Performance of miniaturized atomic clocks in static laboratory and dynamic flight environments

Abstract

Miniaturized atomic clocks with high frequency stability as local oscillators in global navigation satellite system (GNSS) receivers promise to improve real-time kinematic applications. For a number of years, such oscillators are being investigated regarding their overall technical applicability, i.e., transportability, and performance in dynamic environments. The short-term frequency stability of these clocks is usually specified by the manufacturer, being valid for stationary 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. 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. For the static case, all three oscillators are characterized in terms of their frequency stability at Physikalisch-Technische Bundesanstalt, Germany's national metrology institute. The resulting Allan deviations agree well with the manufacturer's data. Furthermore, a flight experiment was conducted in order to evaluate the performance of the oscillators under dynamic conditions. Here, each oscillator is replacing the internal oscillator of a geodetic-grade GNSS receiver and the stability of the receiver clock biases is determined. The time and frequency offsets of the oscillators are characterized with regard to the flight dynamics recorded by a navigation-grade inertial measurement unit. 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. 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.

Improved high‐precision GNSS navigation with a passive hydrogen maser

“…Therefore, we refer to Jain et al. (2021) where the performance of this particular oscillator is evaluated in an airborne experiment. The results are analyzed and discussed in terms of typical GNSS performance parameters such as precision, accuracy, and reliability of the position and velocity estimates.…”

“…Since these are phase observations, they can be modeled as white phase noise over time. Besides conducting individual clock comparisons and calculating instrument‐specific frequency stability parameters thereof (Jain et al., 2021), this information can be and is usually derived from manufacturer's data. Note that the latter might deviate considerably from the actual oscillator behavior as shown by Krawinkel and Schön (2014).…”

Analytical and numerical study of diffusion and localization of cold atoms in 3D optical speckles

“…Otherwise, various ICT devices such as satellite, GPS and quantum computers are based on oscillation clocks that should have a stable frequency to achieve high performances in their functions [ 28 , 29 ]. For this purpose, the quartz clocks based on quartz oscillation have been replaced by atomic clocks to improve the efficiency and the performance of ICT devices [ 30 ]. Indeed, the time counter in atomic clocks is achieved by exploiting the energy difference between two stationary quantum states in an ultra-cold atom Rubidium or Cesium [ 28 , 31 ].…”

Development of a Compact and Accurate Auto-Update Digital Clock with Real-Time Location Display using Organic Light Emitting Diode and Crystal Oscillator

“…(Tun, 2008). To maintain a steady and regular interval, clocks must either use the associated power's frequency (often 50 or 60Hz) or a separate crystal oscillator (Jain et al, 2021).The study of timekeeping is called horology (Allehabi et al, 2022). More often than not, the need to automatically update the time displayed on a clock arises as a result of factors such as vibrations, electrical transients, and so on, which can distort the workings and displacement of electronic components, affecting the accuracy of the time.…”