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:

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• 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

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• 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

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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

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• 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

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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

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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

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EPS – USB battery charger

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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

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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.

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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

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OBC - COM Tx module

Framing of telemetries

COM TxSend AX.25

BUFFER Tx

Telemetries

Configuration of modulator

AX.25 encoding

MOD.

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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

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OBC - Measurement module

Cyclic sampling

MeasurementRecording of measures

Retrieval of measures

EEPROM

Period of retrieval

Telemetries

ADCs

Software measures

Types & frequency of measures

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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

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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

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5. Conclusion

• Design almost completed

• High technical complexity

• Strongly motivated team

• Professional approach

• Ambitious schedule

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Thank you for your attention !

www.oufti.ulg.ac.be