New incoherent scatter radar measurement techniques and data analysis methods
1University of Oulu, Faculty of Science, Department of Physical Sciences
|Online Access:||PDF Full Text (PDF, 1.4 MB)|
|Persistent link:|| http://urn.fi/urn:isbn:9514273125
|Publish Date:|| 2004-04-16
|Thesis type:||Doctoral Dissertation
|Defence Note:||Academic dissertation to be presented, with the permission of the Faculty of
Science of the University of Oulu, for public discussion in Raahensali
(Auditorium L10), Linnanmaa, on 16 April, 2004, at 12 o´clock noon.
This dissertation presents new incoherent scatter radar measurement techniques and data analysis methods. The measurements used in the study were collected by connecting a computer-based receiver to the EISCAT (European Incoherent SCATter) radar on Svalbard. This hardware consists of a spectrum analyzer, a PCI-bus-based programmable digital I/O card and a desktop computer with a large-capacity hard disk. It takes in the 70-MHz signal from the ESR (Eiscat Svalbard Radar) signal path and carries out downconversion, AD conversion, quadrature detection, and nally stores the output samples ective sampling rate is 1 MHz, large enough to span all the frequency channels used in the experiment. Hence the total multichannel signal was stored instead of separate lagged products for each frequency channel, which is the procedure in the standard hardware. This solution has some benets including elimination of ground clutter with only a small loss in statistical accuracy. The capability of our hardware in storing the incoherent scatter radar signals directly allows us to use very exible and versatile signal processing methods, which include clutter suppression, ltering, decoding, lag prole calculation, inversion and optimal height integration. The performance of these incoherent scatter radar measurement techniques and data analysis methods are demonstrated by employing an incoherent scatter experiment that applies a new binary phase code. Each bit of this code has been further coded by a 5-bit Barker code. In the analysis, stochastic inversion has been used for the rst time in decoding Barker-coded incoherent scatter measurements, and this method takes care of the ambiguity problems associated with the measurements. Finally, we present new binary phase codes with corresponding sidelobe-free decoding lters that maximize the signal-to-noise ratio (SNR) and at the same time eliminate unwanted sidelobes completely.
Report series in physical sciences
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