ESA EJSM/JGORadio & Plasma Wave

Instrument(RPWI)

Prag meeting 100218

Lennart Åhlén

Electric fieldsPlasma measurementsConductivities B

Plasma waves

Radio

•Backplane with power distribution, analog and digital interfaces•Board size: 20x15cm TBC•Connectors: Micro-D type•Box : 21x16x12 cm average 4.7mm wall thickness for Al.•Distance between Boards: 20mm

Main box mechanics

Power

Voltages:+3.3V Digital interface supply+1.8V Digital DPU and FPGA core supply +-8V Analog

•Software current limiters (msec turn off at latch up)•Common ground for all voltages•Only one ground in the backplane•Total power: 6.6W average 10W peak (100ms)

Instrument interfaces• Digital: Differential • Analog: Single ended (TBC)

Satellite interfaces• 2 Mbit SpaceWire• Single ended (TBC)

Radiation protection

•Spot shielding should be used for all S/C external electronics•Box and spot shielding should be used for the RPWI Box•Use of Rad Hard components•Box shielding 4.7mm•1.1 kg extra mass needed for 8mm box protection•3kg allocated by ESA for radiation shielding of RPWI

Action: Calculations of internal box radiation levels using GEANT 4

Generic Instrument

LP-PWI Bias control, LF wave analyzer and MIME

HFwave analyzer

WHY Should we use the ESA ASICs ?

•They are guarantied Rad hard•ESA will do the paper work•ESA will pay for the qualification•We will save mass (up to 650g)•We may save power that can be used for signal processing•We may save money •We can convert saved mass into antenna length•If they are not delivered in time we blame ESA for the delay

RA-PWI, RWI and LP-PWI Preamplifiers

Lennart Åhlen

LP_PWI PreamplifierSpecifications:•Switchable E-field / Density•100mW power consumption • 500kRad Radiation hardend • Positive feed back current generator•E-field:

DC-300Hz +-100V input rangeDC to 3MHz small signal bandwidth Better than 10^12 input resistance1nA – 100nA Current Bias range16 nV/sqr(Hz) noise

•Density:DC to 10kHz bandwidth10pA to 100uA input current range +-100V Voltage Bias range

New development: Find new low noise Rad hard operational amplifiersDevelop a MEMS chip including nano-switches and amplifiers

MEMS amplifier 10x10x1mm total mass 4x30g (4x250g)

RA_PWI and RWI PreamplifierFET follower or FET input negative feed back amplifier ?

•High distortion•Limited output range•Low power•Simple

•Low distortion•Medium power•Complex

Specifications:1kHz to 50MHz Bandwidth 2 nV/sqr(Hz) noise+-1V input range 100mW power consumption

Amplifier from Tohoku University 100Hz to 50MHz 0.6W

RPWI Grounding block diagram

EMC Actions.Define acceptable satellite RE and CE levels for the frequency range DC to 45 MHz.

MIL-STD-462D ECSS-E-ST-20-07C(31July2008)

1. All spacecraft surfaces exposed to the plasma environment shall be sufficiently conductive and grounded. < 5 kohm/sq

2. Small surfaces differential charging potential shall not exceed +-10 V, assuming a plasma current of 5 nA/cm2

3. The S/C structure shall not be used as return path for power and signals except for sensor signals to avoid common impedance coupling and magnetic disturbances.

4. Isolated receivers and balanced differential signals should be used as subsystem signal interfaces.

5. All active wires shall be twisted with its return wire and loops on circuit boards should be minimize to reduce magnetic disturbances.

6. The spacecraft system shall use a Distributed Single Point Grounding. 7. Secondary power shall be grounded to structure only once in each unit / experiment.8. Cable shields shall be grounded to structure ground at both ends. Shields shall not be

used as the return path for signal or power.9. Non-magnetic materials shall be used wherever possible.The use of ferro-magnetics

shall be avoided wherever possible.

10. It is recommended to use crystal oscillator controlled DC/DC converters

Experimenter EMC requirements

Develop the RPWI EMC requirements for the S/C by interaction during S/C design

Low Voltage Power Supply (LVPS)

Göran Olsson

Royal Institute of Technology (KTH)

Space and Plasma Physics

LFA + AM

+8V / -8V

SCM PREAMP

RWI Preamps

RA-PWI Preamp

LP-PWI Preamps

3.3V

LV

PS

-A

1.8V

3.3V

LV

PS

-B T

BD

LV

PS

CO

NT

RO

L &

MO

NIT

OR

ING

1.8V

3.3V

1.8V

+8V

-8V DPU

Clock, Control, Data and Emergency Power-Off, A + B

CE

B B

AC

KP

LA

NE

SCM

+8V / -8V 3.3V1.8V

LP-PWI

+8V / -8V 3.3V1.8V

+8V / -8V 3.3V1.8V RWI RA-PWI

HFA

LVPS IN RPWI JGO

Functional:

•DC power to all RPWI instruments:

• ±8V +3.3V, +1.8 V from 25-36 V input, nominal total power output: ~10 W

•CEB Form Fit:

• PCB Dimensions 200x 150 x 1.6 mm

• Component height 12 mm upper side, 3 mm lower side

• Backplane connector 160 pin, 3 row Airborn WG series

• Mass 300 g

•Primary to secondary isolation

•Temperature range: -30 °C to +50 °C operating

•Redundant DC/DC converters and digital controllers TBD

•Power Switching: 5 instruments having two to four supply voltages

•Voltage and Current Monitoring

•Overcurrent Tripping; Limits under software control

•Temperature Monitoring: DC/DC converter and SCM sensor

Performance:

•No-load Power (Including DC/DC converter, controller, monitoring and switches): 1.1 W

•Differential Efficiency: 82%

•Output Deviation: ±5% from nominal including all effects

•Output Ripple: < 5 mVrms

LVPS Requirements

Controller BFPGA

VoltageAnd

Current Monitors

(4)

PowerSwitches

(9Instruments)

Voltageand

CurrentMonitors

(24)

1.8, 3.3 V

From SCM Thermistor

FromSC28V

CEBBPLN

FromSC28V

DPU

1.8, 3.3, ±8 V

DC/DC Converter A

1.8, 3.3 V

CDPU-A Ctrl: Clock, Command, Data, EPO

DC/DC Converter B

Housekeeping

Controller AFPGA

Common-ModeFilter

Common-ModeFilter

•Redundant TBD DC/DC Converters and Controllers chained with the DPU

•Unused chain is a cold spare

•Common power bus for all instruments. Design to minimize risk of single point failures here.

•What if both chain A and B are powered? Must be survivable, but no functional requirement. - No mutual interlock implemented. Subject of further study.

•1.8 V is regulated to 1.5 V locally on each subsystem

•Power switches have turn-on ramping

•Emergency Power-Off

Common Bus

LVPS Block Diagram

Main Transformer

Sync

hron

ous

Rec

tifi

ers

Out

put

Filt

ers

•Primary to Secondary Isolation

•Double Shielding

SecondaryPrimary

Outputs:

+1.8 V, 1.1 A

+3.3 V, 1.1 A

+8 V, 350 mA

-8 V, 300 mA

Input: 27- 36 V

13-14 V DC

EMI Filter

•Full-Wave Rectification

•No Feedback from Secondary

•LC Pi Filters

Switchmode Regulator Controller

•Push-Pull

•Full-Wave

•210 kHz

Pulse-Width Modulator ‘Forward’ Converter

420 kHz

Tra

nsfo

rmer

Dri

ver

•Regulated input voltage to Transformer Driver

•Current positive feedback: Counterbalances losses in driver transistors, transformer and rectifiers.

First Stage Second Stage

Shielded Shielded

Two-stage Conversion:

Excellent input and load regulation

Low noise

Low output cross-regulation

Slightly lower efficiency

-

+

50mΩ

Internal: ±15 V

•Inrush current limiter

DC/DC Converter A/B

FPGA3.3 V

Linear Regulators:

1.5 V

2.5 V

Power Switch Control (9)

LVDS

HK Control (ADC, Mux, Gain Switch)

•System clock derived from the CDPU interface clock: 1.048 MHz

•If three consecutive samples (~15 ms) exceed the limit ► All voltages turned off for the affected instrument

Housekeeping ADC Data

CD

PU

A/B

•Instrument Power Control

•Housekeeping Control with Storage and Readout

•Overcurrent Tripping, limits under software control

•IVM: Actel ProASIC3 A3P250

•FM: Actel RTSX72

DC

/DC

A/B

Digital Controller A/B

1. DC/DC Converter, Housekeeping System and Stepper Motor Controller for EMMA, a plasma payload on the Swedish Astrid-2 satellite, launched December 10, 1998. Dimensions 177 x 134 x 16 mm. DC/DC design power 10 W. COTS components. This design has many features in common with the MMS LVPS.

2. DC/DC Converter for SPEDE, a plasma payload on the SMART-1 ESA Lunar Orbiter, launched 2003. Dimensions 71 x 44 x 11 mm. Design power is a mere 1.2 W.

Impacted on the Moon as planned on September 3, 2006.

Design Heritage

LVPS IVM on the UNH lab bench with co-delivered dummy load board

Mass

Circuit board Main Box     Antennas/Sensors    

Width 21cm meter g/m

Depth 15cm SCM 650

Card mass/cm¨2 0.7 SCM Harness 480 4 120

Number of cadrs 6 Preamp 100

Box mass 1000g LP-PWI 1800

Material density 2.8 LP-PWI Harness 375 15 25

Card mass 1449g Preamp 200

Box thickness 4.7mm RWI 1400

Box surface 1191cm^2 RWI Harness 120 3 40

Total Box Mass 3000g RWI Preamp 100

RA-PWI 200

Harness mass 1059g RA-PWI Harness 84 3 28

Preamp mass 600g RA-PWI Preamp 200

Sensor mass 4050g

Sensor + Box+Preamp 7650g

Total 8709g

Scientists dream receiver

A downgrade is needed for the JGO receivers.

Low and high frequency analyzers

Lennart Åhlen

TDA: Development of FPGA algorithms for digital analyzers to obtain high dynamic measurement range 

JGO Scientists dream receiver

A downgrade is needed for the JGO receivers.

Dynamic range: The ratio of the specified maximum signal level capability of a system to its noise level in a record of continues sampled data.

What is required to fulfill the JGO since objective?

Questions to be answered by the RPWI scientists.

1.Ranges and overlap for the low and high frequency receivers?2.Wave-form capture?3.Low and High frequency data coverage?4.Number of parallel data channels? 5.Type of on-board data analyzes?

Low frequency receiver

• Signal processing: FFT, I/Q, Filter bank, Wavelets, PFT, • Buffer memory for wave form capture and Burst data.• Dynamic range: 80dB to ~120dB @ 100Hz bandwidth

High frequency receiver

• Burst data signal processing: FFT, I/Q, Filter bank, Wavelets, PFT, • Buffer memory for wave form capture and Burst data.• Dynamic range: 70dB to ~100dB @ 10kHz bandwidth

• Measurement range: 70dB to ~120dB @ 10kHz bandwidth • Dynamic range: 70dB to ~100dB @ 10kHz bandwidth

Under sampling high frequency receiver

• All high speed ADCs has a higher analog bandwidth than the maximum sampling rate. •This makes it possible to build HF digital receivers by use of under-sampling.•Under-sampling design approach is replacing mixer-based heterodyne receivers.•Signal processing: FFT, I/Q, Filter bank, Wavelets, PFT,

Principle of under sampling

Dual 1 0 -1 I/Q Mixer including SH

•Conventional mixer using high speed analog switches.

Antenna impedance measurements

•Net work analyzer S11 type measurements •Impedance antenna to plasma vs. frequency•Useful for side-by-side antenna comparisons