Towards GPS orbit accuracy of tens of centimeters

Lichten, S. M.

doi:10.1029/gl017i003p00215

Cited by 16 publications

(6 citation statements)

References 6 publications

(3 reference statements)

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“…In the course of the multiday arc analysis, a stochastic model was tested for the GPS satellite solar radiation pressure coefficients. This model, described by Lichten and Bertiger [1989] and Lichten [1990b], allows for estimation of tightly constrained accelerations acting on the spacecraft in order to compensate for effects such as gas leaks and deficiencies in the solar pressure model which can build up over data arcs of several days or more. However, when applied to the 1986 Caribbean data set, no statistically significant improvement in baseline repeatability was noticed.…”

Section: Multiday Arcs: Reducing Orbit Errorsmentioning

confidence: 99%

First epoch geodetic measurements with the Global Positioning System across the Northern Caribbean Plate Boundary Zone

Dixon¹,

González²,

Lichten³

et al. 1991

J. Geophys. Res.

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The first geodetic survey across the northern Caribbean plate boundary zone with the Global Positioning System (GPS) was conducted in June 1986. Baseline vectors defined by the six station regional GPS network ranged from 170 to 1260 km in length. Repeatability of independent daily baseline estimates was better than 8 mm plus 1.3 parts in 108 of baseline length for horizontal components. The wet tropospheric path delay during the experiment was both high, sometimes exceeding 30 cm at zenith, and variable, sometimes exceeding 5 cm variation over several hours. Successful carrier phase cycle ambiguity resolution (“bias fixing”) could not be achieved prior to construction of a regional troposphere model. Tropospheric calibration was achieved with water vapor radiometers at selected sites, and with stochastic troposphere models and estimation techniques at remaining sites. With optimum troposphere treatment and single‐day orbital arcs, we resolved most biases on baselines up to about 550 km in length. With multiday orbital arcs we resolved most biases in the network regardless of baseline length. Our results suggest that constraints on plate boundary zone deformation in the Greater Antilles, and on the North America‐Caribbean relative plate motion vector, can be obtained with a series of GPS experiments spanning less than 10 and 15 years, respectively.

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Section: Multiday Arcs: Reducing Orbit Errorsmentioning

confidence: 99%

First epoch geodetic measurements with the Global Positioning System across the Northern Caribbean Plate Boundary Zone

Dixon¹,

González²,

Lichten³

et al. 1991

J. Geophys. Res.

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“…The GPS ephemerides in this analysis are determined to accuracies from 0.5 m to slightly over 1 m. By comparison, current GPS ephemerides produced in precise global geodetic solution are believed to have an accuracy of 0.2-0.6 m [Lichten, 1990b]. Improvement in the future is also expected.…”

Section: Units In Milligalsmentioning

confidence: 91%

TOPEX orbit determination and gravity recovery using global positioning system data from repeat orbits

Wu¹,

Yunck²

1992

J. Geophys. Res.

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A covariance analysis is presented for satellite tracking and gravity recovery with a differential Global Positioning System-based technique to be demonstrated on TOPEX in the early 1990s. The technique employs data from an ensemble of repeat ground tracks to recover a unique satellite epoch state for each track and a set of invariant positional parameters common to all tracks. The positional parameters represent the effect of mismodeled gravitational field on the satellite orbit. At an altitude of 1336 km, where gravity modeling is the dominant systematic error, averaging of random error over many arcs and adjustment of the gravity model reduce the final satellite position error. The positional parameters can then be used to produce a refined global gravity model. The analysis indicates that errors ranging from 5 to 8 cm in TOPEX altitude and 0.05 to 0.2 mGal for the gravity field can be achieved, depending on the number of repeat arcs used. INTRODUCTIONNASA's Ocean Topography Experiment (TOPEX) will carry an orbiting radar altimeter to measure sea surface height, with the primary goal of charting global ocean circulation [Born et al., , 1985. TOPEX will fly in a 1336-km circular orbit inclined at 66.1 ø. The altimeter measurements, averaged over a several kilometer footprint, will be precise to about 2.5 cm. In order to make maximum use of the precise altimetry it is necessary to independently track the satellite geocentric altitude with comparably high precision. The baseline tracking system for TOPEX is a global network of laser-ranging systems which is expected to deliver about 13-cm altitude accuracy for TOPEX [Born et al., , 1985. In addition, an experimental tracking system employing the Global Positioning System (GPS) will be used in a special demonstration. The experimental system will make use of an on-board GPS receiver operating in concert with a network of six ground receivers distributed around the globe [Lichten et al., 1985]. A number of estimation techniques have been proposed to determine the TOPEX orbit using the GPS data [Yunck et al., 1990; Melbourne et al., 1986]. The most thoroughly studied techniques are variations on the traditional dynamic technique which requires the use of accurate force models. Systematic errors in the force models lead directly to systematic errors in the orbit solution. At the 1336-km TOPEX altitude, which is well above the regime of significant atmospheric drag, errors in the model for the Earth's gravity field are the major source of dynamic orbit error [Lichten et al., 1985; Wu et al., 1986].Because it provides continuous coverage with accurate measurements, the GPS system allows alternative tracking techniques which are less dependent on the nominal dynamic models. Two recently proposed alternatives to dynamic orbit estimation, the kinematic and reduced dynamic techniques Wu et al., 1991], make use of geometric information in GPS observations to greatly reduce the sensitivity to force model errors. A third ap-

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“…The International GPS Service for Geodynamics (IGS) and its members have been improving the accuracy by solving for GPS satellite orbits over a globally distributed network of geodetic-quality GPS receivers [7]. Computing orbits over a distributed network provides an opportunity to improve the solutions using double-difference ambiguity resolution [8], bootstrapping (a process of fixing observations of shorter baselines that reduces the uncertainties in the other estimates, which then improves the likelihood of fixing the ambiguities for longer baselines) [1], improved orbit modeling [9], and various other orbit improvement strategies [10]. In the course of computing these precise postprocessed GPS orbits, ambiguity resolution is applied to a large, globally distributed network of receivers.…”

Section: A New Approachmentioning

confidence: 99%

“…The four single-differenced measurements for each satellite combination j and k in units of range are (6) (7) (8) (9) where the specific receiver subscript has been dropped from the notation to be replaced by a numbered subscript referring to the frequency of the signal. Also, is the single difference of ionospheric delay to satellites j and k (m) -a delay for range calculations, but an advance in phase; and ⌬ is the single difference of receiver antenna phase center offset corrections (m).…”

Section: Derivation Of Widelane Biasesmentioning

confidence: 99%

Satellite-Satellite Single-Difference Phase Bias Calibration As Applied to Ambiguity Resolution

Gabor

Nerem²

2002

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Towards GPS orbit accuracy of tens of centimeters

Cited by 16 publications

References 6 publications

First epoch geodetic measurements with the Global Positioning System across the Northern Caribbean Plate Boundary Zone

First epoch geodetic measurements with the Global Positioning System across the Northern Caribbean Plate Boundary Zone

TOPEX orbit determination and gravity recovery using global positioning system data from repeat orbits

Satellite-Satellite Single-Difference Phase Bias Calibration As Applied to Ambiguity Resolution

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