Issue |
Astron. Astrophys. Suppl. Ser.
Volume 147, Number 1, November II 2000
|
|
---|---|---|
Page(s) | 51 - 74 | |
DOI | https://doi.org/10.1051/aas:2000289 | |
Published online | 15 November 2000 |
Data streams from the low frequency instrument on-board the PLANCK satellite: Statistical analysis and compression efficiency *
1
Osservatorio Astronomico di Trieste, Via G.B. Tiepolo 11, I-34131 Trieste, Italia e-mail: $<$name$>$@ts.astro.it
2
Istituto TeSRE, Consiglio Nazionale delle Ricerche, Via Gobetti 101, I-40129 Bologna, Italia e-mail: burigana@tesre.bo.cnr.it
Send offprint request to: M. Maris, e-mail: maris@ts.astro.it
Received:
22
May
2000
Accepted:
7
August
2000
The expected data rate produced by the Low Frequency Instrument
(LFI) planned to fly on the ESA Planck mission in 2007, is over a
factor 8 larger than the bandwidth allowed by the spacecraft
transmission system to download the LFI data. We discuss the
application of lossless compression to Planck-LFI data streams in
order to reduce the overall data flow. We perform both theoretical
analysis and experimental tests using realistically simulated data
streams in order to fix the statistical properties of the signal
and the maximal compression rate allowed by several lossless compression
algorithms.
We studied the influence of signal
composition and of acquisition parameters on the compression rate
and develop a semiempirical formalism to account for it.
The best performing compressor tested up to now is the arithmetic
compression of order 1, designed for optimizing the compression of
white noise like signals,
which allows an overall compression rate
.
We find that such result is not improved by other lossless compressors,
being the signal almost white noise dominated.
Lossless compression algorithms alone will not solve
the bandwidth problem but needs to be combined with other
techniques.
Key words: methods: data analysis / methods: statistical / instrumentation: miscellaneous / space vehicles / cosmology: cosmic microwave background
© European Southern Observatory (ESO), 2000