Improved GPS-based Satellite Relative Navigation Using Femtosecond Laser Relative Distance Measurements

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This study presents the generation and accuracy assessment of predicted orbital ephemeris based on satellite laser ranging (SLR) for geostationary Earth orbit (GEO) satellites. Two GEO satellites are considered: GEO-Korea Multi-Purpose Satellite (KOMPSAT)-2B (GK-2B) for simulational validation and Compass-G1 for real-world quality assessment. SLR-based orbit determination (OD) is proactively performed to generate orbital ephemeris. The length and the gap of the predicted orbital ephemeris were set by considering the consolidated prediction format (CPF). The resultant predicted ephemeris of GK-2B is directly compared with a pre-specified true orbit to show 17.461 m and 23.978 m, in 3D root-mean-square (RMS) position error and maximum position error for one day, respectively. The predicted ephemeris of Compass-G1 is overlapped with the Global Navigation Satellite System (GNSS) final orbit from the GeoForschungsZentrum (GFZ) analysis center (AC) to yield 36.760 m in 3D RMS position differences. It is also compared with the CPF orbit from the International Laser Ranging Service (ILRS) to present 109.888 m in 3D RMS position differences. These results imply that SLR-based orbital ephemeris can be an alternative candidate for improving the accuracy of commonly used radar-based orbital ephemeris for GEO satellites.

Section: Introductionmentioning

confidence: 99%

Validation of Geostationary Earth Orbit Satellite Ephemeris Generated from Satellite Laser Ranging

Park

Lim

et al. 2018

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“…Although laser ranging has been used extensively for satellite laser ranging (SLR) (Jo et al 2011;Lim et al 2011;Choi et al 2014;Kim et al 2015;Oh et al 2017), the technique can also be employed for measuring an inter-satellite distance (Jung et al 2012;Lee et al 2018). In this study, it was assumed that the satellite navigation algorithms were properly performed to figure out satellite's position and velocity vectors (Oh et al 2016;Shin et al 2016;Kim et al 2017;Lee et al 2017a, b). One possible scientific mission that could be achieved with such configuration is a satellite gravimetry mission akin to GRACE with formation flying.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Inter-satellite Ranging Precision for Gravity Recovery in a Satellite Gravimetry Mission

Kim

Park²,

Kang

et al. 2018

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In a satellite gravimetry mission similar to GRACE, the precision of inter-satellite ranging is one of the key factors affecting the quality of gravity field recovery. In this paper, the impact of ranging precision on the accuracy of recovered geopotential coefficients is analyzed. Simulated precise orbit determination (POD) data and inter-satellite range data of formation-flying satellites containing white noise were generated, and geopotential coefficients were recovered from these simulated data sets using the crude acceleration approach. The accuracy of the recovered coefficients was quantitatively compared between data sets encompassing different ranging precisions. From this analysis, a rough prediction of the accuracy of geopotential coefficients could be obtained from the hypothetical mission. For a given POD precision, a ranging measurement precision that matches the POD precision was determined. Since the purpose of adopting inter-satellite ranging in a gravimetry mission is to overcome the imprecision of determining orbits, ranging measurements should be more precise than POD. For that reason, it can be concluded that this critical ranging precision matching the POD precision can serve as the minimum precision requirement for an on-board ranging device. Although the result obtained herein is about a very particular case, this methodology can also be applied in cases where different parameters are used.

“…Furthermore, it was more precise than the algorithm using only laser measurements when the error of the angle data was large. Oh et al (2016) improved carrier-phase differential GPS (CDGPS) by applying the laser measurements to GPS integer ambiguity estimation. The relative navigation algorithm by Oh et al (2016) had not been compared with the other methods.…”

Section: Introductionmentioning

confidence: 99%

“…Oh et al (2016) improved carrier-phase differential GPS (CDGPS) by applying the laser measurements to GPS integer ambiguity estimation. The relative navigation algorithm by Oh et al (2016) had not been compared with the other methods. The algorithms were verified using theoretically simulated laser measurement data that did not consider the hardware properties of the instrument.…”

Section: Introductionmentioning

confidence: 99%

Characteristics of Relative Navigation Algorithms Using Laser Measurements and Laser-GPS Combined Measurements

Kang

Park²,

Son

2018

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This paper presents a satellite relative navigation strategy for formation flying, which chooses an appropriate navigation algorithm according to the operating environment. Not only global positioning system (GPS) measurements, but laser measurements can also be utilized to determine the relative positions of satellites. Laser data is used solely or together with GPS measurements. Numerical simulations were conducted to compare the relative navigation algorithm using only laser data and laser data combined with GPS data. If an accurate direction of laser pointing is estimated, the relative position of satellites can be determined using only laser measurements. If not, the combined algorithm has better performance, and is irrelevant to the precision of the relative angle data between two satellites in spherical coordinates. Within 10 km relative distance between satellites, relative navigation using double difference GPS data makes more precise relative position estimation results. If the simulation results are applied to the relative navigation strategy, the proper algorithm can be chosen, and the relative position of satellites can be estimated precisely in changing mission environments.