Signal Processing Techniques For LIDAR System

LIDAR is an important technique for the measurement of range, velocity and vibration, as well as atmospheric parameters. In literature, direct detection, coherent heterodyne detection and coherent homodyne detection represent the main basic detection structures used in FMCW lidar system. We investigated the different detection techniques especially direct detection, coherent heterodyne detection and coherent homodyne detection on FMCW lidar system using Optisystem package for the first time. A model for target, propagation channel and various detection techniques were developed using Optisystem package. A comparative study among various detection techniques for FMCW lidar systems is done analytically and simulated using the developed model.Through this work; the lidar receiver utilizes Mach-Zehender intensity (MZI) modulator for the first time and cooperated with a single photodetector for range and velocity measurement. This overcomes the unbalanced photodetection problem of dual photodetetor used in coherent detection and isn’t affected by the phase diversity problem which faces the homodyne detection.Distance detection and Doppler detection based on MZI modulator cooperated with single photodetector are presented for FMCW lidar system. A mathematical analysis for both proposed detection is introduced. Proposed distance and Doppler detection based on MZI modulator are modeled and simulated using Optisystem package.Performance analysis of both proposed detection is presented at different operating points for MZI modulator especially quadrature point and null transmission point. An analytical comparison of both proposed distance detection and Doppler detection based on MZI modulator with traditional direct detection is presented through this work.The developed model using Optisystem package verifies the mathematical model of both proposed detection. The results demonstrate that the operation of proposed detection based on MZI modulator at null transmission point improves the range resolution by two orders than other traditional detection techniques. In addition to the performance of proposed distance detection based on MZI modulator achieved better performance than direct detection in thermal noise limited case.