Determination of the Incoherent Scatter Signal Statistical Characteristics

Methodological features of the determination of the incoherent scatter signal statistical characteristics are considered. The variants of the receiving-processing channel structures are analyzed taking into account the specifics of the incoherent scatter radar. Under the proposed method of I/Q demodulation, digital signal samples are formed in quadrature dependence as a result of analog-to-digital conversion directly and they are accordingly used in the subsequent signal processing. It enables estimating the quadrature components of the autocorrelation function (ACF) of the incoherent scatter signal using one channel of the radio receiver and ADC and eliminating a number of drawbacks of an analog I/Q demodulator. The coherence of the incoherent scatter radar operation is ensured by the formation of clock pulses for the ADC from the signal of the radar synthesizer. A method of correlation processing is proposed. Due to the increase in the frequency of analog-to-digital signal conversion, the number of ACF ordinates on the correlation interval length (ACF argument) is increased. This makes it possible to reduce errors of estimation of the signal autocorrelation function and consequently errors of ionospheric parameters determination for different heights of the ionosphere.