{"id":517,"date":"2015-04-28T13:59:26","date_gmt":"2015-04-28T20:59:26","guid":{"rendered":"https:\/\/chuckrino.com\/?p=517"},"modified":"2019-07-11T21:21:54","modified_gmt":"2019-07-12T04:21:54","slug":"a-comparison-of-phase-locked-loops-and-frequency-hypothesis-tracking","status":"publish","type":"post","link":"https:\/\/chuckrino.com\/?p=517","title":{"rendered":"A Comparison of Phase Locked Loops and Frequency Hypothesis Tracking"},"content":{"rendered":"<p>Processing low orbiting beacon satellite data has been a challenge largely because of the limited vehicle space for a VHF, UHF, L-band antenna system. The effective antenna patterns severely limit range of uniform illumination range with a common phase center. Low SNR, particularly at acquisition severely, constrains phase-locked-loop (PLL) performance. However, with post-pass processing substantially more processing can be devoted to the critical frequency tracking operation. Several schemes have been used effectively to construct a narrow band filter centered on the Doppler frequency defined over a local time segment. An analysis of these procedures was presented in a paper <i><a href=\"https:\/\/chuckrino.com\/wp-content\/uploads\/2018\/08\/Rino_et_al-2015-Radio_Science.pdf\">REF<\/a>.<\/i><br \/>\nIn the paper it was hypothesized but not demonstrated that typical PLL performance was degraded for SNRs below 10 dB to the point that direct frequency estimation was a preferable alternative. The note <a href=\"https:\/\/chuckrino.com\/wp-content\/uploads\/2015\/04\/SoftwarePLL.pdf\">SoftwarePLL<\/a> compares frequency estimates derived from a conventional PLL and direct frequency estimation.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Processing low orbiting beacon satellite data has been a challenge largely because of the limited vehicle space for a VHF, UHF, L-band antenna system. The effective antenna patterns severely limit range of uniform illumination range with a common phase center. &hellip; <a href=\"https:\/\/chuckrino.com\/?p=517\">Continue reading <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[16],"tags":[],"class_list":["post-517","post","type-post","status-publish","format-standard","hentry","category-signal-processing"],"_links":{"self":[{"href":"https:\/\/chuckrino.com\/index.php?rest_route=\/wp\/v2\/posts\/517","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/chuckrino.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/chuckrino.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/chuckrino.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/chuckrino.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=517"}],"version-history":[{"count":2,"href":"https:\/\/chuckrino.com\/index.php?rest_route=\/wp\/v2\/posts\/517\/revisions"}],"predecessor-version":[{"id":711,"href":"https:\/\/chuckrino.com\/index.php?rest_route=\/wp\/v2\/posts\/517\/revisions\/711"}],"wp:attachment":[{"href":"https:\/\/chuckrino.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=517"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/chuckrino.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=517"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/chuckrino.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=517"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}