期刊名称：Scientific Journals of the Maritime University of Szczecin
印刷版ISSN：1733-8670
电子版ISSN：2392-0378
出版年度：2015
卷号：44
页码：57-60
DOI：10.17402/057
语种：English
出版社：MUS
摘要：Many radio–navigation systems dating from the seventies and eighties of the last century were replaced by a single Global Positioning System (GPS) a dozen or so years ago.However,for several years the opinion that the GPS monopoly is becoming dangerous has been expressed increasingly often in navigational literature.Even when supplemented with other systems from this group,such as Global Navigational Satellite Systems (GNSS),it cannot be treated as the source of reliable and universally accessible navigational information.This results from the similar sensibility of all GNSS systems to the same disturbances as a consequence of using a similar band of radiofrequencies and a similarly low powered signal.There is a growing recognition in the maritime world that GNSS will not provide the resilience required because of these common vulnerabilities.The World Wide Radio Navigation System should be seen as a combination of systems,which can cooperate and work effectively even when GNSS does not work.Lately different authors commonly point–out the potential advantages of a modified Loran (e–Loran),however it still remains only a potential option–particularly in the southern hemisphere,where this system has never existed.Meanwhile as the general threat of the disturbance of GNSS systems increases,the matter of initiating alternative possibilities becomes more urgent.A proposal which combines lower financial outlays with adjustments to the existing techniques and the law in force is desirable.In this context radar seems to be the attractive option,however for utilization as an alternative to GNSS it should reach considerably higher technical performances.In the paper the general limitations in the use of existing radar as a means of ships’ positioning are presented,and information published about the investigation into the methods for overcoming these limitations is discussed.The accessible information appears to prove that a greater accuracy of position can be achieved with modified radar in the future,especially if the suitable navigational infrastructure is present on shore.However,the level of accuracy of this method does not seem to compare favorably with GNSS.
其他摘要：Penelitian ini bertujuan untuk mengetahui faktor–faktor yang berpengaruh terhadap peringkat obligasi pada perusahaan manufaktur.Faktor–faktor yang akan diuji di dalam penelitian ini meliputi rasio cakupan,rasio likuiditas,rasio solvabilitas,rasio profitabilitas,dan risiko bisnis.Populasi dalam penelitian ini adalah semua perusahaan manufaktur yang terdaftar di BEI,yang mempunyai kriteria yang pertama,perusahaan tersebut terdaftar di BEI selama 5 tahun,yang kedua perusahaan tersebut menerbitkan obligasi berturut–turut selama 5 tahun.Berdasarkan kriteria tersebut didapatkan sebanyak 8 perusahaan yang menjadi sampel penelitian.Analisis data pada penelitian ini menggunakan analisis regresi berganda.Hasilnya menunjukkan bahwa dari kelima variabel yang diteliti hanya satu yang memiliki pengaruh terhadap peringkat obligasi,yaitu risiko bisnis.Hasil ini memberikan kontribusi terhadap teori dan prkatisi..
关键词：radar;positioning;accuracy;solid state radar;resilent positioning and time system
