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| Titel |
Phase-coded pulse aperiodic transmitter coding |
| VerfasserIn |
I. I. Virtanen, J. Vierinen, M. S. Lehtinen |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 27, no. 7 ; Nr. 27, no. 7 (2009-07-14), S.2799-2811 |
| Datensatznummer |
250016590
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| Publikation (Nr.) |
 copernicus.org/angeo-27-2799-2009.pdf |
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| Zusammenfassung |
| Both ionospheric and weather radar communities have already adopted the
method of transmitting radar pulses in an aperiodic manner when measuring
moderately overspread targets. Among the users of the ionospheric radars,
this method is called Aperiodic Transmitter Coding (ATC), whereas the weather
radar users have adopted the term Simultaneous Multiple Pulse-Repetition
Frequency (SMPRF). When probing the ionosphere at the carrier frequencies of
the EISCAT Incoherent Scatter Radar facilities, the range extent of the
detectable target is typically of the order of one thousand kilometers –
about seven milliseconds – whereas the characteristic correlation time of
the scattered signal varies from a few milliseconds in the D-region to only
tens of microseconds in the F-region. If one is interested in estimating the
scattering autocorrelation function (ACF) at time lags shorter than the
F-region correlation time, the D-region must be considered as a moderately
overspread target, whereas the F-region is a severely overspread one. Given
the technical restrictions of the radar hardware, a combination of ATC and
phase-coded long pulses is advantageous for this kind of target. We evaluate
such an experiment under infinitely low signal-to-noise ratio (SNR)
conditions using lag profile inversion. In addition, a qualitative evaluation
under high-SNR conditions is performed by analysing simulated data. The
results show that an acceptable estimation accuracy and a very good lag
resolution in the D-region can be achieved with a pulse length long enough
for simultaneous E- and F-region measurements with a reasonable lag extent.
The new experiment design is tested with the EISCAT Tromsø VHF (224 MHz) radar. An example of a full D/E/F-region ACF from the test run is
shown at the end of the paper. |
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