1. Solar Orbiter RPW - Low Frequency Receiver
LFR team at LPP
Thomas Chust
Lead Co-I (CNRS)
science, calibration, tests
Paul Leroy
Technical Manager (CNRS)
flight software development + SGSE
Alexis Jeandet
Lead Engineer (CNRS)
GSE + SGSE
Martin Morlot
Study Engineer (CDD)
VHDL developement
Jean-Christophe Pellion
Gérald Saule
flight software specification/validation
Vincent Leray (20%)
Engineer (CDD)
product assurance software
William Recart (20%)
product assurance hardware
Bruno Katra
Study Engineer (CNRS)
software development, calibration, tests
Fouad Sahraoui
Co-I (CNRS)
Yannis Zouganelis
Co-I (UPMC)
Alessandro Retino
...
LPP/CNRS – SO RPW Team Meeting #14 – January 29-30, 2014 – CNES Paris, France

2. Status of LFR resolution (design)
Outline
Status of LFR resolution (design)
Need for a greater gain of the BIAS differential AC signals ?
LPP/CNRS – SO RPW Team Meeting #14 – January 29-30, 2014 – CNES Paris, France

3. LFR downsampling and processing strategy
8 ADCs @ Hz
decimation
down to  Hz
( f0 )
(14 bits ideally)
:32 :3
(16 bits)
=> 18 bits ?
(15 bits)
(16 bits)
(16 bits) Hz
4 096 Hz
16 Hz
256 Hz
shaping :3 :2
:64 :4
=> 20 bits ?
( f1 )
( f3 )
( f2 ) :4
( f0 )
2  E
3  B
1  V
2  E
3  B
2  E
3  B
1  V
2  E
3  B
1  V
2  E
(3  B)
2  E
3  B
1  V
2  E
3  B
FFT
FFT
FFT
(15 bits)
Spectral matrices
(ASM)
Waveforms
(WF)
Spectral matrices
(ASM)
Waveforms
(WF)
Waveforms
(WF)
Spectral matrices
(ASM)
Waveforms
(WF)
Basic parameters
(BP)
Basic parameters
(BP)
Basic parameters
(BP)
LPP/CNRS – SO RPW Team Meeting #14 – January 29-30, 2014 – CNES Paris, France

4. BIAS 5 analogue inputs DC V (G=1/15) DC dV ~ E (G=1)
AC dV ~ E (G=5, 50Hz)
LPP/CNRS – SO RPW Team Meeting #14 – January 29-30, 2014 – CNES Paris, France

5. Current set of Basic Parameters
𝐒𝐌 ω 𝑗 𝑚 = 𝐵 1 𝐵 1 ∗ 𝐵 1 𝐵 2 ∗ 𝐵 1 𝐵 3 ∗ 𝐵 1 𝐸 1 ∗ 𝐵 1 𝐸 2 ∗ 𝑐𝑐 𝐵 2 𝐵 2 ∗ 𝐵 2 𝐵 3 ∗ 𝐵 2 𝐸 1 ∗ 𝐵 2 𝐸 2 ∗ 𝑐𝑐 𝑐𝑐 𝐵 3 𝐵 3 ∗ 𝐵 3 𝐸 1 ∗ 𝐵 3 𝐸 2 ∗ 𝑐𝑐 𝑐𝑐 𝑐𝑐 𝐸 1 𝐸 1 ∗ 𝐸 1 𝐸 2 ∗ 𝑐𝑐 𝑐𝑐 𝑐𝑐 𝑐𝑐 𝐸 2 𝐸 2 ∗
𝐀𝐒𝐌 ω 𝑗 𝑚 = 1 𝑁 𝑆𝑀 𝑚 𝑘=1 𝑁 𝑆𝑀 𝑚 𝐒𝐌 𝑘 ω 𝑗 𝑚 = 𝐒𝐌 𝑡𝑖𝑚𝑒
𝐒 ω 𝑗 𝑚 = 𝐀𝐒𝐌 𝑓𝑟𝑒𝑞𝑢𝑒𝑛𝑐𝑦
BP1 set 1: Power spectrum of the magnetic field
BP1 set 2: Power spectrum of the electric field
BP1 set 3: Wave normal vector (from B)
BP1 set 4: Wave ellipticity estimator (from B)
BP1 set 5: Wave planarity estimator (from B)
BP1 set 6: XSO-component of the Poynting vector
BP1 set 7: Phase velocity estimator
BP2 set 1: Autocorrelations
BP2 set 2: Normalized cross correlations
[ RPW Team Meeting #6 – Prague ]
[ RPW Team Meeting #7– Toulouse ]
LPP/CNRS – SO RPW Team Meeting #14 – January 29-30, 2014 – CNES Paris, France

6. Cadences of the spectral matrix computation
FSM_m
sampling frequency
𝑁 𝐹𝐹𝑇 =256
f0 = Hz
96 SM / s
...
...
f1 = 4096 Hz
16 SM / s
...
...
...
...
f2 = 256 Hz
1 SM / s
...
...
time
1 s
LPP/CNRS – SO RPW Team Meeting #14 – January 29-30, 2014 – CNES Paris, France

7. LFR Normal Mode (1) Basic Parameters sampling frequency ...
BP: bps
WF: bps
ASM: bps
TM: bps
Basic Parameters
sampling frequency
BP1
&
BP2
BP1
&
BP2
BP1
BP1
BP1
ASM
BP1
4 SMs
64 SMs
384 SMs
4 SMs
64 SMs
384 SMs
4 SMs
64 SMs
384 SMs
4 SMs
64 SMs
384 SMs
4 SMs
64 SMs
384 SMs
4 SMs
64 SMs
384 SMs
4 SMs
64 SMs
384 SMs
f0 = Hz
...
TBP1_0= 4 s
...
f1 = 4096 Hz
...
TBP1_1= 4 s
...
f2 = 256 Hz
...
TBP1_2= 4 s
...
...
4 s
continuous WF
...
f3 = 16 Hz
20 s
time
LPP/CNRS – SO RPW Team Meeting #14 – January 29-30, 2014 – CNES Paris, France

8. LFR spectral frequencies
The spectral matrices are averaged over packets of 8 consecutive frequencies :
128 possible frequencies for NFFT = 256 (mean value is dropped)
Δ 𝑓 𝑚 = 𝑓 𝑚 𝑁 𝐹𝐹𝑇 × 𝑁 𝑓𝑟𝑒𝑞 𝑚
𝑁 𝑓𝑟𝑒𝑞 𝑚 =8
f3 = 16 Hz => wave form [DC, 8Hz] f3 / 2.5 = 6.4 Hz
f2 = 256 Hz => 12 frequencies [6.5Hz, 102.5Hz] Δ f (2) = 8 Hz f2 / 2.5 = Hz
f1 = 4096 Hz => 13 frequencies [88Hz, 1752Hz] Δ f (1) = 128 Hz f1 / 2.5 = Hz
f0 = Hz => 11 frequencies [1584Hz, 10032Hz] Δ f (0) = 768 Hz f0 / 2.5 = Hz
10-1
100
101
102
103
104 Hz
6.4Hz
6.5Hz
102.5Hz
88Hz
1752Hz
1584Hz
10032Hz
𝐒= 𝐀𝐒𝐌 𝑓𝑟𝑒𝑞𝑢𝑒𝑛𝑐𝑦
LPP/CNRS – SO RPW Team Meeting #14 – January 29-30, 2014 – CNES Paris, France

9. LFR Normal Mode (2) WaveForms & Averaged Spectral Matrices
TASM= 3600 s
sampling frequency
TWF= 300 s WF
BP1
ASM
BP1 WF
384 SMs
384 SMs
384 SMs
f0 = Hz
1/12 s
...
...
...
64 SMs
64 SMs
64 SMs
f1 = 4096 Hz
1/2 s
...
...
...
4 SMs
4 SMs
4 SMs
f2 = 256 Hz
8 s
...
...
...
2048 pts
...
f3 = 16 Hz
4 s
...
continuous WF
...
time
LPP/CNRS – SO RPW Team Meeting #14 – January 29-30, 2014 – CNES Paris, France

10. Binary representation of the waveform data
14-bit ADCs :
Hz)
x 𝐴𝐷𝐶 𝑡 𝑗 = 𝑏 𝑏 𝑏 𝑏 𝑏 𝑏 𝑏 ≡ 𝑏 13 𝑏 12 𝑏 11 𝑏 10 𝑏 9 𝑏 8 𝑏 7 𝑏 6 𝑏 5 𝑏 4 𝑏 3 𝑏 2 𝑏 1 𝑏 0
𝐿𝑆𝐵 14 = 2× 𝑉 𝑚𝑎𝑥 2 𝑛 with𝑛=14and 𝑉 𝑚𝑎𝑥 =3.0V ≃366μV (at LFR input)
16 bits in the FPGA after decimation
down to f0 = Hz and f1 = 4096 Hz :
x 𝐹𝑃𝐺𝐴 𝑡 𝑗 = 𝑏 𝑏 𝑏 𝑏 𝑏 𝑏 𝑏 𝑏 −1 2 −1 + 𝑏 −2 2 −2 ≡ 𝑏 13 𝑏 12 𝑏 11 𝑏 10 𝑏 9 𝑏 8 𝑏 7 𝑏 6 𝑏 5 𝑏 4 𝑏 3 𝑏 2 𝑏 1 𝑏 0 𝑏 −1 𝑏 −2
𝐿𝑆𝐵 15 = 𝐿𝑆𝐵 ≃183μV
𝐿𝑆𝐵 16 = 𝐿𝑆𝐵 ≃92μV
In case of small signals, possibility of 18 bits for f2 = 256 and 20 bits for f3 = 16 Hz :
x 𝐹𝑃𝐺𝐴 𝑡 𝑗 = 𝑏 𝑏 𝑏 𝑏 𝑏 𝑏 −4 2 −4 + 𝑏 −5 2 −5 + 𝑏 −6 2 −6 ≡ 𝑏 13 𝑏 12 𝑏 11 𝑏 10 𝑏 9 𝑏 8 𝑏 7 𝑏 6 𝑏 5 𝑏 4 𝑏 3 𝑏 2 𝑏 1 𝑏 0 𝑏 −1 𝑏 −2 𝑏 −3 𝑏 −4 𝑏 −5 𝑏 −6
Should be ok for SCM data
but for BIAS data?
𝐿𝑆𝐵 20 = 𝐿𝑆𝐵 ≃6μV
LPP/CNRS – SO RPW Team Meeting #14 – January 29-30, 2014 – CNES Paris, France

11. Finite number of bits in computation of the FFT
The FFT input are 16-bit integers :
x 𝐹𝑃𝐺𝐴 𝑡 𝑗 = 𝑏 13−𝑑 −𝑑 + 𝑏 12−𝑑 −𝑑 𝑏 0−𝑑 −𝑑 + 𝑏 −1−𝑑 2 −1−𝑑 + 𝑏 −2−𝑑 2 −2−𝑑 ≡ 𝑏 13−𝑑 𝑏 12−𝑑 𝑏 11−𝑑 𝑏 10−𝑑 𝑏 9−𝑑 𝑏 8−𝑑 ... 𝑏 2−𝑑 𝑏 1−𝑑 𝑏 0−𝑑 𝑏 −1−𝑑 𝑏 −2−𝑑
The FFT output are also16-bit integers :
FFT 𝑚𝑖𝑛 = 𝐿𝑆𝐵 16
- Currently
X 𝐹𝑃𝐺𝐴 ω 𝑖 = 𝑏 13−𝑑 −𝑑 𝑏 −1−𝑑 2 −1−𝑑 + 𝑏 −2−𝑑 2 −2−𝑑 ≡ 𝑏 13−𝑑 𝑏 12−𝑑 𝑏 11−𝑑 𝑏 10−𝑑 𝑏 9−𝑑 𝑏 8−𝑑 ... 𝑏 2−𝑑 𝑏 1−𝑑 𝑏 0−𝑑 𝑏 −1−𝑑 𝑏 −2−𝑑
- with 1 extra bit
X 𝐹𝑃𝐺𝐴 ω 𝑖 = 𝑏 12−𝑑 −𝑑 𝑏 −1−𝑑 2 −1−𝑑 + 𝑏 −2−𝑑 2 −2−𝑑 + 𝑏 −3−𝑑 2 −3−𝑑 ≡ 𝑏 13−𝑑 𝑏 12−𝑑 𝑏 11−𝑑 𝑏 10−𝑑 𝑏 9−𝑑 𝑏 8−𝑑 ... 𝑏 2−𝑑 𝑏 1−𝑑 𝑏 0−𝑑 𝑏 −1−𝑑 𝑏 −2−𝑑 𝑏 −3−𝑑
FFT 𝑚𝑖𝑛 = 𝐿𝑆𝐵 = 𝐿𝑆𝐵 17
LPP/CNRS – SO RPW Team Meeting #14 – January 29-30, 2014 – CNES Paris, France

12. SCM preamp noise & LFR resolution
1 extra bit for the FFT result :
FFT 𝑚𝑖𝑛 = 𝐿𝑆𝐵 = 𝐿𝑆𝐵 17
𝑑𝑓= 𝑓 sampling 256
𝑁 𝐹𝐹𝑇 =256
f3 = 16 Hz
Smallest onboard
calculable FFT :
768
PSD_FFT≃ FFT 𝑚𝑖𝑛 2 × 2 𝑑𝑓
f2 = 256 Hz
768
192
Quantification noise
for n-bit (ideal) digitization :
PSD_WF≃ 𝐿𝑆𝐵 𝑛 × 2 𝑓 sampling
f1 = 4096 Hz
f0 = Hz
LPP/CNRS – SO RPW Team Meeting #14 – January 29-30, 2014 – CNES Paris, France

13. SCM dynamic range MAXIMUM EXPECTED MAGNETIC PERTURBATION AT LFR INPUT
sigma 1Hz-100kHz = V
sigma 1Hz-10kHz = V
sigma 1Hz-1750Hz = V
sigma 1Hz-100Hz = V
sigma 1Hz-6.5Hz = V
=> 16 (+ 4 bits) for f3=16Hz ?
LPP/CNRS – SO RPW Team Meeting #14 – January 29-30, 2014 – CNES Paris, France

14. LPP/CNRS – SO RPW Team Meeting #14 – January 29-30, 2014 – CNES Paris, France

15. BIAS required sensitivity level & LFR resolution
f2 = 256 Hz
f1 = 4096 Hz
f3 = 16 Hz
f0 = Hz
LPP/CNRS – SO RPW Team Meeting #14 – January 29-30, 2014 – CNES Paris, France

16. BIAS required sensitivity level & max PSD
AC cutoff at :
MAXIMUM EXPECTED ELECTRIC PERTURBATION AT LFR INPUT
1) DC dV (Gain=1) &
PSD_max = 1.0e-05 (V/m)^2/Hz
sigma_f0 (0.0Hz-10kHz) = V
sigma_f1 (0.0Hz-1750Hz) = V
=> 4 (+ 2 bits) for f1=4096Hz ?
sigma_f2 (0.0Hz-100Hz) = V
=> 16 (+ 4 bits) for f2=256Hz ?
sigma_f3 (0.0Hz-6.5Hz) = V
5 Hz ?
50 Hz
2) AC dV (Gain=5, cutoff=50Hz) &
PSD_max = 1.0e-09 (V/m)^2/Hz
sigma_f0 (50.0Hz-10kHz) = 0.1 V
sigma_f1 (50.0Hz-1750Hz) = V
sigma_f2 (50.0Hz-100Hz) = V
=> 4 (+ 2 bits) for f1=4096Hz ?
=> 16 (+ 4 bits) for f2=256Hz ?
MOREOVER !
20 times larger seems possible for AC signals => Gain = 100 ?
push AC cutoff frequency down to 5 Hz ?
LPP/CNRS – SO RPW Team Meeting #14 – January 29-30, 2014 – CNES Paris, France

17. An additional mode for the BIAS AC dV signals ?
DC V
(G=1/15)
DC dV ~ E (G=1)
AC dV ~ E (G=5, 50Hz) ? R2
LPP/CNRS – SO RPW Team Meeting #14 – January 29-30, 2014 – CNES Paris, France

18. Additional slides I
LPP/CNRS – SO RPW Team Meeting #14 – January 29-30, 2014 – CNES Paris, France

19. Averaging random variables
LPP/CNRS – SO RPW Team Meeting #14 – January 29-30, 2014 – CNES Paris, France

20. Increase of the precision by averaging (1)
LPP/CNRS – SO RPW Team Meeting #14 – January 29-30, 2014 – CNES Paris, France

21. Increase of the precision by averaging (2)
LPP/CNRS – SO RPW Team Meeting #14 – January 29-30, 2014 – CNES Paris, France

22. LFR block diagram

23. L.F.R Processing chain

24. LFR 11 analogue inputs
LPP/CNRS – SO RPW Team Meeting #14 – January 29-30, 2014 – CNES Paris, France

25. BIAS configurations
LPP/CNRS – SO RPW Team Meeting #14 – January 29-30, 2014 – CNES Paris, France

26. LFR operational modes data produced and sent to DPU: data subsequently
transmitted to S/C:   NM
all
(SW In-Situ) BM
LFR
~10 min
all NM
(Shock) SBM1
~15 min NM
all
(Type III) SBM2
min
LPP/CNRS – SO RPW Team Meeting #14 – January 29-30, 2014 – CNES Paris, France

27. LFR (Shock) Selected-Burst Mode 1
BP: bps
WF: bps
ASM: bps
TM: bps
sampling frequency
BP1
&
BP2
BP1
&
BP2
BP1
BP1
BP1
BP1
BP1
24 SMs
24 SMs
24 SMs
24 SMs
24 SMs
24 SMs
24 SMs
f0 = Hz
...
TBP1_0= 0,25 s
...
0,25 s
f1 = 4096 Hz
...
...
continuous WF
1 s
time
LPP/CNRS – SO RPW Team Meeting #14 – January 29-30, 2014 – CNES Paris, France

28. LFR (Solar Wind In-Situ) Burst Mode
BP: bps
WF: bps
ASM: bps
TM: bps
sampling frequency
BP1
&
BP2
BP1
&
BP2
BP1
BP1
BP1
BP1
BP1
96 SMs
96 SMs
96 SMs
96 SMs
96 SMs
96 SMs
96 SMs
f0 = Hz
...
TBP1_0= 1 s
...
16 SMs
16 SMs
16 SMs
16 SMs
16 SMs
16 SMs
16 SMs
f1 = 4096 Hz
...
TBP1_1= 1 s
...
...
1 s
f2 = 256 Hz
continuous WF
...
5 s
time
LPP/CNRS – SO RPW Team Meeting #14 – January 29-30, 2014 – CNES Paris, France

29. LFR (Type III) Selected-Burst Mode 2
BP: bps
WF: bps
ASM: bps
TM: bps
Same products as for the BM
sampling frequency
BP1
&
BP2
BP1
&
BP2
BP1
BP1
BP1
BP1
BP1
96 SMs
96 SMs
96 SMs
96 SMs
96 SMs
96 SMs
96 SMs
f0 = Hz
...
TBP1_0= 1 s
...
16 SMs
16 SMs
16 SMs
16 SMs
16 SMs
16 SMs
16 SMs
f1 = 4096 Hz
...
TBP1_1= 1 s
...
f2 = 256 Hz
...
1 s
continuous WF
...
5 s
time
LPP/CNRS – SO RPW Team Meeting #14 – January 29-30, 2014 – CNES Paris, France