DATA_SET_DESCRIPTION |
Data Set Overview:The data from the ROSETTA PLASMA CONSORTIUM (RPC) FluxgateMagnetometer(MAG)was submitted by Ingo Richter (TM) for the RPCMAGteam. The PI of the team is Karl-Heinz Glassmeier.Data have been measured during the COMET ESCORT 1 Phase of ROSETTA.Included are the following sub-phases:MTP0010 - STP0030 from 2014-11-22T00:00 to 2014-11-25T23:25MTP0010 - STP0031 from 2014-11-25T23:25 to 2014-12-02T23:25MTP0010 - STP0032 from 2014-12-02T23:25 to 2014-12-09T23:25MTP0010 - STP0033 from 2014-12-09T23:25 to 2014-12-16T23:25MTP0010 - STP0034 from 2014-12-16T23:25 to 2014-12-19T23:25MTP0011 - STP0035 from 2014-12-19T23:25 to 2014-12-23T23:25MTP0011 - STP0036 from 2014-12-23T23:25 to 2014-12-30T23:25MTP0011 - STP0037 from 2014-12-30T23:25 to 2015-01-06T23:25MTP0011 - STP0038 from 2015-01-06T23:25 to 2015-01-13T23:25MTP0012 - STP0039 from 2015-01-13T23:25 to 2015-01-20T23:25MTP0012 - STP0040 from 2015-01-20T23:25 to 2015-01-27T23:25MTP0012 - STP0041 from 2015-01-27T23:25 to 2015-02-03T23:25MTP0012 - STP0042 from 2015-02-03T23:25 to 2015-02-10T23:25MTP0013 - STP0043 from 2015-02-10T23:25 to 2015-02-17T23:25MTP0013 - STP0044 from 2015-02-17T23:25 to 2015-02-24T23:25MTP0013 - STP0045 from 2015-02-24T23:25 to 2015-03-03T23:25MTP0013 - STP0046 from 2015-03-03T23:25 to 2015-03-10T23:25All magnetic field data are calibrated data. That means the datarepresent the 3 components of the magnetic field measured in physicalunits (nT). Data are given in instrument coordinates (LEVEL_A),S/C coordinates (LEVEL_B) or CSEQ coordinates (LEVEL_C).Calibration has been applied according to the Ground calibrationresults which means:- temperature dependent offset calibration- temperature dependent sensitivity calibration- temperature dependent misalignment calibrationBad vectors have been removed. Any s/c generated noise and s/ccaused residual magnetic fields are not eliminated. The groundtemperature model for the sensor calibration has been improved(expanded for a wider temperature range down to - 130 deg C) usinglong term temperature model obtained from flight data.The data are sorted by the sensor (OB: outboard sensor, IB: inboardsensor)and the measurement mode (M1..M6). They can uniquely beidentified by their file names.Normally the OB is the Primary (Pri) and the IB is the Secondary (Sec)sensor. However, this order can be toggled by TCs. This feature hasbeen tested especially during the commissioning phases.In cases where the PRIMARY and SECONDARY sensor were toggled theindividual data files (OB/IB) will contain data measured withdifferent sampling rates according to the actual sampling rates ofthe PRIMARY and SECONDARY sensors. Refer to the MODE DESCRIPTIONtable below. The actual sampling rate is the only indicatorshowing which sensor is the primary and which is the secondaryone.REMARK:: Due to strong magnetic disturbance by the ORBITER the magnetic field data are influenced by s/c generated magnetic fields. The source of these disturbance is manifold: - transient currents flowing on the spacecraft - Heater pulses These rectangular disturbances are in the order of 1-2 nTpp, depending on the heaters and occur with the PWM periods of the heaters (usually a few seconds up to minutes) - Thruster related magnetic field disturbances These signatures are in the order of 3 nTpp and occur during Wheel off loading (WOL) maneuvres and Orbit correction maneuvres (OCM). Endurance is usually up to 20 minutes. Additional spikes occur during OCMs with periods of 625 mHz and amplitudes of 6 nTpp and about 200ms width. - Reaction wheel (RW) signatures The four rotating s/c RWs are causing four different sinusoidal disturbances with usually slowly varying frequencies in the range of 1-10 Hz with amplitudes of about 3nTpp. The 'tilted traces' of these signatures can clearly be seen in the dynamic spectra and can easily be distinguished from external magnetic field variations. - Interference by the RPC-LAP instrument There are times where the LAP instrument can be seen in the magnetic field spectrum. The disturbance occurs at a constant frequnecy of either 3.2 Hz or 3.6 Hz with an amplitude of about 1 nT. - etc. Due to the complexity of these circumstances a proper data cleaning is an ongoing task. Thus the data of the present dataset still contain the mentioned disturbance signatures. Therefore, any use of the data for scientific research has to be done under consideration of these disturbances.REMARK ON TIMING: It turned out that the OB data are shifted against IB data and also against ROMAP data by 1s. This behavior has not been corrected in the data. Therefore, for proper comparison in high resolution analyses, a time shift of 1s should be subtracted from all OB data. Alternatively OB data can be left as they are and a 1s shift had to be added to the IB and ROMAP data.Mode description::MODE SAMPLE RATE PACKET PERIOD PACKET LENGTH VECTOR RATEMinimum Mode M1 1/32 Hz 1024 s 32 Pri Vec 0.03125 vec/s 1 Sec Vec 0.000976 vec/sNormal Mode M2 1 Hz 32 s 32 Pri Vec 1 vec/s 1 Sec Vec 0.03125 vec/sBurst Mode M3 20 Hz 16 s 320 Pri Vec 20 vec/s 16 Sec Vec 1 vec/sMedium Mode M4 5 Hz 32 s 160 Pri Vec 5 vec/s 1 Sec Vec 0.03125 vec/sLow Mode M5 0.25 Hz 128 s 32 Pri Vec 0.25 vec/s 1 Sec Vec 0.007812 vec/sTest Mode M6 20 Hz 16 s 320 Pri Vec 20 vec/s 1 Sec Vec 0.0625 vec/sHK Mode 32 s 8 words 0.03125 vec/sThe HK mode contains coarse magnetic field information, measured bythe primary sensor with 16 bit resolution only. These data will notbe calibrated and are not used for any purpose.FILENAME CONVENTION & Mode Coding:Due to operational constraints it might happen that the instrumentmode or the primary sensor has to be switched during a specificobservation.The actual mode and the primary sensor of the instrument can easilybe identified by analyzing the filename of the actual data files. Thecomplete filename convention is listed in the EAICD, chapter 3.1.4.The filenames for EDITED and CALIBRATED data are coded as follows: ___.RPCMAG yymmddThhmm RAW IB M1..M6 LBL CLA OB TAB CLB CLCExample: RPCMAG040528T1230_RAW_OB_M3.LBL RPCMAG040528T1230_RAW_OB_M3.TABThe filenames for Housekeeping data are coded as follows: _.RPCMAG yymmddThhmm HK LBL TABExample: RPCMAG040528T1230_HK.LBL RPCMAG040528T1230_HK.TABLEVEL Description, Science Data:LEVEL_A : Calibrated data in INSTRUMENT coordinates (Unit Reference frame) Table content: Time (UTC), Time(OBT), Magnetic Field (Bx, By, Bz) [nT], Sensor Temperature [K], Quality FlagsLEVEL_B : Calibrated data in s/c-coordinates Table content: Time (UTC), Time(OBT), Magnetic Field (Bx, By, Bz) [nT], Sensor Temperature [K], Quality FlagsLEVEL_C : Calibrated data in CSEQ-coordinates Table content: Time (UTC), Time(OBT), Position (X,Y,Z) [km], Magnetic Field (Bx, By, Bz) [nT], Quality FlagsLEVEL Description, Housekeeping Data:LEVEL_A : Calibrated Housekeeping data in Physical units Table Content: Time (UTC), Time (OBT), Temperatures (IB,OB) [K], Stage_IDs (Flag A,Flag B), Filter Config Flag, Voltages (Mag_Ref (2.5V), Mag_Neg (-5V), Mag_Pos (+5V)) [V], Magnetic Field (OB-X,OB-Y,OB-Z) [nT] (Instrument coord.),LEVEL_B : No HK DataLEVEL_C : No HK DataGeometry Information - Coordinate System:The geometry items SC_SUN_POSITION_VECTOR SC_TARGET_POSITION_VECTOR SC_TARGET_VELOCITY_VECTORprovided in the label of the data product are relative to theECLIPJ2000 frame. This reference frame is built up by EclipticCoordinates related to Equinox of Epoch J2000.Orientation: X: Pointing from SUN to Vernal Equinox, Y: perpendicular to X in Ecliptic Plane, Z: Perpendicular to Ecliptic plane, pointing upThe items SUB_SPACECRAFT_LATITUDE SUB_SPACECRAFT_LONGITUDEare given in the PLANETOCENTRIC coordinate system.All these geometry parameters are computed at time t:START_TIME.Distances are given in km, angles in degrees.Version Information:The first version of RPCMAG datasets being archived for this cometphase and calibration level was V6.0.
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