Research On Key Technologies Of Marine Atmospheric Duct Detection Methods

The troposphere is the bottom layer of the atmospheric stratification, and has a closestrelationship with human activities. Electromagnetic (EM) wave signal propagation in thetroposphere over sea surface is often a complicated phenomenon which can be influencedby variety of meteorological and hydrological factors. For these factors，the refractive indexof the troposphere is not evenly distributed, so anomalous propagation environment of EMwaves such as atmosphere duct happens occasionally in the marine atmosphere.Atmospheric duct detection is significant for the radio detection instruments such as radarto be normally operated.The thesis analyzes the formation mechanism of the duct and the theory of air-seaboundary layer with a thorough discussion on the hydro-meteorological method detectingthe atmospheric duct. The thesis introduced A model, PJ model and the air-sea flux modeland summarize the process for the three algorithms followed with a sensitive analysis. Aprogram application were designed and accomplished under the Visual C++platform.According to the phenomenon that the propagation paths of GNSS satellites in lowelevation are affected by the atmospheric duct, a method is investigated using GNSSsatellites’ elevation to detect atmospheric duct. A program is designed to meet therequirements for detecting atmospheric duct.Based on these methods, the thesis proposed a method and an architecture usingmulti-sensor fusion technology to detect atmospheric duct. The structure adoptsmultiple-satellite, multi-model and multi-sensor system to collect data, and followed with aprocedure of information fusion.A field test was carried out to verify the stability and functional integrity of theprogram and to accumulate the experimental data for future research. This method mayprovide ideas for the development of duct detection technology.Innovations include:1. Conducting a research on the algorithm of PJ model, A model and air-sea fluxmodel. A comprehensive sensitivity and applicability analysis on the three models werediscussed, giving types of parameters needed to detect the atmospheric duct.2. The possibility of using multi-sensor fusion technology in duct detection systemwas discussed. Methods and Structure were designed for the atmospheric duct multi-sensorco-detection system, and were verified with Monte Carlo simulation method.3. A field experiment was carried out. The evaporation duct height was calculated with algorithms of three methods after data analysis. The thesis obtained a final evaporationduct height using information fusion technology with the results of the three models,providing method and data for the subsequent duct detection.This thesis discussed choice of the sensors, procedure of the detection and the methodof data processing to form a complete duct detection process and has an importantsignificance for duct detection in marine environment.