WAAS measurement processing; current design and potential improvements

Shallberg, Karl; Fang, Sheng

doi:10.1109/plans.2008.4570014

Cited by 17 publications

(18 citation statements)

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“…The SP performs its own independent data screening on the input WRE data. Its Code Noise and MultiPath (CNMP) monitor performs data screening, carrier smoothing, and produces a confidence bound for the remaining uncertainty on the smoothed pseudorange values. Figure shows the SP monitoring algorithms and information flow.…”

Section: Waas Architecture Overviewmentioning

confidence: 99%

“…The algorithm has continuously been presented with changing input conditions due to the deployment of different reference station hardware at varied locations with significantly different environmental factors. The algorithm has undergone many improvements to improve its performance both under nominal and challenging conditions …”

Section: Performance Improvementsmentioning

confidence: 99%

“…This was especially important with northern latitude stations added from Alaska and Canada where phase scintillation can present very challenging tracking conditions for L2P(Y) processing . The full cross‐thread edit logic was added in the 2007 timeframe . In addition to this editing, several specialized detection algorithms were added over time to assist with anomalous carrier tracking that was found to be common mode.…”

Section: Performance Improvementsmentioning

confidence: 99%

“…The algorithm has undergone many improvements to improve its performance both under nominal and challenging conditions. 4 The most important robustness measure added to CNMP was processing all three threads in the SP and then taking advantage of data editing across threads. Crossthread pseudorange editing in particular allowed mitigation of large multipath errors that sometimes resulted in CNMP not passing its bounding requirement at the most challenging multipath sites.…”

Section: Safety Processor Code Noise and Multipathmentioning

confidence: 99%

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WAAS at 15

Walter

Shallberg²,

Altshuler

et al. 2018

NAVIGATION

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The Wide Area Augmentation System (WAAS) achieved Initial Operating Capability (IOC) in July 2003. At IOC, WAAS had 25 reference stations in the Conterminous United States, Hawaii, Alaska, and San Juan, Puerto Rico, two master stations, and four uplink stations supporting two narrowband L1 only Geostationary Earth Orbit (GEO) satellites. Today, WAAS has 38 reference stations including four in Canada and five in Mexico, three master stations, and six uplink stations supporting three wide band L1/L5 GEO satellites. In addition to the architectural expansion, the Federal Aviation Administration (FAA) continued to evolve and maintain the algorithms, hardware, and software. With WAAS now turning 15 years of age, this paper takes stock of these modifications and details the improved service and integrity that has occurred since 2003.

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Section: Waas Architecture Overviewmentioning

confidence: 99%

Section: Performance Improvementsmentioning

confidence: 99%

Section: Performance Improvementsmentioning

confidence: 99%

Section: Safety Processor Code Noise and Multipathmentioning

confidence: 99%

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WAAS at 15

Walter

Shallberg²,

Altshuler

et al. 2018

NAVIGATION

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“…In response to this type of event [Shallberg and Sheng, 2008], WAAS has implemented several robustness measures in the operational system algorithms. One is in the code noise and multipath algorithms and looks for the L1 and L2 runaway signature such as that illustrated in Figure 11b.…”

Section: Ionospheric Scintillation On 9 October 2012mentioning

confidence: 99%

Space Weather Quarterly Volume 11, Issue 1, 2014

2014

Space Weather Quarterly

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In memoriam of Robert D. Hunsucker, an authority on radio propagation, radio sensing of the ionosphere, and the effects of AGWs on the ionosphere. Effects of solar cycle 24 activity on WAAS navigationBy Seebany Datta-Barua, Todd Walter, Gary S. Bust, and William WannerThe effects of geomagnetic activity of solar cycle 24 on WAAS navigation service. Meeting ReportA spacecraft immersed in an energetic plasma environment can experience significant charging. Typically driven by electrons with energies between a few tens of eV to ~100 keV, the charge can build up externally and, depending on surface properties, produce potential differences of near the ambient electron temperature (~100 V to 10 kV). At higher energies, electrons between 100 keV and ~10 MeV can penetrate a typical spacecraft surface and deposit charge internally on isolated conductors or in dielectrics. Again, the buildup of this charge can lead to large potential differences. Ultimately potential differences on or internal to the spacecraft can lead to arc discharges and other deleterious effects. Spacecraft charging/arcing is recognized as one of the main concerns for designing survivable spacecraft.Since about 1974 engineers and scientist who study charging have met to review the latest technologies, flight results, and modeling efforts. These meetings have evolved into a biennial international conference that provides the opportunity for the world's spacecraft charging experts and persons new to the discipline to meet and to discuss the latest issues in the field. The thirteenth Spacecraft Charging Technology Conference (SCTC) will be hosted by the California Institute of Technology's Jet Propulsion Laboratory with the support of NASA and the domestic and international spacecraft charging community.Topics of interest to the conference include the following: (1) Charging and arcing testing, (2) Charging and arcing mitigation, (3) Material aging effects, (4) Space Weather: Cause and effect, (5) Charging simulation, (6) Internal charging, (7) On-orbit investigations, (8) Plasma propulsion and tethers, (9) Materials characterization, (10) Electrostatic discharge test standardization, (11) Radiation effects, and (12) Other relevant charging topics.Papers and posters addressing all aspects of charging in the space environment are solicited for the conference. Abstracts for the conference are due by 22 February 2014. The website for registering for the meeting and submitting abstracts is http:// sctc.jpl.nasa.gov. Points News NOAA will host a workshop in Boulder, Colorado, on the comparison and intercalibration of solar energetic particle measurements. It will take place on the afternoon of Friday, 11 April 2014, at the Millennium Harvest House, following the annual Space Weather Workshop. Solar energetic particles (SEPs) consist of ions (protons, helium nuclei, and heavier ions), electrons, and even energetic neutral atoms emitted by the Sun in association with solar flares and coronal mass ejections. Of long-standing scientific interest since the...

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Effects of solar cycle 24 activity on WAAS navigation

et al. 2014

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This paper reviews the effects of geomagnetic activity of solar cycle 24 from 2011 through mid‐2013 on the Federal Aviation Administration's Wide Area Augmentation System (WAAS) navigation service in the U.S., to identify (a) major impacts and their severity compared with the previous cycle and (b) effects in new service regions of North America added since last solar cycle. We examine two cases: a storm that reduced service coverage for several hours and ionospheric scintillation that led to anomalous receiver tracking. Using the 24–25 October 2011 storm as an example, we examine WAAS operational system coverage for the conterminous U.S. (CONUS). The WAAS algorithm upgrade to ionospheric estimation, in effect since late 2011, is able to mitigate the daytime coverage loss but not the nighttime loss. We correlate WAAS availability to maps of the storm plasma generated with the data assimilative model Ionospheric Data Assimilation 4‐D, which show a local nighttime corotating persistent plume of plasma extending from Florida across central CONUS. We study the effect of scintillation on 9 October 2012 on the WAAS reference station at Fairbanks, Alaska. Data from a nearby scintillation monitor in Gakona and all‐sky imaging of aurora at Poker Flat corroborate the event. Anomalous receiver processing triggered by scintillation reduces accuracy at Fairbanks for a few minutes. Users experiencing similar effects would have their confidence bounds inflated, possibly trading off service continuity for safety. The activity to date in solar cycle 24 has had minor effects on WAAS service coverage, mainly occurring in Alaska and Canada.

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WAAS measurement processing; current design and potential improvements

Cited by 17 publications

References 1 publication

WAAS at 15

WAAS at 15

Space Weather Quarterly Volume 11, Issue 1, 2014

Effects of solar cycle 24 activity on WAAS navigation

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