Improvement in tracking loop threshold of high dynamic GNSS receiver by installation of crystal oscillator on gyroscopic mounting

摘要

In high dynamic GNSS receivers, replica carrier is polluted by dynamic loads which modulated on it and generate clock drift as frequency and phase error. These dynamic loads consist of steady state acceleration, sinusoidal vibration, mechanical and acoustic random vibrations. As steady state load exists all over the trajectory and causes great phase deviation, therefor phase lock is lost and the sensitive phase lock detector distinguishes it and transits back to FLL, therefore the dominant tracking loop in high dynamic receivers is FLL. According to the calculations, all dynamic loads cause some amount of frequency deviation (f) or jitter(3σv), it is also worth remembering that among them random vibration causes great frequency jitter and impacts FLL significantly.