scholarly journals Investigation of the technology of mutual navigation and orientation of small space vehicles flying in formation

2019 ◽  
Vol 18 (1) ◽  
pp. 88-93
Author(s):  
A. V. Nebylov ◽  
V. V. Perliouk ◽  
T. S. Leontieva
Keyword(s):  
Video Camera ◽  
Space Vehicles ◽  
Radio Communication ◽  
Small Space ◽  
Modeling Simulation ◽  
Ground Station ◽  
Bench Experiment ◽  
Radio Communication System ◽  
The Cost ◽  
Orbital Constellation

The paper presents the problem of ensuring support of the flight of a group of small spacecraft (microsatellites) taking into account the small mutual distances between them. The purpose of using the orbital constellation specified is to create a radio communication system to control remote objects like unmanned aerial vehicles and ground robots located in hard-to-reach areas of the Earth from the Central ground station. To reduce the cost of microsatellite design, it was decided to rigidly fix the receiving and transmitting antennas on their housings and use the spatial orientation of the entire apparatus for antenna guidance. This seriously complicated the tasks of navigation and orientation of microsatellites in a formation and required the development of a new method for determining the orientation of a single microsatellite. The essence of the method is to process the image obtained by means of a video camera mounted on a nearby microsatellite. We used methods of computer vision. The results of mathematical modeling simulation, as well as the results of full-scale bench experiment confirming the efficiency of the proposed method are presented.

scholarly journals Path loss Optimization in WIMAX Network using Genetic Algorithm

2020 ◽  
pp. 24-30
Keyword(s):  
Genetic Algorithm ◽  
Path Loss ◽  
Base Station ◽  
Mobile Systems ◽  
Broadband Access ◽  
Radio Communication ◽  
Radio Communication System ◽  
The Cost ◽  
Access Services ◽  
Station Site

The most necessary factors effect on the standard of broadband access services in mobile systems are WIMAX signal throughput and area coverage range. The environment controls are based on the sign power of any radio communication system. The sign power in any base station site relies on the space between the transmitter and the receiver, carrier frequency for the transmitter and the receiver along on the path loss. One of the most generally utilized experimental model to predict the path loss is the COST-231 Hata model. In this paper, the path loss rates have calculated based on the WIMAX criterion frequency at an area with 3.5GHz, that constant distances (7km) of transmitting base station into receive base station in urban, suburban environments. The execution of the COST-231 Hata paradigm and optimized paradigm are rated over the path loss. This model is optimized using Genetic Algorithm Technique using a computational tool MATLAB. Path loss results acquired show that the optimized paradigm rates a little higher than rates standard. The distance (7km)is good because of achieving the lowest value for path loss.

scholarly journals Aplikasi Monitoring Energi SHS Off-Grid Menggunakan Lora

2021 ◽  
Vol 13 (1) ◽  
pp. 26-32
Author(s):  
Satrio Yudho
Keyword(s):  
Internet Of Things ◽  
Long Range ◽  
Spread Spectrum ◽  
Communication System ◽  
Electricity Consumption ◽  
Radio Communication ◽  
Energy Monitoring ◽  
Chirp Spread Spectrum ◽  
Solar Home System ◽  
Radio Communication System

The manner of efficiency and effective of power usage is the main objective in electricity consumption, one major steps to control the usage is by providing a monitoring to aim the power usage data and process it to information needed. Internet of Things benefit in power and electricity has involved sensors to work as data reader continuously.  LoRa or well known as Long Range radio communication system work with chirp spread spectrum which work from 920 to 923 Mhz in Indonesia. This paper presents implementation of LoRa system to support the prototype of energy monitoring in Solar Home System off-grid

Universal Software Radio Peripheral/GNU Radio-Based Implementation of a Software-Defined Radio Communication System

2019 ◽  
pp. 227-240
Author(s):  
Ehsan Sheybani
Keyword(s):  
Communication System ◽  
Software Defined Radio ◽  
Software Radio ◽  
Block Code ◽  
Radio Station ◽  
Frequency Change ◽  
Gnu Radio ◽  
Radio Communication ◽  
Space Communications ◽  
Radio Communication System

Challenges involved in space communications across wireless channels call for new approaches to radio systems. Due to the growing need for frequency change in modern wireless systems, an adaptive radio system has the highest demand. Software-defined radios (SDR) offer this type of adaptivity as well as compatibility with other standard platforms such as USRP/GNU radio. Despite limitations of this approach due to hardware components, viable modeling and simulation as well as deployable systems are possible using this platform. This chapter presents a detailed implementation procedure for a USRP/GNU radio-based SDR communication system that can be used for practical experiments as well as an academic lab in this field. In this experiment the USRP has been configured to receive signal from a local radio station using the BasicRX model daughterboard. The programmable USRP executes Python block code implemented in the GNU Radio Companion (GRC) on Ubuntu OS.

Performance Bounds for VDES R-mode

2019 ◽  
Vol 73 (1) ◽  
pp. 92-114 ◽  
Author(s):  
Jan Šafář ◽  
Alan Grant ◽  
Paul Williams ◽  
Nick Ward
Keyword(s):  
Data Exchange ◽  
Estimation Error ◽  
Additive White Gaussian Noise ◽  
Automatic Identification ◽  
Identification System ◽  
Performance Bounds ◽  
Radio Communication ◽  
Very High Frequency ◽  
Radio Communication System ◽  
The Impact

The Very High Frequency (VHF) Data Exchange System (VDES) is a new radio communication system being developed by the international maritime community, with the principal objectives to safeguard existing Automatic Identification System (AIS) core functions and enhance maritime communication applications, based on robust, efficient and secure data transmission with wider bandwidth than the AIS. VDES is also being considered as a potential component of the R-mode concept, where the same signals used for communication are also used for ranging, thus mitigating the impact of disruptions to satellite positioning services. This paper establishes statistical performance bounds on the ranging precision of VDES R-mode, assuming an additive white Gaussian noise propagation channel. Modified Cramér-Rao bounds on the pseudorange estimation error are provided for all waveforms currently proposed for use in terrestrial VDES communications. These are then used to estimate the maximum usable ranges for AIS/VDES R-mode stations. The results show that, under the assumed channel conditions, all of the new VDES waveforms provide better ranging performance than the AIS waveform, with the best performance being achieved using the 100 kHz bandwidth terrestrial VDE waveforms.

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