The influence of LC components' quality factor Q for GNSS receiver's group delay equalization

Abstract

For the satellite navigation receiver, the channel characteristic including amplitude and group delay is a determining factor for ranging and zero estimating accuracy. The technology about group delay equalizing by all-pass network in the RF system is analyzed in this paper. The quality factor Q of LC components, which affects the group delay equalization, is the key of application research. Computer simulation results based on some special RF system shows the way to make a target of the delay equalization and choose LC components with special Q, and give out three important conclusions to guidance the homologous application. Finally, the analytical results are verified, completes the second-order all-pass network circuit hardware, and cascades it with the RF circuit, the entire amplitude and group delay characteristics is im-proved as wish. The test results analyzed with Agilent vector network analyzer show that, group delay fluctuations of the equalization passband is about 7∼8ns, amplitude-frequency passband fluctuation is 1.5dBm, the initial value is 137ns and 1dBm. The method could be used to improve the group delay equalization in the wider passband of RF front-end channel, and has important reference value in group delay equalization goal setting, program feasibility study and Q value selection.