Mercury trapped ion frequency standard for space applications
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frequency standard space clock↗
Engineering topics
Tjoelker, R. L.
Publications and source records attributed to Tjoelker, R. L..
Mercury-ion clock based on a linear multi-pole ion trap
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ion clock↗
Multi-purpose time analyzer and monitor for Deep Space Network time synchronization
We report the development of a multi-purpose, automated, and continuously operating Time Analyzer to measure and monitor distributed 1 pps reference signals in the NASA Deep Space Network (DSN).
time interval time stability↗
Advanced atomic clock standards
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clocks oscillators linear ion trap↗
Multi-purpose time analyzer and monitor for Deep Space Network time synchronization
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time time analysis↗
Stabilized reference frequency distribution for radio science with the Cassini spacecraft and the Deep Space Network
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SFODA CSO reference frequency stability phase nois↗
Nitrogen buffer gas experiments in Mercury trapped ion frequency standards
Practical, continuous operating mercury trapped ion frequency standards have traditionally used a helium buffer gas to increase loading efficiency and cool ions to near room temperature.
frequency standards atomic clocks↗
Precise Clock Solutions Using Carrier Phase from GPS Receivers in the International GPS Service
As one of its activities as an Analysis Center in the International GPS Service (IGS), the Jet Propulsion Laboratory (JPL) uses data from a globally distributed network of geodetic-quality GPS receivers to estimate precise clock solutions, relative to a chosen reference, for both the GPS satellites and GPS receiver internal clocks, every day. The GPS constellation and ground network provide geometrical strength resulting in formal errors of about 100 p sec for these estimates. Some of the receivers in the global IGS network contain high quality frequency references, such as hydrogen masers. The clock solutions for such receivers are smooth at the 20-p sec level on time scales of a few minutes. There are occasional (daily to weekly) shifts at the microsec level, symptomatic of receiver resets, and 200-p sec-level discontinuities at midnight due to 1-day processing boundaries. Relative clock solutions among 22 IGS sites proposed as "fiducial" in the IGS/BIPM pilot project have been examined over a recent 4-week period. This allows a quantitative measure of receiver reset frequency as a function of site. For days and-sites without resets, the Allan deviation of the relative clock solutions is also computed for subdaily values of tau..
Zumberge, J. F.↗
Precise Clock Solutions using Carrier Phase From GPS Receivers in the International GPS Service
As one of its activities as an Analysis Center in the International GPS Service (IGS), the Jet Propulsion Laboratory (JPL) uses data from a globally distributed network of geodetic-quality GPS receivers to estimate precise clock solutions, relative to a chosen reference, for both the GPS satellites and GPS receiver internal clocks, everyday.
GPS↗
Cryo-cooled Sapphire Oscillator with Ultra-High Stability
We present test results and design details for the first short-term frequency standard to achieve ultra-high stability without the use of liquid helium.
Cryo-cooled Compensated Sapphire Oscillator (CSO) ↗
The JPL Hg(sup +) Extended Linear Ion Trap Frequency Standard: Status, Stability, and Accuracy Prospects
Microwave frequency standards based on room temperature (sup 199)Hg(sup +) ions in a Linear Ion Trap (LITS) presently achieve a Signal to Noise and line Q inferred short frequency stability. Long term stability has been measured for averaging intervals up to 5 months with apparent sensitivity to variations in ion number/temperature limiting the flicker floor.
Hg+ linear ion trap frequency LITE LITS microwave ↗
A Mercury Frequency Standard Engineering Prototype for the NASA Deep Space Network
An engineering prototype linear ion trap frequency standar (LITS-4) using (sup 199)Hg+ is operational and currently under test for NASA's Deep Space Network (DSN). The DSN requires high stability and reliability with continuous operation.
ion trap LITS-4 DSN LITS-1 LITS-2 ion trap frequen↗
Formation of GPS-Linked Global Ensemble of Hydrogen Masers, and Comparison to JPL's Linear Ion Trap
This paper will describe the use of precision GPS time transfer to form an ensemble of hydrogen maser clocks. The performance of this ensemble, including the GPS time-transfer system, was measured relative to a stable Linear Ion Trap Standard.
GPS maser clocks hydrogen maser clock maser Ion Tr↗
High Stability Frequency Standards Based on (sup 1999)Hg+Ions in a Linear Ion Trap
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Microwave-Optical Mercury ions helium buffer gas a↗
Recent Stability Comparisons with the JPL Linear Trapped Ion Frequency Standards
The Hg research frequency standards LITS-1 and LITS-2 were developed to provide continuous, reliable, high stability performance. For simplicity, a Hg lamp is used for state selection and a helium buffer gas for ion cooling.
Helium buffer gas ion cooling LITS-2 ion microwave↗
Doppler Sideband Spectra for Hg Ions in a Linear Ion Trap
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sideband spectra ions LIT high frequency peak↗
Long Term Stability of Hg(sup +) Trapped Ion Frequency Standards
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Oscillator (SCMO)↗
Improved Linear Ion Trap
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Linear Ion Trap (LIT) ions microwave resonance reg↗