SEDSAT-2 Interface Tables

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To all subsystems: please update your interface templates in a following way

  • Input entry: To [to which subsystem] - [from which subsystem] - [component] - value
  • Output entry: From [from which subsystem] - [to which subsystem] - [component] - value

This would make these interface tables of more use to the team.

Systems


Contents

ADCS

Inputs

Edit: Attitude Control


Outputs

Edit: Attitude Control

Environmental constraints

Edit: Attitude Control


Command and Data Handling

Inputs

Edit: Command and Data Handling

Outputs

Edit: Command and Data Handling


Environmental constraints

Edit: Command and Data Handling


Communications

Inputs

Edit: Communications

  • To: Communications - Power - power to terminal node controller, 45 mA
  • To: Communications - Power - power to antenna
  • To: Communications - Power - power to transceiver, 200mA @ 3.3V (average)
  • To: Communications - Power - power to amplifier
  • To: Communications - Ground Station - commands for satellite control
  • To: Communications - Payload - data to be transmitted to ground station (?) Unless this goes to CDH which then transmits it to Communications?
  • To: Communications - Command and Data Handling - data that needs to be transmitted to the ground station (such as ADCS, Payload, systems)
  • To: Communications - Test - Test bus input
  • To: Communications - Structures - Transceiver, 40 x 80 x 20 mm, 70g (approx)
  • To: Communications - Structures - Main board, 80 x 80 x 10mm, 50g (approx)
  • To: Communications - Structures - Antenna, 50 x 50 x 15mm, 100g (approx)

Outputs

Edit: Communications


  • From: Communications - Ground station - data from payload and ADCS will be transmitted to ground station.
  • From: Communications - Structures - dimensions of the circuit board housing the communications subsystem modules. It was suggested that there be only one board on which all the components of the satellite may be slotted. This will probably save us a LOT of space.
  • From: Communications - Structures - Heat from the operation of the components.
  • From: Communications - CDH - Hard reset signal.
  • From: Communications - Test - Test Bus output

Environmental constraints

Edit: Communications

  • On: Communications - Temperature - it will affect the functioning of some of the components in the subsystem.
  • On: Communications - Orbit - LEO will require us, most probably, in the UHF range.
  • On: Communications - Proximity to ground stations - Cannot transmit data if there is no radio link with ground station.
  • On: Communications - Frequency - The frequencies assigned to us by the IARU will also be a constraint.


Ground

Inputs

Edit: Ground

It's questionable to perhaps put some points to communications and see ground as a mere channel for data transfer.

  • To: Ground - Test input - description of test input
  • To: Ground - CDH/Networks: www - administration of ground station network around the globe
  • To: Ground - WWW to ground station (software updates (?), instructions)
  • To: Ground - Structure: Environmental sensor data (temperature, vibrations, etc) or moveable parts
  • To: Ground - ADCS --> attitude/orientation and position data comes down
  • To: Ground - Payload --> images and other output information down
  • To: Ground - Power --> Battery and Supply Data come down
  • To: Ground - Communication --> Data transmission

Outputs

Edit: Ground


  • From: Ground - test output - test output description
  • From: Ground - Ground to WWW
  • From: Ground - ADCS <-- data might go up (eg gps?)
  • From: Ground - Payload <-- instructions up
  • From: Ground - Payload <-- orientation setting of camera
  • From: Ground - Payload <-- power on/off
  • From: Ground - Payload <-- instructions secondary payload (to be confirmed)
  • From: Ground - CDH <-- flash software updates?
  • From: Ground - CDH <-- commands in general
  • From: Ground - Power <-- instructions for control? distribution controlling? (ie storage, consumption on different subsystems...)
  • From: Ground - Communication <-- commands for control of working modes

Environmental constraints

Edit: Ground

  • On: Ground - test output - test output description


Payload

Inputs

Edit: Payload

  • To: Payload - Power - 3.3/2.8 VDC. Voltage and current is uncertain until the payload hardware is better defined. It is almost certain that we will include both a microcontroller and FLASH storage in the payload - so power values are not only defined by the CMOS imaging device.
  • To: Payload - Control Interface - The interface for the payload will be implented using an I2C busI2C. The CDH controller will have direct access to the Payload flash memory, most likely using SPI.
  • To: Payload - Control Command Set - The payload will operate as instructed trough the command set. Typical commands will be; "Power up/down", "Standby", "Set image sensor property N to M", "Capture an image at time X", "Get info about the captured image X", "Start transfer the captured image X at offset Y size Z".

Outputs

Edit: Payload

  • From: Payload - Data Output - The MISO of the Payload SPI interface will be the channel for returning requests sent by ODH.

Environmental constraints

Edit: Payload

  • On: Payload - Launch vibrations - Lens system must remain properly aligned.
  • On: Payload - Temperature - Electronics will have a limited operating temperature range. Optics may be affected by temperature cycling.

Power

Inputs

Edit: Power

  • To: Power - A medium to send housekeeping signals to the ground

-To get the critical functions of power MCU redundantly implemented in CDH's MCU to take over control in situation of power MCU failure or malfunctionPower input: various satellite systems input into the circuit board to receive power; circuit board inputs into the batteries and solar panel to receive power, solar panel input into the batteries (by way of charger) to charge the batteries.

Outputs

Edit: Power

- 5.0 and 3.3VDC standard voltage for logic devices

- 3.3V DC and 150mA for the camera unit - 2.8VDC 10 mA 28 mW (for 3 axis magnetometer)

- 2.8VDC 55 mW (for attitude control VGA sensor)

-To communications:Trasceiver(transmit:1.2A@3.7V for 10 min per orbit,receive:60mA@3.7V for 90 min per orbit),MCU and TNC each(10mA@3.3V for 90 min orbit)

--Other subsystem may add the voltages, amps and at what tolerance they need in their own input table and it will be added as a Power output here.-- Solar panel outputs ~10V to systems; Lithium-Ion batteries output ~3.7V

Environmental constraints

Edit: Power

Space-grade solar panels should work in the space environment and temperatures.

Lithium-ion batteries operating tempuratures- charge: 0-45C, discharge: -20-60C, storage: -20-45C.

Circuit board should work under normal satellite operating conditions.


Structure

Inputs

Edit: Structure

  • To: Structure - Area - The total area that your component will cover. Necessary to determine total base area requirements and also to make a judgement of height combined with data on volume and mass.
  • To: Structure - Volume - The volume occupied by your component. Necessary to determine height of CubeSat. Height is the only quantity we can alter within the basic structure of the satellite.
  • To: Structure - Mass - The mass, along with the location of your component defines changes to the centre of mass of the satellite.
  • To: Structure - Heat - Some components generate heat during operation.
  • To: Structure - Location - You can provide this by means of design drawings as to where you'd like your components to be located within the 10cmx10cm base space that we are provided with.

Outputs

Edit: Structure

  • From: Structure - Base area is 10cm x 10cm.

Environmental constraints

Edit: Structure

  • On: Structure - Launch vibrations - What is the typical profile of launch vibrations? Need to consider how to create structure to survive vibrations and how to mount other components of satellite to structure so that satelite is operable in orbit.


Environments

Temperature: YamSat Paper



Ground and launch environment:

Quasi-static and Dynamic Loads: Satellite structures pages 33-38


Launch Vibration:

Vibration testing report of a German CubeSat project:
88kN shaker used (2016 U):
Sine Sweep 5-2000 Hz ; 0.5 g ; 2 Oct/min

LV Qualification High level 20-2000 Hz ; 8.073 grms ; 35 s

LV Qualification Low level 20-2000 Hz ; 4.374 grms ; 831 s

High Level Sine Sweep 5-100 Hz ; 3.0 g ; 2 Oct/min

UTIAS/NFL Qualification 20-2000 Hz ; 12.87 grms ; 60 s

Thesis on Launch Vibrations in PPODs




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