Design and validation of broadcast ephemeris for low Earth orbit satellites

Xie, Xin; Geng, Tao; Zhao, Qile; Liu, Xianglin; Zhang, Qiang; Liu, Jingnan

doi:10.1007/s10291-018-0719-9

Cited by 25 publications

(36 citation statements)

References 20 publications

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“…Due to the short visible window, the broadcast ephemeris design has different requirements as current GNSS satellites. There are a few studies discussing how to reasonably select the broadcast parameters to represent the centimeter-level LEO orbit [ 28 , 29 , 30 ]. However, all these methods are curve fitting based on precise orbit determination results.…”

Section: In-orbit Performance Evaluation Resultsmentioning

confidence: 99%

“…They also analyzed the error sources for LEO navigation signals and attempted to model them [ 27 ]. A few researchers even investigated the optimal design of broadcast ephemeris for LEO navigation satellites [ 28 , 29 , 30 ]. Rabinowitz systematically investigated certain challenging issues of LEO navigation receiver implementation [ 31 ].…”

Section: Introductionmentioning

confidence: 99%

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Initial Assessment of the LEO Based Navigation Signal Augmentation System from Luojia-1A Satellite

Wang

Chen

et al. 2018

Sensors

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A low Earth orbiter (LEO)-based navigation signal augmentation system is considered as a complementary of current global navigation satellite systems (GNSS), which can accelerate precise positioning convergence, strengthen the signal power, and improve signal quality. Wuhan University is dedicated to LEO-based navigation signal augmentation research and launched one scientific experimental satellite named Luojia-1A. The satellite is capable of broadcasting dual-frequency band ranging signals over China. The initial performance of the Luojia-1A satellite navigation augmentation system is assessed in this study. The ground tests indicate that the phase noise of the oscillator is sufficiently low to support the intended applications. The field ranging tests achieve 2.6 m and 0.013 m ranging precision for the pseudorange and carrier phase measurements, respectively. The in-orbit test shows that the internal precision of the ephemeris is approximate 0.1 m and the clock stability is 3 × 10−10. The pseudorange and carrier phase measurement noise evaluated from the geometry-free combination is about 3.3 m and 1.8 cm. Overall, the Luojia-1A navigation augmentation system is capable of providing useable LEO navigation augmentation signals with the empirical user equivalent ranging error (UERE) no worse than 3.6 m, which can be integrated with existing GNSS to improve the real-time navigation performance.

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Section: In-orbit Performance Evaluation Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Initial Assessment of the LEO Based Navigation Signal Augmentation System from Luojia-1A Satellite

Wang

Chen

et al. 2018

Sensors

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“…Studies have shown that when using the 16 ephemeris parameters as used in the GPS LNAV message, the fitting interval needs to be shortened to 10 to 20 min for LEO satellites to match the similar fitting errors as those for the GPS satellites with a fitting interval of 4 h [ 3 ]. It was also shown in [ 11 ] that adding additional ephemeris parameters and transforming certain ephemeris parameters are helpful to reduce the fitting errors and avoid the singularity problems. In this study, 20 ephemeris parameters were used to fit the predicted orbits within a fitting interval of 20 min.…”

Section: Processing Proceduresmentioning

confidence: 99%

“…Compared to the GNSS satellites, the LEO satellites experience more complicated dynamics due to their lower altitudes and, as a result, suffer from higher influences of the Earth’s gravitational field and the air drag [ 11 ]. As shown in [ 3 ], using the same set of the ephemeris parameters as the Global positioning system (GPS) legacy navigation (LNAV) message, an orbital user range error (OURE) induced by orbital fitting amounts to about 7 cm for the GPS satellites within a fitting interval of 4 h. For LEO satellites, however, this is only achievable within a much shorter fitting interval—i.e., from about 10 to 20 min.…”

Section: Introductionmentioning

confidence: 99%

“…As shown in [ 3 ], using the same set of the ephemeris parameters as the Global positioning system (GPS) legacy navigation (LNAV) message, an orbital user range error (OURE) induced by orbital fitting amounts to about 7 cm for the GPS satellites within a fitting interval of 4 h. For LEO satellites, however, this is only achievable within a much shorter fitting interval—i.e., from about 10 to 20 min. Additional and transformed ephemeris parameters are reported to be helpful to improve the OUREs [ 11 ]. The ephemeris parameters, however, need to be fit to the predicted but not the precise orbits.…”

Section: Introductionmentioning

confidence: 99%

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Proposed Orbital Products for Positioning Using Mega-Constellation LEO Satellites

Wang

El‐Mowafy

2020

Sensors

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With thousands of low Earth orbit (LEO) satellites to be launched in the near future, LEO mega-constellations are supposed to significantly change the positioning and navigation service for ground users. The goal of this contribution is to suggest and discuss the feasibility of possible procedures to generate the LEO orbital products at two accuracy levels to facilitate different positioning methods—i.e., Level A orbits with meter-level accuracy as LEO-specific broadcast ephemeris, and Level B orbits with an accuracy of centimeters as polynomial corrections based on Level A orbits. Real data of the LEO satellite GRACE FO-1 are used for analyzing the error budgets. For the Level A products, compared to the orbital user range errors (OUREs) of a few centimeters introduced by the ephemeris fitting, it was found that the orbital prediction errors play the dominant role in the total error budget—i.e., at around 0.1, 0.2 and 1 m for prediction intervals of 1, 2 and 6 h, respectively. For the Level B products, the predicted orbits within a short period of up to 60 s have an OURE of a few centimeters, while the polynomial fitting OUREs can be reduced by a few millimeters when increasing the polynomial degree from one to two.

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Prototype of Real-Time Orbit Service for LEO Navigation Satellite System

Meng,

Ge,

2023

Lecture Notes in Electrical Engineering

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Design and validation of broadcast ephemeris for low Earth orbit satellites

Cited by 25 publications

References 20 publications

Initial Assessment of the LEO Based Navigation Signal Augmentation System from Luojia-1A Satellite

Initial Assessment of the LEO Based Navigation Signal Augmentation System from Luojia-1A Satellite

Proposed Orbital Products for Positioning Using Mega-Constellation LEO Satellites

Prototype of Real-Time Orbit Service for LEO Navigation Satellite System

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