scholarly journals Low-orbit satellite grouping of the system for monitoring geodesic parameters of the Earth and the direction of its development

Author(s):  
С.П. Кузин

Спутниковые миссии наряду с наземными геодезическими сетями различных космических технологий являются второй важной составляющей российского сегмента системы контроля геодезических параметров Земли (ГПЗ). Спутники имеют неоспоримое преимущество в том, что они непрерывно собирают однородные данные над большими частями земной поверхности. Они позволяют сбор данных, которые не могут быть зарегистрированы на поверхности Земли. Такие спутники в наше время оборудованы множеством датчиков, контролирующих поверхности суши, океана и льда, а также гравитационное поле Земли и его временные изменения. Потенциал и влияние спутниковых миссий для наблюдений Земли значительно возрастут в связи с тем, что: (1) будут запускаться все больше и больше спутниковых созвездий, вместо отдельных спутников, увеличивая тем самым временное и пространственное разрешение получаемых данных; (2) спутники будут летать в «формированиях», образуя большие наблюдательные приборы, состоящие из датчиков, расположенных на нескольких спутниках. В работе автор, с учетом рекомендаций международного геодезического сообщества, предлагает набор низкоорбитальных спутниковых миссий различных направлений, необходимых для полноценного функционирования системы контроля ГПЗ, и рассматривает направления развития данных миссий. Satellite missions, along with ground-based geodesic networks of various space technologies, will be the second important component of the Russian segment of the system for monitoring geodesic parameters of the Earth (GPE). Satellites have the undeniable advantage of continuously collecting uniform data over large parts of the Earth’s surface. They allow the collection of data that cannot be registered on the Earth’s surface. Such satellites are now equipped with a variety of sensors that monitor the surface of land, ocean and ice, as well as the Earth’s gravitational field and its temporal changes. The potential and impact of satellite missions for Earth observations will increase significantly as: (1) more and more satellite constellations will be launched, instead of individual satellites, thereby increasing the temporal and spatial resolution of the data received; (2) satellites will fly in “formations”, forming large observation instruments consisting of sensors located on several satellites. In this article the author taking into account the international geodetic community recommendations proposes a set of low-orbit satellite missions to various areas, necessary for proper operation of the system for monitoring GPE, and the directions of development of these missions are considered.

2021 ◽  
Vol 13 (11) ◽  
pp. 2201
Author(s):  
Hanlin Ye ◽  
Huadong Guo ◽  
Guang Liu ◽  
Jinsong Ping ◽  
Lu Zhang ◽  
...  

Moon-based Earth observations have attracted significant attention across many large-scale phenomena. As the only natural satellite of the Earth, and having a stable lunar surface as well as a particular orbit, Moon-based Earth observations allow the Earth to be viewed as a single point. Furthermore, in contrast with artificial satellites, the varied inclination of Moon-based observations can improve angular samplings of specific locations on Earth. However, the potential for estimating the global outgoing longwave radiation (OLR) from the Earth with such a platform has not yet been fully explored. To evaluate the possibility of calculating OLR using specific Earth observation geometry, we constructed a model to estimate Moon-based OLR measurements and investigated the potential of a Moon-based platform to acquire the necessary data to estimate global mean OLR. The primary method of our study is the discretization of the observational scope into various elements and the consequent integration of the OLR of all elements. Our results indicate that a Moon-based platform is suitable for global sampling related to the calculation of global mean OLR. By separating the geometric and anisotropic factors from the measurement calculations, we ensured that measured values include the effects of the Moon-based Earth observation geometry and the anisotropy of the scenes in the observational scope. Although our results indicate that higher measured values can be achieved if the platform is located near the center of the lunar disk, a maximum difference between locations of approximately 9 × 10−4 W m−2 indicates that the effect of location is too small to remarkably improve observation performance of the platform. In conclusion, our analysis demonstrates that a Moon-based platform has the potential to provide continuous, adequate, and long-term data for estimating global mean OLR.


2020 ◽  
Vol 72 (1) ◽  
Author(s):  
Guillaume Ropp ◽  
Vincent Lesur ◽  
Julien Baerenzung ◽  
Matthias Holschneider

Abstract We describe a new, original approach to the modelling of the Earth’s magnetic field. The overall objective of this study is to reliably render fast variations of the core field and its secular variation. This method combines a sequential modelling approach, a Kalman filter, and a correlation-based modelling step. Sources that most significantly contribute to the field measured at the surface of the Earth are modelled. Their separation is based on strong prior information on their spatial and temporal behaviours. We obtain a time series of model distributions which display behaviours similar to those of recent models based on more classic approaches, particularly at large temporal and spatial scales. Interesting new features and periodicities are visible in our models at smaller time and spatial scales. An important aspect of our method is to yield reliable error bars for all model parameters. These errors, however, are only as reliable as the description of the different sources and the prior information used are realistic. Finally, we used a slightly different version of our method to produce candidate models for the thirteenth edition of the International Geomagnetic Reference Field.


1985 ◽  
Vol 38 (02) ◽  
pp. 216-217
Author(s):  
G. A. Wilkins

New techniques of measurement make it possible in 1984 to determine positions on the surface of the Earth to a much higher precision than was possible in 1884. If we look beyond the requirements of navigation we can see useful applications of global geodetic positioning to centimetric accuracy for such purposes as the control of mapping and the study of crustal movements. These new techniques depend upon observations of external objects, such as satellites or quasars rather than stars, and they require that the positions of these objects and the orientation of the surface of the Earth are both known with respect to an appropriate external reference system that is ‘fixed’ in space. We need networks of observing stations and analysis centres that monitor the motions of the external objects and the rotation of the Earth. Observations of stars by a transit circle are no longer adequate for this purpose.


2021 ◽  
Vol 13 (1) ◽  
pp. 1616-1642
Author(s):  
Sai Kiran Kuntla

Abstract The repetitive and destructive nature of floods across the globe causes significant economic damage, loss of human lives, and leaves the people living in flood-prone areas with fear and insecurity. With enough literature projecting an increase in flood frequency, severity, and magnitude in the future, there is a clear need for effective flood management strategies and timely implementation. The earth observatory satellites of the European Space Agency’s Sentinel series, Sentinel-1, Sentinel-2, and Sentinel-3, have a great potential to combat these disastrous floods by their peerless surveillance capabilities that could assist in various phases of flood management. In this article, the technical specifications and operations of the microwave synthetic aperture radar (SAR) onboard Sentinel-1, optical sensors onboard Sentinel-2 (Multispectral Instrument) and Sentinel-3 (Ocean and Land Color Instrument), and SAR altimeter onboard Sentinel-3 are described. Moreover, the observational capabilities of these three satellites and how these observations can meet the needs of researchers and flood disaster managers are discussed in detail. Furthermore, we reviewed how these satellites carrying a range of technologies that provide a broad spectrum of earth observations stand out among their predecessors and have bought a step-change in flood monitoring, understanding, and management to mitigate their adverse effects. Finally, the study is concluded by highlighting the revolution this fleet of Sentinel satellites has brought in the flood management studies and applications.


1986 ◽  
Vol 24 (2) ◽  
pp. 357 ◽  
Author(s):  
Frederick B. House ◽  
Arnold Gruber ◽  
Garry E. Hunt ◽  
Ann T. Mecherikunnel

2021 ◽  
Author(s):  
Anna Klos ◽  
Jürgen Kusche ◽  
Artur Lenczuk ◽  
Grzegorz Leszczuk ◽  
Janusz Bogusz

<p>Global Positioning System (GPS) stations are affected by a plethora of real and system-related signals and errors that occur at various temporal and spatial resolutions. Geophysical changes related to mass redistribution within the Earth system, common mode components, instability of GPS monuments or thermal expansion of ground, all contribute to the GPS-derived displacement time series. Different spatial resolutions that real and system-related errors occur within are covered thanks to the global networks of GPS stations, characterized presently by an unprecedented spatial density. Various temporal resolutions are covered by displacement time series which span even 25 years now, as estimated for the very first stations established. However, since the GPS sensitivity remains unrecognized, retrieving one signal from this wide range of processes may be very uncertain. Up to now, a comparison between GPS-observed displacement time series and displacements predicted by a set of models, as e.g. environmental loading models, was used to demonstrate the accuracy of the model to predict the observed phenomena. Such a comparison is, however, dependent on the accuracy of models and also on the sensitivity of individual GPS stations. We present a new way to identify the GPS sensitivity, which is based on benchmarking of individual GPS stations using statistical clustering approaches. We focus on regional sets of GPS stations located in Europe, where technique-related signals cover real geophysical changes for many GPS permanent stations and those located in South America and Asia, where hydrological and atmospheric loadings dominate other effects. We prove that combining GPS stations into smaller sets improves our understanding of real and system-related signals and errors.</p>


2021 ◽  
pp. SP518-2021-167
Author(s):  
Rajesh K. Srivastava ◽  
Richard E. Ernst ◽  
Kenneth L. Buchan ◽  
Michiel de Kock

AbstractIdentification of large volume, short duration mafic magmatic events of intraplate affinity in both continental and oceanic settings on the Earth and other planets provides invaluable clues for understanding several vital geological issues of current concern. Of particular importance is understanding the assembly and dispersal of supercontinents through Earth's history, dramatic climate change events including mass extinctions, and processes that have produced a wide range of LIP-related resources such as Ni-Cu-PGE, Au, U, base metals, and petroleum. This current volume presents some of the latest developments and new information on the temporal and spatial distribution of LIPs in both the Precambrian and Phanerozoic, their origin, the plumbing system of mafic dyke swarms, sill provinces, and layered inrusions, and links to mantle plumes/superplumes events, supercontinent reconstructions and associated metallogeny.


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