Common coordinate-quartz loop for reducing the impact of shock and vibration on global navigation satellite system measurements

Abstract

A navigation receiver operably coupled to an antenna can determine location by receiving and processing radiofrequency navigation signals from global navigation satellites. The navigation receiver includes a quartz crystal oscillator that serves as a reference frequency source for a local oscillator signal that is mixed with the radiofrequency navigation signals to generate intermediate signals at intermediate frequencies lower than the radiofrequencies. In particular applications, the quartz crystal oscillator and the antenna are subjected to vibration and shock. A shift in the frequency or phase of the intermediate signals can result, and performance of phase-lock loops can degrade. Performance is improved with a phase-lock loop that processes a combination of individual channel control signals and common control signals. The common control signals are generated by a common coordinate-quartz loop discriminator that processes signals generated from the entire group of navigation signals received by the navigation receiver.