The same applies to the satellite timescales to which the GNSS measurements refer. This bias must be estimated to synchronize the receiver's timescale with the GNSS timescale. Positioning, navigation and timing (PNT) applications using global navigation satellite system (GNSS) measurements require at least four satellites in view to solve for three-dimensional coordinates and a receiver clock bias. Also, the two quartz oscillators show a significant g-sensitivity resulting in frequency shifts of − 1.2 × 10 −9 and + 1.5 × 10 −9, respectively, while the rubidium clocks are less sensitive, thus enabling receiver clock modeling and strengthening of the navigation performance even in high dynamics. The results of the experiment show that the frequency stability of each oscillator is degraded by about at least one order of magnitude compared to the static case. The time and frequency offsets of the oscillators are characterized with regard to the flight dynamics recorded by a navigation-grade inertial measurement unit. Here, each oscillator is replacing the internal oscillator of a geodetic-grade GNSS receiver and the stability of the receiver clock biases is determined. Furthermore, a flight experiment was conducted in order to evaluate the performance of the oscillators under dynamic conditions. The resulting Allan deviations agree well with the manufacturer's data. For the static case, all three oscillators are characterized in terms of their frequency stability at Physikalisch-Technische Bundesanstalt, Germany's national metrology institute.
#Atomic clock sync download for mac mac#
We present the performance of three different oscillators (Microsemi MAC SA.35m, Spectratime LCR-900 and Stanford Research Systems SC10) for static and dynamic applications. Since the performance of most oscillators is likely degraded in dynamic conditions, various oscillators are tested to find the limits of receiver clock modeling in dynamic cases and consequently derive adequate stochastic models to be used in navigation.
The short-term frequency stability of these clocks is usually specified by the manufacturer, being valid for stationary applications. For a number of years, such oscillators are being investigated regarding their overall technical applicability, i.e., transportability, and performance in dynamic environments. Miniaturized atomic clocks with high frequency stability as local oscillators in global navigation satellite system (GNSS) receivers promise to improve real-time kinematic applications.
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