NUTS - NTNU Test Satellite, a Norwegian CubeSat Project

Project assignments for 2014

Written by: Roger Birkeland
Published: 11.04.14
Below are the assignment proposals from the NUTS project. All NUTS student will work together in a team, with their individual assigned task.

As we are a multidisciplinary group with project members from several departments, different types of team- and group work must be expected. It will be required that the student joins weekly meetings with the rest of the team (consisting of staff, other project/master students and other students) to share experience and knowledge.

Students are also encouraged to apply for participation at relevant international and national workshops and conferences during their project work.

For all assignments, contact the project management team Amund Gjersvik (amund.gjersvik@iet.ntnu.no) or Roger Birkeland (roger.birkeland@iet.ntnu.no) if you have any questions.

Design and development of a satellite ground station based on software defined radio (the USRP kit), GNU-radio or LabView

Often, student satellites use ham radio frequencies at VHF and UHF bands. Usually this also implies the use of ham radio equipment. For reception of digital packet data, this is not ideal. We would like to build our own ground station equipment based on the USRP radio with a suitable extension card. This radio system can then be controlled by the use of GNU-radio or LabView. In addition to be more configurable, we will also be able to receive and record a broader part of the received spectrum for later analysis, and we can experiment with other modulation types, besides BPSK/GMSK.

The task will include work on designing and setup of the ground station, set up a test bench and do measurements. The student must also think of the whole ground station as a system and look at the need for low noise amplifiers for reception and power amplifiers for transmission.

Subtopics can include

  • Satellite tracking
  • Integration between ground station hardware and the control- and logging software for the satellite
  • Setup and configuration of the USRP and its control software (GNU-radio or LabView)
  • System for live decoding of received packets during a satellite pass
  • System for recording of a broader part of the received signal for later analysis

Amplifier for VHF and UHF frequencies optimized for efficiency

The student will study designs for VHF and UHF amplifiers with high efficiency for GMSK (constant envelope) signals. The amplifier should deliver between 1 and 2 W to the antenna (this should be configurable). A suitable transistor technology must be found

Specifications

  • Modulation scheme: GMSK (Gaussian filtered FSK)
  • Bitrate: 9600 bps
  • Frequency deviation: 2,4 kHz
  • Goal for Power Added Efficiency (PAE): between 75 and 85 %
  • Possible amplifier classes: Class D or E

Test and analysis of the ADCS subsystem

The attitude determination and control (ADCS) subsystem is responsible for pointing the satellite to a given direction. The system consists of coils mounted on three orthogonal sides of the satellite. When current is applied, these coils can generate a magnetic momentum when interacting with the Earth’s magnetic field.  

The task will be to perform tests, analysis and final integration of the NUTS ADCS-system.

Satellite system Integration

The main tasks in the project now will be to construct and integrate the different sub systems and build the NUTS engineering model.

Several assignments can be given, and the assignment will be adapted to fit the student’s qualification, background, interests and the project’s needs.

Some relevant topics are:

  • Verification of the backplane and the backplane control bus and systems (watchdogs, failure mode analysis, JTAG, power distribution and more, design using Altium Designer)
  • Design and development of a VHF and UHF radio system (amplifiers, embedded software, transceiver drivers, communications protocols, error correction and detection, link budget, measurements, antennas)
  • Design and development of the NUTS system software. This will run on FreeRTOS on the OBC, but "load sharing" or fall-over to the radio sub-system must also be considered. (AVR32UC3, FreeRTOS, drivers (flash, sensors, ram), error detection and correction)

Students interested in embedded programming and systems, design and test of hardware, space technology and communications systems should contact the listed supervisors for more information.

All project members will be assigned their individual problem description. This final assignment text will be created together with the student, to fit both the project's needs and the student's fields of interest.

Students are also encouraged to apply for participation at relevant international and national workshops and conferences during their project work.

Take a look at http://nuts.cubesat.no for more information, or contact project manager Roger Birkeland

Thermal analysis of a double CubeSat

The student must perform a study and analysis of the thermal environment inside the satellite. There will be no active thermal management, so the design and analysis must ensure that all components have a temperature within their operating range at all times. This is especially important for components exposed to high currents such as amplifiers and power regulators. The student must propose passive thermal management that will suit these needs.

ESA has several analysis tools that can be used (ESATAN, ESARAD (Spenvis)) for this purpose.