Scientific Journal of Polish Naval Academy (SJ of PNA)
2015, no. 1 (200)
Henryk Jafernik, Janusz Ćwiklak, Radosław Fellner
Selected aspects of implementing a GNSS system in aviation
This article presents a risk analysis relating to the implementation of Localizer Performance and Vertical Guidance (LPV) procedures, using a GNSS sensor, for the airports in Warsaw and Katowice. Detailed information is included in a report worked out in the framework of an international project SHERPA. The results of this research were used to determine the probability of risk occurrence, and to set safety targets, as well as to refer them to an ILS system. Following the preliminary safety system assessment (PSSA), safety requirements indispensible for reaching the required safety level were determined. The requirements are presented in respective tables. It should be emphasized that the quantitative requirements were determined using fault tree analysis (FTA).
GNSS, flight safety, flight procedures.
Krzysztof Naus, Łukasz Marchel
SLAM aided Inertial Navigation System
The interdisciplinary nature of navigation leads us to drawing on knowledge contained in solutions used in related technical fields. An example of this trend is combining it with elements of robotics, in which SLAM (Simultaneous Localization And Mapping) is commonly used for positioning a vehicle. To calculate position changes, the location of characteristic objects on a continuously updated map of an environment is used. The attractiveness of the implementation of this technology in connection with marine navigational aids, stems from the possibility of enhancing positioning accuracy in harbor, off-shore or narrow areas. That is in the areas where there is a built up hydro-technical infrastructure, such as breakwaters, waterfronts or navigational infrastructure in the form of marked water fairways and anchorages. In this article an analysis of SLAM combined with INS (Inertial Navigation System) is carried out. It focuses on the possibilities of enhancing accuracy in fixing position coordinates for a submarine. The first part of the article presents a mathematical base for combining INS and SLAM using the Extended Kalman Filter. The second part describes a study on the accuracy in positioning a mobile robot (in this instance a wheeled vehicle) which employs a navigation system based on INS and INS aided SLAM. The final part of the article includes the results of the study and their analysis. It also contains generalized conclusions indicating advantages and disadvantages of the proposed solution.
SLAM, inertial navigation, data fusion, Extended Kalman Filter.
Krzysztof Naus, Paulina Turek
The still picture camera as a tool for angular measurements of surface objects in an off-shore area
This article presents investigations conducted for the purpose of assessing the possibility of using still picture cameras to fix the positions of surface objects in an off-shore area. The first part describes the research methodology relating to the accurate assessment of angular measurements made with a still picture camera. The second part includes the method used to calculate horizontal angles using photos, and the method of calculating horizontal angles, based on three points whose geographical coordinates are known. The final part contains the results of the investigations, which justify using a still picture camera as a tool for angular measurements.
marine photogrammetry, digital camera, photo-based measurement.
Piotr Sulewski, Ryszard Motyka
Power analysis of independence testing for contingency tables
Six tests for independence in a two-way contingency table namely chi-squared test, log likelihood ratio test, Neyman-modified chi-squared test, Kullback-Leibler test, Freeman-Tukey test, Cressie-Read test, were examined. It was accomplished with the Monte Carlo method. The Goodman-Kruskal τ index was used to fix dependence in two-way contingency table in Monte Carlo experiments. The examination consisted in determining power functions of the tests. Next, the power functions were compared to each other. It was revealed that differences in power are negligible.
two-way contingency table, independence test, Monte Carlo method.
Underwater objects’ detection system choice for harbor surveillance purposes
The paper presents an analysis of various hydrographic systems, in order to find the most suitable set of equipment for hydroacoustic harbor surveillance system. Singe beam and multibeam echosounders, sweep systems, sidescan sonars, scanning sonars, interferometric sonars and underwater vehicles were analyzed in terms of their usefulness for mentioned purpose. The preferred hydroacoustic systems were chosen based on the analysis results.
harbor surveillance system, hydroacoustic systems, hydrographic equipment.
Bogdan Żak, Stanisław Hożyń
A surface and air object identification set
This article presents an optic-thermal set which is designed to continuously control monitored space using two vision cameras and a thermo-vision camera installed on a rotary head. On receiving data this set recognizes and identifies floating and low-flying objects on the basis of their classification features and thermal characteristics. The data on location of detected targets is displayed on an electronic chart of the monitored area pursuant to the requirements specified for automated command systems. In addition, the set is capable of tracking movement of selected objects in real time.
opitc-thermal set, optical sensors, thermal sensors, object recognition.