Pre-processing LFI

Overview

The first processing level of the LFI DPC is the so called Level 1. The source data of the Level 1 software includes:

• raw housekeeping telemetry packets retrieved from different satellite subsystems: the LFI instrument, the Sorption cooler, the HFI instrument and the Central Data Management Unit (CDMU).
• the LFI raw scientific telemetry
• Additional auxiliary data provided by the MOC and the Flight dynamics:
  • The Attitude History File (AHF)
  • Time correlation data (time correlation coefficients and time couples)
  • The Sorption cooler out of limit data

Only a subset of the raw housekeeping telemetry packets is daily processed and converted into TOIs, i.e. those relevant to the LFI DQR production and the estimation of the LFI instrument systematic effects.

The LFI scientific telemetry

Each LFI radiometer provides two analog outputs, one for each amplifier chain. In a nominal configuration, each output yields a sequence of alternating [math]V_{load}[/math], [math]V_{sky}[/math] signals at the frequency of the phase switch. By changing the phase switches configuration, the output can be a sequence of either [math]V_{sky}[/math] or [math]V_{load}[/math] signals.