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User's Manual for Lidar Target Simulator



J A. Worthey, Kathleen M. Higgins


This is the operator's manual for a target simulator for speed-measuring lidars, and for the computer program VS, which is a key part of the simulator. This is the simulator referred to in DOT HS 808 539, Model minimum performance specifications for lidar speed measurement devices, published by the National Highway Traffic Safety Administration, February 1997. The program is flexible and interacts with the user through menus and forms. The components of the simulator include a commercial delay generator, a custom-made receive-send unit, a PC with two commercial interface cards in it, plus cables, switches, and the program VS. During the simulation, the program has the time-critical task of sending the next delay to the delay generator. Before and after each simulation, the program aids the user in recording the data. The simulator works with lidar units that have a fixed pulse repetition rate, or PRR. The PRR is measured in a preliminary experiment. The user selects the speed and initial range of the simulated target vehicle. These settings, together with the PRR and the speed of light in air are used to compute a sequence of delay times, modeling the echoes from a vehicle moving at constant speed. The lidar under test should respond to the sequence of delays as it would to a real moving target, and its reading should agree with the simulated speed. The software guides the user through the description of the unit under test, the PRR measurement, the test parameters, and the running of the simulation. Then it can record the data to computer disk. The sequence of delays generated by the software, when graphed against elapsed time, normally follows a straight-line graph, representing constant motion. The sequence can optionally be perturbed by a periodic function that the user supplies. When constant motion is simulated, this provides an accuracy reference for the unit under test.
NIST Interagency/Internal Report (NISTIR) - 6418
Report Number


laser, lidar, motor vehicle, police, speed measurement, traffic


Worthey, J. and Higgins, K. (2000), User's Manual for Lidar Target Simulator, NIST Interagency/Internal Report (NISTIR), National Institute of Standards and Technology, Gaithersburg, MD (Accessed April 16, 2024)
Created February 29, 2000, Updated October 12, 2021