Data set Overview
      =================
      Rosetta was at distances between 152 and 1501 km from the comet
      during this time.
      ROSINA was permanently analyzing the coma of the comet with all
      three sensors, except during wheel offloadings when the mass
      spectrometers DFMS and RTOF were in standby and during orbit
      control manoeuvers, when all sensors were off. The explanation
      of the generated data of the ROSINA sensors can be found in the
      OPERATION_LOGBOOK.ASC
 
      Parameters
      ==========
      DFMS and RTOF data contain neutral gas data as well as ion data.
      The data are raw, uncalibrated data. COPS contain pressure data
      of the background pressure and of some thruster firings from the
      nude gauge. For calibrated data we refer the user to the level 3
      data.
 
      Calibration
      ===========
      COPS data are calibrated. However, the calibration factor has
      been determined for Nitrogen gas, and may not be appropriate for
      the the coma composition. For this the data from RTOF or DFMS
      have to be taken into account.
 
 
      Note on the DFMS and RTOF data:
      The user of our level 2 data has to make the conversion from
      pixel to mass and from ADC counts to ion current himself. In
      this way he will be aware that the precision is limited and
      depends on many parameters and he will use the data accordingly.
      The procedure required to calibrate the DFMS is described in our
      User manual, Annex D1 (DOCUMENT directory). ROSINA team are
      currently developing the necessary algorithms, putting emphasis
      on the quality control for the algorithm. They are defining
      quality flags for the data which will then tell the user how
      well the mass scale and the intensity scale have been defined.
      They are also working to produce level 3 data with calibrated
      mass scale and intensity. Once this SW is in place they will
      produce calibrated data for the mission at the comet.
 
 
      Processing
      ==========
      No processing was applied to the data.
 
 
      Software
      ========
      No software is provided.
 
      Media/Format
      ============
      The standard distribution format for the data is an electronic
      volume.
 
      Coordinate System
      =================
      The geometry items SC_SUN_POSITION_VECTOR,
      SC_TARGET_POSITION_VECTOR and SC_TARGET_VELOCITY_VECTOR provided
      in the label of the data product are relative to the Earth Mean
      Equator and Equinox reference frame of J2000.
      SUB_SPACECRAFT_LATITUDE, SUB_SPACECRAFT_LONGITUDE are given in
      the Cheops reference frame.
      The SPACECRAFT_ALTITUDE gives the distance to the spacecraft
      from the target center of mass. These parameters are computed at
      time t=START_TIME.
      Distances are given in km, angles in degrees.
 
      Cheops Reference Frame
      ======================
      Scholten, F., Preusker, F., Jorda, L, and Hviid, S.,
      Reference Frames and Mapping Schemes of Comet 67P/C-G,
      RO-C-MULTI-5-67P-SHAPE-V1.0:CHEOPS_REF_FRAME_V1,
      NASA Planetary Data System and ESA Planetary Science Archive,
      2015.

Confidence Level Overview
      =========================
      All data have been validated by the ROSINA team and found as
      expected. Any exceptions are noted by the DATA_QUALITY field in
      the label files.