Instrument monitoring is required to

• ensure health and safety of the instrument


• provide up-to-date information on instrument status in order to maintain high data product quality

• Realtime monitoring (on-board): The built-in autonomy allows instrument internal monitoring of the status of pre-defined housekeeping parameters. In case of non-nominal events the instrument triggers a corrective action (CA). The type of CA defines whether SCIAMACHY is transferred to a safe mode or whether measurements continue and only an entry in the history area is generated.

• Near-Realtime monitoring (on-ground): As part of on-ground operation control, SCIAMACHY is monitored at the Flight Operation Control Centre (FOCC). Instrumental non-nominal events initiate procedure driven activities aimed to understand and to correct the anomaly in order to return to nominal operations as soon as possible.

• Longterm monitoring (on-ground): This type of monitoring is an offline task. It occurs at FOCC for health status of the APSM. At SOST, the operational longterm monitoring comprises
  – trend analyses of housekeeping (HK) telemetry and measurement parameters
  – detailed analysis of particular measurement parameters in case of operation modifications
  – generation of detector throughput
  – generation of m-factors

The operational longterm monitoring is embedded in the ground segments as depicted here.

SCIAMACHY operational longterm monitoring and its interfaces with the Payload Data Segment (PDS) an Flight Operation Segment (FOS)

• Analysis of measurement data

SCIAMACHY generates HK telemetry and measurement data. The latter include scientific data as nadir, limb, occultation and calibration & monitoring information. The measurement data are stored on-board for a period of, at least, 1 orbit and transmitted via X- and Ka-band to the ground stations in Kiruna (X-band) and ESRIN (Ka-band).

Measurement data for monitoring purposes are used in the form of level 0 and level 1b data products. Level 0 data are raw data containing detector data, PMD data and supplemental auxiliary information. Final level 1b data are calibrated spectral radiances, i.e. Earth shine, solar/lunar or calibration/montoring spectra as measured along the orbit.


– Level 0 analysis

Processing of level 0 data yields an overview of the instrument status during one orbit, usually. SOST-IMF operates several level 0 tools (e.g. Screener, SCIAMACHY Offline Graphics - SOG). tool in order to analyse system related aspects. With the Screener complete orbits can be analyzed in a standard way. This tool generates predefined output pages of various instrument parameters. For an interactive, in-depth analysis of level 0 data, the SOG tool. Originally developed by Astrium, this tool has been transferred to SOST-IMF for further usage. Together with the tools Scanner Simulator, State Design Checking and State Evaluation - all have been provided by Astrium - the SOG allows to investigate instrument's state operations at a very detailed level.


– Level 1b analysis

Monitoring of level 1b data concentrates on specific aspects of detectors and optics. This operational monitoring function is assigned to SOST-IFE. Further details can be found at the IFE’s SCIAMACHY site (note that the detector throughput provided on these pages is derived from level 0 data).



• Analysis of HK telemetry

Longterm analysis of HK telemetry provides system oriented information, supplemental to those derived from level 0 measurement data. During routine operations SOST-IMF concentrates on HK parameters defined in the Realtime Reduced Format (RTR) and Realtime Format (RTF). Further formats as e.g. Test Format, Report Format were usually analysed by Astrium in the Commissioning Phase. With the end of this phase, it was decided to continue the anomaly reporting at SOST-IMF

The reduced time resolution of the RTR and RTF HK telemetry of 1/16 Hz allows only to get an overview of instrument operations during one orbit. However, as the HK parameters copied into the level 0 data product is only a small subset of all available RTR and RTF information, the analysis of the HK telemetry stream is indeed required to get the full picture of instrument behaviour. SOST-IMF processes the retrieved HK telemetry data by using specific HK Telemetry tools, either SOST developments or packages provided by Astrium.

Currently, the following items are monitored on a routine basis:


• Operations Summary: An overview of the operational status on a monthly basis is provided to indicate the overall availability of the instrument.
• Anomalies: Based on the Report Formats, a weekly anomaly report is generated which outlines any anomaly occurring in the report period.
• Thermal history: Since the thermal behaviour of the instrument is of prime importance for data anaylsis, the history of the associated thermal settings are tracked.
• Detector Temperatures: The temperatures of all 8 detectors are monitored and plotted on a weekly basis
• OMB Temperatures: The derived OBM temperature and ATC power settings are monitored and plotted on a weekly basis.
• PMD Parameters: Parameters yielding evidence for a SEU event are monitored and plotted on a weekly basis.
• Data quality history: Operation activities which might degrade the quality of the data are tracked.
• Data unavailability history: The intervals when SCIAMACHY was 'off' are listed. These can either be planned or unplanned events.
• Life Limited Items: LLI usage is derived for each planning cycle. The accumulated budgets provide information of the status of each LLI.
• Mechanism checks & PMD ADC calibration: A record of APSM/NDFM health check and PMD ADC calibrations is provided.

The monitoring of the Detector Temperatures, OMB Temperatures and PMD Parameters is organized by SOST-IMF such that the requirements of the IOM for specific monitoring procedures are fulfilled.