Method of diagnosing broadband microwave reflection of plasma sheath

<sec>During the re-entry process of aircraft, a layer plasma sheath wrapping its surface will be generated, which lead communication quality to deteriorate and even interrupt, resulting in phenomenon “radio blackout”. The blackout” problem has plagued aerospace industry for many years. One very important reasons is lack awareness transmission environment caused by limitations measurements. Therefore, realization in-situ measurement parameters key research hypersonic vehicles.</sec><sec>In this work, broadband microwave reflection method presented developed diagnosing reentry .The relationship between data derived theoretically, effective diagnostic frequency points are selected. Then, obtained inversely using selected realize simultaneous diagnosis electron density collision frequency.</sec><sec>This makes up deficiency that traditional reflectometer cannot diagnose high plasma, it can parameter vehicle complex environment.</sec><sec>A simulation model an experimental platform established, analysis ground experiment carried out verify method. diagnosed diagnostics provide control experiments. results show difference two small, verifies effectiveness method.</sec><sec>The real-time sheaths vehicles or under various flight conditions, accumulate large number first-hand data, great scientific value recognizing characteristics comprehensively, objectively accurately. It also used input link adaptive system environment. In addition, jet monitoring changes without changing shape.</sec>