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A Radical Approach to Reducing Effects of Quartz Crystal Oscillator Instability on GNSS Receiver Performance
The paper is devoted to a radical way to increase vibration resistance of global navigation satellite systems (GNSS) signal receivers (GLONASS, GPS, etc.). The method is based on the use of a common (quartz) loop in addition to individual loops– traditional for GNSS receivers phase locked loops (PLL), each of which monitors a separate radio signal of one of the GNSSs. Such a system with one common loop and many individual loops will be called quartz locked loop (QLL) system. In the absence of common loop, to increase the vibration resistance, the PLL band is expanded, but this leads to a decrease in the noise immunity of the receiver. The method discussed in the paper makes it possible to increase the vibration resistance much more than it can be done by expanding the band of independent PLLs, and at the same time practically avoids reducing noise immunity of GNSS receivers.
Different analytical methods (based on z-transformations) are used in the paper, as well as a simulation method (only some results are given without detail description), semi-natural simulation, and full-scale tests carried out with a vibrational bench. In the paper the specified methods of semi-natural simulation and full-scale tests are used for studying the QLL system, as well as systems of independent PLLs.