilities that are desirable for integrating the system with typical commercial systems on trains. One signal that commercial train systems typically have, which the LIDAR prototype does not have, is a foot pulse. The foot pulse is usually generated by a tachometer on the wheel of the train and aims to send out a pulse every time the train has travelled a foot. This signal is used for multiple other systems on the train, so in order to simplify integration of the developed LIDAR prototype into commercial train systems, the prototype was upgraded to include additional features. Other than the foot pulse, the upgrade also included acceleration detection, direction indication, and laser-enable signals to have a more complete prototype. The upgrade was executed using an external microcontroller and accelerometer to provide proof of concept while leaving the current LIDAR prototype’s software (and already proven capabilities) untouched. This paper focuses on using the information generated by the current LIDAR system to implement the additional features in an inexpensive, reliable, and easily retrofittable manner.