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The Space System
Published in Ron Burch, Resilient Space Systems Design: An Introduction, 2019
The space segment generally consists of one or more satellites orbiting the Earth. The key attributes of the space segment are the type, number, and orbit of each satellite, as well as other related features, such as inter-satellite crosslinks. Satellites can be large or small, depending upon the extent of their capabilities and role in the overall system. Commercial satellites vary in size but tend to be relatively large. Recently, “new space” companies have been trending toward larger constellations of smaller satellites. Most modern military satellites are large and complex and often support multiple missions. As a result of their high cost, there are usually a small number of satellites per system, although some systems, such as GPS, are composed of a larger number.
Global navigation satellite systems
Published in Mike Tooley, David Wyatt, Aircraft Communications and Navigation Systems, 2017
GPS is now widely available for use by many applications including aircraft navigation. The system comprises a space segment, user segment and control segment. Twenty-four satellites (the space segment) in orbit around the earth send data via radio links that allow aircraft receivers (the user segment) to calculate precise position, altitude, time and speed on a 24-hour, worldwide, all-weather basis. The principles of satellite navigation are based on radio wave propagation, precision timing and knowledge of each satellite’s position above the earth; this is all monitored and controlled by a network of stations (the control segment).
Ground Segment
Published in Shen-En Qian, Hyperspectral Satellites and System Design, 2020
Ground stations provide radio interfaces between the space segment and the ground segment for telemetry, tracking, and command (TT&C), as well as payload data transmission, and reception. There are typically backup ground stations from which radio contact can be maintained if the primary ground station is unable to operate due to any reason, such as a natural disaster. Such contingencies are considered in a continuity of operations plan.
Analysis of Amplitude Scintillation and Positioning Error of IRNSS/GPS/SBAS Receiver for Heavy Rainy Days
Published in IETE Journal of Research, 2023
Mitchell Prajapati, Abhishek Rawat, Divyash Kumbhani
India Regional Navigation Satellite System (IRNSS) has two main components: Space segment and Ground segment. IRNSS satellites send signals to ground receiver with the carrier frequency of 1.17 and 2.49 GHz. IRNSS provides standard positioning services to public and precise positioning to military applications [1]. The IRNSS/GPS/SBAS receiver receives signal in L1, L5 and S band. The diffraction due to ionospheric irregularities is variable in nature with different carrier frequencies; this may result in amplitude and phase scintillation. Scintillation occurs due to electron density variation in the ionosphere when signal passes through it. Amplitude scintillation degrades the amplitude of carrier to noise ratio and phase scintillation changes the phase of navigation signal. Degradation of signal can affect the performance of navigation receiver from precise positioning accuracy to loss of data. Ionospheric delay and positioning error are highly proportional to total electron count present in ionosphere. As the signal is affected by strong scintillation, the receiver will face the loss of lock with the satellite. The effect of scintillation is highly dependent on weather, geographical location, solar radiation and geomagnetic disturbances. So it is required to analyze the effect of scintillation at various geographical locations. Various researchers have investigated the effect of amplitude scintillation at low and high equatorial region, anomaly crest regions, and equatorial ionization anomaly region under various solar and magnetic activities, and weather conditions. Many researchers have studied GPS scintillation events at various locations, but a few have done it on IRNSS as it is a newly developed Indian satellite-based navigation system.
A Brief Review on mm-Wave Antennas for 5G and Beyond Applications
Published in IETE Technical Review, 2023
Paikhomba Loktongbam, Debasish Pal, A. K. Bandyopadhyay, Chaitali Koley
The internet of things (IoT) applications are to be evolved into the Internet of Space Things (IoST), covering things on the ground and in the air and space [211]. The IoST may consist of a ground segment (network of ground stations, on-earth sensing devices, client premises) and a space segment [network of Space-station, satellites, CubeSats, Unmanned Aerial Vehicles (UAVs) and near-earth sensing devices].
First results of using the second generation SBAS in Australian urban and suburban road environments
Published in Journal of Spatial Science, 2020
Ahmed El-Mowafy, Norman Cheung, Eldar Rubinov
Any SBAS system is constituted by a ground segment, i.e. a network of reference stations and master stations, and a space segment, i.e. a set of geostationary (GEO) satellites (Enge et al. 1996, Roturier et al. 2001). The SBAS system augments the GNSS systems in three ways: