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LOCATION ESTIMATION IN NON-LINE-OF-SIGHT CONDITIONS USING DIGITAL TERRAIN MODEL
Grigoriy A. Fokin, The Bonch-Bruevich St. Petersburg State University of Telecommunications, St. Petersburg, Russia, grihafokin@gmail.com
This work was supported by the Ministry of Science and Education of the Russian Federation with Grant of the President of the Russian Federation for the state support of young Russian scientists № MK-3468.2018.9
Abstract
This study presents the results of mathematical and simulation modeling of non-line-of-sight conditions for positioning of radio emission sources (RES). The need for identification and exclusion of reflected signals from the location estimation process (LEP) is mathematically substantiated. By means of simulation model, a toolkit was developed and tested to assess the conditions of signal reflection based on geometric ray tracing using a digital terrain model (DTM). The contents of this work can be divided into two parts. The first part of this paper presents a mathematical proof of the need for identification and exclusion of reflected signals from the positioning process. To do this, first, a mathematical formalization of the RES location estimation is given by the average of a sample of intermediate coordinate estimates (ICE). Based on the presented mathematical model, an analytical study of the LEP by two different sets of measurements is then performed. The estimation of RES coordinates from measurements with the presence of LOS (Line of Sight) and absence of line of sight NLOS (Non-Line of Sight) is considered as a special case of the presented model for calculating the estimation of coordinates based on two different sets of measurements. The proof of the bias of the resulting estimate obtained under NLOS conditions is presented, for the exclusion of which it is recommended to identify and exclude the sources of reflected signals from the positioning process. The second part of this work presents the results of research and development of software tools for predicting the conditions of NLOS for a given LEP scenario/terrain. Evaluation of the conditions of signal reflections is carried out by means of simulation modeling based on a digital terrain model using the mechanism of geometric ray tracing. The resulting toolkit contains convenient visualization means, is of practical interest for positioning using unmanned aerial vehicles (UAVs), and can be used to justify UAV motion paths in applications for search and rescue operations, emergency medical services, law enforcement, and tracking for personnel, vehicles, etc.
Keywords: unmanned aerial vehicle, dispersion, simulation, radio emission source, mean, location estimation, non-line-of-sight, positioning, intermediate coordinate estimation, receiving point, ray tracing, digital terrain model.
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Information about author:
Grigoriy A. Fokin, candidate of technical sciences, docent, associate professor of the department of radio communications and broadcasting of the Bonch-Bruevich St. Petersburg State University of Telecommunications, St. Petersburg, Russia