scholarly journals Ionosphere disturbance during cosmodrome “Vostochniy” launches

2018 ◽  
Vol 62 ◽  
pp. 01008
Author(s):  
Zinaida F. Dumbrava ◽  
Vladimir P. Sivokon ◽  
Yuriy A. Teslyuk ◽  
Sergey Y. Khomutov
Keyword(s):  
Acoustic Waves ◽  
Ionospheric Plasma ◽  
Global Navigation Satellite Systems ◽  
Plasma Properties ◽  
Satellite Systems ◽  
Ground Station ◽  
Ionosphere Disturbance ◽  
Global Navigation Satellite ◽  
Carrier Rocket ◽  
Supersonic Motion

It is known that during spacecraft launches ionospheric plasma properties are modified in the result of impact of shock-acoustic waves generated during carrier rocket supersonic motion. As a rule, investigation of ionospheric plasma variations is carried out by the signals of Global Navigation Satellite Systems GPS/GLONASS that implies ground station network. There is no such a system near the “Vostochniy” cosmodrome that makes it necessary to search for an alternative solution. One of them may be the application of ionosphere vertical and oblique sounding stations. Based on the analysis of such station data, the possibility of evaluation of ionosphere modification during “Vostochniy” cosmodrome launches is shown.

Novel Integrity Concept for CAT III Precision Approaches and Taxiing: Extended GBAS (E-GBAS)

2011 ◽  
Vol 64 (4) ◽  
pp. 695-710 ◽  
Author(s):  
Wolfgang Schuster ◽  
Washington Ochieng
Keyword(s):  
Measurement Errors ◽  
High Performance ◽  
Performance Monitoring ◽  
Global Navigation Satellite Systems ◽  
Monitoring Scheme ◽  
Satellite Systems ◽  
Accuracy Requirement ◽  
Ground Station ◽  
Full Benefit ◽  
Global Navigation Satellite

Future air navigation envisages increased use of Global Navigation Satellite Systems (GNSS) together with advanced communications and surveillance technologies to facilitate the required increase in capacity, efficiency and safety without adversely impacting the environment. The full benefit of GNSS is expected from its ability to support en-route to en-route or gate-to-gate air navigation. This presents challenges particularly for the phases of flight with stringent required navigation performance. Significant work has so far been devoted to the phases of flight up to CAT I. However, more work is required for CAT III precision landing (with an accuracy requirement at the metre level) and taxiing (with an accuracy requirement at sub-metre level) and both with very high integrity and continuity requirements. The main limitation in using GBAS for CAT III landings is the potential decorrelation of the measurement errors between the GBAS ground station (GGS) and the user. The threats in this respect are the atmospheric anomalies. Periods of strong solar activity can cause large local spatial and temporal gradients in the delays induced on the GNSS signals by the ionosphere. The local nature of the effects results in significant decorrelation between GGS measurements and the user. Therefore, a reliable ground based ionospheric anomaly monitoring scheme is required to guarantee integrity.This paper critically reviews state-of-the-art monitors, identifies their limitations and addresses them by proposing a high-performance monitoring scheme for the ionosphere. Preliminary analyses suggest that the proposed scheme has the potential to enable GNSS to meet the navigation requirements for CAT III and taxiing.

scholarly journals C3 in UAS as a Means for Secondary Navigation

2012 ◽  
Vol 66 (1) ◽  
pp. 115-134
Author(s):  
Jorge Ramirez ◽  
Dagoberto Salazar ◽  
Xavier Prats ◽  
Cristina Barrado
Keyword(s):  
Kalman Filter ◽  
Global Navigation Satellite Systems ◽  
Civil Aviation ◽  
Navigation Satellite ◽  
International Civil Aviation Organization ◽  
Satellite Systems ◽  
Ground Station ◽  
Performance Based Navigation ◽  
Global Navigation Satellite ◽  
Navigation Accuracy

Unmanned Air Systems (UAS) navigate using Global Navigation Satellite Systems (GNSS), but GNSS vulnerability precludes its use as the only means of navigation and requires a secondary means of navigation. A differentiating characteristic of UAS is their periodic communications with the ground station. This paper analyses the adequacy of employing UAS Command, Control and Communications (C3) as a secondary means of navigation. With no additional infrastructure, an Extended Kalman Filter (EKF) is used to process C3 messages and to obtain the positions of the UAS. Navigation accuracy and integrity are calculated in a scenario with three UAS. The obtained results meet the International Civil Aviation Organization (ICAO) Performance-Based Navigation (PBN) requirements.

scholarly journals Analysis of DME/DME Navigation Performance and Ground Network Using Stretched-Front-Leg Pulse-Based DME

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3275 ◽  
Author(s):  
Euiho Kim
Keyword(s):  
Measuring Equipment ◽  
Federal Aviation Administration ◽  
The United States ◽  
Significant Loss ◽  
Global Navigation Satellite Systems ◽  
Positioning Accuracy ◽  
Satellite Systems ◽  
Ground Station ◽  
Aircraft Navigation ◽  
Global Navigation Satellite

Global navigation satellite systems (GNSS) have become a primary navigation means for aircraft. However, the signal power of GNSS is very weak, and its service can be disrupted at any time when there is interference or jamming. For this reason, the Federal Aviation Administration (FAA) in the United States has recently chosen a distance measuring equipment (DME)-based aircraft navigation technique, called DME/DME, as an alternative aircraft navigation means for use by around 2030. The reason that the FAA plans to use DME/DME in such a short duration, by around 2030, is presumed to be because the ranging accuracy of DMEs is between 70 to 300 m, which is about 7 to 30 times worse than that of GNSS. Thus, a significant loss of positioning performance is unavoidable with current DMEs. To make DME/DME a more competent alternative positioning source, this paper proposes an advanced DME that could provide a ranging accuracy of around 30 m by employing a recently developed Stretched-Front-Leg (SFOL) pulse. The paper introduces optimal ground station augmentation algorithms that help to efficiently transform the current DME ground network to enable a DME/DME positioning accuracy of up to 0.3 nm or 92.6 m with a minimal number of new ground DME sites. The positioning performance and augmented ground network using the proposed SFOL pulse-based DME are evaluated in two regions which have distinct terrain conditions.

Hydrogeophysical Survey of Groundwater Development at Okada Community Ovia North – East L.G.A. Edo State

2018 ◽  
Vol 2 (1) ◽  
pp. 39-45
Author(s):  
M. O. Ehigiator
Keyword(s):  
Global Navigation Satellite Systems ◽  
Geophysical Investigation ◽  
Satellite Systems ◽  
North East ◽  
Long Time ◽  
Electrical Sounding ◽  
Edo State ◽  
Global Navigation Satellite ◽  
Water Problems ◽  
Aquifer Unit

Geophysical investigation was conducted at Okada community in ovia North Local Govertment area of Edo state to determine the prospect of aquifer zone. The Petrozenith PZ-02 Terrameter, one of the Electrical Resistivity Equipment was used to conduct a Vertical Electrical Sounding (VES) in the study area. The Garmin Etrex 10 Global Navigation satellite systems (GNSS) was used to acquire Geodetic coordinates of point where VES observations were made. This research was carried out as a pre-drilling Hydro-geophysical survey conducted for the purpose of surveying and studying the proposed water borehole site at Okada Community that has suffered acute water problems for a very long time. There have been series of boreholes drilled in the studied area but all are dry wells. This survey was conducted to investigate the subsurface complexity of the sites in respect of lithology and to recommend the total drill depth based on the prospective aquifer unit so identified. Result of interpretation suggests that the area is underlain with substantive aquiferous formation but at a depth not exceeding 121.60 m (398.95 ft), which is the lower aquifer unit. The value of elevation at point of observation referenced to mean sea level is 94 m.

scholarly journals Forty-three years of absolute gravity observations of the Fennoscandian postglacial rebound in Finland

2021 ◽  
Vol 95 (2) ◽  
Author(s):  
Mirjam Bilker-Koivula ◽  
Jaakko Mäkinen ◽  
Hannu Ruotsalainen ◽  
Jyri Näränen ◽  
Timo Saari
Keyword(s):  
Gravity Data ◽  
Gravity Change ◽  
Global Navigation Satellite Systems ◽  
Absolute Gravity ◽  
Data Sets ◽  
Postglacial Rebound ◽  
Land Uplift ◽  
Satellite Systems ◽  
Gravity Measurements ◽  
Global Navigation Satellite

AbstractPostglacial rebound in Fennoscandia causes striking trends in gravity measurements of the area. We present time series of absolute gravity data collected between 1976 and 2019 on 12 stations in Finland with different types of instruments. First, we determine the trends at each station and analyse the effect of the instrument types. We estimate, for example, an offset of 6.8 μgal for the JILAg-5 instrument with respect to the FG5-type instruments. Applying the offsets in the trend analysis strengthens the trends being in good agreement with the NKG2016LU_gdot model of gravity change. Trends of seven stations were found robust and were used to analyse the stabilization of the trends in time and to determine the relationship between gravity change rates and land uplift rates as measured with global navigation satellite systems (GNSS) as well as from the NKG2016LU_abs land uplift model. Trends calculated from combined and offset-corrected measurements of JILAg-5- and FG5-type instruments stabilized in 15 to 20 years and at some stations even faster. The trends of FG5-type instrument data alone stabilized generally within 10 years. The ratio between gravity change rates and vertical rates from different data sets yields values between − 0.206 ± 0.017 and − 0.227 ± 0.024 µGal/mm and axis intercept values between 0.248 ± 0.089 and 0.335 ± 0.136 µGal/yr. These values are larger than previous estimates for Fennoscandia.

scholarly journals Injury prevention in Super-G alpine ski racing through course design

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Matthias Gilgien ◽  
Philip Crivelli ◽  
Josef Kröll ◽  
Live S. Luteberget ◽  
Erich Müller ◽  
...  
Keyword(s):  
Ground Reaction Force ◽  
Course Design ◽  
Reaction Force ◽  
Global Navigation Satellite Systems ◽  
World Cup ◽  
Satellite Systems ◽  
Turn Radius ◽  
Energy Dissipated ◽  
Global Navigation Satellite ◽  
High Level

AbstractIn Super-G alpine ski racing mean speed is nearly as high as in Downhill. Hence, the energy dissipated in typical impact accidents is similar. However, unlike Downhill, on Super-G courses no training runs are performed. Accordingly, speed control through course design is a challenging but important task to ensure safety in Super-G. In four male World Cup alpine Super-G races, terrain shape, course setting and the mechanics of a high-level athlete skiing the course were measured with differential global navigation satellite systems (dGNSS). The effects of course setting on skier mechanics were analysed using a linear mixed effects model. To reduce speed by 0.5 m/s throughout a turn, the gate offset needs to be increased by + 51%. This change simultaneously leads to a decrease in minimal turn radius (− 19%), an increase in impulse (+ 27%) and an increase in maximal ground reaction force (+ 6%). In contrast, the same reduction in speed can also be achieved by a − 13% change in vertical gate distance, which also leads to a small reduction in minimal turn radius (− 4%) impulse (− 2%), and no change in maximal ground reaction force; i.e. fewer adverse side effects in terms of safety. It appears that shortening the vertical gate distance is a better and safer way to reduce speed in Super-G than increasing the gate offset.

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