Research On Photon Counting Laser Bathymetry

Compared with the traditional lidar system based on linear detection method,the photon counting lidar system has many advantages such as higher sensitivity,farther detection distance,better detection efficiency,and lower system power consumption and so on.The research on photon counting laser bathymetric system can get rid of the shortcomings of the traditional laser bathymetric system,such as high energy requirement,relatively complicated system,higher power consumption,smaller detection depth and lower precision,etc.,which is of great strategic significance for China with long coastline and rich continental shelf.Photon counting lidar has been more comprehensively researched in China,but its application to shallow bathymetric mapping is still in its infancy.The research results of this thesis can make up for the research gap in photon counting laser bathymetry.This thesis focuses on photon counting laser bathymetric system.The basic principle and detection model of photon counting lidar are analyzed in detail.Based on the principle of photon counting laser bathymetry,the detection model of system is established,and the methods of operation mode selection,performance analysis and system parameters design are proposed.The laser energy model and detection probability model for shallow bathymetry of photon counting lidar are developed,and a prototype of photon counting laser bathymetric system is successfully developed.This thesis firstly uses the photon counting laser bathymetric system in the water depth detection experiment in China to verify the rationality and feasibility of the principle,parameters design method and the key technology of photon counting laser bathymetry.The data preprocessing,filtering and water depth extraction based on the data of the echo point cloud and its statistical histogram are constructed.A lot of valuable data are obtained,which lay the foundation for further development and application of photon counting lidar in water depth measurement.This thesis has such innovative aspects:(1)The detection probability model of the photon counting laser bathymetry is established,and the influence of the deadtime of the single photon detector,the laser energy,the background noise and other factors on the depth measurement capability of the system is analyzed.(2)The photon counting lidar is applied to water depth measurement for the first time,and the bathymetry experiments have been carried out first.The underwater information within two meters is measured and a lot of valuable data have been obtained.(3)The performance analysis method of the bathymetric system is proposed,which provides a theoretical basis for the analysis of depth measurement capability of photon counting laser bathymetry.