Simulation and Experiment Waveform Comparison for Undersea Pulsed Laser in Application to Target Localization

This study has the objective of assessing the feasibility of using LiDAR (Light Detection and Ranging) and laser communications techniques for localization of moving undersea targets using coordinated multiple UUV operations. This coordination includes creating an array of multiple cooperative UUVs to create a baseline system that is interconnected and spans a ranged area. The primary importance is the detection of the reflected laser pulse from the target in the presence of overlapping multiple scattering signal from the natural background particle field of coastal waters. This signal must be detectable to derive an accurate time of arrival (TOA) for ranging and tracking purposes. To properly simulate the complexities of real world underwater communication, a model was created that complies to natural variation and complexity, while still allowing for a controlled environment. To meet these standards, a simulation recreates a similar setup and operations method as a controlled experiment. Tested in simulation and experiments are the expected characteristic waveforms for monostatic and bistatic transmitter via receiver geometry. With the data collection of expected delays, scattering and target reflection the result is to create a proficient localization system model for real world application for a range of distances and turbidity. Simulation results are compared with controlled experimental results regarding: expected waveform similarities, target impulse response and receiver geometries while practical hardware constraints ensures the feasibility of target detection in real world application. Experiments were conducted in reflection to simulation parameters to show validation of the simulation itself, as well, to compare and ensure reliable waveform and TOA. Presented is the comparison between ideal simulation and the real-world TOA waveforms of similar scenarios with their application to localization and accurate target positioning in a three-dimensional plane. Localization techniques include the multilateration equation referred to as Fang's method. A statistical analysis of how this method performs is also presented in application to the cooperative UUV system for accuracy and precision. The denouement from the simulations and experiments presented are to create a robust localization model which accounts for differentiating propagation path geometry, water turbidity, and target orientation.