PLANCK LFI Data Quality Checking

Data quality checking is a critical part of mission operations and the long term performance of the experiment. The data quality checking tasks during operations are likely to be divided into the following categories:

Data Quality Checking During Operations

Instrument Science Performance

Does the instrument produce a high quality raw data stream?
Is the within reasonable operating ranges?
Are the trends indicating an incipient problem?
Are the data being tranmitted in proper condition?
Are all science channels in nominal mode?
Is on -board software handling the data pr

Ground Data Quality

Are the data being received properly?
Are the data being unpacked and archived properly?
Do the data exhibit the appropriate behavior?

Does the noise appear to be right level?
Power spectra of signals?
Integration and Signal Average performance?
Calibration signals at correct times and levels?
Planet and other source signals at appropriate levels

Are calibration and ancillary data in place and appropriate.
Are all calibrations and baselines at appropriate levels and in reasonable trends?
Is the necessary ancillary and housekeeping data in place?
verification and validation of results

Data Quality Software development

Software repository contains correct source codes and data base files?
Data and results transfer and interfaces working properly?
Development and testing of new on-board software and processing and its testing
Verification and validation of data quality checking results

Verification and Validation of Data Quality Checking

This is a management issue foremost but requires additional resources
Focus on continued scientific data quality monitoring processes
Special software development for comparison and testing of data quality
Verification and validation of instrument performance monitoring processes

For PLANCK LFI data quality checking will require substantial preparation and also a reservoir of experienced scientists and engineers. Work will need to be done prior to launch to develop the data quality checking guidelines and then more effort after launch to refine and further develop those procedures. We can also anticipate that a significant effort will be needed to understand the science data quality checking in much greater detail than the simple filter, status, sieve, and trending done for the routine monitoring. This will require the same personnel with the expertise to understand the detectors and instrument at a deep level. e.g. thermal performance, sensor behavior, etc.and those that understand the next level of data processing leading ultimately to the map-making and scientific results. These are called out roughly in the following list.

Data Quality Checking Preparation and In-Depth

Definition and Development of Data Quality Checking

Specify and define required checking
Define normal modes and operations and expected data quality
Define nominal operating status and conditions and data stream
Develop and define approriate data base for comparison, calibration, and trending data from I&T phase
Outline nominal data quality checking processes
How does the on-board software and data processing affect data quality?
Are there special diagnostic modes of operation or data that can be utilized, if necessary?

Specify software development for data quality checking

Software and instrument data base definition
Data formats for input and output
Specify instrument performance monitoring results for review and analysis
Define software and instrument monitoring results reporting and exchange
Outline future special software development for in-flight data quality checking in special modes
Development of on-board software and processing for instrument performance monitoring and data quality checking
How is software verified, validated and delivered?

In-Depth Analysis of Data Quality during Operations

Expert personnel and scientists investigate the detailed data quality - related to instrument performance
Investigation of data taken during special operations or sky targets
Investigation of data taken for calibration, beam mapping, sources, etc. as a test and check of instrument performance
Follow up of anomalous signals and effects
Development and testing of new software for data quality checking as a result of operations
In-Depth Reports of data quality checking

However, all the expertise and knowledge about the instrument and its various subsystems will not reside at the institution with primary responsibiltiy for data quality checking. So the knowledgeable and responsible personnel will have to provide support in both the development of the data quality checking processes, in the processes remotely, through verification and validation of the data quality checking, e.g. review of reports and results, and through in-depth monitoring of the instrument performance and long-term health. This is one of the areas in which the US and NASA supported staff can be very valuable to the Planck mission.

Tasks and Roles for Scientists in Data Quality Checking

Definition and Development of Data Quality Checking
Software specification and development for Data Quality Checking
Provide Expertise and Support for Data Quality Checking

Daily shifts of reviewing data early in the mission until baselines and performance norms well-established
Interpretation and Review of results of data quality checks
Verification and Validation of data quality
Suggest and Develop data quality checks, software, and processes based on in-flight results

In-Depth Analysis of Data Quality During Operations