Off-line radiometric analysis of Planck/LFI data

TL;DR

This paper describes the development and application of the LIFE software suite for off-line radiometric analysis of Planck/LFI data, enabling calibration, verification, and ongoing status monitoring of the instrument during ground tests and in-flight operations.

Contribution

It introduces a versatile, cross-platform analysis tool that integrates multiple modules for analyzing both ground test and flight data of the Planck/LFI instrument.

Findings

LIFE suite successfully used in RCA/RAA tests

Passed verification for in-flight use during System Operations Verification Tests

Enabled consistent analysis of ground and flight data

Abstract

The Planck Low Frequency Instrument (LFI) is an array of 22 pseudo-correlation radiometers on-board the Planck satellite to measure temperature and polarization anisotropies in the Cosmic Microwave Background (CMB) in three frequency bands (30, 44 and 70 GHz). To calibrate and verify the performances of the LFI, a software suite named LIFE has been developed. Its aims are to provide a common platform to use for analyzing the results of the tests performed on the single components of the instrument (RCAs, Radiometric Chain Assemblies) and on the integrated Radiometric Array Assembly (RAA). Moreover, its analysis tools are designed to be used during the flight as well to produce periodic reports on the status of the instrument. The LIFE suite has been developed using a multi-layered, cross-platform approach. It implements a number of analysis modules written in RSI IDL, each accessing the data through a portable and heavily optimized library of functions written in C and C++. One of the most important features of LIFE is its ability to run the same data analysis codes both using ground test data and real flight data as input. The LIFE software suite has been successfully used during the RCA/RAA tests and the Planck Integrated System Tests. Moreover, the software has also passed the verification for its in-flight use during the System Operations Verification Tests, held in October 2008.