GPS IIF-the next generation

Fisher, Sarah; Ghassemi, Kamran

doi:10.1109/5.736340

Cited by 65 publications

(32 citation statements)

References 3 publications

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“…In the current GPS system (where the satellites have an altitude of 20 000 km), the errors in the ephemeris data result in a UERE of about ±2.5 m [12,13]. For the new system, however, the altitude of the satellites is much smaller; specifically, 3180 km.…”

Section: Ephemeris Errorsmentioning

confidence: 99%

Third‐generation GPS: A low‐maintenance, high‐reliability future GPS system

Bakhoum

2010

Int J Communication

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SUMMARYThis paper introduces the principles of the third-generation Global Positioning Satellite (GPS) system, which is now in the early development phase. The new system has substantial advantages, including the elimination of the Doppler correction and signal tracking circuitry in the receivers. The benefits will be a significantly reduced receiver size and low-maintenance requirements for the satellites. Another objective of the paper is to present a closed-form solution for the GPS geolocation equations that does not depend on range data. Such a solution did not exist previously in the literature. Simulations that characterize the User Equivalent Range Errors in the new system are given.

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Section: Ephemeris Errorsmentioning

confidence: 99%

Third‐generation GPS: A low‐maintenance, high‐reliability future GPS system

Bakhoum

2010

Int J Communication

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“…The orientation of the spacecraft coordinate system is shown in Fig. 4 based on design drawings contained in Fisher and Ghassemi (1999) and Dorsey et al (2006). The direction of the positive x-axis can most easily be identified from the placement of the large auxiliary payload receive antenna, which extends from the Àx-face.…”

Section: Gpsmentioning

confidence: 99%

GNSS satellite geometry and attitude models

Montenbruck

Schmid

Mercier

et al. 2015

Advances in Space Research

196

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This article discusses the attitude modes employed by present Global (and Regional) Navigation Satellite Systems (GNSSs) and the models used to describe them along with definitions of the constellation-specific spacecraft body frames. A uniform convention for the labeling of the principal spacecraft axes is proposed by the International GNSS Service (IGS), which results in a common formulation of the nominal attitude of all GNSS satellites in yaw-steering mode irrespective of their specific orbit and constellation. The conventions defined within this document provide the basis for the specification of antenna phase center offsets and variations in a multi-GNSS version of the IGS absolute phase center model in the ANTEX (antenna exchange) format. To facilitate the joint analysis of GNSS observations and satellite laser ranging measurements, laser retroreflector array coordinates consistent with the IGS-specific spacecraft frame conventions are provided in addition to representative antenna offset values for all GNSS constellations.

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“…To de-correlate them, measurements other than pseudo-range code and carrier phase may be used to determine GEO satellites' orbits. For example, GEO single-satellite precise orbit determination (SPOD) using satellite laser ranging (SLR) data and two-way C-band ranging is able to obtain the orbital error of about 3 m evaluated by orbital overlapping, with C-band ranging data fitting root-mean-squares (RMS) of 0.205 m, and SLR data fitting of about 0.133 m. For 2-hour orbital prediction, radial error is about 0.373 m [1][2][3][4].…”

Section: Introductionmentioning

confidence: 99%

Orbit determination and time synchronization for a GEO/IGSO satellite navigation constellation with regional tracking network

Zhou

et al. 2011

Sci. China Phys. Mech. Astron.

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Aiming at regional services, the space segment of COMPASS (Phase I) satellite navigation system is a constellation of Geostationary Earth Orbit (GEO), Inclined Geostationary Earth Orbit (IGSO) and Medium Earth Orbit (MEO) satellites. Precise orbit determination (POD) for the satellites is limited by the geographic distribution of regional tracking stations. Independent time synchronization (TS) system is developed to supplement the regional tracking network, and satellite clock errors and orbit data may be obtained by simultaneously processing both tracking data and TS data. Consequently, inconsistency between tracking system and TS system caused by remaining instrumental errors not calibrated may decrease navigation accuracy. On the other hand, POD for the mixed constellation of GEO/IGSO/MEO with the regional tracking network leads to parameter estimations that are highly correlated. Notorious example of correlation is found between GEO's orbital elements and its clock errors. We estimate orbital elements and clock errors for a 3GEO+2IGSO constellation in this study using a multi-satellite precise orbit determination (MPOD) strategy, with which clock error elimination algorithm is applied to separate orbital and clock estimates to improve numerical efficiency. Satellite Laser Ranging (SLR) data are used to evaluate User Ranging Error (URE), which is the orbital error projected on a receiver's line-of-sight direction. Two-way radio-wave time transfer measurements are used to evaluate clock errors. Experimenting with data from the regional tracking network, we conclude that the fitting of code data is better than 1 m in terms of Root-Mean-Square (RMS), and fitting of carrier phase is better than 1 cm. For orbital evaluation, difference between computed receiver-satellite ranging based on estimated orbits and SLR measurements is better than 1 m (RMS). For clock estimates evaluation, 2-hour linear-fitting shows that the satellite clock rates are about 1.E-10 s/s, while receiver clock rates are about 1×10 13 -1×10 12 s/s. For the 72-hour POD experiment, the average differences between POD satellite clock rates estimates and clock measurements based on TS system are about 1×10 13 s/s, and for receiver clock rates, the differences are about 1×10 15 s/s. POD, time synchronization, clock errors elimination, SLR evaluationPACS: 95.10.Eg, 93.85.Bc, 06.30.Ft, 95.55.Sh, 93.30.Db

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GPS IIF-the next generation

Cited by 65 publications

References 3 publications

Third‐generation GPS: A low‐maintenance, high‐reliability future GPS system

Third‐generation GPS: A low‐maintenance, high‐reliability future GPS system

GNSS satellite geometry and attitude models

Orbit determination and time synchronization for a GEO/IGSO satellite navigation constellation with regional tracking network

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