Demonstration of In-Car Doppler Laser Radar at 1.55 $\mu\hbox {m}$ for Range and Speed Measurement

Laser radar provides better spatial resolution than millimeter-wave radar (MWR) due to the high directivity of the laser beam. However, commercial in-car laser radar approximates the target speed by a range differentiation method, which has the problems of excessive time consumption and the introduction of large errors. In this paper, a new Doppler laser radar scheme for simultaneously measuring target range and speed in automotive applications is presented. The scheme includes a new laser radar architecture, a new method to modulate the transmitted signal, and a method for calculating the range and speed from the signal returned from the target. The length of the transmitted signal is several microseconds, giving the possibility of realizing a high scan speed in automotive applications. In addition, simulations based on Simulink/Matlab were carried out to validate the proposed scheme. Finally, an experimental demonstration of simultaneous range and speed measurements was performed. The moving target for the experiment was a highly reflecting sheet attached to an electric grinder.