GPS orbit determination using the double difference phase observable

2005 ◽  
pp. 31-46
Author(s):  
G. Beutler
Keyword(s):  
Orbit Determination ◽  
Double Difference

scholarly journals The Preliminary Results for Five-System Ultra-Rapid Precise Orbit Determination of the One-Step Method Based on the Double-Difference Observation Model

2018 ◽  
Vol 11 (1) ◽  
pp. 46 ◽  
Author(s):  
Fei Ye ◽  
Yunbin Yuan ◽  
Bingfeng Tan ◽  
Zhiguo Deng ◽  
Jikun Ou
Keyword(s):  
Orbit Determination ◽  
Precise Orbit Determination ◽  
Double Difference ◽  
Observation Model ◽  
Software Platform ◽  
Step Method ◽  
Precise Orbit ◽  
One Step ◽  
The One ◽  
Prototype Software

The predicted parts of ultra-rapid orbits are important for (near) real-time Global Navigation Satellite System (GNSS) precise applications; and there is little research on GPS/GLONASS/BDS/Galileo/QZSS five-system ultra-rapid precise orbit determination; based on the one-step method and double-difference observation model. However; the successful development of a software platform for solving five-system ultra-rapid orbits is the basis of determining and analyzing these orbits. Besides this; the different observation models and processing strategies facilitate to validate the reliability of the various ultra-rapid orbits. In this contribution; this paper derives the double-difference observation model of five-system ultra-rapid precise orbit determination; based on a one-step method; and embeds this method and model into Bernese v5.2; thereby forming a new prototype software platform. For validation purposes; 31 days of real tracking data; collected from 130 globally-distributed International GNSS Service (IGS) multi-GNSS Experiment (MGEX) stations; are used to determine a five-system ultra-rapid precise orbit. The performance of the software platform is evaluated by analysis of the orbit discontinuities at day boundaries and by comparing the consistency with the MGEX orbits from the Deutsches GeoForschungsZentrum (GFZ); between the results of this new prototype software platform and the ultra-rapid orbit provided by the International GNSS Monitoring and Assessment System (iGMAS) analysis center (AC) at the Institute of Geodesy and Geophysics (IGG). The test results show that the average standard deviations of orbit discontinuities in the three-dimension direction are 0.022; 0.031; 0.139; 0.064; 0.028; and 0.465 m for GPS; GLONASS; BDS Inclined Geosynchronous Orbit (IGSO); BDS Mid-Earth Orbit (MEO); Galileo; and QZSS satellites; respectively. In addition; the preliminary results of the new prototype software platform show that the consistency of this platform has been significantly improved compared to the software package of the IGGAC.

scholarly journals Sentinel-3A/3B orbit determination using non-gravitational force modeling and single-receiver ambiguity resolution

2020 ◽  
Author(s):  
Xinyuan Mao ◽  
Daniel Arnold ◽  
Adrian Jäggi
Keyword(s):  
High Precision ◽  
Radiation Pressure ◽  
Ambiguity Resolution ◽  
Orbit Determination ◽  
Gravitational Force ◽  
Dynamic Models ◽  
European Space Agency ◽  
Double Difference ◽  
Force Modeling ◽  
Single Receiver

<p>Sentinel-3 is an Earth observation satellite formation of the European Space Agency (ESA) devoted to oceanography and land-vegetation monitoring. It operates as a crucial segment of the Copernicus Programme coordinated by the European Union. Up until now, two identical Sentinel-3 satellites, Sentinel-3A and -3B, have been launched into a circular sun-synchronous orbit with an altitude of about 800 km. Their prime onboard payload systems, e.g. radar altimeter, necessitate high-precision orbits, particularly in the radial direction. This can be fulfilled by using the collected measurements from the onboard dual-frequency high-precision multi-channel Global Positioning System (GPS) receivers. The equipped laser retro-reflector allows for external and independent validation to the GPS-derived orbits.</p><p>This research will outline the recent Precise Orbit Determination (POD) methodology developments at the Astronomical Institute of the University of Bern (AIUB) and investigate  the POD comparison between Sentinel-3A and -3B satellites. On one hand, a refined satellite non-gravitational force modeling strategy is newly implemented into the BERNESE GNSS software. It consists of comprehensive modeling of atmospheric drag, solar radiation pressure and Earth albedo/radiation pressure based on an 8-plate satellite macromodel. Radiation pressure is modeled considering spontaneous re-emission for non-solar plates. Besides, a linear interpolation between monthly Clouds and the Earth's Radiant Energy System (CERES) S4 grid products is specifically done for the Earth albedo/radiation pressure modeling. On the other hand, use is made of the GNSS Observation-Specific Bias (OSB) products provided by the Center for Orbit Determination in Europe (CODE), allowing for the so-called single-receiver ambiguity resolution.</p><p>A test period is selected from 7/Jun/2018 to 14/Oct/2018 (Day of Year: 158-287), when Sentinel-3A and -3B satellites operated in a tandem formation maintained at a separation of about 30 s. This foresees nearly identical in-flight environment for both satellites and thereby enables direct POD performance comparison. The single-receiver (zero-difference) ambiguity-fixed orbit solutions can also be compared with the double-difference ambiguity-fixed baseline solution. Results reveal that the implemented non-gravitational force modeling in POD leads to a reduction of empirical acceleration estimates, which are designated to compensate uncertainties in the satellite dynamic models. Single-receiver ambiguity resolution further improves the reduced-dynamic orbits and significant enhancement occurs to the kinematic orbits. This research implies promising benefits to the Sentinel-3 scientific research community.</p>

Efficient LEO Dynamic Orbit Determination with Triple Differenced GPS Carrier Phases

2007 ◽  
Vol 60 (2) ◽  
pp. 217-232 ◽  
Author(s):  
Tae-Suk Bae ◽  
Dorota Grejner-Brzezinska ◽  
Jay Hyoun Kwon
Keyword(s):  
Orbit Determination ◽  
Precise Orbit Determination ◽  
Low Earth Orbit ◽  
Double Difference ◽  
Arc Length ◽  
Alternative Approach ◽  
Cycle Slip Detection ◽  
Orbit Estimation ◽  
Better Than

The dynamic precise orbit determination of a Low Earth Orbit satellite using triple differenced GPS phases is presented in this study. The atmospheric drag parameters are estimated to compensate the incomplete atmosphere model for better precision of the orbit solution. In addition, the empirical force parameters, especially once- and twice-per-revolution components, along with the new IERS Conventions and models to compute the perturbing forces are introduced to absorb the remaining unmodelled forces. The optimal arc length for the parameterization and the data processing strategy are also tested and analyzed for the best orbit solutions. The triple differencing technique enables fast and efficient orbit estimation, because no ambiguity resolution and cycle slip detection are required. With the triple differenced ion-free GPS phase observables, the orbit and the velocity solutions for 24 hours of CHAMP are calculated; they compare with the published Rapid Science Orbit with the accuracy of 8 cm and 0·12 mm/s in 3D RMS for the orbit and the velocity, respectively, and are statistically consistent with the RSO when it is not better than 4 cm in terms of an absolute accuracy. The approach presented here provides an efficient and simple, but robust, alternative approach, while the solution's accuracy is still comparable to the double-difference results.

scholarly journals Kinematic and reduced-dynamic precise orbit determination of low earth orbiters

2003 ◽  
Vol 1 ◽  
pp. 47-56 ◽  
Author(s):  
D. Švehla ◽  
M. Rothacher
Keyword(s):  
Ambiguity Resolution ◽  
Orbit Determination ◽  
Precise Orbit Determination ◽  
Double Difference ◽  
Phase Measurements ◽  
Precise Orbit ◽  
First Results ◽  
Orbit Dynamic ◽  
Reduced Dynamic

Abstract. Various methods for kinematic and reduced-dynamic precise orbit determination (POD) of Low Earth Orbiters (LEO) were developed based on zero- and double-differencing of GPS carrier-phase measurements with and without ambiguity resolution. In this paper we present the following approaches in LEO precise orbit determination: – zero-difference kinematic POD, – zero-difference dynamic POD, – double-difference kinematic POD with and without ambiguity resolution, – double-difference dynamic POD with and without ambiguity resolution, – combined GPS/SLR reduced-dynamic POD. All developed POD approaches except the combination of GPS/SLR were tested using real CHAMP data (May 20-30, 2001) and independently validated with Satellite Laser Ranging (SLR) data over the same 11 days. With SLR measurements, additional combinations are possible and in that case one can speak of combined kinematic or combined reduced-dynamic POD. First results of such a combined GPS/SLR POD will be presented, too. This paper shows what LEO orbit accuracy may be achieved with GPS using different strategies including zerodifference and double-difference approaches. Kinematic versus dynamic orbit determination is presently an interesting issue that will also be discussed in this article.Key words. POD, kinematic orbit, dynamic orbit, LEO, CHAMP, ambiguity resolution, GPS, SLR

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