SNR-based multipath error correction for GPS differential phase

Axelrad, Penina; Comp, C.J.; Macdoran, P. F.

doi:10.1109/7.489508

Cited by 113 publications

(76 citation statements)

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“…Accordingly, multipath is often considered the most limiting factor in precise GPS positioning (e.g. Lau and Mok 1999;Axelrad et al 1996). Short-term positions will be subject to quasi-periodic errors with characteristic timescales varying from seconds to minutes depending on the satellite-reflector geometry.…”

Section: Introductionmentioning

confidence: 99%

GPS sidereal filtering: coordinate- and carrier-phase-level strategies

Ragheb

Clarke

Edwards

2006

J Geod

109

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Multipath error is considered one of the major errors affecting GPS observations. One can benefit from the repetition of satellite geometry approximately every sidereal day, and apply filtering to help minimize this error. For GPS data at 1 second interval processed using a double-difference strategy, using the day-to-day coordinate or phase residual autocorrelation determined with a 10 hour window leads to the steadiest estimates of the error-repeat lag, although a window as short as 2 hours can produce an acceptable value with >97% of the optimal lag's correlation. We conclude that although the lag may vary with time, such variation is marginal and there is little advantage in using a satellite-specific or other time-varying lag in double-difference processing.We filter the GPS data either by stacking a number of days of processed coordinate residuals using the optimum "sidereal" lag (23h 55m 54s), and removing these This is the authors' version of a manuscript that has been accepted by Journal of Geodesy. The final publication is available at Springer via doi:10.1007/s00190-006-0113-1 2 stacked residuals from the day in question (coordinate space), or by a similar method using double-difference phase residuals (observational space). Either method results in more consistent and homogeneous set of coordinates throughout the dataset compared with unfiltered processing. Coordinate stacking reduces geometry-related repeating errors (mainly multipath) better than phase residual stacking, although the latter takes less processing time to achieve final filtered coordinates. Thus the optimal stacking method will depend on whether coordinate precision or computational time is the over-riding criterion.

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Section: Introductionmentioning

confidence: 99%

GPS sidereal filtering: coordinate- and carrier-phase-level strategies

Ragheb

Clarke

Edwards

2006

J Geod

109

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“…[8] Multipath occurs when the GPS signal reflects before arriving at the antenna, resulting in a phase difference relative to the direct signal [e.g., Axelrad et al, 1996]. Multipath-induced errors can appear in many forms: The annual repeat in the GPS satellite configuration could cause an approximately annually ($350 day) repeating multipath signal [Ray et al, 2007]; unmodeled subdaily signals, including those from multipath, could propagate to longerperiod signals [Penna et al, 2007;King et al, 2008]; seasonal signals could be caused by changes in the vegetation, snow pack, and surface water of the local area around the antenna [Dong et al, 2002;Larson et al, 2008]; and changes in multipath could appear or disappear at random as the local environment changes [Dong et al, 2002].…”

Section: Introductionmentioning

confidence: 99%

Characterization of site‐specific GPS errors using a short‐baseline network of braced monuments at Yucca Mountain, southern Nevada

et al. 2009

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[1] We use a short-baseline network of braced monuments to investigate site-specific GPS effects. The network has baseline lengths of $10, 100, and 1000 m. Baseline time series have root mean square (RMS) residuals, about a model for the seasonal cycle, of 0.05-0.24 mm for the horizontal components and 0.20-0.72 mm for the radial. Seasonal cycles occur, with amplitudes of 0.04-0.60 mm, even for the horizontal components and even for the shortest baselines. For many time series these lag seasonal cycles in local temperature measurements by 23-43 days. This could suggest that they are related to bedrock thermal expansion. Both shorter-period signals and seasonal cycles for shorter baselines to REP2, the one short-braced monument in our network, are correlated with temperature, with no lag time. Differences between REP2 and the other stations, which are deep-braced, should reflect processes occurring in the upper few meters of the ground. These correlations may be related to thermal expansion of these upper ground layers, and/or thermal expansion of the monuments themselves. Even over these short distances we see a systematic increase in RMS values with increasing baseline length. This, and the low RMS levels, suggests that site-specific effects are unlikely to be the limiting factor in the use of similar GPS sites for geophysical investigations.

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“…Thus, building boundary data, digital terrain models and building models were used. [8], [14], [33], [50], [80], [98], [99] [4], [14], [30], [33], [35], [92], [47], [48], [50], [51], [58], [67], [68], [70], [74], [81], [82], [83], [85] Via person [18], [22] [43], [49], [66], [71] (No information) [28], [29], [31], [32], [34], [37], [73], [84], [86], [87], [88] Simulation Static measurement…”

Section: Recent Solutions For Positioning Under Nlos Conditionsmentioning

confidence: 99%