scholarly journals Optimizing the Communication Capacity of a Ground Station Network

2019 ◽  
Author(s):  
Rogerio Atem de Carvalho
Keyword(s):  
Low Earth Orbit ◽  
Field Of View ◽  
Lead Times ◽  
Small Satellites ◽  
Physical Constraints ◽  
Ground Station ◽  
Communication Capacity ◽  
Communication Time ◽  
Total Communication ◽  
Synchronization Procedure

Small satellites are growing in use for educational, scientific, and commercial purposes, usually in Low Earth Orbit (LEO) flights, given their lower costs and associated risks, as well as smaller lead times for assembling and testing. However, the typically short periods of LEO passes bring the need to find ways of optimizing the communication between the ground and space segments. In that direction, several projects have relied on ground station networks to increase the total time of contact with the satellites. In this type of arrangement, the stations agree in monitoring one or more satellites in such a way that, as the spacecraft exits one station’s field of view, another station assumes its tracking, extending the total communication time and compensating the short passes. This type of solution, while very efficient in terms of costs, on the other hand demands a good synchronization procedure, so that all constraints present in its operations are taken into account and the network can operate effectively. This paper aims at describing a model implemented for orchestrating ground station networks that optimizes the communication capacity of the ground network, while taking into account physical constraints not usually considered in other models currently proposed.

scholarly journals Guidance Stabilization of Satellites Using the Geomagnetic Field

2012 ◽  
Vol 2012 ◽  
pp. 1-9
Author(s):  
Francisco Miranda
Keyword(s):  
Geomagnetic Field ◽  
Technological Development ◽  
Low Cost ◽  
Low Earth Orbit ◽  
Earth Orbit ◽  
Small Satellites ◽  
Attitude Stabilization ◽  
Short Period ◽  
Low Earth Orbit Satellite ◽  
Games Theory

In the last years the small satellites have played an important role in the technological development. The attractive short period of design and low cost of them and the capacity to solve problems that are usually considered as problems to big and expensive spacecrafts lead us to study the control problem of these satellites. Active three-axis magnetic attitude stabilization of a low Earth orbit satellite is considered in this work. The control is created by interaction between the magnetic moment generated by magnetorquers mounted on the satellite body and the geomagnetic field. This problem is quite complex and difficult to solve. To overcome this difficulty guidance control is considered, where we use ε-strategies introduced by Pontryagin in the frame of differential games theory. Qualitative analysis and results of numerical simulation are presented.

scholarly journals Attitude Sensor from Ellipsoid Observations: A Numerical and Experimental Validation

Sensors ◽  
2020 ◽  
Vol 20 (2) ◽  
pp. 433
Author(s):  
Dario Modenini ◽  
Alfredo Locarini ◽  
Marco Zannoni
Keyword(s):  
Experimental Validation ◽  
Attitude Determination ◽  
Closed Form Solution ◽  
Infrared Camera ◽  
Form Solution ◽  
Low Earth Orbit ◽  
Preliminary Design ◽  
Small Satellites ◽  
Attitude Sensor ◽  
Rms Errors

The preliminary design and validation of a novel, high accuracy horizon-sensor for small satellites is presented, which is based on the theory of attitude determination from ellipsoid observations. The concept consists of a multi-head infrared sensor capturing images of the Earth limb. By fitting an ellipse to the imaged limb arcs, and exploiting some analytical results available from projective geometry, a closed form solution for computing the attitude matrix is provided. The algorithm is developed in a dimensionless framework, requiring the knowledge of the shape of the imaged target, but not of its size. As a result, the solution is less sensitive to the limb shift caused by the atmospheric own radiance. To evaluate the performance of the proposed method, a numerical simulator is developed, which generates images captured in low Earth orbit, including also the presence of the atmosphere. In addition, experimental validation is provided due to a dedicated testbed, making use of a miniature infrared camera. Results show that our sensor concept returns rms errors of few hundredths of a degree or less in determining the local nadir direction.

Comparative Study of LEO and GEO SSPS for Some Identified Sites in India

2009 ◽  
Vol 10 (4) ◽  
Author(s):  
Kalpana Chaudhary ◽  
Babau R. Vishvakarma
Keyword(s):  
Power Plant ◽  
Power Output ◽  
Low Earth Orbit ◽  
Earth Orbit ◽  
Power Station ◽  
Constant Energy ◽  
Ground Station ◽  
Base Load ◽  
Solar Power Station ◽  
Selection Of

The analysis of satellite solar power station (SSPS) is carried out for some specified locations in India and consequently the performance of the system is evaluated for geostationary earth orbit (GEO)-based SSPS and low earth orbit (LEO)-based SSPS for sites located at different latitudes. The analysis of power, the received energy over a year, and the received energy during a day for the same beam intensity show better results for LEO-based SSPS system as compared to GEO-based system. However GEO-based system is advantageous in the sense that it will deliver constant energy to the load throughout a year. Thus it is concluded that GEO-based system is suitable for base load power plant. The weight of the rectenna and hence the space required for ground station for same power output for GEO-based system is greater than that for LEO-based system which will in turn increase the overall cost of the GEO-based system. These findings may help for judicious selection of orbit for placing the satellite for SSPS.

scholarly journals Potential Of VIRAC* RT-32 And RT-16 Antennas To Serve As Satellite Ground Station

2015 ◽  
Vol 52 (1) ◽  
pp. 68-74
Author(s):  
M. Bleiders ◽  
J. Trokss ◽  
M. Elerts
Keyword(s):  
Large Scale ◽  
Research Work ◽  
Full Time ◽  
Positioning Systems ◽  
Small Satellites ◽  
Ground Station ◽  
Data Rates ◽  
Pointing Accuracy ◽  
Satellite Signal ◽  
Satellite Ground Station

Abstract The basic application of RT-32 and RT-16 parabolic antennas is radio astronomy observations, both the radio-telescopes have been upgraded with state-of-the art cryogenic receivers, and now a large-scale modernization of the infrastructure is underway. Since the radio-astronomical observations are not full-time activities, a research work has been done to clear up whether these antennas, besides the mentioned activities, can be used as a satellite ground station. The main goal of this added functionality is to make possible the use of the extremely high reception systems’ figure-of-merit thus raising the satellite downlink data rates without increasing the on-board power consumption, which would be particularly important for developers of small satellites. In this paper, the progress in the research project is reported, which includes successful S-band satellite signal reception experiments and possible options as to integration of the related equipment into the system so that both functionalities could successfully coexist. Performance of the existing and the upgraded antenna positioning systems is estimated to determine if the latter are usable even for servicing low-Earth orbiting satellites. In addition, possible options are considered as to upgrading the system with automatic beam tracking capability, which would increase the antenna pointing accuracy even further.

scholarly journals LATLAUNCH AIR-LAUNCH SYSTEM FOR LOW-COST LAUNCHING OF SMALL SATELLITES INTO LOW EARTH ORBIT

Aviation ◽  
2021 ◽  
Vol 25 (2) ◽  
pp. 73-78
Author(s):  
Aleksandrs Urbahs ◽  
Sergey Kravchenko ◽  
Margarita Urbaha ◽  
Kristine Carjova ◽  
Natalja Panova ◽  
...  
Keyword(s):  
Low Cost ◽  
Low Earth Orbit ◽  
Earth Orbit ◽  
Competitive Advantages ◽  
Characteristic Velocity ◽  
Small Satellites ◽  
Aerial Platform

The paper presents the air-launch system enabling the delivery of small satellites into low Earth orbit. One of the most important advantages of the concept is its cost. Generally, the paper proves that launching a carrier from an aerial platform (a movable launch pad) provides the whole range of competitive advantages. In particular, the total losses during the launch from an aerial platform will reduce by 20–35%, and the characteristic velocity of the maneuver will reduce by 4–7%.

scholarly journals Localization of Multi-Class On-Road and Aerial Targets Using mmWave FMCW Radar

Electronics ◽  
2021 ◽  
Vol 10 (23) ◽  
pp. 2905
Author(s):  
Khushi Gupta ◽  
Soumya Joshi ◽  
M. B. Srinivas ◽  
Srinivas Boppu ◽  
M. Sabarimalai Manikandan ◽  
...  
Keyword(s):  
Traffic Control ◽  
Autonomous Systems ◽  
Vital Role ◽  
Field Of View ◽  
Monitoring Systems ◽  
Frequency Range ◽  
Angle Of Arrival ◽  
Fmcw Radar ◽  
Ground Station ◽  
Mechanical Rotation

mmWave radars play a vital role in autonomous systems, such as unmanned aerial vehicles (UAVs), unmanned surface vehicles (USVs), ground station control and monitoring systems. The challenging task when using mmWave radars is to estimate the accurate angle of arrival (AoA) of the targets, due to the limited number of receivers. In this paper, we present a novel AoA estimation technique, using mmWave FMCW radars operating in the frequency range 77–81 GHz by utilizing the mechanical rotation. Rotating the radar also increases the field of view in both azimuth and elevation. The proposed method estimates the AoA of the targets, using only a single transmitter and receiver. The measurements are carried out in a variety of practical scenarios including pedestrians, a car, and an UAV, also known as a drone. With measured data, range-angle maps are created, and morphological operators are used to estimate the AoA of the targets. We also process radar range-angle images for improved visual representation. The proposed method will be extremely beneficial for practical ground stations, traffic control and monitoring frameworks for both on-ground and airborne vehicles.

scholarly journals Small Satellites Constellations and Their Impact on CBRNe Management in Africa

2021 ◽  
Vol 11 (4) ◽  
pp. 387-395
Author(s):  
Donato Morea ◽  
Giacomo Primo Sciortino
Keyword(s):  
Optical Quality ◽  
Low Earth Orbit ◽  
Space Technology ◽  
Demand Model ◽  
Small Satellites ◽  
Relative Pricing ◽  
Ground Segment ◽  
User Terminal ◽  
Space Economy ◽  
International Astronautical

A wave of small satellites massive constellations, in the range of hundreds of units each, is progressively populating the Low Earth Orbit (LEO) with a low-price, and varied, offer of Telecom (speed band) and Earth Imaging services (Starlink, Planet, One Web, etc.). It is a market - driven trend based on new satellite interlocking technologies, which cut down the supplier costs of launch and in orbit operations compared to the traditional technology based on big (and much heavier) geostationary satellites operating at high altitudes. This is a disruptive phenomenon especially for the developing world, where such vital services have always been hard to access, and their use therefore remained scarce, not consolidated, or even completely missing. Among these, Emergency management is definitely crucial. The geographical focus of this study is Africa and it deals not only with Institutional PRS users but with a wider potential context (corporations, private subjects, etc.). It clearly appears that a general degree of “Country readiness” toward Space technology and organization is necessary for these initiatives to take place. This can be achieved through certified international cooperation. The authors then, based on an estimated demand Model for services with their relative pricing corresponding to a cost-designed constellation of small microsatellites, presented already, among other, at several International Astronautical Federation(IAF)Symposia on Space Economy, simulate the resulting type of services available: TLC by band types and relative upload and download rates, Earth imaging by refresh rates and optical quality and resolution, Ground segment configuration for signal backhauling and user terminal receiving.. This info isapplied to a specific African Country case (Nigeria) whose significance emerged over other Countries after the application of comparative grids. Finally, an insight on the specifically configuration of services for Chemical, Biological, Radiological, Nuclear, and Explosive (CBRNe) like management by local users, both maritime and land, with the relative costs, is offered. This is consequently left open for follow ups and discussion, due to the customer – design, project financing approaches of this Model programme.

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