Using an FPGA digital clock manager to generate sub-nanosecond phase shifts for lidar applications

Abstract

When using a Light Detection and Ranging (LIDAR) gun for civil engineering applications, anomalous data were observed. A laboratory system was developed to simulate ranging to moving targets in a controlled environment in order to study the anomalous data and the performance of the LIDAR gun. The laboratory system was found to require the ability to generate sub-nanosecond phase shifts which can be updated in real time. This capability is available in high-quality laboratory, but the required equipment was not available to the authors. This research examines the design and implementation of a low cost system. The final design uses an embedded processor for computation of the necessary phase shifts and possible anomalies and an FPGA system to generate the dynamic precision phase shifts.