250 MHz/GHz scintillation parameters in the equatorial, polar, and auroral environments. Environmental research papers
Ionospheric scintillation effects encountered in the equatorial-anomaly crest, polar-cap, and auroral regions have been contrasted to provide information for the design and evaluation of the performance of satellite communication links in these regions. The equatorial-anomaly region is identified as the most-disturbed irregularity environment where the amplitude and phase structures of VHF/L-band scintillations are primarily dictated by the strength of scattering rather than ionospheric motion. In the anomaly region, the spectra of intense amplitude scintillations at VHF and L-band are characterized by uniform power spectral density from the lowest frequency (10 MHz) to 4 Hz at VHF and to 1 Hz at L-band and steep rolloff at higher fluctuation frequencies with power law indices of -5 to 07. Such structures are compatible with intensity decorrelation times of 0.1 and 0.3 sec at VHF and L-band frequencies, respectively. The phase spectra are described by power-law variation of psd with frequency with typical spectral indices of -2. 4. The strong scattering at VHF induces extreme phase rates of 200 deg. in 0.1 sec. The 90th percentile values of rms phase deviation at 250 MHz with 100-sec detrend are found to be 16 rads in the early evening hours whereas amplitude scintillation can cover the entire dynamic range of 30 dB not only at 250 MHz but at L-band as well.
- Research Organization:
- Emmanuel Coll., Boston, MA (USA)
- OSTI ID:
- 7185350
- Report Number(s):
- AD-A-172211/5/XAB
- Country of Publication:
- United States
- Language:
- English
Similar Records
Coherence scales of wavefield during propagation through naturally disturbed ionosphere in the polar cap, auroral, and equatorial regions
Nightime VHF and GHz scintillations in the East-Asian sector of the equatorial anomaly