Medium Earth orbit ≈ Medium Earth orbit
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LEO Satellite Constellation for Internet of Things Open
Internet of Things (IoT) is one of the evolutionary directions of the Internet. This paper focuses on the low earth orbit (LEO) satellite constellation-based IoT services for their irreplaceable functions. In many cases, IoT devices are di…
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Basic performance and future developments of BeiDou global navigation satellite system Open
The core performance elements of global navigation satellite system include availability, continuity, integrity and accuracy, all of which are particularly important for the developing BeiDou global navigation satellite system (BDS-3). Thi…
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A Review of the Space Environment Effects on Spacecraft in Different Orbits Open
The space environment consists of various complex phenomena, which could have a strong influence on the spacecraft operation in different aspects. Since the very beginning of space exploration, numerous studies have been done on the space …
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LEO Enhanced Global Navigation Satellite System (LeGNSS): progress, opportunities, and challenges Open
With the completion of Chinese BeiDou Navigation Satellite System (BDS), the world has begun to enjoy the Positioning, Navigation, and Timing (PNT) services of four Global Navigation Satellite Systems (GNSS). In order to improve the GNSS p…
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Optimal Walker Constellation Design of LEO-Based Global Navigation and Augmentation System Open
Low Earth orbit (LEO) satellites located at altitudes of 500 km~1500 km can carry much stronger signals and move faster than medium Earth orbit (MEO) satellites at about a 20,000 km altitude. Taking advantage of these features, LEO satelli…
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Sentinel-1A – First precise orbit determination results Open
Sentinel-1A is the first satellite of the European Copernicus programme. Equipped with a Synthetic Aperture Radar (SAR) instrument the satellite was launched on April 3, 2014. Operational since October 2014 the satellite delivers valuable …
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The Parameters Comparison of the “Starlink” LEO Satellites Constellation for Different Orbital Shells Open
Communications-integrated satellite-terrestrial networks used for global broadband services have gained a high degree of interest from scientists and industries worldwide. The most convenient structures for such use are low Earth orbit sat…
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Assessment of BeiDou differential code bias variations from multi-GNSS network observations Open
The differential code bias (DCB) of global navigation satellite systems (GNSSs) affects precise ionospheric modeling and applications. In this paper, daily DCBs of the BeiDou Navigation Satellite System (BDS) are estimated and investigated…
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Evolution of orbit and clock quality for real-time multi-GNSS solutions Open
High-quality satellite orbits and clocks are necessary for multi-GNSS precise point positioning and timing. In undifferenced GNSS solutions, the quality of orbit and clock products significantly influences the resulting position accuracy; …
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Validation of Galileo orbits using SLR with a focus on satellites launched into incorrect orbital planes Open
The space segment of the European Global Navigation Satellite System (GNSS) Galileo consists of In-Orbit Validation (IOV) and Full Operational Capability (FOC) spacecraft. The first pair of FOC satellites was launched into an incorrect, hi…
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Precise orbit determination of the Fengyun-3C satellite using onboard GPS and BDS observations Open
The GNSS Occultation Sounder instrument onboard the Chinese meteorological satellite Fengyun-3C (FY-3C) tracks both GPS and BDS signals for orbit determination. One month’s worth of the onboard dual-frequency GPS and BDS data during March …
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Dynamic GPS-based LEO orbit determination with 1 cm precision using the Bernese GNSS Software Open
The Astronomical Institute of the University of Bern (AIUB) has been performing GPS-based Precise Orbit Determination (POD) for a large variety of Low Earth Orbit (LEO) satellites since two decades. Traditionally, LEO orbits have been gene…
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A 30‐Year Simulation of the Outer Electron Radiation Belt Open
As society becomes more reliant on satellite technology, it is becoming increasingly important to understand the radiation environment throughout the Van Allen radiation belts. Historically most satellites have operated in low Earth orbit …
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Comparison of solar radiation pressure models for BDS IGSO and MEO satellites with emphasis on improving orbit quality Open
In order to simplify the attitude control for inclined geosynchronous orbit (IGSO) and medium earth orbit (MEO) satellites of the BeiDou Navigation Satellite System (BDS) in eclipse seasons, two attitude modes, namely yaw-steering (YS) and…
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Handover Solutions for 5G Low-Earth Orbit Satellite Networks Open
Low-Earth orbit (LEO) satellite networks are meant to be fundamental to closing the digital divide, enabling new market opportunities and providing fifth-generation (5G) New Radio (NR) connectivity everywhere at any time. Despite the advan…
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Enhanced orbit determination for BeiDou satellites with FengYun-3C onboard GNSS data Open
A key limitation for precise orbit determination of BeiDou satellites, particularly for satellites in geostationary orbit (GEO), is the relative weak geometry of ground stations. Fortunately, data from a low earth orbiting satellite with a…
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Challenges of Using the L-Band and S-Band for Direct-to-Cellular Satellite 5G-6G NTN Systems Open
This article presents a comprehensive study of the potential utilization of the L-band and S-band frequency ranges for satellite non-terrestrial network (NTN) technologies. This study encompasses an interference analysis in the S-band, inv…
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Low cost satellite constellations for nearly continuous global coverage Open
Satellite services are fundamental to the global economy, and their design reflects a tradeoff between coverage and cost. Here, we report the discovery of two alternative 4-satellite constellations with 24- and 48-hour periods, both of whi…
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BeiDou Augmented Navigation from Low Earth Orbit Satellites Open
Currently, the Global Navigation Satellite System (GNSS) mainly uses the satellites in Medium Earth Orbit (MEO) to provide position, navigation, and timing (PNT) service. The weak navigation signals limit its usage in deep attenuation envi…
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The FIREBIRD-II CubeSat mission: Focused investigations of relativistic electron burst intensity, range, and dynamics Open
FIREBIRD-II is a National Science Foundation funded CubeSat mission designed to study the scale size and energy spectrum of relativistic electron microbursts. The mission consists of two identical 1.5 U CubeSats in a low earth polar orbit,…
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GNSS rapid precise point positioning enhanced by low Earth orbit satellites Open
The Low Earth Orbit (LEO) satellites can be used to effectively speed up Precise Point Positioning (PPP) convergence. In this study, 180 LEO satellites with a global distribution are simulated to evaluate their contribution to the PPP conv…
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Versatile On-Orbit Servicing Mission Design in Geosynchronous Earth Orbit Open
Covers advancements in spacecraft and tactical and strategic missile systems, including subsystem design and application, mission design and analysis, materials and structures, developments in space sciences, space processing and manufactu…
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Kepler � Satellite Navigation without Clocks and Ground Infrastructure Open
Global Navigation Satellite Systems receivers use pseudorange measurements for positioning and time determination. The control system uses the same measurements for estimating the satellite orbits, clock offsets and signal biases in a comp…
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First Flight-Testing of LoRa Modulation in Satellite Radio Communications in Low-Earth Orbit Open
At present, the use of LoRa modulation in satellite radio communications and the construction of a CubeSat constellation for the satellite Internet of Things based on LoRa technology has already begun. However, the limits of applicability …
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Integrated Precise Orbit Determination of Multi-GNSS and Large LEO Constellations Open
Global navigation satellite system (GNSS) orbits are traditionally determined by observation data of ground stations, which usually need even global distribution to ensure adequate observation geometry strength. However, good tracking geom…
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Performance Evaluation of High-Frequency Mobile Satellite Communications Open
Communication satellites have a much longer propagation delay than terrestrial communication networks such as cellular or WiFi. In addition, as the carrier frequency moves up, mobile satellite communications show worse performances than th…
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MDM: A flight mission to observe materials degradation in-situ on satellite in super low Earth orbit Open
Satellites in low Earth orbit (LEO) are subject to several environmental factors, atomic oxygen (AO) having the greatest effect on space materials, especially polymers. Recently, the possibility of utilizing orbits at an altitude lower tha…
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Receiver architectures for positioning with low earth orbit satellite signals: a survey Open
Positioning, Navigation and Timing (PNT) are services generally provided by Global Navigation Satellite Systems (GNSS). GNSS reside in medium to high orbital altitudes from the Earth’s surface, resulting in weak signal reception. However, …
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Navigation in GEO, HEO, and Lunar Trajectory Using Multi-GNSS Sidelobe Signals Open
Positioning of spacecraft (e.g., geostationary orbit (GEO), high elliptical orbit (HEO), and lunar trajectory) is crucial for mission completion. Instead of using ground control systems, global navigation satellite system (GNSS) can be an …
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Characteristics of BeiDou-3 Experimental Satellite Clocks Open
The characteristics of the improved Atomic Frequency Standard (AFS) operated on the latest BeiDou-3 experimental satellites are analyzed from day-of-year (DOY) 254 to 281, of the year 2017, considering the following three aspects: stabilit…