ROSETTA SESAME-DIM DATA CALIBRATION DESCRIPTION
=================================================
                        
Revisions
---------

2015-06-22   0.1 first draft
2015-07-06   release 1.0

Purpose
-------

This document describes the calibration of the SESAME-DIM flight data 
retrieved during comet phase operations and delivered in the SESAME-DIM 
level 3 data set. 

The bit operations 'AND' and 'bitshift' are indicated with '&' and '>>'
or '<<', respectively. When writing integer numbers in based notation,
the method specified in para. 12.3.1.2 of the Planetar Data System
Standards Reference (JPL D-7669, Part 2, version 3.8, Febr. 27, 2009) was
followed. Dimensions are shown in <> brackets.
 

Introduction
============

The calibration of SESAME-DIM data is divided into 3 different groups:

1) Healthcheck data from DIM Healthcheck
2) DIM Burst Continuous measurements on one sensor face
3) DIM Burst Continuous test mode 2 measurements on one sensor face

The description of the calibration of the common SESAME Healthcheck data 
is included in a common SESAME calibration description file.
Error codes are summarized in the last section of the calibration
description file. Error codes might be combined.


1) Healthcheck data
   =================
The DIM Healthcheck (HC)  data are organized as tables corresponding to 
different modes: Power Check, Noise Test, Sensor Test and Calibration. 
===========================================================================
DIM Power Check (DIM_PC)
Packet type ID: 3000
Byte-No Meaning         Calibration function                    Comment
---------------------------------------------------------------------------
16,17   +5V             IF (x & 16384) >> 14 == 1       Voltage on +5V line
                                (x & 4095)*(-1) <mV>    bit 0-12: abs value
                        ELSE    x & 4095 <mV>           bit 14: sign bit
18,19   -5V             IF (x & 16384) >> 14 == 1       Voltage on -5V line
                                (x & 4095)*(-1) <mV>    bit 0-12: abs value
                        ELSE    x & 4095 <mV>           bit 14: sign bit
20      Error Code      N/A                             see the last
                                                        section

DIM Noise Test (DIM_NT)
Packet type ID: 3100
Byte-No Meaning         Calibration function                    Comment
---------------------------------------------------------------------------
16      Margin          x <dB>                          Margin rounded to 
                                                        multiples of 10 dB 
                                                        for which no
                                                        amplifier noise was
                                                        measured
17      Error Code      N/A                             see the last
                                                        section

DIM Sensor Test (DIM_ST)
Packet type ID: 3202
Byte-No Meaning         Calibration function                    Comment
---------------------------------------------------------------------------
16      Direction/      (x & 224)/32                    IF 2#100#: X dir.
                                                        IF 2#010#: Y dir.
                                                        IF 2#001#: Z dir. 
        Margin          (x & 7)*10 <dB>                 Margin rounded to 
                                                        multiples of 10 dB
17      Error Code      N/A                             see the last
                                                        section
20,21   Average signal  x <mV>
22,23   Peak Voltage    x <mV>
24,25   Impact time     x/20 <microsec>
26      Average Sample  x <dB>
27      Peak Voltage dB x <dB>                        
28      Impact time dB  x <dB>

DIM Calibration (DIM_CA)
Packet type ID: 3302
Byte-No Meaning         Calibration function                    Comment
---------------------------------------------------------------------------
16      Low Margin      x <dB>                          Margin rounded to 
                                                        multiples of 10 dB
17      High Margin     x <dB>                          Margin rounded to 
                                                        multiples of 10 dB
next data block (the following items between 'begin data block' and 'end
data block' may occur up to 8 times)
begin data block
+3      Margin          x <dB>                          Margin rounded to 
                                                        multiples of 10 dB
+4      Level           N/A                             IF 2#00# = Low
                                                        IF 2#FF# = High
+5,+6   Timer Count     x
+7,+8   Peak Voltage    x <mV>
+9      Time dB         x <dB>
+10     Peak Voltage dB x <dB>
+11     Error Code      N/A                             see the last
                                                        section
end data block
+1,+2   Total error     N/A                             errors are summed
                                                        over all trials, 
                                                        see also the last
                                                        section


2) DIM Burst Continuous measurements
   =================================
---------------------------------------------------------------------------
Single events on one sensor face are registered in Burst Continuous Mode.
Measured values (peak amplitude U and impact duration T) are stored in a
compressed way. First they are scaled to 1 <= U[dB] <= 83 dB and
10 <= T[dB] <= 70. The counts for events with a particular (U[db], T[db])
combination are stored in memory cells of different sizes depending on the
expected frequency of such events. The resulting matrix of packed counts
has a fixed size of 3585 byte (independent of the actual number of events).
Note: the ranges of U[dB] and T[dB] and thus the size of the (U, Tc)-matrix
have been reduced starting with flight software version FM-2. Additionally
average samples can be measured. Note: The instrument is not sensitive for
single impacts while averaging. Each Burst Continuous Mode starts with a 10
seconds instrument warm-up period, which is not included in the measuring
time (the warm-up period is skipped when Burst Continuous is executed as
part of the DIM Autonomous Mode).
Packet type ID: 3606
Byte-No Meaning         Calibration function                    Comment
---------------------------------------------------------------------------
16      Direction       N/A                             Echoed Command
                                                        Parameter:
                                                        IF 2#00#: X dir.
                                                        IF 2#01#: Y dir.
                                                        IF 2#10#: Z dir. 
17      Margin          x <dB>                          Margin rounded to 
                                                        multiples of 10 dB
                                                        (Echoed Command
                                                        Parameter)
18      Energy Control  N/A                             00, 01, 02 (Echoed
                                                        Command Parameter)
19      Signal Dec.Time x <ms>                          Echoed Command 
                                                        Parameter
20,21   Sampling Intrv. x <s>                           Echoed Command
                                                        Parameter
22,23   Meas. Time      x <s>                           Echoed Command
                                                        Parameter
26,27   Det.events #    x
28,29   False events #  x
30,31   Long events #   x
32,33   nSamp           x                               Number of Average
                                                        Samples
the next one item occurs 'nSamp' times
+1      Average Sample  x <dB>
+1..+4  Time end        N/A                             SESAME Local Time
                                                        at end of measuring
                                                        period; first two 
                                                        bytes: high word;
                                                        last two bytes: low
                                                        word
+5      Error Code      N/A                             see the last
                                                        section

+1..    220 event         x (2 bytes)                         order of
..+440  counts                                          (U[dB],T[dB] pairs)
                                                        0<U[dB]<21 and
                                                        9<T[dB]<21;
                                                        (1,10),(2,10),
                                                        (3,10),...,(19,20),
                                                        (20,20)
+441..  400 event       x (1 byte)                         order of
..+840  counts                                          (U[dB],T[dB] pairs)
                                                        0<U[dB]<21 and
                                                        20<T[dB]<41
                                                        (1,21),(2,21),
                                                        (3,21),...,(19,40),
                                                        (20,40)
+841..  620 event       x (1 byte)                      order of
..+1460 counts                                          (U[dB],T[dB] pairs)
                                                        20<U[dB]<41 and
                                                        9<T[dB]<41
                                                        (21,10),(22,10),
                                                        (23,10),...,
                                                        ...,(39,40),(40,40)
+1461.. 1200 event      x&15 (odd U)                    order of
..2060  counts          (x&240)/16 (even U)             (U[dB],T[dB] pairs)
                                                        0<U[dB]<41 and 
                                                        40<T[dB]<71
                                                        (1,41),(2,41),
                                                        (3,41),...,(39,70),
                                                        (40,70)
                                                        lower nibble:
                                                        odd U[dB] value
                                                        higher nibble:
                                                        even U[dB] value
+2061.. 3050 event      x&15 (odd U)                    order of
..3585  counts          (x&240)/16 (even U)             (U[dB],T[dB] pairs)
                                                        40<U[dB]<91 and
                                                        9<T[dB]<71
                                                        (41,10),(42,10),
                                                        (43,10),...,
                                                        ...,(89,70),(90,70)
                                                        lower nibble:
                                                        odd U[dB] value
                                                        higher nibble:
                                                        even U[dB] value


3) DIM Burst Continuous test mode 2 measurements
   =============================================
Burst Continuous Test Mode (DIM_BCTEST2) delivers for each single impact
U[mV], U[dB], TC, Tc[dB] and  deviating from DIM_BCTEST of earlier flight
software versions  additionally the Lander Onboard Time (LOBT), when the
impact was registered. The LOBT is determined directly after the event was
accepted as a real impact. With flight software FM-3 a limit of 350 real 
events (impacts) is imposed.
Packet type ID: 3E06
Byte-No Meaning         Calibration function                    Comment
---------------------------------------------------------------------------
16      Direction       N/A                             Echoed Command
                                                        Parameter:
                                                        IF 2#00#: X dir.
                                                        IF 2#01#: Y dir.
                                                        IF 2#10#: Z dir. 
17      Margin          x <dB>                          Margin rounded to 
                                                        multiples of 10 dB
                                                        (Echoed Command
                                                        Parameter)
18      Energy Control  N/A                             00, 01, 02 (Echoed
                                                        Command Parameter)
19      Signal Dec.Time x <ms>                          Echoed Command 
                                                        Parameter
20,21   Sampling Intrv. x <s>                           Echoed Command
                                                        Parameter; not used
22,23   Meas. Time      x <s>                           Echoed Command
                                                        Parameter
26,27   nevent          x                               Number of events
                                                        detected
28,29   False events #  x
30,31   Long events #   x
32,33   nSamp           x                               Number of Average
                                                        Samples
next data block (the following items between 'begin data block' and 'end
data block') occur MIN('nevent', 350) times
begin data block
+1..+4  Event time      N/A                             SESAME Local Time
                                                        at the time of the
                                                        event; first two
                                                        bytes: high word;
                                                        last two bytes:
                                                        low word
+5,+6   Timer Count     x
+7,+8   Peak Amplitude  x <mV>
+9      Timer           x <dB>
+10     Peak Amplitude  x <dB>
end data block
+1..+4  Time end        N/A                             SESAME Local Time 
                                                        at end of measuring
                                                        period; first two 
                                                        bytes: high word;
                                                        last two bytes:
                                                        low word
+5      Error Code      N/A                             see the last
                                                        section


Error codes (might be combined)
===============================
16#01#  EB_OVERCURR     Over-current interrupt detected; warning.
16#02#  EB_NOISY_AMP    DIM_NT: Noise level higher than limit (70 dB);
                        warning.
16#02#  EB_NO_AD_RDY    Error using ADC of C-DPU. Delivered digital value
                        is invalid; warning.
16#04#  EB_NO_PULSE     DIM_ST: No pulse detected but expected; warning.
16#04#  EB_BAD_HEALTH   DIM_PC: Voltage out of limits +- [4.5, 5.5] V;
                        measurement aborted; fatal.
16#08#  EB_LONG_T       Long pulse measured (DIM_CAL, DIM_ST, DIM_BC);
                        warning.
16#10#  EB_BAD_CAL_LOW  Calibration (low level) failed (U not in the range
                        33 to 49 dB or T not in the range 20 to 60 dB);
                        warning.
16#10#  EB_NOISY_TEST   DIM_ST: Average sample exceeds limit (> 20 dB);
                        warning.
16#20#  EB_BAD_CAL_HI   Calibration (high level) failed (U not in the range
                        71 to 83 dB or T not in the range 40 to 70 dB);
                        warning.
16#20#  EB_BAD_TEST     DIM_ST: Peak voltage and signal length out of range
                        (not in the range 40 to 70 dB); warning.
16#40#  EB_MEM_FULL     Allocated SESAME RAM memory space exhausted.
                        Aborted; fatal.
16#80#  EB_OC_PWROFF    Excessive INT4 (over-current) interrupts; DIM
                        instrument switched off; fatal.