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

Gabor, Michael J.; Nerem, R. S.

doi:10.1002/j.2161-4296.2002.tb00270.x

Cited by 27 publications

(20 citation statements)

References 8 publications

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“…wide-lane carrier-phase minus narrow-lane code (Garbor and Nerem, 2002), provides direct access to the wide-lane ambiguities. However it still contains the receiver and satellite biases.…”

Section: Post-processed Rtx-aided Inertial Solutionmentioning

confidence: 99%

Centimeter-Level, Robust GNSS-Aided Inertial Post-Processing for Mobile Mapping Without Local Reference Stations

Hutton¹,

Gopaul²,

Zhang³

et al. 2016

Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.

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ABSTRACT:For almost two decades mobile mapping systems have done their georeferencing using Global Navigation Satellite Systems (GNSS) to measure position and inertial sensors to measure orientation. In order to achieve cm level position accuracy, a technique referred to as post-processed carrier phase differential GNSS (DGNSS) is used. For this technique to be effective the maximum distance to a single Reference Station should be no more than 20 km, and when using a network of Reference Stations the distance to the nearest station should no more than about 70 km. This need to set up local Reference Stations limits productivity and increases costs, especially when mapping large areas or long linear features such as roads or pipelines.An alternative technique to DGNSS for high-accuracy positioning from GNSS is the so-called Precise Point Positioning or PPP method. In this case instead of differencing the rover observables with the Reference Station observables to cancel out common errors, an advanced model for every aspect of the GNSS error chain is developed and parameterized to within an accuracy of a few cm. The Trimble Centerpoint RTX positioning solution combines the methodology of PPP with advanced ambiguity resolution technology to produce cm level accuracies without the need for local reference stations. It achieves this through a global deployment of highly redundant monitoring stations that are connected through the internet and are used to determine the precise satellite data with maximum accuracy, robustness, continuity and reliability, along with advance algorithms and receiver and antenna calibrations. This paper presents a new post-processed realization of the Trimble Centerpoint RTX technology integrated into the Applanix POSPac MMS GNSS-Aided Inertial software for mobile mapping. Real-world results from over 100 airborne flights evaluated against a DGNSS network reference are presented which show that the post-processed Centerpoint RTX solution agrees with the DGNSS solution to better than 2.9 cm RMSE Horizontal and 5.5 cm RMSE Vertical. Such accuracies are sufficient to meet the requirements for a majority of airborne mapping applications.

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“…wide-lane carrier-phase minus narrow-lane code (Garbor and Nerem, 2002), provides direct access to the wide-lane ambiguities. However it still contains the receiver and satellite biases.…”

Section: Post-processed Rtx-aided Inertial Solutionmentioning

confidence: 99%

Centimeter-Level, Robust GNSS-Aided Inertial Post-Processing for Mobile Mapping Without Local Reference Stations

Hutton¹,

Gopaul²,

Zhang³

et al. 2016

Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.

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“…Gabor and Nerem [4] and Laurichesse and Mercier [5] estimated the L1 and L2 phase biases by combining the fractional bias term of the Melbourne-Wübbena combination [6] and the joint bias/ ambiguity term of the geometrypreserving, ionosphere-free phase-only combination. The obtained pseudo-phase biases enable an unbiased estimation of the L1 and L2 integer ambiguities.…”

Section: Introductionmentioning

confidence: 99%

Multi-Stage Satellite Phase and Code Bias Estimation

2012

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Original scientific paperPrecise point positioning with satellite navigation signals requires knowledge of satellite code and phase biases. In this paper, a new multi-stage method is proposed for estimating of these biases using measurements from a geodetic network. The method first subtracts all available a priori knowledge on orbits, satellite clocks and multipath from the measurements to reduce their dynamics. Secondly, satellite phase biases, ionospheric delays, carrier phase integer ambiguities and the geometry combining all non-dispersive parameters are jointly estimated in a Kalman filter. Finally, the a posteriori geometry estimates are refined in a second Kalman filter for the computation of orbital errors, code biases and tropospheric delays. As the first Kalman filter introduces time correlation, a generalized Kalman filter for colored measurement noise is applied in the second stage. The proposed algorithm is applied to dual frequency GPS measurements from a local geodetic network in Germany. A remarkable bias stability with variations of less than 3 cm over 4 hours is observed. Key words: Satellite navigation, Phase biases, Code biases, Ambiguity resolutionVišerazinska procjena faznih i kodnih pomaka satelitskog signala. Precizno odreîivanje položaja uporabom satelitske navigacije zahtjeva poznavanje satelitskog koda te fazna mjerenja. U ovom radu predložena je nova metoda za procjenu faznih pomaka signala uporabom rezultata mjerenja iz geodetske mreže. U prvom koraku iz mjerenja se izuzimaju poznati podaci o orbitama, satelitskim satovima i višestrukim putevima, kako bi se smanjila njihova dinamika. U drugom se koraku uporabom Kalmanovog filtra procjenjuju fazni pomaci, ionosferska kašnje-nja, neodreîenost broja valnih duljina nosioca i geometrija koja uključuje sve nedisperzivne parametre. Konačno, odreîuje se korigirana geometrija u drugom Kalmanovom filtru radi proračuna orbitalnih pogrešaka, pogrešaka koda i troposferskog kašnjenja. S obzirom na to da prvi Kalmanov filtar unosi vremensku korelaciju, opći Kalmanov filtar primjenjuje se u drugom koraku. Predloženi algoritam primijenjen je u dvofrekvencijskim GPS-mjerenjima u lokalnoj geodetskoj mreži u Njemačkoj. Postignuta je visoka stabilnost rezultata uz varijacije manje od 3 cm tijekom 4 sata.

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“…Double differencing cancels out fractional phase contributions from the transmitters and receivers to the carrierphase measurements [1,2]. An alternative approach to resolving ambiguities by calibrating the two satellite and one receiver single-difference combinations (SSR single differences) has been attempted and documented [3]. The development of this method included an investigation into the behavior of the GPS satellite phase biases.…”

Section: Introductionmentioning

confidence: 99%

“…The equation for the widelane biases is derived in [3] as (1) where is the widelane bias measurement formed by differencing and , the two satellite and one receiver single-differenced widelane carrier-phase and pseudorange measurements, respectively, and dividing by the widelane wavelength, w .…”

Section: Introductionmentioning

confidence: 99%

“…where is the single-difference widelane carrierphase fractional bias, is the single-difference widelane carrier-phase integer ambiguity, and and are the two associated group delay biases. Because the group delay biases are inseparable from the widelane biases, a new fractional bias term is defined such that the group delay biases are aliased: (3) in order to simplify notation. Hereafter in this paper, is assumed to include the widelane group delay combination.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Characteristics of Satellite-Satellite Single-Difference Widelane Fractional Carrier-Phase Biases

Gabor

Nerem²

2004

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To analyze the behavior characteristics of widelane fractional carrier-phase biases, time series of biases were analyzed. Single-differenced widelane fractional phase bias calibration values, involving two GPS satellites and one receiver, were analyzed for long-term characteristics between January 1, 1997, and May 30, 1998. The single differencing removes receiver effects, and differencing of the code and carrier-phase measurements isolates the widelane ambiguity. This ambiguity term includes a fraction that is consistent for each single-difference satellite pair. These fractional terms were averaged over a global tracking network using directional statistics to calculate daily fractional phase bias calibration values. Trends were then computed for individual GPS satellites. Over the test period, satellites 22, 26, 27, 29, 31, and 32 experienced near-zero drift rates in widelane and signals with amplitudes smaller than 0.1 widelane cycle. Satellites 30, 33, and 40 had high drift rates between 0.78 and 1.4 widelane cycles/year and substantial second-order signals. These groupings are correlated with mission launch date.

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

Cited by 27 publications

References 8 publications

Centimeter-Level, Robust GNSS-Aided Inertial Post-Processing for Mobile Mapping Without Local Reference Stations

Centimeter-Level, Robust GNSS-Aided Inertial Post-Processing for Mobile Mapping Without Local Reference Stations

Multi-Stage Satellite Phase and Code Bias Estimation

Characteristics of Satellite-Satellite Single-Difference Widelane Fractional Carrier-Phase Biases

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