g-Effects on Oscillator Performance in GPS Receivers

This paper considers the effects of vibration of the antenna and oscillator in a GPS receiver. These combine to cause a vibration-induced phase shift in the carrier phase tracking loop. While the vibration (motion) of the antenna is not under the designer's control, the g-sensitivity of the oscillator is amenable to choice. The quantitative effects are analyzed with reference to the design of a GPS receiver for ground-mobile use. It is shown that the loss of lock of GPS signals under severe vibration is avoidable. A well-designed equipment will exhibit increased carrier cycle slip when vibrated. This may be related to an equivalent loss of signal-to-noise ratio in mild cases.