An approach to GPS clock prediction for real-time PPP during outages of RTS stream

Nie, Zhixi; Gao, Yang; Wang, Zhenjie; Ji, Shengyue; Yang, Huazhong

doi:10.1007/s10291-017-0681-y

Cited by 49 publications

(25 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Pronounced sinusoidal variations are found in GPS satellite clocks and the period equals the orbital period [23]. The clock prediction model with periodic terms can be expressed as [24]…”

Section: Clock Prediction Modelmentioning

confidence: 99%

“…Specifically, we first fit the clock models to the 24-h clock products to determine the model coefficients in (2) and extrapolate the models to generate predicted clocks for the next 4 h. It is noted that the preprocessing should be carried out to get rid of the large data gaps, outliers as well as the clock jumps [26]. The constant coefficient a 0 is computed with the latest satellite clock estimates in products to avoid possible deviation across the processing boundary [24]. Then, the predicted clocks are compared to the corresponding products, resulting in prediction errors.…”

Section: Constraining Of Predicted Clockmentioning

confidence: 99%

See 1 more Smart Citation

Precise Orbit Determination for GNSS Maneuvering Satellite with the Constraint of a Predicted Clock

et al. 2019

View full text Add to dashboard Cite

Precise orbit products are essential and a prerequisite for global navigation satellite system (GNSS) applications, which, however, are unavailable or unusable when satellites are undertaking maneuvers. We propose a clock-constrained reverse precise point positioning (RPPP) method to generate the rather precise orbits for GNSS maneuvering satellites. In this method, the precise clock estimates generated by the dynamic precise orbit determination (POD) processing before maneuvering are modeled and predicted to the maneuvering periods and they constrain the RPPP POD during maneuvering. The prediction model is developed according to different clock types, of which the 2-h prediction error is 0.31 ns and 1.07 ns for global positioning system (GPS) Rubidium (Rb) and Cesium (Cs) clocks, and 0.45 ns and 0.60 ns for the Beidou navigation satellite system (BDS) geostationary orbit (GEO) and inclined geosynchronous orbit (IGSO)/Median Earth orbit (MEO) satellite clocks, respectively. The performance of this proposed method is first evaluated using the normal observations without maneuvers. Experiment results show that, without clock-constraint, the average root mean square (RMS) of RPPP orbit solutions in the radial, cross-track and along-track directions is 69.3 cm, 5.4 cm and 5.7 cm for GPS satellites and 153.9 cm, 12.8 cm and 10.0 cm for BDS satellites. When the constraint of predicted satellite clocks is introduced, the average RMS is dramatically reduced in the radial direction by a factor of 7–11, with the value of 9.7 cm and 13.4 cm for GPS and BDS satellites. At last, the proposed method is further tested on the actual GPS and BDS maneuver events. The clock-constrained RPPP POD solution is compared to the forward and backward integration orbits of the dynamic POD solution. The resulting orbit differences are less than 20 cm in all three directions for GPS satellite, and less than 30 cm in the radial and cross-track directions and up to 100 cm in the along-track direction for BDS satellites. From the orbit differences, the maneuver start and end time is detected, which reveals that the maneuver duration of GPS satellites is less than 2 min, and the maneuver events last from 22.5 min to 107 min for different BDS satellites.

show abstract

“…Pronounced sinusoidal variations are found in GPS satellite clocks and the period equals the orbital period [23]. The clock prediction model with periodic terms can be expressed as [24]…”

Section: Clock Prediction Modelmentioning

confidence: 99%

Section: Constraining Of Predicted Clockmentioning

confidence: 99%

Precise Orbit Determination for GNSS Maneuvering Satellite with the Constraint of a Predicted Clock

et al. 2019

View full text Add to dashboard Cite

show abstract

“…It is evident to find that all processing scenarios achieve similar positioning accuracy at about 0.4 m, 0.3 m, 0.6 m in the east, north, up directions for the middle latitude region and 0.4 m, 0.2 m, 0.6 m for the low latitude region, respectively. It should be noted that the accuracy of the IGU predicted orbit and clock products is lower than the open‐access RT service products [40]. The obtained final positioning accuracy is limited owing to the quality of the used satellite orbit and clock products.…”

Section: Rt Sf Ppp Results and Analysismentioning

confidence: 99%

Least‐squares collocation modelling of regional ionospheric TEC for accelerating real‐time single‐frequency PPP convergence

Gong

Cai

Dai

et al. 2019

IET Radar, Sonar & Navigation

View full text Add to dashboard Cite

“…It is transmitted over the internet based on the Networked Transport of RTCM via Internet Protocol (NTRIP) [ 41 ]. In spite of numerous studies to evaluate the performance of real-time PPP with RTS correction products [ 42 , 43 , 44 , 45 , 46 ], there are few studies, to our knowledge, devoted to real-time coseismic displacement retrieval based on TPP method with RTS correction products.…”

Section: Introductionmentioning

confidence: 99%

Real-Time Coseismic Displacement Retrieval Based on Temporal Point Positioning with IGS RTS Correction Products

Zhang

Nie

Wang

et al. 2021

Sensors

Self Cite

View full text Add to dashboard Cite

With the rapid development of the global navigation satellite system (GNSS), high-rate GNSS has been widely used for high-precision GNSS coseismic displacement retrieval. In recent decades, relative positioning (RP) and precise point positioning (PPP) are mainly adopted to retrieve coseismic displacements. However, RP can only obtain relative coseismic displacements with respect to a reference station, which might be subject to quaking during a large seismic event. While PPP needs a long (re)convergence period of tens of minutes. There is no convergence time needed in the variometric approach for displacements analysis standalone engine (VADASE) but the derived displacements are accompanied by a drift. Temporal point positioning (TPP) method adopts temporal-differenced ionosphere-free phase measurements between a reference epoch and the current epoch, and there is almost no drift in the displacement derived from TPP method. Nevertheless, the precise orbit and clock products should be applied in the TPP method. The studies in recent years are almost based on the postprocessing precise orbits and clocks or simulated real-time products. Since 2013, international GNSS service (IGS) has been providing an open-access real-time service (RTS), which consists of orbit, clock and other corrections. In this contribution, we evaluated the performance of real-time coseismic displacement retrieval based on TPP method with IGS RTS correction products. At first, the real-time precise orbit and clock offsets are derived from the RTS correction products. Then, the temporal-differenced ionosphere-free (IF) combinations are formed and adopted as the TPP measurements. By applying real-time precise orbit and clock offsets, the coseismic displacement can be real-timely retrieved based on TPP measurements. To evaluate the accuracy, two experiments including a stationary experiment and an application to an earthquake event were carried out. The former gives an accuracy of 1.8 cm in the horizontal direction and 4.1 cm in the vertical direction during the whole period of 15-min. The latter gives an accuracy of 1.2 cm and 2.4 cm in the horizontal and vertical components, respectively.

show abstract

An approach to GPS clock prediction for real-time PPP during outages of RTS stream

Cited by 49 publications

References 15 publications

Precise Orbit Determination for GNSS Maneuvering Satellite with the Constraint of a Predicted Clock

Precise Orbit Determination for GNSS Maneuvering Satellite with the Constraint of a Predicted Clock

Least‐squares collocation modelling of regional ionospheric TEC for accelerating real‐time single‐frequency PPP convergence

Real-Time Coseismic Displacement Retrieval Based on Temporal Point Positioning with IGS RTS Correction Products

Contact Info

Product

Resources

About