Level Zero Data

What is it?

Most spacecraft mission data is typically divided into "levels" of processing and refinement. Typically, "raw" data is the basic telemetry transferred from the spacecraft to the ground station, packaged as a file, with only basic r/f integrity checks run, and no processing done to it. Level Zero refers to the cleanest, time-ordered set of data for a given instrument or spacecraft. The only processing done is typically the removal of duplicate data points (due to multiple file sends or a solid state recorder overlap), the removal or minimal repair of bad r/f data, and the matching of the end of one packet to the beginning of the next. The images taken by an instrument are left "as is" - not manipulated, not flat-fielded nor otherwise calibrated.

The JSOC, for the AIA & HMI instruments, defines the processes of Level Zero data to be:

1. Telemetry Checking
2. APID Lookup
3. Image Reconstruction
4. Housekeeping Processing

All of the Level Zero data is recorded in the JSOC DRMS (database). More information on Level Zero is contain in JSOC Level Zero Software Functional Specification.

Who uses it?

Typically, mission operations personnel and instrument operators want to see Level Zero data. It is available usually within minutes of receipt and persons very familiar with instrument/spacecraft engineering specs can make the best use of it. All kinds of raw image data and housekeeping data are present, including many useful temperatures, voltages and positions. Those requiring the most immediate spacecraft images are sometimes also Level Zero data users, such as CISM (Center for Integrated Space Weather Modeling).

What is Level 0.X?

The JSOC team has further segregated Level Zero data by making intermediate processing steps between Level Zero and Level One. These include:

• [:Lev0.1Doc:Level 0.1]

• [:Lev0.3Doc:Level 0.3/Level 0.5]

MOC Product Server

• [:MOCServer:Accessing the server] -- Information about accessing the MOC Product Server