Space subsystems design: (navigation, control, structure and…)
Arian Zakiani; Seyed Hassan Sedighy; Razieh Narimani
Volume 17, Issue 1 , March 2024, , Pages 73-79
Abstract
Due to the limited communication time between LEO satellites and the ground station and large volume of satellite image data, it is necessary to establish a high transmission rate connection. Therefore, the use of a high-efficiency satellite antenna is inevitable. In order to use the limited viewing ...
Read More
Due to the limited communication time between LEO satellites and the ground station and large volume of satellite image data, it is necessary to establish a high transmission rate connection. Therefore, the use of a high-efficiency satellite antenna is inevitable. In order to use the limited viewing time of the satellite, it must be possible to communicate with the ground station at low angles and change the main beam direction of satellite antenna to the direction of the ground station. The proposed array is composed of 8 antenna elements with a compact microstrip feed network. Low profile structure, circular polarization, high gain and low cost specifications of this proposed antenna array, candidate it for conformal array antenna in satellite applications.
Space Ground Segment: receiving, transmitting, controlling and data processing
Afshin Eskandari; S. Hassan Sedighi
Volume 15, Issue 4 , December 2022, , Pages 45-56
Abstract
In this paper, Design, optimization, and implementation of a Transparent Pseudo-Noise satellite Ranging relay are presented. CCSDS and DSN standards were studied for requirements of on board hardware for LEO satellites and ground station. To optimize the performance of the relay, a ground station for ...
Read More
In this paper, Design, optimization, and implementation of a Transparent Pseudo-Noise satellite Ranging relay are presented. CCSDS and DSN standards were studied for requirements of on board hardware for LEO satellites and ground station. To optimize the performance of the relay, a ground station for a two-way ranging system was modeled in MATLAB according to the DSN standard architecture. The effects of non-ideal hardware for the Implementation of an on-board relay were simulated. The simulation results confirmed that the designed transparent relay hardware satisfies the requirements of CCSDS and DSN ranging standards system and has no detrimental effect on it. Finally, the implemented relay was tested with a Transceiver similar to the ranging Transceiver was confirmed for operation.
recognition, evaluation, and detection of space radiation
Kavoos Ghordoyi Milan; Ali Sadr; S. Hasan Sedighy; Hamideh Daneshvar
Volume 14, Issue 2 , June 2021, , Pages 71-76
Abstract
In this paper, multi layer radiation shield is designed for electrons and protons space environments to protect in all satellite orbits. The designed shield layer material and thickness is analyzed and optimized by MCNPX linked with Matlab. In Matlab, genetic algorithm is employed for optimization where ...
Read More
In this paper, multi layer radiation shield is designed for electrons and protons space environments to protect in all satellite orbits. The designed shield layer material and thickness is analyzed and optimized by MCNPX linked with Matlab. In Matlab, genetic algorithm is employed for optimization where the cost function is obtained from MCNPX. The designed shield achieves more than 53% TID reduction for proton environment and more 72% TID reduction for electron environment compared with aluminum by similar thickness. This good specifications prove the capability and ability of the deigned multilayer shields to protect the electronic parts in the satellite applications.
Space Ground Segment: receiving, transmitting, controlling and data processing
Ali Sadeghzade; S. Hasan Sedighi; Mohamad Soleimani
Volume 13, Issue 3 , September 2020, , Pages 63-68
Abstract
In this paper, an anti-jamming GPS array antenna with seven antenna elements on the conformal structure is proposed for GPS applications by switching on/off the antenna ports. In this proposed antenna, when the received power is high, the antenna feeds are switched off to create null in the direction ...
Read More
In this paper, an anti-jamming GPS array antenna with seven antenna elements on the conformal structure is proposed for GPS applications by switching on/off the antenna ports. In this proposed antenna, when the received power is high, the antenna feeds are switched off to create null in the direction of jammer to reduce the jammer effect. This structure composed of seven patch elements where each element placed on special face of the structure. Whatever antennas be more directive, we can create deeper nulls. These specifications introduce this antenna as a good candidate for GPS applications to mitigate the jammer effects.
Space systems design (spacecraft, satellites, space stations and their equipment)
Alireza HeshmatiMoez; S. Hassan Sedighi; Mohamad Soleimani; Mohamad Khalaj AmirHoseini
Volume 13, Issue 2 , June 2020, , Pages 99-104
Abstract
This paper presents a new unit to design dual linearly polarized reflectarray antenna at ku for satellite telecommunication. Two orthogonal sets of parallel dipoles are used for each polarization to achieve more degree of freedom in the design and wider phase variation in the unit cells, consequently. ...
Read More
This paper presents a new unit to design dual linearly polarized reflectarray antenna at ku for satellite telecommunication. Two orthogonal sets of parallel dipoles are used for each polarization to achieve more degree of freedom in the design and wider phase variation in the unit cells, consequently. A 0.3m Reflectarray Antenna with two distinct beams is fabricated and measured in an anechoic chamber. The measurements have been carried out for both polarizations (X and Y ) in the azimuth and elevation planes. This antenna has x-polarized beam at (θ0=30º, ϕ0=90º) with 23.7 dBi gain and y-polarized beam at (θ0=30º, ϕ0=0º) with 24.2 dBi gain at Ku-band. The proposed design has one layer and simple structure compared to the references as well as dual band and dual polarization capabilities.
