View
2
Download
0
Category
Preview:
Citation preview
Status and perspectives
29 June 2011University of Liège
2
Outline
1. The OUFTI-1 project
2. Technical status
3. Design review
4. 2011-2012 schedule
5. Conclusion
3
Outline
1. The OUFTI-1 project
• In a few words
• Objectives
• Student team
2. Technical status
3. Design review
4. 2011-2012 schedule
5. Conclusion
4
1. The OUFTI-1 project: in a few words
CubeSat standard Three payloads
10 cm
1kglitrewatt
Initially selected for VEGA Maiden Flight
Subsystems developed by students
5
Fun and education
Operating the satellite
Design of the OUFTI-1 system
Launch of OUFTI-1
Satellite alive in space
Having the D-STAR functional
Operating the secondary payloads
1. The OUFTI-1 project: objectives
6
1. The OUFTI-1 project: student team
2 universities + 3 engineering schools
7
Outline
1. The OUFTI-1 project
2. Technical status
• STRU• COM• EPS• OBC• THER• VIB• HAM• SDR
3. Design review
4. 2011-2012 schedule
5. Conclusion
8
Outline
1. The OUFTI-1 project
2. Technical status
• STRU: Structure and configuration• COM• EPS• OBC• THER• VIB• HAM• SDR
3. Design review
4. 2011-2012 schedule
5. Conclusion
9
STRU - Structure and configuration
• Interface CubeSat – Launcher: P-POD• Maximum mass: 1 kg• Available volume:
- In blue: 100 x 100 x 113.5 mm- In red: 6.5 x 83 x 113.5 mm
Volume:
10
STRU - Structure and configuration
11
OUFTI-1 mass budget:Subsystems Nominal case (g) Worst case (g)
STRU 438,04 446,80
MECH 45,51 47,22
ADCS 3,79 4,05
THERM 26,4 34,45
EPS 196,13 204,08
OBC 118,04 120,50
COM 50,36 65,42
Cabling 15 30
Adhesive 15 30
OUFTI‐1 TOTAL MASS 908,27 982,52
STRU - Structure and configuration
12
STRU - Antennas deployment system
• 1 antennas support: AlMg3 ¼ anodized• 2 antennas: Coppro-beryllium 1 VHF antenna + 1 UHF
antenna• 1 retention wire: Dyneema Fusion temperature: 144 –
152 °C• 2 thermal knives: titanium wire• 2 serial resistors: 2.7 ohm• I: 513.3 mA – 798.5 mA
Design:
13
• Complete prototype• Vacuum environment tests
Objective: Thermal knives alimentation timeAntennas deployment was detected after 8.9 seconds
STRU - Antennas deployment system
Prototype and tests:
14
Outline
1. The OUFTI-1 project
2. Technical status
• STRU• COM: Communication subsystem• EPS• OBC• THER• VIB• HAM• SDR
3. Design review
4. 2011-2012 schedule
5. Conclusion
15
COM – Block-diagram
Low NoiseRF
Front End
Low NoiseRF
Front End
D-STARD-STAR
AX.25AX.25
BCNBCN
RF Power Amplifier
RF Power Amplifier
Rx435 MHz Tx
145 MHz
(De)modulation & data processing
16
Low NoiseRF
Front End
Low NoiseRF
Front End
D-STARD-STAR
AX.25AX.25
BCNBCN
RF Power Amplifier
RF Power Amplifier
Rx435 MHz Tx
145 MHz
COM – Block-diagram
(De)modulation & data processing
17
• Continuous emission• Message in Morse code• Information regarding satellite health• Collected and transmitted to Liège by amateur-radio operators
all over the world
COM – Beacon
18
Low NoiseRF
Front End
Low NoiseRF
Front End
D-STARD-STAR
AX.25AX.25
BCNBCN
RF Power Amplifier
RF Power Amplifier
Rx435 MHz Tx
145 MHz
COM – Block-diagram
(De)modulation & data processing
19
• Widely used by ham community, especially for satellite communication
• Telecommand and telemetry
• Always listening, priority
COM – AX.25
20
Low NoiseRF
Front End
Low NoiseRF
Front End
D-STARD-STAR
AX.25AX.25
BCNBCN
RF Power Amplifier
RF Power Amplifier
Rx435 MHz Tx
145 MHz
COM – Block-diagram
(De)modulation & data processing
21
• Main payload of OUFTI-1
• OUFTI-1: first repeater in space dedicated to D-STAR
• Digital transmission protocol– 2 modes: Digital Voice (DV) & Digital Data (DD)
COM – D-STAR
22
Low NoiseAmplifier
Low NoiseAmplifier
D-STARDemodulator
D-STARDemodulator
AX.25Demodulator
AX.25Demodulator
Rx435 MHz
Splitter
µC COM(D-STAR)µC COM(D-STAR)
µC OBC(AX.25)µC OBC(AX.25)
Demodulators: Analog Devices ADF7021µC: Texas Instruments MSP430
COM – RX channel
23
Power AmplifierPower
Amplifier
Tx145 MHz
MixerAX.25/D-STAR
ModulatorAX.25/D-STAR
Modulator
µC COM(D-STAR)µC COM(D-STAR)
µC OBC(AX.25)µC OBC(AX.25)
Modulateurs: Analog Devices ADF7021µC: Texas Instruments MSP430MUX: Multiplexer
MUXMUX
BCN
COM – TX AX.25 & D-STAR channel
24
µC BCN 1µC BCN 1
µC BCN 2µC BCN 2
BCN 1Modulator
BCN 1Modulator
BCN 2Modulator
BCN 2Modulator
ControlMixer
D-STAR/AX.25
…
COM – Beacon channel
25
Outline
1. The OUFTI-1 project
2. Technical status
• STRU• COM• EPS: Electrical Power Supply• OBC• THER• VIB• HAM• SDR
3. Design review
4. 2011-2012 schedule
5. Conclusion
26
EPS – Electrical Power Supply
Role• Power source• Power storage• Power conditioning
Functionalities
• Antenna Deployment System• USB Battery Charger• Measurement Circuit• Power Budget• Connectors• Protection circuits
27
EPS – Antenna Deployment Circuit
28
EPS – USB battery charger
29
Measurement Circuit
Voltage, current and temperature measurements
Adaptations:• Current measurements• Temperature sensors• Voltage dividers
Protection Circuits
• Replacement of current limiter• Battery protection circuits moved to EPS board
EPS – Other circuits
30
Outline
1. The OUFTI-1 project
2. Technical status
• STRU• COM• EPS• OBC: On Board Computer• THER• VIB• HAM• SDR
3. Design review
4. 2011-2012 schedule
5. Conclusion
31
OBC - Software organization
MeasurementMonitorCOM TxCOM Rx LogSequencerModules
Decoding AX.25
Config.ADF Rx
TCstorage
Executionof TC
Send Doppler
correction
Measures
Storage ofmeasures
. Retrieval of measures
. Antennadeployment
RedundancyMonitoring .
Journalupdate
. Journalretrieval
Config. ADF Tx
Encoding AX.25
AX.25 reception
AX.25 transmission
Roles
Interrupts
Time reference
(De)Act ofs-s &p-l
FAULTs subsystems.
DriversI²C
ADCs EEPROMUARTWDT USB
32
OBC - COM Rx module
Waiting for an AX.25 frame
COM Rx
AX.25Bits
reception
BUFFER Rx
Storage of received commands
Configurationof
demodulator
Decoding of AX.25 frames
Interpretation of commands
DEMOD.
33
OBC - Sequencer module
Search for a command to execute
Sequencer
Correction of Doppler
Change of mode
Array of commands
UART
Temporalreference
Retrieval of Log & Meas.
Modif. ofconfiguration of measures
Measures & sampling
frequencies
34
OBC - COM Tx module
Framing of telemetries
COM TxSend AX.25
BUFFER Tx
Telemetries
Configuration of modulator
AX.25 encoding
MOD.
35
OBC - Log module
Journal update
Log
Journal retrieval
Events to store
EEPROM
Periode of retrieval
Telemetries
Storage of events
36
OBC - Monitor module
Monitoring of redundancy
Reset of WDT
Monitor
(De)Activation of a
subsystem or payload
Reset of 1 subsystem or
payload
Desired mode
Pins ON of MAX890
FAULTs
I²C
MUX ctrlD‐STAR
Event to store
ADCs
37
OBC - Measurement module
Cyclic sampling
MeasurementRecording of measures
Retrieval of measures
EEPROM
Period of retrieval
Telemetries
ADCs
Software measures
Types & frequency of measures
38
OBC - Test method
OUFTI-1 HyperTerminal application:
39
Outline
1. The OUFTI-1 project
2. Technical status
• STRU• COM• EPS• OBC• THER: Thermal Control System• VIB• HAM• SDR
3. Design review
4. 2011-2012 schedule
5. Conclusion
40
TCS:• Mostly passive• Active TCS for the batteries
THERMAL ISSUES:
Low temperature of the batteries (≅-15oC)
Detrimental dissipation of the EPS transistor (≅5.5W)
Hotspot COM amplifier (≅80oC)
PROPOSED SOLUTIONS:
Heaters + Thermostats + Insulation
Partial shunt of the power + Strap
Still unsolved
THER – OUFTI-1 TCS and thermal issues
41
THER – Batteries TCS
42
THER – Results of the test
43
mint,w2
M( )
with
GL(t,w2 ) ≥ GLmin
w2 ≤ 8mmw2 ≥ 0t ≥ 0
⎧
⎨
⎪⎪
⎩
⎪⎪
THER – EPS transistor
44
• Geometrical Mathematical Model (GMM)
THER – Numerical model
• Thermal Mathematical Model (TMM)
45
OUFTI-1 thermal issues:
Numerical model:– Batteries and Transistor issues fixed– No new issues– Thermal design range [-40, 70]oC
Issue Design Manufacturing Validation
Batteries ✓ ✓ ✓EPS Transistor ✓ ✗ ✗COM Amplifier ✗ ✗ ✗
THER – Conclusion
46
Outline
1. The OUFTI-1 project
2. Technical status
• STRU• COM• EPS• OBC• THER• VIB: Vibrations • HAM• SDR
3. Design review
4. 2011-2012 schedule
5. Conclusion
47
VIB - Launch environment
48
VIB - Modelling of the electronic cards
• Several simplification techniques:– Simple method– Global mass smearing
method– Global mass and
stiffness smearing method
– Local smearing method
49
VIB - Experimental analysis and update
50
VIB - Global FE model of OUFTI-1
51
VIB - Finite element simulations
• Several analysis were performed:– Modal analysis
• Fundamental frequency above the prescribed lower value
– Quasi-static accelerations analysis• All margins of safety found positive
– Sine accelerations analysis• All margins of safety found positive
52
Outline
1. The OUFTI-1 project
2. Technical status
• STRU• COM• EPS• OBC• THER• VIB• HAM: D-STAR on a classic ham transceiver• SDR
3. Design review
4. 2011-2012 schedule
5. Conclusion
53
HAM – Problem to be solved
• D-STAR communications through OUFTI-1
• Easy access to the spectrum• Return to the amateur-radio community
A B
Implementation of the D-STAR protocol on a classic ham transceiver.
54
• Link budget– Power– Error rate
• Doppler effect: Frequency deviation• 3,9 kHz for VHF• 11,6 kHz for UHF
HAM – Problem to be solved
Space constraints
55
HAM - Possible solutions
Adaptation of a dedicated D-STAR transceiver
Adaptation of a classic transceiver
• Step of 5kHz or 6,25kHz
• limited documentation
• Change HW and SF
• Unpractical
• Step of 0,1kHz
• D-STAR protocol well known
• External circuit
• Plug and Play
56
HAM - Block diagram
• Tx mode
57
HAM - Tests within the complete system
A BON0ULG G
ON0ULG C
ON0ULG B
ON0ULG G
ON0ULG C
ON0ULG B
VE2RQT G
VE2RQT C
VE2RQT B
Internet
58
Outline
1. The OUFTI-1 project
2. Technical status
• STRU• COM• EPS• OBC• THER• VIB• HAM• SDR: Software Defined Radio
3. Design review
4. 2011-2012 schedule
5. Conclusion
59
SDR - Goal
To provide knowledge on software defined radio’s (SDR) for the OUFTI-1 project.
Three main points:• SDR concept• Demonstration of the use of an SDR for two protocols: AX.25 and D-STAR• Spatial constraints
60
SDR - What is it?
- Data conversion- Radio tasks defined in software- Flexibility- Reprogrammability
61
SDR - Strategy
USRP (Frequency conversion) + PC (Baseband digital signal processing)
62
SDR - Implementation of the protocols
- Encoding/Decoding routines- Baseband modulators/demodulators (GMSK,2-FSK, and
FM)- Results (demonstration)
63
SDR - aboard a nanosatellite
Constraints:-Size, weight-Power consumption-Radiations-Reconfiguration strategy-Doppler correction
64
Outline
1. The OUFTI-1 project
2. Technical status
3. Design review
4. 2011-2012 schedule
5. Conclusion
65
• Based on ECSS standard• 14-week long• External experts (CSL, Thales, Spacebel, …)• Weekend of work and meetings at EuroSpace Center (Redu)
Design Review (Feb.-May 2011)
Preparation ofdata-packages
Review of documentation and
RIDs
Collocation meetings
Initiation of the review
Kick-off meeting
Close-out meeting
Review team report
Review authority report
T=0 T + 6 weeks T + 8 weeks T + 11 weeks T + 13 weeks T + 14weeks
Preparation of answers
to RIDs
66
Outline
1. The OUFTI-1 project
2. Technical status
3. Design review
4. 2011-2012 schedule
5. Conclusion
67
4. 2011-2012 schedule
April JuneJanuaryAugust
New team
Production of engineering-model boards
March
2011-2012
Oct.
Interconnections and tests of engineering-model boards
Production of flight model equipments
Tests of flight model equipments and integration
Tests of flight model Summer
2012
68
5. Conclusion
• Design almost completed
• High technical complexity
• Strongly motivated team
• Professional approach
• Ambitious schedule
69
Thank you for your attention !
www.oufti.ulg.ac.be
Recommended