Application of matched filtering and parameter estimation technique to lowlatitude whistlers

The Matched Filtering and Parameter Estimation (MFPE) technique developed f or the analysis of mid/high latitude whistlers has been extended to analyze whistlers recorded at low latitude ground station Varanasi, India (geomagn etic latitude 14 degrees 55' N, longitude 153 degrees 59' E, L = 1.07). Som e of the whistlers recorded at Varanasi are found to have propagated along higher L-values (L > 2). It has been argued that these whistlers after exit ing the ionosphere have propagated towards the equator in the Earth-ionosph ere waveguide. Trace splitting is observed below the nose frequency and abo ve 2.0 kHz, a result in agreement with mid/high latitude whistlers. The tra ce splitting structure revealed by MFPE demonstrates the complexities of wh istler wave propagation and is quite helpful in deriving information about high resolution features of the duct structure. The banded features observe d in the dynamic spectrum are clearly seen in the output of the matched fil ter. The observed banded features may arise due to interference between the wavelets propagating in the duct/waveguide. (C) 1999 Elsevier Science Ltd. All rights reserved.