22 April 2008
Master's thesis projet
Ground station for OUFTI-1: Control of satellite
2 students
 One EE/CS/Phys/Science student from ULg: to be found
 One EE student from ISIL: to be found
Context
In general:development, construction, and launch of first ULg nano-satellite/CubeSat, OUFTI-1.
More specifically: development and construction of related ground station (“ ground segment ”).
The role of the ground station is (1) to control the CubeSat by sending (tele)commands to it and to
monitor it by receiving and interpreting its telemetry, and (2) to manage its payload, in this case the
D-STAR COMM subsystem. While users can communicate via the satellite directly, one important
mode of operation is for communications to go through the ground station, which is connected to
the ON0ULG D-STAR repeater and also to the internet via its gateway, thereby ensuring worldwide
communications. The main elements of the ground station are: (1) the control-center room located
at Montefiore, (2) the tracking antennas, most probably located on the roof of the PCC (Central
Command Post of ULg), and/or perhaps at Montefiore, (3) the VHF/UHF
transmitter/receiver(Tx/Rx) for communicating with the satellite and located close to the tracking
antennas, and (4) the intranet link between PCC and Montefiore. As alluded to above, the CubeSatdedicated Tx/Rx system will be connected to the D-STAR ON0ULG repeater and its gateway. The
work concerned with the ground station is divided into 3 parts: (1) control of satellite, (2) mission
(related to the current D-STAR payload), and (3) construction of tracking antennas. The present
project is concerned with part (1): Control of satellite.
Goal
Design, construct, and test part of ground station dedicated to control of CubeSat, and develop
corresponding software.
Description
For the foreseable future, the ground station for OUFTI-1 and its successors will be part of the ULg
ham-radio station at Montefiore. An antenna tower (of at least 18m) will be built near Montefiore
and support most of the antennas of the ham-radio station, such as directive Yagi antennas for HF
operation, allowing direct worldwide radio-communications. As indicated above, the satellite
tracking antennas will most probably be installed at the PCC (but could, instead, be installed at
Montefiore). Although it is clear that the station must be able to handle all radio-communication
aspects of OUFTI-1, the station should be able to listen to all current and future ham-radio
satellites. Therefore, a primary goal of this project is to create a general-purpose radio station that
will be extremely well equipped for ham-radio satellite communications. We should also be able to
listen to satellites not operating on the ham frequency bands, whenever appropriate.
Tasks
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Design architecture and layout of ham-radio station, keeping in mind that it must be
particularly well equipped for communications with all existing and future amateur-radio
satellites, and that it must serve as the ground station for OUFTI-1, and thus be capable of
handling its D-STAR payload and the emergency CW beacon. Architecture/layout should
include furniture (tables, cabinets, ...), various equipments, including various transceivers
(HF, satellites, etc), large wall-mounted displays, and computers. Consult relevant literature.
Determine early on where the tracking antennas should be located (roof of PCC, or
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Montefiore, or both?). There are indeed potentially-conflicting requirements. (1) Roof of
PCC is ideal because of its easy access and proximity to D-STAR repeater. With respect to
this proximity, note that the tracking D-STAR transceiver must be close to the tracking
antennas since it is connected to them. Furthermore, this transceiver must be connected to
the D-STAR repeater. (At this point it is not clear whether the tracking D-STAR transceiver
and the D-STAR repeater must be located in close proximity.) (2) One would like to use the
tracking antennas to track and communicate with any ham-radio satellite. In fact, this is a
necessity since one needs to test the tracking antennas before OUFTI-1 is launched. Is this
possible if the some other key satellite receivers are located in the radio station at
Montefiore? Or will we need two systems of tracking antennas, one at Montefiore and one
at the PCC? Current thinking indicates that one might need 2 separate system of tracking
antennas, perhaps simply copies of each other.
If the tracking antennas are effectively on the roof of the PCC and the tracking D-STAR
receiver is necessarily located close-by, determine the means to bring the D-STAR signals
back to the ground station at Montefiore. More generally, work out the question of where the
various key elements should be located and whether some must be duplicated (see point
above).
Install and configure all necessary software for accessing the ephemerids of any satellite and
for being able to predict its position in space and the corresponding Doppler shift. Consider
Orbitron, STK (which requires a licence), etc. Decide whether software should be Linux- or
Windows-based (or both). Much of the software exists and this is mostly an integration
exercise.
Use above software to command the azimuth and elevation motors of the tracking antennas
and to automatically apply the proper Doppler shift to the receiver. Much of the software
exists and this is also mostly an integration exercise.
Write software for automatically decoding the Morse-code messages that will be sent
continuously by OUFTI-1's emergency CW beacon.
Use relevant, existing software tools (Orbitron, x-planet, ...) to provide a continuous, realtime 3D visualization (possibly in stereo, with stereo googles or equivalent) of (1) current
orbit, (2) position of satellite along its orbit, (3) attitude (if known or estimable), (4)
footprint on ground, (5) illumination conditions, etc. These visualizations should give as
precise an indication as possible of the “ position ” and “ condition ” of the satellite (to
provide situation awareness). Be creative in terms of visualizations. Distance of satellite to
Montefiore could be displayed in real-time along displayed orbit. Several other parameters
could similarly be displayed. One could also imagine simultaneously displaying the
positions of several satellites of interest.
Participate in the installation of the antenna tower and connection of its antennas to the radio
station via coax cables.
Demonstrate all modes of communications between OUTFI-1 and station. (A prototype of
OUFTI-1 could lifted in the air via crane, balloon, or equivalent.)
Develop all related software.
Deliverables
 Fully operational ham-radio station, being able (1) to track any ham-radio satellite and to
communicate with it (if applicable), and (2) to use the various transceivers connected to the
various antennas at Montefiore (tower, etc).
 Fully operational OUFTI-1 ground station, seamlessly integrated in ham-radio station,
capable of (1) issuing commands and receiving telemetry, both via D-STAR, (2) handling all
D-STAR ham-radio communications and routing them to UN0ULG D-STAR repeater at
PCC or to the internet via the corresponding gateway, and (3) receiving and decoding
emergency CW beacon Morse-code messages.
 Demonstration of all modes of communications between ground station and a prototype of
OUFTI-1 lifted in the air by crane, balloon, or equivalent.
Internship
 None envisionned at this point. (Possibly Spacebel.)
Supervision
 Prof. Jacques Verly (Academic promoter)
 ISIL ?
 Luc Halback (Spacebel)
 Assistants?
Other ressource persons
 Jury (tentative): Verly, ISIL ?, Halbach, Kerschen.
Info
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Although the overall goal of the project is well defined,
the details will be refined as we go along.
Don't hesitate to contact us ... We can tailor the project to your desires.