A tool to maximize the scientific output of PWI target physics:

Intelligent Signal Detector Module

J. Lichtenberger (1), P. Steinbach (2) and L. Bodnár (3)

(1) Space Research Group, Department of Geophysics, Eötvös University, Budapest, Hungary

(2) MTA-ELTE Research Group for Geoinformatics and Space Sciences(3) BL Electronics, Solymár, Hungary

Science vs. Technology?

Science in a space experiments is limited by technology → cannot speak about science without taking technology into account

Hard limits: sensors/preamps/sensor location, etc.

Soft(er) limits: data collection/processing policy, mode of operation

Science vs. Technology?

Example 1: measurement averaged over 4 sec spin of MMO (a planned mode) → most of the phenomena (physics) shorter than this period is lost

Example 2: achieving ~1Hz@60kHz resolution at ULF band in PWI, a very long (32768 point) FFT window has to be used, this window is >500msec → the physics inside is lost

Short lived phenomena in Hermean magnetosphere

1. Lion roars: narrow-banded whistler-mode wave packets at the bottom of magnetic trough of magnetosheath mirror waves. (Smith and Tsurutani,1976; Zhang et al. 1998 on Geotail). f~0.1 fce.

May be in Hermean magnetosphere (Baumjohann et. al, 2006)

Short lived phenomena in Hermean magnetosphere

2. Seismo-electromagnetic phenomena (intensive research in Earth): short e.m. emissions (impulses) propagating in magnetoionic medium → dispersion

Is Mercury active in seismological sense?

Mercur model B=20[nT] Ne=1[1/cm3] x=5000[km]

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Mercur model B=220[nT] Ne=1[1/cm3] x=5000[km]

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Short lived phenomena in Hermean magnetosphere

1. Triggered emissions: wave-particle interaction in Hermean magnetosphere with radiation belt particles

Has Mercury radiation belt and ring current (Blomberg and Cumnock, 2004) ?

Technology to maximize the scientific output of PWI target physics:

Intelligent Signal Detector Module

1. Scientific goalDetecting events in PWI VLF data that are shorter

than spinning time (4 sec) of MMO and thus beyond the capabilities of general modes of operation.

The target events are :a. transients generated by

atmospheric/magnetospheric processeslithospheric processesSolar wind-atmosphere interactions

Technology to maximize the scientific output of PWI target physics:

Intelligent Signal Detector Module

b. whistler mode waves generated bytransients (see a.)wave-particle interactionsnonlinear processesSolar wind – magnetosphere interactions

Estimated event durations:for a.: microseconds-few millisecondsfor b.: ten milliseconds-second

Technology to maximize the scientific output of PWI target physics:

Intelligent Signal Detector Module

c. any new phenomena - limited in time- limited in frequency

Theoretical background: UWB short impulse solution of Maxwell’s Equations with arbitrary excitation signal – modeling!

Technology to maximize the scientific output of PWI target physics:

Intelligent Signal Detector Module

Functional description

a. Input data

Raw waveform from EWO or spectrogram (dynamic spectra) of the selected component.

b. Output data

Survey mode: the number of a selected event type during the given period

Burst mode: detected event waveform or spectrogram

Noise background monitoring

Technology to maximize the scientific output of PWI target physics:

Intelligent Signal Detector Module

Functional description

c. Algorithm

2D image correlation using the spectrogram or matched filtering on time domain depending on the signal and CPU load.

d. Patterns

The patterns are generated using theoretical models/assumptions and can be:

- predefined stored in code memory segment

- generated on the fly using different parameter sets and adaptive -procedures depending on the available processing power

- uploaded from the Earth (second phase of operation when enough experience/knowledge have been gathered during the mission)

Technology to maximize the scientific output of PWI target physics:

Intelligent Signal Detector Module

Functional description

c. Algorithm

2D image correlation using the spectrogram or matched filtering on time domain depending on the signal and CPU load.

d. Patterns

The patterns are generated using theoretical models/assumptions and can be:

- predefined stored in code memory segment

- generated on the fly using different parameter sets and adaptive -procedures depending on the available processing power

- uploaded from the Earth (second phase of operation when enough experience/knowledge have been gathered during the mission)

Technology to maximize the scientific output of PWI target physics:

Intelligent Signal Detector Module

HeritageISDM concept is based on various satellite

experiment : - ACTIVE, - COMPASS-2 - SAS2 using ISDM concept flew

here - DEMETER satellites projects in developing phase:

ISS-OBSTANOVKA, VOLCANO series, Venus Entry Probe Mission)

Automatic Whistler Detector and Analyzer system working on various sites all over the world (Hungary; SANAE, Halley, Rothera – Antarctica; South Africa, New Zealand)

Event detection SW diagram

Input DataStream

Evaluationof events

Event dependentdata proc.

Send data toTM process

MDP op system

Publishevent forother apps.

Triggering !

Technology caveat and solution

High frequency resolution in ULF range ↔ optimal time resolution in VLF range.

The domain of signal energy localization proportional to time-bandwidth product T x B

Heisenberg-Gabor inequality: T x B ≥ 1 – a signal cannot have arbitrarily small resolution in time and in frequency

Solution:

a. Alternating long and short FFT window

b. Open ULF data stream with hardware or software