REFERENCE WORK STATION FOR ABSOLUTE PRECISION CALIBRATION OF DELAY OF LETTERED FREQUENCY ENVELOPES IN GLONASS SIGNAL RECEIVER

摘要

FIELD: physics, navigation.;SUBSTANCE: invention relates to means for metrological support of receiver-indicators of GLONASS space navigation systems. The reference work station for precision calibration of delay of lettered frequency envelopes of GLONASS signal receivers consists of a test signal source, the calibrated receiver and a personal computer for processing calibration results. The test signal source used is synthesiser of an array of test frequencies that are phase-modulated by ±90° using range-finding code of a GLONASS pseudorandom sequence. Phase incursions are input into the personal computer, said phase incursions being successively measured by the carrier monitoring system of the calibrated receiver over an interval Δt. Phase incursions measured at the same intervals Δt of the hardware copy of the carrier monitoring system of the calibrated receiver are subtracted therefrom and said differences are divided by Δt to obtain phase response readings for frequencies. Delays directly caused by nonlinearity of the frequency response are calculated; group delay is measured; said delays are summed to obtain spectral density of the delays, or partial delays, which are averaged with the spectrum of the pseudorandom sequence of the range-finding code, successively shifting the centre frequency of the spectrum to the closest lettered frequency.;EFFECT: high accuracy of calibrating the delay of a lettered frequency envelope.;5 dwg