Short‐term GNSS satellite clock stability

Griggs, Erin; Kursinski, E. R.; Akos, Dennis

doi:10.1002/2015rs005667

Cited by 25 publications

(17 citation statements)

References 14 publications

(34 reference statements)

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“…Closely related to the 3CH method is the triple-collocation (TC) method, which was introduced by Stoffelen (1998) and has been widely used since in oceanography and hydrometeorology (e.g., Su et al, 2014;Gruber et al, 2016). It has been used to estimate the error variances of triplets of observation types to measure a diverse set of geophysical properties, including wave heights, sea surface temperatures, precipitation, surface winds over the ocean, leaf area index (LAI) products, and soil moisture.…”

Section: Summary and Discussionmentioning

confidence: 99%

Estimating observation and model error variances using multiple data sets

Anthes

Rieckh

2018

Atmos. Meas. Tech.

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Abstract. In this paper we show how multiple data sets, including observations and models, can be combined using the “three-cornered hat” (3CH) method to estimate vertical profiles of the errors of each system. Using data from 2007, we estimate the error variances of radio occultation (RO), radiosondes, ERA-Interim, and Global Forecast System (GFS) model data sets at four radiosonde locations in the tropics and subtropics. A key assumption is the neglect of error covariances among the different data sets, and we examine the consequences of this assumption on the resulting error estimates. Our results show that different combinations of the four data sets yield similar relative and specific humidity, temperature, and refractivity error variance profiles at the four stations, and these estimates are consistent with previous estimates where available. These results thus indicate that the correlations of the errors among all data sets are small and the 3CH method yields realistic error variance profiles. The estimated error variances of the ERA-Interim data set are smallest, a reasonable result considering the excellent model and data assimilation system and assimilation of high-quality observations. For the four locations studied, RO has smaller error variances than radiosondes, in agreement with previous studies. Part of the larger error variance of the radiosondes is associated with representativeness differences because radiosondes are point measurements, while the other data sets represent horizontal averages over scales of ∼ 100 km.

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Section: Summary and Discussionmentioning

confidence: 99%

Estimating observation and model error variances using multiple data sets

Anthes

Rieckh

2018

Atmos. Meas. Tech.

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“…The solid red line shows the potential discovery reach using the global network of GPS microwave atomic clocks. For T 7 yr, the GPS reach is limited by the modern Rb block IIF satellite clocks 40 (σy(30 s) ∼ 10 −11 ), and for T 7 yr, the reach is limited by the older Rb (block IIR, IIA and II) GPS clocks (σy(30 s) ∼ 10 −10 ). Compared to more accurate optical clocks, microwave clocks provide additional sensitivity to Λq and Λ e/p (optical clocks only have sensitivity to Λα).…”

Section: Astrophysics Constraintsmentioning

confidence: 99%

Search for domain wall dark matter with atomic clocks on board global positioning system satellites

et al. 2017

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Cosmological observations indicate that dark matter makes up 85% of all matter in the universe yet its microscopic composition remains a mystery. Dark matter could arise from ultralight quantum fields that form macroscopic objects. Here we use the global positioning system as a ~ 50,000 km aperture dark matter detector to search for such objects in the form of domain walls. Global positioning system navigation relies on precision timing signals furnished by atomic clocks. As the Earth moves through the galactic dark matter halo, interactions with domain walls could cause a sequence of atomic clock perturbations that propagate through the satellite constellation at galactic velocities ~ 300 km s−1. Mining 16 years of archival data, we find no evidence for domain walls at our current sensitivity level. This improves the limits on certain quadratic scalar couplings of domain wall dark matter to standard model particles by several orders of magnitude.

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“…Unfortunately, the non‐deterministic variations of the GNSS satellite clocks cannot be taken into account in this process. Given a typical Allan deviation of 1–4·10 −12 of the GNSS satellite at a 1 s time scale , this may result in stochastic errors of about 1 mm in the ‘interpolated’ carrier‐phase observations. Even though this error is at the same level as the single‐frequency carrier phase noise, it affects L1 and L2 observations in the same manner and becomes essentially negligible compared to the noise when forming an ionosphere‐free linear combination.…”

Section: Precise Orbit and Baseline Determinationmentioning

confidence: 99%

Precise Orbit and Baseline Determination for the SAOCOM-CS Bistatic Radar Mission

et al. 2018

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This paper presents an overview of the SAOCOM-CS synthetic aperture radar (SAR) interferometry mission and the use of GPS/GNSS for precise orbit and baseline determination. Compared to X-band SAR interferometry missions, the use of L-band SAR in SAOCOM-CS poses less stringent (sub-centimeter rather than mm-level) requirements on the baseline accuracy. At the same time, however, the use of dissimilar spacecraft and GNSS receivers implies a less than optimal precondition for carrier phase differential GPS (CDGPS) navigation and is likely to degrade the baseline determination accuracy compared to ideal conditions. Based on GPS data collected in previous formation flying missions, the achievable baseline performance in SAOCOM-CS is assessed and recommendations for the most suitable processing scheme are given.

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Short‐term GNSS satellite clock stability

Cited by 25 publications

References 14 publications

Estimating observation and model error variances using multiple data sets

Estimating observation and model error variances using multiple data sets

Search for domain wall dark matter with atomic clocks on board global positioning system satellites

Precise Orbit and Baseline Determination for the SAOCOM-CS Bistatic Radar Mission

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