Sub-Systems

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SUB-SYSTEMS IN SATELLITE

RF Communication Subsystem

The subsystem is responsible for designing an RF link between satellite and ground station. The team is working on VHF -UHF band, with the operating frequencies of 145MHz and 437MHz, with BPSK and QPSK as modulation schemes for uplink and downlink respectively, the team will also be working on antennas, the simulation of RF link will be done on STK software. The team also proposed the ground station venue to be PG Block (12.9499N, 77.5019E) in the college campus.

Telemetry Tracking and Command Subsystem

The Telemetry Tracking and Command (TTC) facilitates the data communication between satellite and ground station. The subsystem has 3 major roles telemetry, tracking and commanding. The function of telemetry is to measure the health parameters of the various subsystems of the satellite, and communicate the same to ground station. Certain decisions cannot be taken by satellite alone, it needs the support of ground station, tele command play a role here, it facilitates to command the satellite from ground station. During visibility period the RF signal will be tracked so that the effective data communication can be done for a longer duration by rotating the antenna. Apart from these main functionalities, the subsystem is responsible for controlling the error in the data transmission, to provide data synchronization between satellite and ground station, and to frame the data is such way that both satellite and ground station can communicate effectively.

Attitude Determination and Control Subsystem

The Attitude Determination and Control System (ADCS) is a crucial subsystem of a spacecraft. It provides pointing accuracy and stability of the payloads and antennas as critical parts of the S/C operation and the mission success. A full blown ADCS system including 3-axis pointing control and stabilization is being developed by the Upagraha team.Key areas are hardware development and characterization (reaction wheels, sun sensors, magnetorquers and magnetometers), attitude estimation algorithms, control loop design, system development and testing; Electric propulsion systems mostly based on MEMs technology.

On-Board Computer

The On-board computer (OBC) is the brain of a satellite. The primary role of the OBC is to control all subsystems of the satellite. It collects information from different subsystems of the satellite, analyses the information, and takes necessary and appropriate decisions as and when required. The on-board computer has to perform several different tasks in coordination with various other subsystems. The most important are:

  • Receive and send the commands from the ground station.
  • Handle the general housekeeping of the satellite.
  • Attitude determination and control by monitoring earths magnetic field, rates about 3 axis and attitude errors by using appropriate control algorithms.
  • Observing the temperature of every subsystems and maintains the satellite in an operated temperature range providing the heaters to the satellite.
  • During ground station visibility do station steering to facilitate transfer of payload data.

Payload Subsystem

Imaging of Earth's surface is the mission of this project. This requires the selection of proper camera which will provide the necessary resolution. Remote Sensing payload: Electro optical Camera/ Infrared sensors/Thermal Infrared sensors.

Power Subsystem (Solar and Battery)

The role of Power Subsystem is to ensure efficient and uninterrupted power supply to all the other subsystems by analyzing the required power in various orbital scenarios and to produce the same through solar panels. Power subsystem is also responsible for providing Electrical safety and required power for the ground station components.

Structure Subsystem

The main role is the subsystem is to design and manufacture the structure/chassis of the satellite in compliance with the requirements of the mission, payload and other subsystems. The subsystem also ensures the structural stability of the satellite while launch and during satellite operations. Structure subsystem is divided into Design, Analysis and Fabrication teams.

  • Design team designs the various components and structures of the satellite in accordance with the requirements.
  • Analysis team analyses the components designed by the design team so that the components survive and work nominally under launch and space environment.
  • Fabrication team manufactures the designed and tested models, components according to the required precision and requirements.

Thermal Control Subsystem

Thermal Control Systems Division (TCSD), an integral part of BMSCE Upagraha, is responsible for a wide range of activities and services including Thermal Design, Thermal Load Management, Spacecraft Configuration, Spacecraft Simulations, Environmental Testing Facilities and Air Conditioning Systems for the Earth station. TCSD is responsible for regulating spacecraft temperatures for satisfactory performance and mitigate accidents due to environmental variations in orbit. The team has also been tasked with designing a safe and reliable Air Conditioning System for the Ground Station