ANGEO Annales Geophysicae ANGEO Ann. Geophys. 1432-0576 Springer Verlag Göttingen, Germany 10.1007/s00585-996-1480-x Errors due to random noise in velocity measurement using incoherent-scatter radar Williams P. J. S. 1 Etemadi A. 2 McCrea I. W. 3 Todd H. 4 Adran Ffiseg, Prifysgol Cymru Aberystwyth, SY23 3BZ, Wales Blackett Laboratory, Imperial College, London SW1, England Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, England University of Fiji, Fiji 31 12 1996 14 12 1480 1486 Copyright: © 1996 P. J. S. Williams et al. 1996 © European Geosciences Union 1996 This article is available from https://angeo.copernicus.org/articles/14/1480/1996/angeo-14-1480-1996.html The full text article is available as a PDF file from https://angeo.copernicus.org/articles/14/1480/1996/angeo-14-1480-1996.pdf

The random-noise errors involved in measuring the Doppler shift of an 'incoherent-scatter' spectrum are predicted theoretically for all values of <i>T<sub>e</sub></i>/<i>T<sub>i</sub></i> from 1.0 to 3.0. After correction has been made for the effects of convolution during transmission and reception and the additional errors introduced by subtracting the average of the background gates, the rms errors can be expressed by a simple semi-empirical formula. The observed errors are determined from a comparison of simultaneous EISCAT measurements using an identical pulse code on several adjacent frequencies. The plot of observed versus predicted error has a slope of 0.991 and a correlation coefficient of 99.3%. The prediction also agrees well with the mean of the error distribution reported by the standard EISCAT analysis programme.