JUICE-Laplace/RPWI/JENRAGE Status

JUICE-Laplace/RPWI Team Meeting, Uppsala! May 11th 2012

JUICE-Laplace/RPWI/JENRAGEJovian ENvironment Radio Astronomy and Ganymede Exploration

StatusB. Cecconi, Pôle plasma, LESIA, CNRS-Observatoire de Paris

Status of JENRAGE1/2✤ We are facing BIG problems at LESIA for JENRAGE:

- No project manager available - No engineer available in the technical team (because of Solar Orbiter)- Head of the lab asked us to «choose» between Solar Probe+ and JUICE. This is an impossible (and dangerous) choice to make: different science, different persons.- Schedule of JUICE (as in yellow book) is in direct conflict with Solar Orbiter and Solar Probe+

✤ JENRAGE R&T has just begun with a master’s degree student. PhD to come if funding are available Not sure yet: 4 / 5 applications for funding were negative. Last answer due next month.

✤ So, JENRAGE will probably not be done at LESIA

✤ Now, I can really say «J’ENRAGE !»*(* I’m REALLY upset!)

Status of JENRAGE2/2✤ New collaborations are under study:

- among space physics labs: schedules are already packed for years.- some other labs in the Paris area are doing radio receivers, but none has space experience. Collaboration has to be set up quickly. - industry ? it would be much more expensive ! I’ll ask CNES- other lab of the RPWI consortium (but low heritage)- sharing manpower between labs of the consortium

✤ We still need a Project manager and a Technical manager on LESIA side: - nobody available in lab at this time,- external management from industry ? CNES has never been in favor of this up to now.

✤ Conclusion: The situation is very difficult for now. In case nothing can be set up at this date, we NEED a back up plan...

B. Cecconi, Pôle plasma, LESIA, CNRS-Observatoire de Paris


Presentation / Update on design


✤ «miniaturized low-noise heterodyne multi-channel radio receiver»- Frequency band:~100 kHz à 45 MHz- multi-channel:several channels in parallel (2 now, 4 under study)- heterodyne: we do not sample at 100MHz, but at ~10MHz with heterodyne system- miniaturized: mass = 450 g; power = 1.5 W thanks to ASIC integration of analog part- low noise: measurement noise ~2-5 nV/√Hzcross-channel phase stability ~1° => Goniopolarimetry ! (polarization and location of radio sources)

✤ LESIA Contribution [?]

RPWI/JENRAGEDescription

Dynamic spectrum of SKR (Saturn Kilometric Radiation) observed withCassini/RPWS/HFR.

GoniopolarimetryOr how to ‘see’ radio emissions

Radio Source LocationPrinciple of the method

Radio Source LocationCassini real Data

Radio ImagingSimulation

Simulation of auroral radio emissions of Jupiter seen from Ganymede’s orbit

✤ CNES R&T fundings were not approved this year (although they were 2 years ago!). Reason given: lack of personel to do the R&T.

✤ Description of R&T:- follow-up of «BepiColombo/Sorbet» miniaturization- Implementation of "zero-FI" (or «I-Q») in a space qualified rad-hard ASIC. - Already implemented in many application, but not for space.

✤ Other solution is to sample at 100MHz:- large dynamic required (16 bits?) or more (AGC loop needed?): interferences, antenna resonance... - no heterodyne stage, direct sampling

RPWI/JENRAGER&T CNES

RPWI/JENRAGER&T CNES✤ Heritage: superheterodyne receiver: ok up to 10-20 MHz, but not easy to go at

higher frequencies.

✤ R&T: new type of receiver («zero-fi» or «IQ») => we can go up too 45-50 MHz. - less demanding in ressources, and adapted to ASIC integration- requires RF mixers (ok) and poly-phase VCO (new)

✤ Backup solutions: - classical super-heterodyne (more mass, more power)- direct 100 MHz sampling (no heterodyne), not studied yet (more power)

Telemetry

✤ Heterodyne sweeping frequency mode✤ Overall bandwidth: 100 kHz to 45 MHz✤ Measurement filter: δf = 1kHz✤ 1 sample on 2 channels is: 4 independent measurements

= 2x (1 AGC (12bits) + 1 Auto (12bits)) + 1 Cross (2x12 bits)= 72 bits= 9 bytes

✤ Sweep data length= nfreq x 9 bytes= 2.5 to 2.7 kB per sweep, depending on number of frequency steps.

✤ Sweep duration: from 3 seconds to 30 seconds, depending on integration time (10 ms to 100 ms).

✤ In 3 channels mode: × 2.25 (so ~6 kB per sweep) ✤ In 4 channels mode: × 4 (so ~10 kB per sweep)

✤ Heterodyne Waveform mode✤ 10MHz sampling: 3 Msample/s effective✤ 12 bits per sample✤ => data rate = 15MB/s per channel:

Telemetry (preliminary details)

✤ Technical:- mastering VCO (Voltage Controlled Oscillators) with signals in phase and in quadrature (~1° accuracy required)- ASIC implementation of wide band filters (3MHz), with good rejection, and flat in gain (easy with components, but heavy and big).

✤ More general: - we lack personals to do the job. We cannot hire people easily. Our «radio» permanent technical staff shrunk: 10 people in 2002, 3 in 2012 (+ a few on contracts dedicated to Solar Orbiter).

Open Points


Processing / Software


B. Cecconi, Pôle plasma, LESIA, CNRS-Observatoire de Paris

Onboard processing

✤ With current design, JENRAGE is providing RPWI data series that don’t need any processing.

✤ May be different if other supplier/design is selected.

✤ Data content: - for 2 channels: 4 floating point number/sample (3 power + 3 complex correlations)- for 3 channels: 9 floating point number/sample (3 power + 3 complex correlations)- for 4 channels: 16 floating point number/sample (4 power + 8 complex correlations)

✤ NB: here 1 sample = 1 time at 1 frequency

✤ 4 channel mode sensors: 3E+1B

Ground processing

✤ Mainly:

Goniopolarimetric analysis:- input: power + correlations required- output: wave-vector direction, flux and polarization and possibly source size(if 4 channels: Poynting vector direction, local refraction index)+ magnetic field model & radio source model: radio source location

This processing software already exists for Cassini and STEREO.

✤ Other ideas ?

Documents

JUICE-Laplace/RPWI/JENRAGE Status