00000nam 2200000zi 4500 9.891655 CaOODSP 20221107172938 m o d f cr mn||||||||| 200921s1998 onca ob f000 0 eng d CaOODSP eng rda CaOODSP eng eng fre Co24-3/8-1998-2E-PDF Jenkins, Robert W., author. A comparison of spread and point-source multiple-direction estimation techniques for high latitude HF direction finding / by Robert W. Jenkins. Ottawa : Industry Canada, 1998. 1 online resource (x, 34 pages) : illustrations. text txt rdacontent computer c rdamedia online resource cr rdacarrier CRC technical note ; no. 98-002 Issued by: Communications Research Centre. "Terrestrial Wireless Systems Research Branch." "April 1998." Digitized edition from print [produced by Innovation, Science and Economic Development Canada]. Includes bibliographical references (pages 30-31). "Previous simulation studies were conducted to determine the direction-finding performance of four different antenna array geometries with and without antenna pattern errors, operating with the deterministic maximum-likelihood (ML) algorithm. Here they are extended to a new DF algorithm, 'spread maximum likelihood' (SML), which assumes distributions of signal directions, rather than single directions, to approximate the signal information seen by the array. The SML algorithm is thought to be more appropriate to the high-latitude HF radio environment, where signals often arrive from a spread set of directions due to multiple reflections or scattering from irregularities in the ionosphere and, at the same time, from a single great-circle direction as a result of sporadic-E propagation. Using a performance criterion of 'point-source visibility' in the presence of a stronger spread source, the simulation shows the SML technique to yield substantially better performance than ML, for all arrays and levels of error, and array apertures of four wavelengths or more. The SML technique extended the useful range of array apertures upwards to 10 wavelengths in most cases. As was seen previously for the ML algorithm, the three-pronged star configuration was found to be best of the array geometries tested"--Abstract, page iii. Issued also in print format. Includes abstracts in English and French. Radio wave propagation. Antenna arrays. Antenna radiation patterns. Ondes radioélectriques Propagation. Antennes-réseaux. Diagrammes de rayonnement d'une antenne. Communications Research Centre (Canada), issuing body. CRC technical note ; no. 98-002. (CaOODSP)9.882494 PDF 1.53 MB https://publications.gc.ca/collections/collection_2020/isde-ised/Co24/Co24-3-8-1998-2-eng.pdf