ROSETTA ROMAP DATA CALIBRATION DESCRIPTION
===========================================================================


Revisions                                                                       
---------

2009-04-20   first issue, xxx
                        
Purpose                                                                         
-------                                                                        
This document describes the  calibration of the ROMAP-MAG and ROAMP-SPM data
delivered in the ROMAP level 3 data set.                       

ROMAP-MAG calibration
=====================

Introduction
-------------
There are 2 kinds of calibrations applied to the ROMAP-MAG raw data:

1) Preliminary calibrated magnetometer data  (draft aligned and very 
draft offset corrected). 

2) Final calibration (cleaned from offset and spacecraft disturbances, 
done by TU-BS using RPC data). Only some selected data intervals are
provided to PSA during cruise.

The cleaning procedure consists of the following steps:
 Disturbances which can de identified as lander supply current related
    are removed first. Only stepwise switched currents can be removed. The
    step height is determined as good as possible, Step times are determined
    and a function with constant bias fields between step times is created
    which is subtracted from the original data.
 High frequent disturbances are identified by evaluation of dynamic
    spectra. If significant high frequent disturbances can be identified
    (during cruise in always due to reaction wheels) data are filtered
    down to 1Hz data (0.5Hz corner frequency)
 Interferences due to orbiter sources are determined by comparison of 
    RPC-MAG and ROMAP data. If signals occurs at both sensors with different
    signal amplitude (can be seen in difference) the ratio is determined, 
    the disturbance signal is scaled for both sensors and the scaled signals
    are subtracted from the data.
 Finally the offsets are determined with best effort. For that a solar wind
    analysis is used. For flybys solar wind data before and after are needed
    to interpolate the offset during flyby.


Only final level 3 data, no intermediate products or correction functions
are archived. Level 3 data are only produced for selected time intervals
(e.g. Mars flyby, Steins flyby).


Preliminary calibration (level 3 A, B and C)
-----------------------------------------------
The preliminary calibration is used during cruise phase when sensorhead
 boom is stowed.

The calibration parameters are the rotation matrix (from ROMAP sensor 
system to Lander system and Orbiter system) and the offset vector.
The offset vector is generally time dependent. However, unless otherwise 
specified, a constant offset vector is used.
In the level 3 data the disturbances due to MUPUS instrument are not removed.

Level 3 A 
---------
Calibration in ROMAP system (R). Boom stowed.
 
 (BRx_cal)   ( 1   0   0 )   (BRx +  700 )
 (BRy_cal) = ( 0   1   0 ) . (BRy + 1400 )
 (BRz_cal)   ( 0   0   1 )   (BRz - 1100 )

where
   BR_cal is the calibrated magnetic field vector in the ROMAP system.
   BR is the raw magnetic field vector in the ROMAP system.

The unit for BL, BR, BR_cal and offset is nT.

Level 3 B 
---------
Calibration in the Lander system (L). Boom stowed.

 (BLx_cal)   (  0   0.33569  -0.94197 )   (BRx + 700 )
 (BLy_cal) = (  1      0         0    ) . (BRy + 1400 )
 (BLz_cal)   (  0   0.94197   0.33569 )   (BRz - 1100 )

Calibration in the Lander system (L). Boom deployed.

 (BLx_cal)   (  0   1   0 )   (BRx - 38 )
 (BLy_cal) = (  1   0   0 ) . (BRy - 102 )
 (BLz_cal)   (  0   0   1 )   (BRz - 102 )

where
  BL_cal is the calibrated magnetic field vector in the Lander system  
  BR is the raw magnetic field vector in the ROMAP (sensor) system :

The unit for BL, BR, BL_cal and offset is nT.


Level 3 C 
---------

Calibration in the S/C (Orbiter) system. Boom stowed.

 The calibrated magnetic field vector in the Orbiter system (BO) 
is given by the following transformation of the magnetic field 
vector in the ROMAP  system (BR):
 
            (  0  -0.3357  0.942 )   
 Bs/c_cal = ( -1      0        0 ) . (BR - Boffset)
            (  0   0.942  0.3357 )   

Calibration in the S/C (Orbiter) system. Boom deployed.

 (BLx_cal)   (  0   -1   0 )   (BRx - 38 )
 (BLy_cal) = (  -1   0   0 ) . (BRy - 102 )
 (BLz_cal)   (  0    0   1 )   (BRz - 102 )

where 
   Bs/c_cal is the calibrated magnetic field vector in the S/C system
   BR is the raw magnetic field vector in the ROMAP (sensor) system
   Boffset is the offset vector in ROMAP system.

The unit for BR, Bs/c_cal and Boffset is nT.

The offsets used for converting data from 
CODMAC level 2 to CODMAC level 3 (C type files in ROMAP notation) and the 
corresponding data products are listed below.

Mars phase:

MAG_FSC_060829181608_00087 
MAG_FSC_061128162210_00088  
         ( -900)
Boffset= (-1400)
-1050

MAG_FSC_061206010011_00009  
MAG_FSC_061206011057_00018  
MAG_FSC_061206013312_00009
MAG_FSC_061206014352_00018    
         ( -900)
Boffset= (-1440)
-1070

MAG_FSC_061206070011_00009  
MAG_FSC_061206071051_00018  
MAG_FSC_061206073311_00077  
         ( -895)
Boffset= (-1435)
-1066
 
MAG_FSC_061207030011_00029  
MAG_FSC_061207033312_00697  
         ( -885)
Boffset= (-1405)
-1054
 
MAG_FSC_061208000208_00121  
MAG_FSC_061208034806_00039
MAG_FSC_070224010108_02212 
MAG_FSC_070522142206_00121  
         ( -900)
Boffset= (-1400)
-1050
 
Steins phase:

MAG_FSC_080904183821_02039
         ( -550)
Boffset= (-1800)
-1200

Post Hibernation phase and Pre Delivery Calibration Science:

For all data
         ( -800)
Boffset= (-1500)
-1000
The achieved data quality is level 4 (>100nT)


except for

MAG_FSC_140417025012
         ( -876)
Boffset= (-1481)
-953
MAG_FSC_140714030507
         ( -778)
Boffset= (-1440)
-955
MAG_FSC_140908005005
         ( -810)
Boffset= (-1550)
-1010
MAG_FSC_140915131506
          ( -810)
Boffset= (-1550)
-1010
MAG_FSC_140925055006
         ( -810)
Boffset= (-1550)
-1010
MAG_FSC_141006204506
         ( -800)
Boffset= (-1550)
-1010
MAG_FSC_141016211506
         ( -800)
Boffset= (-1550)
-1010
for all sequences with specific offsets the achieved data quality is level 3 (<100nT)


Separation/Descent/Landing and Rebounds:

all
-38
Boffset= ( 102)
-102
The achieved data quality until boom deployment at 08:56:30 is level 4 (>100nT)and later level 2 (<10nT)
 




Level 3 D 
---------

Calibration in the ECLIPJ2000 system. Boom stowed.

The magnetic field vectors are transformed from orbiter
system (level 3 C) to the ECLIPJ2000 reference frame. 
The rotation matrix is time dependent.


Final calibration (level 5 E, F and G)
--------------------------------------

All level 5 data have a quality level of 1 (<5nT)


Level 5 E
---------
 Final calibrated  data, in physical units, cleaned from offset
 and spacecraft disturbances, in MAG (magnetometer) coordinates

Level 5 F
---------
 Final calibrated SC data, in physical units, cleaned from offset
 and spacecraft disturbances, in Lander coordinates

Level 5 G
---------
 Final calibrated SC data, in physical units, cleaned from offset
 and spacecraft disturbances, in S/C coordinates

Level 5 H 
---------
 Final calibrated SC data, in physical units, cleaned from offset
 and spacecraft disturbances, in ECLIPJ2000 coordinates.


ROMAP-SPM calibration
=====================

Introduction
-------------
The level 3 calibration consists of:
#NOM?
- conversion of Faraday cup currents in nA, 
#NOM?
#NOM?

The ion currents are left in ADC units (signed 16 integers) since the CEM amplifications are not yet clear.

Energy and angle conversion
---------------------------
The energy tables and the correspondences between step numbers and energy and between step numbers and angle (elevation) are given in the following tables. 

Correspondence between step number and elevation:  
Step No        0    1   2   3   4   5   6   7  8  9  10  11  12  13  14  15
Ion1/2 (deg)  -52 -47 -41 -34 -27 -21 -16 -11 -6  0   5  10  15  20  25  31

Correspondence between step number and energy:
"Step No ""64""    0     1     2     3       4       5       6       7       8     9    10    11"
"Step No ""32""          0           1               2               3             4           5"
Ion1/2 (eV)   38.6  42.6  46.6  50.6    54.6    59.9    65.3    70.6    77.3  83.9  90.6  98.6
Electron (eV) 0.35  0.42  0.49  0.56    0.63     0.7    0.84    0.98    1.12   1.3  1.47  1.75

"Step No ""64""    12    13    14    15   16     17    18    19    20    21     22    23"
"Step No ""32""           6           7           8           9          10           11"
Ion1/2 (eV)    107   117   127   138   150   163   178   194   211   230    250   271
Electron (eV) 2.03  2.38  2.74  3.16  3.72  4.28  4.98  5.82  6.73  7.79   9.05  10.5

"Step No ""64""    24    25    26    27  28     29    30    31   32     33   34     35"
"Step No ""32""          12          13         14          15          16          17"
Ion1/2 (eV)    295   321   350   381  414   450   490   533   580   640  700    760
Electron (eV) 12.3  14.2  16.5  19.2  22.3  25.9  30.1 34.9  41.0  47.4  54.7  63.1

"Step No ""64""    36    37    38    39     40    41    42    43    44    45    46    47"
"Step No ""32""          18          19           20          21          22          23"
Ion1/2 (eV)    820   900   980  1060   1160  1260  1360  1480  1620  1760  1920  2080
Electron (eV) 73.7  86.3   100   116    135   156   181   211   245   284   330   383

"Step No ""64""    48    49    50    51    52    53    54    55    56   57     58    59"
"Step No ""32""          24          25          26          27         28           29"
Ion1/2 (eV)   2260  2460  2680  2920  3180  3460  3760  4080  4440  4820  5260  5720
Electron (eV)  445   517   600   695   810   937  1095  1274  1474  1716  1989  2316

"Step No ""64""     60    61    62    63"
"Step No ""32""           30          31"
Ion1/2 (eV)    6220  6760  7360  8000
Electron (eV)  2684  3115  3621  4210

"Step No ""64""                 0     1    2     3     4     5    6     7      8     9"
"Step No ""32""                       0          1           2          3            4"
"Far.Cup -""Ions"" (eV)      10.7  12.7   15  17.6  20.8  24.6  29.2  34.6  40.8  48.6"
"Far.Cup -""Electrons"" (eV)    1     2"

"Step No ""64""           10     11    12    13   14   15   16   17    18    19"
"Step No ""32""                   5           6         7         8           9"
"Far.Cup -""Ions"" (eV)  57.6  67.8  80.2  95.2  113  133  160  190   224   264"

"Step No ""64""           20   21   22   23    24   25    26     27   28     29"
"Step No ""32""                10        11         12           13          14"
"Far.Cup -""Ions"" (eV)  314  370  440  520   614  730   864   1020  1204  1430"

"Step No ""64""            30    31"
"Step No ""32""                  15"
"Far.Cup -""Ions"" (eV)  1690  2000"

Conversion of ion energy and angle distributions (ion 1 and ion 2)
------------------------------------------------------------------

 N[particles/cm-2/s]= C/S/T

Where
  C represent the counts (read from telemetry).
  S is the ion detector surface:
     ion1: 0.08 cm-2
     ion2: 0.1 cm-2
  T is the exposition time (read from the header of the ROMAP TM packets)
     short: 0.04 s
     long:  0.2 s


Conversion of Faraday cup currents
----------------------------------

The currents are given by the Ohm law, I=U/R, where

 R = 5.1e9 Ohm
" U is given by the ADC; the ADC input range is [-2 V, 2 V] and the output resolution is 16 bits."

Thus, the following transfer function is applied:

" R = 5.1e9 Ohm;"
 U = (4.0/65535.0)*Itm -2.0,  where Itm is the raw current (read from telemetry, i.e. ADC output)  
" Ifc [nA] = (U/R)*1e9;   "
