scholarly journals Determination of Space Debris Coordinates by Means of a Space Service Vehicle

2016 ◽  
Vol 3 (1) ◽  
pp. 31-37 ◽  
Author(s):  
Vasyl Kondratiuk ◽  
Еduard Kovalevskiy ◽  
Svitlana Ilnytska
Keyword(s):  
Inertial Navigation System ◽  
Space Debris ◽  
Initial Conditions ◽  
Space Vehicle ◽  
Satellite System ◽  
Coordinate Frame ◽  
Space Industry ◽  
Global Character ◽  
Global Navigation Satellite

Abstract The problem of space debris utilization is quite relevant nowadays and has a global character. The space industry experts from all over the world are working on the task of removing space debris. This article proposes the method of determining space debris coordinates by means of the airborne equipment of a space service vehicle. The set of airborne equipment includes a global navigation satellite system receiver, an inertial navigation system and a laser radar. To study the accuracy characteristics of the proposed method under different initial conditions a series of simulations was performed. They showed that the accuracy of determining space debris coordinates becomes higher with the reduction of the distance between the debris and space service vehicle. Stringent requirements for the accuracy of determining the orientation of the coordinate frame of the space vehicle are essential for providing the accuracy characteristics of the method.

scholarly journals Determination of Conversion Constant between Lagos Datum and Niger Delta Mean Lower Low Water Datum and their Horizontal and Vertical Accuracy Standards using GNSS Observations

2018 ◽  
Vol 2 (1) ◽  
pp. 56-68
Author(s):  
M. O. Ehigiator ◽  
S. O. Oladosu
Keyword(s):  
Niger Delta ◽  
Satellite System ◽  
Constant Factor ◽  
Common Mean ◽  
Height Determination ◽  
The Mean ◽  
Vertical Accuracy ◽  
Global Navigation Satellite ◽  
Gnss Observations

With the use of Global Navigation Satellite System (GNSS) technology, it is now possible to determine the position of points in 3D coordinates systems. Lagos datum is the most common Mean Sea Level used in most parts of Nigeria. In Niger Delta, for instance Warri and its environs, the most commonly used datum for height determination is the Mean Lower Low Water Datum. It then becomes necessary to determine a constant factor for conversion between the two datum when the need arises as both are often encountered during Geomatics Engineering field operations. In this paper, the constant to be applied in converting between both datum was determined. The constant was found to be 17.79m. The horizontal and vertical accuracy standard was also determined as well as the stack maps.

scholarly journals Accurate and Rapid Broadcast Ephemerides for Beidou-Maneuvered Satellites

2019 ◽  
Vol 11 (7) ◽  
pp. 787 ◽  
Author(s):  
Jing Qiao ◽  
Wu Chen ◽  
Shengyue Ji ◽  
Duojie Weng
Keyword(s):  
Orbit Determination ◽  
Piecewise Linear ◽  
Precise Orbit Determination ◽  
Satellite System ◽  
Navigation Satellite ◽  
Beidou Navigation Satellite System ◽  
German Research ◽  
Global Navigation Satellite ◽  
Ranging Errors

The geostationary earth orbit (GEO) and inclined geosynchronous orbit (IGSO) satellites of the Beidou navigation satellite system are maneuvered frequently. The broadcast ephemeris can be interrupted for several hours after the maneuver. The orbit-only signal-in-space ranging errors (SISREs) of broadcast ephemerides available after the interruption are over two times larger than the errors during normal periods. To shorten the interruption period and improve the ephemeris accuracy, we propose a two-step orbit recovery strategy based on a piecewise linear thrust model. The turning points of the thrust model are firstly determined by comparison of the kinematic orbit with an integrated orbit free from maneuver; afterward, precise orbit determination (POD) is conducted for the maneuvered satellite by estimating satellite orbital and thrust parameters simultaneously. The observations from the IGS Multi-Global Navigation Satellite System (GNSS) Experiment (MGEX) network and ultra-rapid products of the German Research Center for Geosciences (GFZ) are used for orbit determination of maneuvered satellites from Sep to Nov 2017. The results show that for the rapidly recovered ephemerides, the average orbit-only SISREs are 1.15 and 1.0 m 1 h after maneuvering for GEO and IGSO respectively, which is comparable to the accuracy of Beidou broadcast ephemerides in normal cases.

scholarly journals Responses to the preparation of strong Kamchatka earth-quakes in the lithosphere–atmosphere–ionosphere system, based on new data from integrated ground and iono-spheric monitoring

2020 ◽  
Vol 196 ◽  
pp. 03005
Author(s):  
Vadim Bogdanov ◽  
Valerey Gavrilov ◽  
Sergey Pulinets ◽  
Dimitar Ouzounov
Keyword(s):  
Earth Quake ◽  
Chemical Potential ◽  
Satellite System ◽  
Daily Monitoring ◽  
Short Term Forecasting ◽  
Total Electronic Content ◽  
Global Navigation Satellite ◽  
Downhole Measurements ◽  
Electronic Content

The experience of short-term forecasting of Kamchatka earthquakes based on complex well measurements at the Petropavlovsk-Kamchatsky geody-namic polygon (PGP) shows that, as a rule, the preparation of strong Kamchatka earthquakes is fairly reliable in the medium-term time scale (months or years be-fore the earthquake). However the determination of the stage beginning imme-diately preceding an earthquake (weeks or days before the main event) is a very difficult task. At present time, the solution of this problem is largely associated with the involvement in the preparation of forecast conclusions of data from continuous monitoring of the ionosphere, carried out by ground-based means of vertical radiosonding and measurements of total electronic content (TEC) using the global navigation satellite system GLONASS and GPS. This is due to the fact that significant changes in a number of ionospheric parameters occur mainly 1-5 days before the Kamchatka earthquakes. The results of the compar-ison of the data of daily monitoring of the ionosphere, including information on TEC, with the data integrated downhole measurements showed a rather high correlation of occurrence of anomalies in the ionosphere before strong earth-quakes with changes in the complex parameters in borehole measurements. As one example, the report presents the results of ionospheric and borehole monitoring obtained in the time neighborhood of the strong (MW = 7.5) the earth-quake that occurred on March 25, 2020 in the area of the Northern Kurils. The results show a high correlation between changes in the specific electrical resis-tivity of the Geospace in the area of the PGP with variations in the TEC and the formation of a number of other anomalies in the ionosphere a few days be-fore the earthquake. These results indicate that it is possible to determine fairly reliably the beginning of the final stage of preparation for a strong earthquake. Currently, methods based on atmospheric parameters monitoring are used quite successfully for predictive estimates of the epicenter and magnitude of an earth-quake: the method of chemical potential corrections for measurements at an altitude of ∼ 100 m, as well as data from measurements of outgoing long-wave infrared radiation (OLR) at the level of the upper edge of clouds (heights of 10 -15 km).

scholarly journals GNSS/INS-Equipped Buoys for Altimetry Validation: Lessons Learnt and New Directions from the Bass Strait Validation Facility

2020 ◽  
Vol 12 (18) ◽  
pp. 3001
Author(s):  
Boye Zhou ◽  
Christopher Watson ◽  
Benoit Legresy ◽  
Matt A. King ◽  
Jack Beardsley ◽  
...  
Keyword(s):  
Inertial Navigation System ◽  
Low Frequency ◽  
Satellite System ◽  
External Forcing ◽  
Empirical Correction ◽  
New Directions ◽  
Ocean Topography ◽  
Global Navigation Satellite ◽  
Systematic Noise

Global Navigation Satellite System (GNSS)-equipped buoys have a fundamental role in the validation of satellite altimetry. Requirements to validate next generation altimeter missions are demanding and call for a greater understanding of the systematic errors associated with the buoy approach. In this paper, we assess the present-day buoy precision using archived data from the Bass Strait validation facility. We explore potential improvements in buoy precision by addressing two previously ignored issues: changes to buoyancy as a function of external forcing, and biases induced by platform dynamics. Our results indicate the precision of our buoy against in situ mooring data is ~15 mm, with a ~8.5 mm systematic noise floor. Investigation into the tether tension effect on buoyancy showed strong correlation between currents, wind stress and buoy-against-mooring residuals. Our initial empirical correction achieved a reduction of 5 mm in the standard deviation of the residuals, with a 51% decrease in variance over low frequency bands. Corrections associated with platform orientation from an Inertial Navigation System (INS) unit showed centimetre-level magnitude and are expected to be higher under rougher sea states. Finally, we conclude with further possible improvements to meet validation requirements for the future Surface Water Ocean Topography (SWOT) mission.

scholarly journals Determination of sea surface height from moving ships with dynamic corrections

2012 ◽  
Vol 2 (3) ◽  
pp. 172-187 ◽  
Author(s):  
J. Reinking ◽  
A. Härting ◽  
L. Bastos
Keyword(s):  
Satellite System ◽  
Ocean Dynamics ◽  
Sea Surface ◽  
Sea Surface Heights ◽  
Positioning Analysis ◽  
Remote Sensing Techniques ◽  
Global Navigation Satellite

AbstractWith the growing global efforts to estimate the influence of civilization on the climate change it would be desirable to survey sea surface heights (SSH) not only by remote sensing techniques like satellite altimetry or (GNSS) Global Navigation Satellite System reflectometry but also by direct and in-situ measurements in the open ocean. In recent years different groups attempted to determine SSH by ship-based GNSS observations. Due to recent advances in kinematic GNSS (PPP) Precise Point Positioning analysis it is already possible to derive GNSS antenna heights with a quality of a few centimeters. Therefore it is foreseeable that this technique will be used more intensively in the future, with obvious advantages in sea positioning. For the determination of actual SSH from GNSS-derived antenna heights aboard seagoing vessels some essential hydrostatic and hydrodynamic corrections must be considered in addition to ocean dynamics and related corrections. Systematic influences of ship dynamics were intensively analyzed and sophisticated techniques were developed at the Jade University during the last decades to precisely estimate mandatory corrections. In this paper we will describe the required analyses and demonstrate their application by presenting a case study from an experiment on a cruise vessel carried out in March 2011 in the Atlantic Ocean.

scholarly journals OBSERVATIONS OF SPACE DEBRIS IN THE VICINITY OF ORBITS OF GLOBAL NAVIGATION SATELLITE SYSTEMS

2020 ◽  
Vol 6 (3) ◽  
pp. 115-123
Author(s):  
Ivan Korobtsev ◽  
Tatyana Tsukker ◽  
Marina Mishina ◽  
Vladimir Goryashin ◽  
Maxim Eselevich
Keyword(s):  
Space Debris ◽  
Satellite System ◽  
Global Navigation Satellite Systems ◽  
Optical Measurements ◽  
Navigation Satellite ◽  
Satellite Systems ◽  
Orbital Parameters ◽  
Space Objects ◽  
Global Navigation ◽  
Global Navigation Satellite

The problem of the amount and characteristics of space debris in the vicinity of orbits of Global Navigation Satellite Systems (GNSS) is of significant interest from the viewpoint of safe operation of these systems. Attempts have repeatedly been made to search for space debris fragments in a given region of orbits, but have not led to cataloging such objects. Only in 2018, eight space objects were discovered which were not related to active or inactive spacecraft or their launch elements. Photometrical and trajectory observations with optical telescopes are practically the only source of information about characteristics of such objects. The paper presents a summary of the design features and technical characteristics of the new AZT-33VM telescope. We describe a technique for determining orbital parameters of non-cataloged space debris from optical measurements. We report the results of photometric observations of a space object, detected in the vicinity of orbits of the Global Navigation Satellite System GLONASS.

scholarly journals PRELIMINARY ANALYSES OF BEIDOU SIGNAL-IN-SPACE ANOMALY SINCE 2013

2016 ◽  
Vol XLI-B1 ◽  
pp. 517-523 ◽  
Author(s):  
Y. Wu ◽  
J. Ren ◽  
W. Liu
Keyword(s):  
Global Navigation Satellite System ◽  
Space Vehicle ◽  
Estimation Algorithm ◽  
Satellite System ◽  
Ground Control ◽  
Navigation Satellite ◽  
Receiver Autonomous Integrity Monitoring ◽  
Global Navigation Satellite ◽  
System Knowledge ◽  
Advanced Receiver

As BeiDou navigation system has been operational since December 2012. There is an increasing desire to use multiple constellation to improve positioning performance. The signal-in-space (SIS) anomaly caused by the ground control and the space vehicle is one of the major threats to affect the integrity. For a young Global Navigation Satellite System, knowledge about SIS anomalies in history is very important for not only assessing the SIS integrity performance of a constellation but also providing the assumption for ARAIM (Advanced Receiver Autonomous Integrity Monitoring). <br><br> In this paper, the broadcast ephemerides and the precise ones are pre-processed for avoiding the false anomaly identification. The SIS errors over the period of Mar. 2013-Feb. 2016 are computed by comparing the broadcast ephemerides with the precise ones. The time offsets between GPST (GPS time) and BDT (BeiDou time) are estimated and removed by an improved estimation algorithm. SIS worst-UREs are computed and a RMS criteria are investigated to identify the SIS anomalies. The results show that the probability of BeiDou SIS anomalies is in 10-3 level in last three years. Even though BeiDou SIS integrity performance currently cannot match the GPS integrity performances, the result indicates that BeiDou has a tendency to improve its integrity performance.

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