A.A. Sokolov, Yu.S. Yurchenko

Accuracy of the signal-noise ratio (SNR) evaluation in user equipment of the satellite radio-navigation system is estimated. The SNR evaluation accuracy estimating method based on using known principle of correlator output signal quadrature components narrow and wide sums computation in the satellite radio-navigation system receiver is investigated. Mean-square value of numerator evaluation relative error containing signal power as well as mean-square value of denominator evaluation relative error containing noise power are obtained to estimate the SNR evaluation precision. It is shown that the signal power evaluation relative error decreases with SNR increasing and the noise power evaluation relative error depends on quantity of summing signal components. Mean-square value of the SNR evaluation relative error is obtained as the sum of the numerator and denominator evaluation relative errors. It is shown that the mean-square value of the SNR evaluation relative error is bounded below by value 0,227 in case of informa-tion message bit length 20 ms and correlator accumulation time 1 ms. The SNR evaluation method based on using signal components of several channels of multi-channel navigation receiver getting signals of H satellites simultaneously is offered. The method allows to reduce the low bound of mean-square value of SNR evaluation relative error to times. On the other hand, the method is suitable for a code division system only where the signal channels are located in the same frequency band. Regarding a frequency division system, noise power spectrum can vary in different frequency signal channels. Further improving the SNR evaluation accuracy is possible by increasing the noise power evaluating accuracy by using additional accumulators for signal components taken from correlator input. The method improves SNR evaluation accuracy by more than order comparing the other methods. On the other hand, the method requires additional accumulators working at sampling rate.