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.The data have been measured during the EXTENDED MISSION PHASE 3 (EXT3)of ROSETTA. Included are the following sub-phases:MTP0031 STP0115 from 2016-06-28T23:25 to 2016-07-05T23:25MTP0031 STP0116 from 2016-07-05T23:25 to 2016-07-12T23:25MTP0031 STP0117 from 2016-07-12T23:25 to 2016-07-19T23:25MTP0031 STP0118 from 2016-07-19T23:25 to 2016-07-26T23:25MTP0032 STP0119 from 2016-07-26T23:25 to 2016-08-02T23:25MTP0032 STP0120 from 2016-08-02T23:25 to 2016-08-09T23:25MTP0033 STP0121 from 2016-08-09T23:25 to 2016-08-15T06:40MTP0033 STP0122 from 2016-08-15T06:40 to 2016-08-21T06:40MTP0033 STP0123 from 2016-08-21T06:40 to 2016-08-30T06:40MTP0033 STP0124 from 2016-08-30T06:40 to 2016-09-02T06:40MTP0034 STP0125 from 2016-09-02T06:40 to 2016-09-05T06:40MTP0034 STP0126 from 2016-09-05T06:40 to 2016-09-11T06:40MTP0034 STP0127 from 2016-09-11T06:40 to 2016-09-20T06:40MTP0034 STP0128 from 2016-09-20T06:40 to 2016-09-26T06:40MTP0035 STP0129 from 2016-09-26T06:40 to 2016-09-29T19:30MTP0035 STP0130 from 2016-09-29T19:30 to 2016-09-30T10:39All magnetic field data are calibrated, resampled data. That means thedata represent the 3 components of the magnetic field measured inphysical units (nT). Calibration has been applied according to theGround calibration results which means:- temperature dependent offset calibration- temperature dependent sensitivity calibration- temperature dependent misalignment calibrationData are given in different coordinates, dependent on the calibrationLEVEL. LEVEL_F : averaged data in s/c-coordinates Source of these data are LEVEL_B data.Bad vectors have been removed. Any s/c caused residual magnetic fieldsare not eliminated. The ground temperature model for the sensorcalibration has been improved (expanded for a wider temperature rangedown to - 130 deg C) using long term temperature model obtainedfrom flight data.The data are sorted by the sensor (OB: outboard sensor, IB: inboardsensor)and the measurement mode (M1..M6) and average interval (A,where n denotes the average interval in seconds). Data can uniquely beidentified by their file names.Averaging means calculating a mean value of of the specified intervalin time domain. It does not mean any mixing of data from the OB and IBsensor.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 RESAMPLED averaged data (CLF,CLG) are codedas follows: ___A.RPCMAG yymmdd CLF IB A60 LBL CLG OB TABExample: RPCMAG040528_CLG_OB_A20.LBL RPCMAG040528_CLG_OB_A20.TABAverage denotes the time interval for one average period in seconds.The filenames for RESAMPLED Heater or Reaction Wheel influenced data(CLH) are coded as follows: ___.RPCMAG yymmddThhmm CLH IB M1..M6 LBL OB TABExample: RPCMAG040528T1230_CLH_OB_M3.LBL RPCMAG040528T1230_CLH_OB_M3.TABLEVEL Description, Science Data:LEVEL_F : Calibrated data in s/c-coordinates Table content: Time (UTC), Time(OBT), Magnetic Field (Bx, By, Bz) [nT], Sensor Temperature [K], Quality FlagsGeometry 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 actual version of this dataset is V6.0, the first being archived.
|
CITATION_DESCRIPTION |
Glassmeier K.-H., Richter I., Koenders C., Goetz C., Eichelberger. H, Cupido E., ROSETTA-ORBITER 67P RPCMAG 4 EXT3 RESAMPLED V6.0, RO-C-RPCMAG-4-EXT3-RESAMPLED-V6.0, ESA Planetary Science Archive and NASA Planetary Data System, 2016
|