An Integrated Meteor Radar System for Wind and Density Measurements in the Upper Atmosphere

摘要

The theory of radio reflection from meteor trails is reviewed, and, based on its predictions, the specifications for a multiparameter meteor radar are derived. The synthesis of a completely integrated, coherent pulse radar is described; with this radar, echo strength, range, elevation angle, and doppler shift of the signals reflected from trails can be measured. The main features of this system are digital recording and processing of the data; the use of a composite signal waveform that permits simultaneous measurement of range, amplitude, and doppler at low peak power; and the recording of both amplitude and sign of the doppler shift in one channel. Data are processed automatically; the radar station is inexpensive and reliable enough to provide the basis for multistation synoptic measurements of upper atmospheric winds. The performance of the system is analyzed and measurements with three antenna arrangements are described. Echo heights are determined directly at high elevation angles from range and angle of arrival. It is shown that the height of reflection can be related to the amplitude decay of a certain class of echoes. If these echoes are selected properly (a procedure for this selection is given) and if a daily variation of the decay/height relationship is taken into account, height can be estimated from signal decay to within plus or minus 1 km. At low elevation angles, winds are measured from the doppler shift of the trail echoes and their height is determined from the amplitude decay, using the relationship between them that was previously established. With theoretical relationships, atmospheric density can be estimated directly from the echo decay. (Author)