microscope : electronics architecture &...

MICROSCOPE : Electronics Architecture & Performance

Damien Boulanger

3 Damien Boulanger, 29th & 30th January 2013, ONERA Palaiseau.

SU’sQM

30 cm x 25 cm x 11 cm – 5.5kg – 2 x 11W

36 cm x 34.8 cm x 18 cm -25kg

Instrument Description

• Sensor Unit core = differential accelerometer• 2 SU on a Mechanics Interface (SUMI)• Each SU = 2 concentric Test-Masses (Pt-Rh/Pt-Rh or Ti/Pt-Rh) • Each mass = inertial sensor (defines measurement frame)

• Front End Electronics Unit (FEEU)• Low noise analog electronic with high stability• One FEEU for each SU• Each FEEU = measure + electrostatic control of 6 degrees of

freedom

• Interface Control Unit (ICU)• 2 ICU stacked = ICUME• 1 ICU for each FEEU• Each ICU embarks 1 DSP + 1 FPGA for test-mass control and

data conditioning for the On Board Computer• Each ICU embarks 2 Power Control Unit (1 nominal + 1

redundant) which converts the sattelite 28V in very stable secondary voltages (+/-48V, +/-15V,+5V,+3.3V)

MQV

2 x { 28 cm x 17 cm x 9 cm - 3.5kg - 7W }

MQV1 MV2


Vi = Bias

+ G(1+K1) Vi

+ K2G2Vi2

+ Noise

Proof Mass Control Loop: 6 channels per proof mass

Mission CHAMP GRACE GOCE Microscope (Pt/Ti)

Vd (Vrms) 5 5 7.6 5

Vp (V) 20 10 7.5 5

Gel Acceleration Sensitivity (ms2/V)

1.8·10-4 1.7·10-5 9.8·10-7 0.45 / 1.1 10-7

Position Sensitivity (V/µm)

0.4 0.33 1.7 0.26 / 0.30

Range (ms-2) 10-4 5·10-5 6.5·10-6 4.6 / 5.3·10-7

Resolution(ms-2 /Hz1/2 )

< 10-8 10-10 2·10-12

10-2 Hz2·10-12

10-3 Hz

Vn detection = 10 µVHz-1/2 (1+ 10-4Hz/f)Vn actuation = 2.4 µVHz-1/2(1+2.5Hz/f)

ICU

DACDVA

DVA

Capacitive Position Sensor ADC

Digital

ControllerVp,Vd

ADC processingReadout circuit

Gel+

-

goldwire offsets

ProofMass

Gel

@1027 Hz

@1027 Hz

FEEUSU

DFACS Data

@4 Hz

Science Data

@4 Hz


FEEU Performance

FEEU Spare SpecificationRéférence document [7070] [7170] [7208] [7093] [7209] [7207] [5030]Version 1 1 1 1 1 1 5

AxeValeur [µV/sqrt(Hz)]

Valeur [µV/sqrt(Hz)]





< à valeur [µV/sqrt(Hz)]

X1i 9.89 9.67 8.06 8.80 12 9.9 < 12X1e 5.43 5.71 5.39 5.13 5.6 5.3 < 10Y1i 5.51 5.15 5.63 4.41 4.3 4.47 < 6.5Y1e 3.41 3.11 3.03 2.77 2.8 2.85 < 5Y2i 5.38 5.05 5.23 4.42 4.4 4.4 < 6.5Y2e 3.24 3.07 3.05 2.80 2.7 2.7 < 5X2i - 10.80 9.26 9.37 12 8.84 < 12X2e 9.91 10.50 9.58 9.31 5.5 14 < 12Z1i 5.27 4.99 5.25 4.75 4.3 4.71 < 6.5Z1e 3.33 3.09 2.99 2.78 2.8 2.88 < 5Z2i 5.44 5.05 5.21 4.74 4.4 4.7 < 6.5Z2e 3.35 3.08 3.04 2.92 2.7 2.83 < 5

MV2MQV1

X inner: 2.6 105 V/m <10µV= 3.8 10-11mX outer: 3.0 105 V/m < 6µV = 2.0 10-11 m

Y,Z inner: 2.3 105 V/m < 6µV= 2.6 10-11mY,Z outer: 3.1 105 V/m < 4µV= 1.3 10-11m

Bias better than specified on MQV1 and MV2, Spare too.Bias & Scale factor thermal sensitivity better than required on MQV1 and MV2, Spare too.Back action better than specified effects lower than 2.10-16ms-2

Digital

Pos Det ADC ControlLaws

DACDVA (+)

Drag Free Control

Science Data

PM

DVA (-) DAC

ADC


Thermal Sensitivty Performance

Results compatible with FEEU thermal control:

• 5 mK tone fluctuations• 3 K/Hz1/2

Tests of thermal sensitivity

Performed on all electronics function of each unit for :- Offsets- Sensitivity

Needs long term observations with frequency analyses

1mK

5 mK

Axe Résultat [µV/°C] Spécification X1i 64.68 <300µV/C X1e 16.66 <300µV/C Y1i 11.70 <20µV/C Y1e 14.68 <20µV/C Y2i 8.40 <20µV/C Y2e 9.34 <20µV/C X2i 36.56 <300µV/C X2e 130.93 <1800µV/C Z1i 12.15 <20µV/C Z1e 37.63 <20µV/C Z2i 16.37 <20µV/C Z2e 13.26 <20µV/C

CNES


Vp Thermal Sensitivity

Vp = test mass electrical potentialThermal sensitivity electrostatic bias force fluctuations inertial sensor scale factor fluctuations

EM in specs, FM out!Plastic component – ceramic component

AD587 KN UQ/883ppm/°C Plastic CeramicDATA Sheet 10 5Onera Test 2.5 9.3

/°C in [15-45]°C

non linear sensitivity

non linear sensitivity


FEEU Performance

The 3 FEEU FM were successfully tested in performance and are now ready for test with ICUME & qualification.


1 DSP board per differential accelerometer (No redundancy) :1 DSP 1 SU 12 servo-loops channels1 DSP = 1 Oslink customer

Architecture on TSC21020F:•Rad-tolerant FPGA •SEL immune SRAM (SEU protected by EDAC)•PROM containing the master (Boot) software ( IMSW )•EEPROM containing the application software ( ASW ) and the parameter tables.

Software and Hardware tested, accuracy verified.

FM Interface Control Unit :DSP Hardware


Interface Control Unit : DSP Software

1.25Mb/s Main tasks of the DSP software:

Critical Issues:

CPU charge: Control loop operation cycle: 973µs,Optimisation of the CPU charge leading to:77 % typ. and 95 % max => no more margin.

Accuracy:Optimisation of the computation to minimise the effect of 32 bits arithmetic (extension to 40bits needed for some critical operation)

•FEEU Interface•OBC interface•12 command laws launched periodically (973µs) by hardware interrupts•Format TM/receive TC•Datation / synchronisation•Data validation•Parameter table handling

-command parameters-calibration signal parameters (sine, square wave,…)-TM filters parameters


Interface Control Unit Performance

The ICU EM and the Software 2.5 were successfully tested in performance.

• ICUME FM Produced : Under test.

Functional anomaly between the DSP and the FPGA.Discover only for temperature above 40°C.

Thanks to CNES help the precise location and the anomaly process is now understood.

A hardware solution has been proposed and is being implemented on a test board.


Developement Status - Electronics

• FEEU: FM• 2 FM + 1 spare produced• 3 units tested in performance : OK• Ready for test with ICUME & qualification

• ICUME : QM• Produced & under perf. test in Onera • « DSP-FPGA link anomaly » @ T > 40°C:

• Timing problem of acknowledge signals of <1 ns• Hardware recovery solution under final test before

implementation => February 2013• Qualification and acceptance of electronics: June 2013.

• ICU Flight software• Validation of 2.5 version in Oct 2011 • Update to 2.6 : June 2013

Meas. Pick-up noise (red) vs spec. (blck)


Thanks to MICROSCOPE partners

Physikalisch-Technische

Bundesanstalt

Observatoire de la Côte d’Azur

1 10 4 1 10 3 0.011 10 18

1 10 17

1 10 16

1 10 15

1 10 14

1 10 13

1 10 12

1 10 11

1 10 10

Calibrated centringNon Calibrated1E-15 EP signal @ 730km

Hz

Diff

eren

tial A

ccele

ratio

n (m

/s²)

1 10 4 1 10 3 0.011 10 18

1 10 17

1 10 16

1 10 15

1 10 14

1 10 13

1 10 12

1 10 11

1 10 10

Calibrated centringNon Calibrated1E-15 EP signal @ 730km

Hz

Diff

eren

tial A

ccele

ratio

n (m

/s²)

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