satellite communication jntuh
Satellite Subsystems: Attitude and Orbit Control System, Telemetry, Tracking, Command And
Monitoring, Power Systems, Communication Subsystems, Satellite Antennas, Equipment Reliability
and Space Qualification.
The document discusses the key components and subsystems that make up the space segment of a satellite system. It describes:
1) The main components of a satellite including the payload (service equipment), bus (vehicle), and subsystems that provide power, attitude control, thermal control, and telemetry/command functions.
2) Specific subsystems like transponders, solar cells and batteries for power supply, momentum wheels and gas jets for attitude control, and thermal blankets/shields for thermal control.
3) The telemetry, tracking and control subsystem provides communication between the satellite and ground stations for monitoring and control.
Attitude & orbital control system, TTC & M system, Power system, Communication subsystem, Satellite antenna, Space qualification, Equipment Reliability, redundancy
This document describes a satellite tracking system that uses a microcontroller to track a satellite's position and correct its orbit if it drifts from its intended path. The system includes an orbital correction engine that calculates needed adjustments and a tracking processor that monitors the satellite's position over time to detect any deviations. It sends the satellite's location data to an earth station via an RS-232 interface. The microcontroller compares the data to an orbital database and determines corrections to guide the satellite back to its proper orbit. A visual basics program is used to model and simulate the satellite's movement and drift.
Satellite communication full report original 2Pranoosh T
The document provides an overview of satellite communication techniques for military aircraft. It discusses that while currently used UHF satellite communication is inexpensive and simple to install, it has limited capacity and is prone to interference. SHF and EHF satellite techniques offer increased bandwidth and capabilities like adaptive antennas. The document then discusses various components of satellite communication systems like different frequency bands used, types of satellites including GEO and LEO, advantages of satellite communication over terrestrial networks, and applications.
This document summarizes different types of solar tracking systems that orient photovoltaic panels, reflectors, or other devices toward the sun to increase solar energy collection. It describes single-axis and dual-axis tracking systems, including horizontal, vertical, tilted, and polar-aligned single-axis trackers as well as tip-tilt and azimuth-altitude dual-axis trackers. It also discusses active trackers that use motors and passive trackers that use compressed gas or fluid movement in response to solar heating.
The document discusses satellite communication course details taught by Dr. R. Raman. It outlines the course outcomes, contents, prerequisites, and textbooks. It focuses on describing the various satellite subsystems, including the bus (structure, power, attitude control, thermal control, command/telemetry) and payload (transponders, antennas). It explains spin and three-axis stabilization methods and components like reaction wheels and control jets that maintain satellite orientation.
The document discusses various subsystems of communication satellites, including:
- Spacecraft structure, power, attitude control, thermal control, and propulsion systems
- Communication payloads including transponders and supporting subsystems
- Telemetry, tracking and command systems that allow communication between the satellite and ground stations for control and monitoring
- Attitude control is needed to point antennas and instruments, and is achieved through methods like spinning, momentum wheels, and thrusters
- Thermal control and solar arrays are used to regulate temperatures and provide power to satellite subsystems
The document discusses different types of earth station technologies and satellite constellation designs. It describes the basic components of earth stations including transmitters, receivers, antennas, and tracking equipment. It also explains different types of satellite orbits such as equatorial orbits, inclined orbits, elliptical orbits, Molniya orbits, and sun synchronous orbits. Finally, it summarizes seven non-geostationary satellite constellation designs including their orbital configurations and purposes.
The document discusses the key components and subsystems that make up the space segment of a satellite system. It describes:
1) The main components of a satellite including the payload (service equipment), bus (vehicle), and subsystems that provide power, attitude control, thermal control, and telemetry/command functions.
2) Specific subsystems like transponders, solar cells and batteries for power supply, momentum wheels and gas jets for attitude control, and thermal blankets/shields for thermal control.
3) The telemetry, tracking and control subsystem provides communication between the satellite and ground stations for monitoring and control.
Attitude & orbital control system, TTC & M system, Power system, Communication subsystem, Satellite antenna, Space qualification, Equipment Reliability, redundancy
This document describes a satellite tracking system that uses a microcontroller to track a satellite's position and correct its orbit if it drifts from its intended path. The system includes an orbital correction engine that calculates needed adjustments and a tracking processor that monitors the satellite's position over time to detect any deviations. It sends the satellite's location data to an earth station via an RS-232 interface. The microcontroller compares the data to an orbital database and determines corrections to guide the satellite back to its proper orbit. A visual basics program is used to model and simulate the satellite's movement and drift.
Satellite communication full report original 2Pranoosh T
The document provides an overview of satellite communication techniques for military aircraft. It discusses that while currently used UHF satellite communication is inexpensive and simple to install, it has limited capacity and is prone to interference. SHF and EHF satellite techniques offer increased bandwidth and capabilities like adaptive antennas. The document then discusses various components of satellite communication systems like different frequency bands used, types of satellites including GEO and LEO, advantages of satellite communication over terrestrial networks, and applications.
This document summarizes different types of solar tracking systems that orient photovoltaic panels, reflectors, or other devices toward the sun to increase solar energy collection. It describes single-axis and dual-axis tracking systems, including horizontal, vertical, tilted, and polar-aligned single-axis trackers as well as tip-tilt and azimuth-altitude dual-axis trackers. It also discusses active trackers that use motors and passive trackers that use compressed gas or fluid movement in response to solar heating.
The document discusses satellite communication course details taught by Dr. R. Raman. It outlines the course outcomes, contents, prerequisites, and textbooks. It focuses on describing the various satellite subsystems, including the bus (structure, power, attitude control, thermal control, command/telemetry) and payload (transponders, antennas). It explains spin and three-axis stabilization methods and components like reaction wheels and control jets that maintain satellite orientation.
The document discusses various subsystems of communication satellites, including:
- Spacecraft structure, power, attitude control, thermal control, and propulsion systems
- Communication payloads including transponders and supporting subsystems
- Telemetry, tracking and command systems that allow communication between the satellite and ground stations for control and monitoring
- Attitude control is needed to point antennas and instruments, and is achieved through methods like spinning, momentum wheels, and thrusters
- Thermal control and solar arrays are used to regulate temperatures and provide power to satellite subsystems
The document discusses different types of earth station technologies and satellite constellation designs. It describes the basic components of earth stations including transmitters, receivers, antennas, and tracking equipment. It also explains different types of satellite orbits such as equatorial orbits, inclined orbits, elliptical orbits, Molniya orbits, and sun synchronous orbits. Finally, it summarizes seven non-geostationary satellite constellation designs including their orbital configurations and purposes.
The document discusses the key components and subsystems of satellite communication systems. It is broken down into two main segments:
1) The space segment, which includes the satellites in orbit that provide the communication relay services, and the ground control stations that monitor and control the satellites.
2) The ground segment, which consists of the terminals on the Earth's surface that utilize the satellite communication capabilities. These include fixed, transportable, and mobile terminals.
The space segment has two main components - the satellite bus, which provides basic support functions like structure, power, thermal control etc., and the payload which provides the actual communication relay equipment like transponders and antennas.
The document discusses the key subsystems of satellites, including telemetry tracking command and monitoring (TT&C), power systems, and communication subsystems. The TT&C system controls the satellite's orbit, monitors sensor data, and enables commanding. Telemetry collects sensor data and sends it to earth stations for monitoring. Tracking provides position data. The command system controls satellite operations. Power is generated by solar cells and stored in batteries. Communication payloads relay voice, video and data using transponders across multiple frequency bands based on international agreements.
This document provides an overview of satellite communications and orbital mechanics. It discusses the key forces that act on satellites in stable orbits, including centrifugal force and gravitational attraction. Kepler's laws of planetary motion are also summarized. The document outlines different types of satellite orbits, orbital parameters, and how to calculate look angles to track a satellite's position from an earth station. It describes the general architecture of satellite communication systems, including the space segment consisting of the satellite and ground control station, as well as different types of ground terminals.
This document provides an overview of solar tracking systems. It discusses how solar trackers orient solar panels toward the sun to minimize the angle of incidence and maximize energy production. Single-axis and dual-axis trackers are described, as well as the components and control systems used. Historical developments are reviewed and recent trends showing that tracking is less cost-effective as panel prices decline. Future research directions could improve dual-axis closed-loop control systems to further increase energy harvesting from solar installations.
This document provides an introduction to satellite communication. It discusses the basic structure of a satellite link with uplinks and downlinks using separate frequency bands. Common frequency bands used include C-band, extended C-band, Ku-band, and Ka-band. The document also describes geostationary satellites, signal levels, propagation delay, transponder equipment on satellites, and India's INSAT satellite program. Advantages of satellite communication include wide coverage area, suitability for both digital and analog transmission, high quality, flexibility, and ability to provide quick services and mobile/emergency communication.
Presentation for the 16th EUROSTAR Users Conference June 2008Antonios Arkas
The document describes an orbital and attitude simulator called OR.A.SI that can model spacecraft dynamics. It has modules for orbital propagation, attitude dynamics, Earth-spacecraft geometry calculations, and mission analysis. The orbital module can model orbits with high accuracy and support orbital maneuvers. The attitude module can simulate rigid body dynamics under torques and integrate spacecraft rotation with quaternions. It provides outputs for spacecraft orientation and motion. The document demonstrates how OR.A.SI can be used to model realistic attitude scenarios like dual-spin spacecraft and precision dumping of spacecraft precession with impulsive torques.
1. The document describes a proposed system for wireless power transmission from solar power satellites (SPS) to rectennas on Earth.
2. The SPS would have large spacetennas made of solar panels and microwave antennas that would transmit the collected solar energy to rectennas on Earth as microwave beams.
3. The rectennas would convert the microwave energy back into electricity and feed it into local power grids to provide a continuous 24-hour power supply that is independent of weather or daylight.
The document discusses solar tracking systems which orient photovoltaic panels, reflectors, or other devices toward the sun for maximum exposure. It describes several types of solar trackers, including single-axis and dual-axis models. Single-axis trackers rotate around one axis, while dual-axis trackers rotate around two perpendicular axes for improved sun-following. The document also covers types of drives, controls, and algorithms used in solar tracking systems.
Space Radiation & It's Effects On Space Systems & Astronauts Technical Traini...Jim Jenkins
This course is designed for technical and management personnel who wish to gain an understanding of the fundamentals and the effects of space radiation on space systems and astronauts. The radiation environment imposes strict design requirements on many space systems and is the primary limitation to human exploration outside of the Earth's magnetosphere. The course specifically addresses issues of relevance and concern for participants who expect to plan, design, build, integrate, test, launch, operate or manage spacecraft and spacecraft subsystems for robotic or crewed missions. The primary goal is to assist attendees in attainment of their professional potential by providing them with a basic understanding of the interaction of radiation with non-biological and biological materials, the radiation environment, and the tools available to simulate and evaluate the effects of radiation on materials, circuits, and humans
Wireless power transmission and reception using solar power satellites and ...PRADEEP Cheekatla
1. The document describes a proposed system for wireless power transmission from solar power satellites (SPS) to rectifying antennas (rectennas) on Earth using microwaves.
2. The SPS would have large photovoltaic panels to generate solar power, which would be converted to microwaves and transmitted via a large transmitting antenna to rectennas on Earth.
3. The rectennas would receive the microwaves and convert them back to electric power, providing a renewable energy source unaffected by weather or nighttime.
This document discusses satellite communication systems and concepts. It covers satellite subsystems, types of satellites including active and passive satellites, satellite transponders, satellite communication links including uplinks, downlinks and crosslinks. It also discusses satellite footprints, radiation patterns, types of earth stations and their transmitter and receiver components, and satellite frequency bands.
This document provides a preliminary study for the AROSAT satellite system. It discusses several key requirements including coverage area, resolution capabilities, duty cycle, onboard storage and download rates. It evaluates three potential spacecraft configurations and their impact on drag, solar array effectiveness and risk. Configuration #2 is preferred as it minimizes drag while having a simple solar array design. The document also examines how spacecraft altitude affects optical instrument parameters and the propulsion systems needed to compensate for atmospheric drag at different altitudes. Electric propulsion is recommended to enable lower orbits. Overall architectures are proposed for Configuration #2 that could meet requirements.
Two Axes Sun Tracking System for Heliostat in Algeriaijeei-iaes
In this paper, using Proteus software, sun tracking system with two axes program has developed
and simulated for site of GHARDAIA, in the south of ALGERIA. Two direct current motors have used to
move heliostat in North–South and East–West axis polar, in order to tracking the sun path.In addition, the
distinction between day and night has provided by light dependent resistor (LDR).An algorithm of two axes
sun tracking system hab developed and simulated under Proteus software, after DC motor’s parameters
have verified and simulated under MATLAB software. The results show that: in the first, the development
of the heliostat control requires the knowledge of the position of each heliostat relative to the tower to
ensure the proper operation of the motors, and the uniformity of the reflected beam to the target.Then the
choice of the drive motors is based on the useful power, including the weight of the heliostat, and all efforts
affects on operation of motors in different seasons of the year, like the wind.And The position of the
heliostat depends of chopper duty cycle.Finally,Conducting a power tower with mobile heliostats requires a
techno-economic study on all components (heliostats, tower...) of the plant, for example weather two
motors for each heliostat field.
This document discusses the key subsystems of satellites and earth stations. It describes the functions of subsystems including the mechanical structure, propulsion, thermal control, attitude and orbit control, telemetry tracking and command, power supply, payload and antenna. It provides details on the power supply subsystem and its solar panels, batteries and electrical power systems. It also covers the telemetry, tracking and command subsystem and its functions for monitoring health, controlling orbit and attitude, and commanding the satellite.
This document describes a design for a dual gain control system for a helical feed parabolic reflector antenna. The system uses 5 stepper motors - 4 to control the position of sectors of the parabolic reflector to vary its diameter and gain, and 1 to control the position of the helical feed to vary its number of turns and gain. The microcontroller-based system allows entering the number of steps for each motor from a keypad to control the antenna gains. Simulation results show the antenna gain can be varied +/- 10% by adjusting the reflector diameter or helical feed position.
This document discusses satellite communication systems. It provides details on the components of satellites, including antennas, solar panels, batteries, radio transmitters and receivers, rocket motors and fuel, and cameras. It describes the space and ground segments of satellite systems. The space segment consists of the satellite itself, while the ground segment consists of earth stations that transmit and receive signals. It discusses different types of antennas used in satellites, including wire, horn, array, and reflector antennas. It also covers the different frequency bands, satellite orbits including low earth orbit, geostationary orbit, and medium earth orbit, and the uplink and downlink frequencies used in different bands.
1) The document describes the design of a software driver for a satellite dish antenna positioning system that uses stepper motors to adjust the azimuth, elevation, and polarization angles of the antenna remotely.
2) The software takes in the antenna's latitude, longitude, and the satellite's longitude as inputs, performs calculations to determine the required adjustment angles, and outputs signals to control the stepper motor drivers and position the antenna.
3) The system allows a user to point the antenna to different satellites without manually adjusting the dish, simply by entering the location coordinates into the software.
The KMEC mission involves sending two spacecraft to Saturn over 6 years to study cosmic dust, ultraviolet imaging, and space recognition between the payloads. Each spacecraft is octagonal and 6m tall, made of aluminum. The 100kg payload includes dust, UV, and ranging instruments. A chemical propulsion system will perform orbital maneuvers. Power comes from an RTG and backup battery. Thermal control uses an RTG and radiator. The spacecraft structure is sized to withstand launch stresses and the environment at Saturn.
Importance of SSPS in SDG and ESG, and importance of antennas in SSPSAdvanced-Concepts-Team
SSPS has benefits for achieving SDGs and ESG goals by providing low emission, sustainable power. Key technologies include large antennas that can precisely direct microwave beams for power transmission. Antennas face challenges like developing arrays of thousands of precisely controlled elements. The presentation outlines a roadmap including technology verification experiments and test satellites to demonstrate SSPS technologies like deployable antennas in space before developing commercial-scale systems in geosynchronous orbit capable of generating several GW of power.
This document discusses using shepherd satellites to provide guidance, navigation, and control for arrays of microsatellites performing formation flying. It proposes using optical scattering and gradient forces generated by lasers on the shepherd satellites to apply corrective forces to the microsatellite array from a distance. Analytic models predict these radiation forces could provide restorative forces of 10-5 N to 10-4 N using laser powers of 10-10 kW to 100 kW. Potential applications include drag makeup for low Earth orbiting satellites, position control for array formation, and correcting perturbations in geosynchronous Earth orbit.
satellite communication jntuh
Satellite Link Design: Basic Transmission Theory, System Noise Temperature, and G/T Ratio,
Design of Down Links, Up Link Design, Design Of Satellite Links For Specified C/N, System Design
Examples.
Multiple Access: Frequency Division Multiple Access (FDMA), Inter modulation, Calculation of C/N,
Time Division Multiple Access (TDMA), Frame Structure, Examples, Satellite Switched TDMA
Onboard Processing, DAMA, Code Division Multiple Access (CDMA), Spread Spectrum Transmission
and Reception.
The document discusses the key components and subsystems of satellite communication systems. It is broken down into two main segments:
1) The space segment, which includes the satellites in orbit that provide the communication relay services, and the ground control stations that monitor and control the satellites.
2) The ground segment, which consists of the terminals on the Earth's surface that utilize the satellite communication capabilities. These include fixed, transportable, and mobile terminals.
The space segment has two main components - the satellite bus, which provides basic support functions like structure, power, thermal control etc., and the payload which provides the actual communication relay equipment like transponders and antennas.
The document discusses the key subsystems of satellites, including telemetry tracking command and monitoring (TT&C), power systems, and communication subsystems. The TT&C system controls the satellite's orbit, monitors sensor data, and enables commanding. Telemetry collects sensor data and sends it to earth stations for monitoring. Tracking provides position data. The command system controls satellite operations. Power is generated by solar cells and stored in batteries. Communication payloads relay voice, video and data using transponders across multiple frequency bands based on international agreements.
This document provides an overview of satellite communications and orbital mechanics. It discusses the key forces that act on satellites in stable orbits, including centrifugal force and gravitational attraction. Kepler's laws of planetary motion are also summarized. The document outlines different types of satellite orbits, orbital parameters, and how to calculate look angles to track a satellite's position from an earth station. It describes the general architecture of satellite communication systems, including the space segment consisting of the satellite and ground control station, as well as different types of ground terminals.
This document provides an overview of solar tracking systems. It discusses how solar trackers orient solar panels toward the sun to minimize the angle of incidence and maximize energy production. Single-axis and dual-axis trackers are described, as well as the components and control systems used. Historical developments are reviewed and recent trends showing that tracking is less cost-effective as panel prices decline. Future research directions could improve dual-axis closed-loop control systems to further increase energy harvesting from solar installations.
This document provides an introduction to satellite communication. It discusses the basic structure of a satellite link with uplinks and downlinks using separate frequency bands. Common frequency bands used include C-band, extended C-band, Ku-band, and Ka-band. The document also describes geostationary satellites, signal levels, propagation delay, transponder equipment on satellites, and India's INSAT satellite program. Advantages of satellite communication include wide coverage area, suitability for both digital and analog transmission, high quality, flexibility, and ability to provide quick services and mobile/emergency communication.
Presentation for the 16th EUROSTAR Users Conference June 2008Antonios Arkas
The document describes an orbital and attitude simulator called OR.A.SI that can model spacecraft dynamics. It has modules for orbital propagation, attitude dynamics, Earth-spacecraft geometry calculations, and mission analysis. The orbital module can model orbits with high accuracy and support orbital maneuvers. The attitude module can simulate rigid body dynamics under torques and integrate spacecraft rotation with quaternions. It provides outputs for spacecraft orientation and motion. The document demonstrates how OR.A.SI can be used to model realistic attitude scenarios like dual-spin spacecraft and precision dumping of spacecraft precession with impulsive torques.
1. The document describes a proposed system for wireless power transmission from solar power satellites (SPS) to rectennas on Earth.
2. The SPS would have large spacetennas made of solar panels and microwave antennas that would transmit the collected solar energy to rectennas on Earth as microwave beams.
3. The rectennas would convert the microwave energy back into electricity and feed it into local power grids to provide a continuous 24-hour power supply that is independent of weather or daylight.
The document discusses solar tracking systems which orient photovoltaic panels, reflectors, or other devices toward the sun for maximum exposure. It describes several types of solar trackers, including single-axis and dual-axis models. Single-axis trackers rotate around one axis, while dual-axis trackers rotate around two perpendicular axes for improved sun-following. The document also covers types of drives, controls, and algorithms used in solar tracking systems.
Space Radiation & It's Effects On Space Systems & Astronauts Technical Traini...Jim Jenkins
This course is designed for technical and management personnel who wish to gain an understanding of the fundamentals and the effects of space radiation on space systems and astronauts. The radiation environment imposes strict design requirements on many space systems and is the primary limitation to human exploration outside of the Earth's magnetosphere. The course specifically addresses issues of relevance and concern for participants who expect to plan, design, build, integrate, test, launch, operate or manage spacecraft and spacecraft subsystems for robotic or crewed missions. The primary goal is to assist attendees in attainment of their professional potential by providing them with a basic understanding of the interaction of radiation with non-biological and biological materials, the radiation environment, and the tools available to simulate and evaluate the effects of radiation on materials, circuits, and humans
Wireless power transmission and reception using solar power satellites and ...PRADEEP Cheekatla
1. The document describes a proposed system for wireless power transmission from solar power satellites (SPS) to rectifying antennas (rectennas) on Earth using microwaves.
2. The SPS would have large photovoltaic panels to generate solar power, which would be converted to microwaves and transmitted via a large transmitting antenna to rectennas on Earth.
3. The rectennas would receive the microwaves and convert them back to electric power, providing a renewable energy source unaffected by weather or nighttime.
This document discusses satellite communication systems and concepts. It covers satellite subsystems, types of satellites including active and passive satellites, satellite transponders, satellite communication links including uplinks, downlinks and crosslinks. It also discusses satellite footprints, radiation patterns, types of earth stations and their transmitter and receiver components, and satellite frequency bands.
This document provides a preliminary study for the AROSAT satellite system. It discusses several key requirements including coverage area, resolution capabilities, duty cycle, onboard storage and download rates. It evaluates three potential spacecraft configurations and their impact on drag, solar array effectiveness and risk. Configuration #2 is preferred as it minimizes drag while having a simple solar array design. The document also examines how spacecraft altitude affects optical instrument parameters and the propulsion systems needed to compensate for atmospheric drag at different altitudes. Electric propulsion is recommended to enable lower orbits. Overall architectures are proposed for Configuration #2 that could meet requirements.
Two Axes Sun Tracking System for Heliostat in Algeriaijeei-iaes
In this paper, using Proteus software, sun tracking system with two axes program has developed
and simulated for site of GHARDAIA, in the south of ALGERIA. Two direct current motors have used to
move heliostat in North–South and East–West axis polar, in order to tracking the sun path.In addition, the
distinction between day and night has provided by light dependent resistor (LDR).An algorithm of two axes
sun tracking system hab developed and simulated under Proteus software, after DC motor’s parameters
have verified and simulated under MATLAB software. The results show that: in the first, the development
of the heliostat control requires the knowledge of the position of each heliostat relative to the tower to
ensure the proper operation of the motors, and the uniformity of the reflected beam to the target.Then the
choice of the drive motors is based on the useful power, including the weight of the heliostat, and all efforts
affects on operation of motors in different seasons of the year, like the wind.And The position of the
heliostat depends of chopper duty cycle.Finally,Conducting a power tower with mobile heliostats requires a
techno-economic study on all components (heliostats, tower...) of the plant, for example weather two
motors for each heliostat field.
This document discusses the key subsystems of satellites and earth stations. It describes the functions of subsystems including the mechanical structure, propulsion, thermal control, attitude and orbit control, telemetry tracking and command, power supply, payload and antenna. It provides details on the power supply subsystem and its solar panels, batteries and electrical power systems. It also covers the telemetry, tracking and command subsystem and its functions for monitoring health, controlling orbit and attitude, and commanding the satellite.
This document describes a design for a dual gain control system for a helical feed parabolic reflector antenna. The system uses 5 stepper motors - 4 to control the position of sectors of the parabolic reflector to vary its diameter and gain, and 1 to control the position of the helical feed to vary its number of turns and gain. The microcontroller-based system allows entering the number of steps for each motor from a keypad to control the antenna gains. Simulation results show the antenna gain can be varied +/- 10% by adjusting the reflector diameter or helical feed position.
This document discusses satellite communication systems. It provides details on the components of satellites, including antennas, solar panels, batteries, radio transmitters and receivers, rocket motors and fuel, and cameras. It describes the space and ground segments of satellite systems. The space segment consists of the satellite itself, while the ground segment consists of earth stations that transmit and receive signals. It discusses different types of antennas used in satellites, including wire, horn, array, and reflector antennas. It also covers the different frequency bands, satellite orbits including low earth orbit, geostationary orbit, and medium earth orbit, and the uplink and downlink frequencies used in different bands.
1) The document describes the design of a software driver for a satellite dish antenna positioning system that uses stepper motors to adjust the azimuth, elevation, and polarization angles of the antenna remotely.
2) The software takes in the antenna's latitude, longitude, and the satellite's longitude as inputs, performs calculations to determine the required adjustment angles, and outputs signals to control the stepper motor drivers and position the antenna.
3) The system allows a user to point the antenna to different satellites without manually adjusting the dish, simply by entering the location coordinates into the software.
The KMEC mission involves sending two spacecraft to Saturn over 6 years to study cosmic dust, ultraviolet imaging, and space recognition between the payloads. Each spacecraft is octagonal and 6m tall, made of aluminum. The 100kg payload includes dust, UV, and ranging instruments. A chemical propulsion system will perform orbital maneuvers. Power comes from an RTG and backup battery. Thermal control uses an RTG and radiator. The spacecraft structure is sized to withstand launch stresses and the environment at Saturn.
Importance of SSPS in SDG and ESG, and importance of antennas in SSPSAdvanced-Concepts-Team
SSPS has benefits for achieving SDGs and ESG goals by providing low emission, sustainable power. Key technologies include large antennas that can precisely direct microwave beams for power transmission. Antennas face challenges like developing arrays of thousands of precisely controlled elements. The presentation outlines a roadmap including technology verification experiments and test satellites to demonstrate SSPS technologies like deployable antennas in space before developing commercial-scale systems in geosynchronous orbit capable of generating several GW of power.
This document discusses using shepherd satellites to provide guidance, navigation, and control for arrays of microsatellites performing formation flying. It proposes using optical scattering and gradient forces generated by lasers on the shepherd satellites to apply corrective forces to the microsatellite array from a distance. Analytic models predict these radiation forces could provide restorative forces of 10-5 N to 10-4 N using laser powers of 10-10 kW to 100 kW. Potential applications include drag makeup for low Earth orbiting satellites, position control for array formation, and correcting perturbations in geosynchronous Earth orbit.
Similar to satellite communication-UNIT-II.pptx (20)
satellite communication jntuh
Satellite Link Design: Basic Transmission Theory, System Noise Temperature, and G/T Ratio,
Design of Down Links, Up Link Design, Design Of Satellite Links For Specified C/N, System Design
Examples.
Multiple Access: Frequency Division Multiple Access (FDMA), Inter modulation, Calculation of C/N,
Time Division Multiple Access (TDMA), Frame Structure, Examples, Satellite Switched TDMA
Onboard Processing, DAMA, Code Division Multiple Access (CDMA), Spread Spectrum Transmission
and Reception.
satellite communication jntuh
Earth Station Technology: Introduction, Transmitters, Receivers, Antennas, Tracking Systems,
Terrestrial Interface, Primary Power Test Methods.
UNIT - IV
Combinational Logic Circuits: Basic Theorems and Properties of Boolean Algebra, Canonical and Standard Forms, Digital Logic Gates, The Map Method, Product-of-Sums Simplification, Don’t-Care Conditions, NAND and NOR Implementation, Exclusive-OR Function, Binary Adder-Subtractor, Decimal Adder, Binary Multiplier, Magnitude Comparator, Decoders, Encoders, Multiplexers.
This document appears to be lecture slides on digital electronics and number systems from an Electronics and Communication Engineering course. It covers topics like:
- Binary and other number systems like octal and hexadecimal
- Converting between number systems like binary to decimal and vice versa
- Digital logic gates and their truth tables
- Logic families like Diode-Transistor Logic and Transistor-Transistor Logic
- Representing and operating on negative numbers in binary
The document provides information, examples, and explanations of key concepts in a way that is likely useful for students taking a course on digital circuits and logic design.
This document contains lecture slides on Bipolar Junction Transistors (BJTs) and transistor amplifiers from a course on Analog and Digital Electronics. It covers BJT characteristics, transistor configurations including common-base, common-emitter, and common-collector, biasing techniques such as fixed bias, collector base bias, and voltage divider bias, and small signal analysis. The slides include diagrams of transistor circuits and characteristics as well as explanations of concepts like stability, thermal runaway, and frequency response.
The document is a lab manual for the Pulse and Digital Circuits lab at ACE Engineering College. It contains instructions and circuit diagrams for experiments on linear and non-linear wave shaping. Experiment 1 involves designing high-pass and low-pass RC filters and observing their responses to a square wave input. Experiment 2 examines the operation of various clipping and clamping circuits using diodes and their output waveforms for sinusoidal inputs. Precise procedures are provided to set up the circuits and measure the relevant voltage levels and waveforms on an oscilloscope.
Standard T, π, L Sections, Characteristic impedance, image transfer constants, Design of
Attenuators, impedance matching network, T and π Conversion, LC Networks and Filters:
Properties of LC Networks, Foster’s Reactance theorem, design of constant K, LP, HP and
BP Filters, Composite filter design
Two port network parameters, Z, Y, ABCD, h and g parameters, Characteristic impedance,
Image transfer constant, image and iterative impedance, network function, driving point and
transfer functions – using transformed (S) variables, Poles and Zeros.
This document discusses resonance circuits and their applications. Resonance occurs when the capacitive and inductive reactances are equal, resulting in a purely resistive impedance. Key parameters of resonance circuits include the resonance frequency, half-power frequencies, bandwidth, and quality factor. Resonance circuits are useful for constructing filters and are used in applications like bandpass and bandstop filters, which allow only certain frequency ranges to pass.
Magnetic Circuits, Self and Mutual
inductances, dot convention, impedance, reactance concept, Impedance transformation and
coupled circuits, co-efficient of coupling, equivalent T for Magnetically coupled circuits,
Ideal Transformer.
This document outlines the terms and conditions for a rental agreement between John Doe and Jane Smith for the property located at 123 Main St. It specifies the monthly rental rate of $1,000 due on the 1st of each month, the security deposit of $500, and responsibilities of landlord and tenant for repairs and maintenance. The initial lease term is one year beginning January 1st, 2023 and the agreement will automatically renew month-to-month unless otherwise terminated.
Standard T, π, L Sections, Characteristic impedance, image transfer constants, Design of
Attenuators, impedance matching network, T and π Conversion, LC Networks and Filters:
Properties of LC Networks, Foster’s Reactance theorem, design of constant K, LP, HP and
BP Filters, Composite filter design
Two port network parameters, Z, Y, ABCD, h and g parameters, Characteristic impedance,
Image transfer constant, image and iterative impedance, network function, driving point and
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satellite communication-UNIT-II.pptx
1. Unit 2
Satellite Sub-Systems
SATELLITE SUB-SYSTEMS
CONTROL SEGMENT (MONITOR STATIONS)
The GPS-System is controlled by the US Army. The
“master control station” and four additional
monitoring stations were set up for monitoring the
satellites.
The Control Segment is composed of
A Master Control Station (MCS)
An Alternate Master Control Station,
Four dedicated Ground Antennas
Six dedicated Monitor Stations
ACE ECE IV SC- UNIT-II
2. Control Segment (Monitor Stations)
• The GPS-System is controlled by the US Army. The “master control
station” and four additional monitoring stations were set up for
monitoring the satellites.
• The Control Segment is composed of
A Master Control Station (MCS)
An Alternate Master Control Station,
Four dedicated Ground Antennas
Six dedicated Monitor Stations
• The flight paths of the satellites are tracked by dedicated U.S. Air Force
monitoring stations in
– Hawaii
– Kwajalein
– Ascension Island
– Diego Garcia
– Colorado Springs
• Monitor stations operated in England, Argentina, Ecuador, Bahrain,
Australia and Washington DC.
The flight paths of the satellites are tracked by
dedicated U.S. Air Force monitoring stations in
Hawaii
Kwajalein
Ascension Island
Diego Garcia
Colorado Springs
Monitor stations operated in England, Argentina,
Ecuador, Bahrain, Australia and Washington DC.
ACE ECE IV SC- UNIT-II
4. Control Segment
• During August and September 2005, six more monitor stations of the
National Geospatial-Intelligence Agency were added to the grid. Now, every
satellite can be seen from at least two monitor stations.
• This allows calculating more precise orbits and ephemeris data. For the end
user, a better position precision can be expected from this.
• In the near future, five more stations will be added so that every satellite can
be seen by at least three monitor stations. This improves integrity monitoring
of the satellites and thus the whole system.
CONTROL SEGMENT
During August and September 2005, six more monitor stations
of the National Geospatial-Intelligence Agency were added to
the grid. Now, every satellite can be seen from at least two
monitor stations.
This allows calculating more precise orbits and ephemeris
data. For the end user, a better position precision can be
expected from this.
In the near future, five more stations will be added so that
every satellite can be seen by at least three monitor stations.
This improves integrity monitoring of the satellites and thus
the whole system.
ACE ECE IV SC- UNIT-II
5. User Segment
• The User Segment is composed of hundreds of thousands of U.S. and allied
military users of the secure GPS Precise Positioning Service, and tens of millions
of civil, commercial and scientific users of the Standard Positioning Service.
• In general, GPS receivers are composed of an antenna, tuned to the frequencies
transmitted by the satellites, receiver-processors, and a highly-stable clock.
USER SEGMENT
The User Segment is composed of hundreds of
thousands of U.S. and allied military users of the
secure GPS Precise Positioning Service, and tens of
millions of civil, commercial and scientific users of
the Standard Positioning Service.
In general, GPS receivers are composed of an
antenna, tuned to the frequencies transmitted by
the satellites, receiver-processors, and a highly-
stable clock.
ACE ECE IV SC- UNIT-II
7. AOCS (Attitude & orbit control
system)
AOCS (ATTITUDE & ORBIT CONTROL SYSTEM)
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8. At GEO orbit altitude the moon’s gravitational force is about twice as strong as the
sun’s
Moon orbit is inclined to the equatorial plane by approximately 5 degrees
The plane of the earth’s rotation around the sun is inclined to 23 degrees to the
equatorial plane
At GEO orbit altitude the moon’s gravitational force is about twice as
strong as the sun’s
Moon orbit is inclined to the equatorial plane by approximately 5 degrees
The plane of the earth’s rotation around the sun is inclined to 23 degrees
to the equatorial plane
ACE ECE IV SC- UNIT-II
9. Net gravitational force on the satellite tends to change the inclination of the satellite.
Approximately 0.86 degrees per year from the equatorial plane.
LEO satellites are less effected by this gravitational pull from the sun and moon.
At the equator there are bulges of about 65m at longitudes 162 degress East and 348
degrees East.
Satellite is accelerated towards one of two stable points on GEO orbit at the longitude
of 75 degree E and 252 degrees E
ACE ECE IV SC- UNIT-II
10. FINE POSITIONING
Two ways to make the satellite stable in orbit
when it is weightless.
Satellite can be rotated at a rate between 30 and
100 rpm to create gyroscopic force that provides
stability (spinner satellites)
Satellites can be stabilized by one or more
momentum wheels, called three-axis stabilized
satellites
ACE ECE IV SC- UNIT-II
11. Two types of motors used on satellites.
Traditional bipropellant thruster
Bipropellants used are Mono-methyl Hydrazine
and Nitrogen tetraoxide.
They are hypogolic, i.e., they ignite
simultaneously on contact without any catalyst or
heater
Arc jets or ion thrusters
High voltage is used to accelerate ions
Fuel stored in GEO satellite is used for two purposes
Apogee kick motor (AKM) that injects the
satellite into its final orbit
Maintain the satellite in that orbit over its
lifetime.
ORBIT INSERTION & MAINTENANCE- GEO
ACE ECE IV SC- UNIT-II
28. SATELLITE ANTENNAS
Antennas form a very important element in communication system,
either terrestrial or extra terrestrial, depending on the mission type and
requirements.
"That part of a transmitting or receiving system which is designed to
radiate or to receive electromagnetic waves".
we use antennas to overcome our inability to lay a physical
interconnection between two remote locations or an antenna can also be
viewed as a transitional structure (transducer) between free-space and a
transmission line (such as a coaxialline).
Antennas cannot add power, instead they can only focus and shape the
radiated power in space e.g. it enhances the power in some wanted
directions and suppresses the power in other directions
ACE ECE IV SC- UNIT-II
29. IMPORTANT DEFINITION
ANTENNA DIRECTIVITY
The directivity of an antenna is defined
as the ratio of the radiation intensity in a given
direction from the antenna, to the radiation
intensity averaged over all directions.
GAIN
Gain of an antenna is a measure of the
antenna’s capability to direct energy in one
direction, rather than all around.
ACE ECE IV SC- UNIT-II
30. ALL the major properties of a linear passive antenna are identical
whether it is used in transmit or receive mode. There is only one exception to
this rule called "reciprocity", and that is when the antenna contains
magnetically biased magnetic materials such as ferrites with resonantly
rotating electron spin systems.
The physical reason for reciprocity is that the only difference
between outgoing and incoming waves lies in the arrow of time. Since the
electromagnetic equations are invariant except for the signs of magnetic fields
and currents, under time reversal, there can be no difference between transmit
and receive mode in the physical current and field distributions. However, if we
have a magnet providing a steady bias field, under time reversed conditions we
would have to reverse the direction of this bias field. But for incoming and
outgoing waves, the bias field direction remains the same. Thus it is possible
for the system to be non-reciprocal.
RECIPROCITY
ACE ECE IV SC- UNIT-II
36. BASIC TRANSMISSION THEORY
The calculation of the power received by an earth station from a
satellite transmitter is fundamental to the understanding of
satellite communications.
Consider a transmitting source, in free space, radiating a total
power 𝑃𝑡 watts uniformly in all directions as shown in below
Figure .
ACE ECE IV SC- UNIT-II
37. At a distance 𝑅 meters from the hypothetical isotropic source
transmitting RF power 𝑃𝑡 watts, flux density crossing the surface
of a sphere with radius 𝑅 is given by:
All real antennas are
directional and radiate
more power in some
directions than in other.
Any real antenna has a
gain 𝐺𝜃, as sketched
below.
ACE ECE IV SC- UNIT-II
38. For a transmitter with output 𝑃𝑡 watts driving a lossless antenna
with gain 𝐺𝑡, the flux density in the direction of the antenna
boresight at distance 𝑅 meter is:
The product 𝑃𝑡𝐺𝑡 is often called the effective isotopically radiated power or
EIRP
ACE ECE IV SC- UNIT-II
39. If we had an ideal receiving antenna with an aperture area of 𝐴 𝑚2, as shown in
Figure 4.3, we will collect power 𝑃𝑟 watts given by:
A practical antenna with a physical aperture area of 𝐴𝑟 𝑚2 will not deliver the
power transmitted, and some is absorbed by lossy components. This reduction
in efficiency is described by using an effective aperture 𝐴𝑒 where:
And 𝜂𝐴 is the aperture efficiency of the antenna.
The power received by a real antenna is
This expression is known as the link equation, and it is essential in the
calculation of power received in any radio link.
ACE ECE IV SC- UNIT-II
40. The term 4𝜋𝑅𝜆 2 is known as the path loss, 𝐿𝑝. Therefore, we can write the 𝑃𝑟
as:
In Communication systems, decibel quantities are commonly used to simplify
calculations:
In practice, we will need to take account of more complex situation in which
we have losses in the atmosphere due to attenuation by oxygen, water vapor,
and rain, losses in the antennas at each end of the link.
where 𝐿𝑎 is the attenuation in the atmosphere, and 𝐿𝑡𝑎,𝐿𝑟𝑎 are the losses
associated with the transmitting and receiving, respectively.
ACE ECE IV SC- UNIT-II
42. Is a useful concept in communications receivers, since it
provides a way to determining how much thermal noise is
generated by active and passive devices in the receiving system.
The noise power is given by:
where 𝑘 denotes Boltzman’s constant = 1.39×10−23 J/K = -228.6
dB W/K/Hz, 𝑇𝑠 is the system noise temperature of source in
kelvin degrees, and 𝐵𝑛 represents the noise bandwidth in which
the noise power is measured, in Hz
Calculate the total noise power at the output of the IF amplifier
of the receiver in the below figure.
NOISE TEMPERATURE
SYSTEM NOISE TEMPERATURE AND G/T
ACE ECE IV SC- UNIT-II
44. The link equation can be rewritten in terms of 𝐶𝑁 at the
earth station:
Thus, , and can be used to specify the quality of
a receiving earth station or a satellite receiving system.
G/T RATIO FOR EARTH STATIONS
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45. Design of Downlinks
The design of any satellite communication is based on
meeting a minimum C/N ratio for a specified percentage of
time.
Any satellite link can be designed with very large antenna to
achieve high C/N ratios under all conditions, but cost will be
high.
The art of good system design is to reach the best
compromise of system parameters that meet the specification
at the lowest cost.
For example if a satellite link is designed with sufficient
margin to overcome a 20 dB rain fade rather than a 3 dB fade,
earth station antennas with seven times the diameter are
required.
ACE ECE IV SC- UNIT-II
46. All satellite communication links are affected by rain attenuation.
In the 6/4 GHz band the effect of rain on the link is small
In the 14/11GHz (Ku) band and even more in the 30/20 GHz (Ka) band, rain
attenuation becomes important.
Rain attenuation is very variable phenomenon, both with time and place.
C/N is simplified by the used of link budget
A link budget is a tabular method for evaluating the received power and noise
power in a radio link.
Link budget must be calculated for an individual transponder, and must be
repeated for each of the individual links.
Link budgets are usually calculated for the worst case, the one in which the
link will have the lowest C/N ratio.
Design of Downlinks
Link Budget
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47. Factors which contribute to a worst case scenario include: an earth
station located at the edge of the satellite coverage zone where the
received signal is typically 3 dB lower than the center of the zone.
This is because the satellite antenna pattern, maximum path length
from the satellite to the earth station, low elevation angle at the earth
station giving the highest atmospheric path attenuation in clear air and
maximum rain attenuation on the link causing loss of received signal
power and increase in receiving system noise temperature.
The calculation of carrier to noise ratio in a satellite link is based on the
two equations for received signal power and received noise power
A receiving terminal with a system noise temperature TsK and a noise
bandwidth Bn Hz has a noise power Pn
ACE ECE IV SC- UNIT-II