Improvement of short-term frequency stability of the Chip Scale Atomic Clock

Bagala, Tomas; Fibich, Adam; Kubinec, P.; Stofanik, V.

doi:10.1109/fcs.2016.7546746

Cited by 5 publications

(2 citation statements)

References 4 publications

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“…The

B_{2}

bias function (Barnes, 1969) was used to convert this two‐sample deviation to an Allan deviation, where

B_{2} false(r, μ false) = 1.8144 \times 10^{5}

for

r = T / τ

and

μ = 1

, which assumes

h_{- 2}

is the dominant spectral component. This yielded an equivalent Allan deviation for

τ = 50 seconds

σ_{y} false(2, τ, τ false) = 1.6 \times 10^{- 11}

, which is consistent with a standard‐quality OCXO (Bagala et al., 2016).…”

Section: Analysis Of Interference From Syriasupporting

confidence: 76%

First results from three years of GNSS interference monitoring from low Earth orbit

et al. 2021

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Observation of terrestrial GNSS interference (jamming and spoofing) from low Earth orbit (LEO) is a uniquely effective technique for characterizing the scope, strength, and structure of interference and for estimating transmitter locations. Such details are useful for situational awareness, interference deterrence, and the development of interference‐hardened GNSS receivers. This paper presents the results of a three‐year study of global interference, with emphasis on a particularly powerful interference source active in Syria since 2017. It then explores the implications of such interference for GNSS receiver operation and design.

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“…The

B_{2}

bias function (Barnes, 1969) was used to convert this two‐sample deviation to an Allan deviation, where

B_{2} false(r, μ false) = 1.8144 \times 10^{5}

for

r = T / τ

and

μ = 1

, which assumes

h_{- 2}

is the dominant spectral component. This yielded an equivalent Allan deviation for

τ = 50 seconds

σ_{y} false(2, τ, τ false) = 1.6 \times 10^{- 11}

, which is consistent with a standard‐quality OCXO (Bagala et al., 2016).…”

Section: Analysis Of Interference From Syriasupporting

confidence: 76%

First results from three years of GNSS interference monitoring from low Earth orbit

et al. 2021

View full text Add to dashboard Cite

show abstract

“…These devices provide very good stability for timeframes of a few hours (Cash et al 2018;Fernández et al 2017), with very low power (1/8 W) and a small form-factor, and they are relatively inexpensive (< $10 k). However, CSACs alone do not provide sufficient long-term stability without external synchronization (Weaver et al 2012;Bagala et al 2016aBagala et al , 2016b. The original SA.45 MicroSemi CSACs also had relatively poor stability for timeframes less than 100 s, and have much higher phase noise than less expensive crystal oscillators.…”

Section: System Clocksmentioning

confidence: 99%

Design of a high-stability heterogeneous clock system for small satellites in LEO

2021

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We describe our investigation into the performance of low-power heterogeneous timing systems for small satellites, using real GPS observables from the GRACE Follow-On mission. Small satellites have become capable platforms for a wide range of commercial, scientific and defense missions, but they are still unable to meet the needs of missions that require precise timing, on the order of a few nanoseconds. Improved low-power onboard clocks would make small satellites a viable option for even more missions, enabling radio aperture interferometry, improved radio occultation measurements, high altitude GPS navigation, and GPS augmentation missions, among others. One approach for providing improved small satellite timekeeping is to combine a heterogeneous group of oscillators, each of which provides the best stability over a different time frame. A hardware architecture that uses a single-crystal oscillator, one or more Chip Scale Atomic Clocks (CSACs) and the reference time from a GPS receiver is presented. The clocks each contribute stability over a subset of timeframes, resulting in excellent overall system stability for timeframes ranging from less than a second to several days. A Kalman filter is used to estimate the long-term errors of the CSACs based on the CSAC-GPS time difference, and the improved CSAC time is used to discipline the crystal oscillator, which provides the high-stability reference clock for the small satellite. Simulations using GRACE-FO observations show time error standard deviations for the system range from 2.3 ns down to 1.3 ns for the clock system, depending on how many CSACs are used. The results provide insight into the timing performance which could be achieved on small LEO spacecraft by a low power timing system.

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Dynamic phase shifting method utilized in the enhanced frequency controlled clock system

Stofanik

Fibich

Bagala

et al. 2017

2017 Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium (EFTF/IFC)

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Improvement of short-term frequency stability of the Chip Scale Atomic Clock

Cited by 5 publications

References 4 publications

First results from three years of GNSS interference monitoring from low Earth orbit

First results from three years of GNSS interference monitoring from low Earth orbit

Design of a high-stability heterogeneous clock system for small satellites in LEO

Dynamic phase shifting method utilized in the enhanced frequency controlled clock system

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