1. Cluster Active Archive – Wideband data BM2 mode
K.H. Yearby, M.A. Balikhin
University of Sheffield
J.S. Pickett, University of Iowa

2. Experiment description
The WBD instrument was designed and built at the University of Iowa.
The digital wideband receiver design provides continuous single axis waveform capture in selected frequency bands up to 577 kHz at sampling rates from ~27 to 220 kHz.
The higher frequency measurements (125 kHz and higher) are obtained via frequency conversion.
Signal inputs are obtained from the electric field (EFW) and magnetic field (STAFF) WEC sensors.
In the BM2 mode the WBD data are acquired via DWP and stored on the spacecraft solid state recorder. The bit rate is reduced by a factor of 3 or 4 (from 220 kbps to 73 kbps or 55 kbps) in DWP, by digital filtering or duty cycling.
The lower bit rate allows EFW and STAFF to operate in burst mode – otherwise they are in normal mode.
The original implementation of the BM2 mode in DWP was not expected to be used and had several limitations (eg. can’t be used with Whisper, poor timing accuracy, non-optimised filter, gain and status information only available in HK telemetry).
These have been overcome using both onboard software patches and innovative ground data processing.

3. BM2 data processing pipeline
Raw data
FN FB GA LA WH WB
Sheffield software
Iowa software
TCOR data
FGM-PEACE
TED
FGM PSDS
WBD-DSD
Decommutated science data
FGM-ROTATION
MK-BM-FILES
Ephemeris
Level one data
CDF archive burst
L1 data
SPEC PLOTTER
GIF PLOTTER
Overviewplots
GIF plots
Archive data
CDF files

4. BM2 data processing software
TED – basic telemetry extraction and decommutation (U. Sheff.)
WBD-DSD – reformats science data into standard 1090 byte packets, computes accurate data sampling times, assigns gains and status to correct packets (U. Sheff.)
MK-BM-FILES – reformats header (meta data) into Iowa ‘level one’ format (U. Iowa)
FGM-PEACE – generates 5 vps FGM Processing Support Data Set (TU Braunschweig)
FGM-ROTATION – uses FGM PSDS to calculate WBD antenna angles relative to B field and GSE axes (U. Iowa)
Ephemeris – database of spacecraft position information (U. Iowa)
GIF PLOTTER – produces high resolution plots covering 30 seconds and 10 minutes for individual spacecraft (U. Iowa)
SPEC PLOTTER – produces overview plots covering the full duration of each observation, and all spacecraft (U. Iowa)
CDF archive burst – produces calibrated waveform data as CDF files (U. Iowa)
Two panel plotter – plots the archive (CDF) and ‘level one’ data together so any differences may be identified (U. Iowa)
Angle plotter – plots the angle information from the CDF files (U. Iowa)
Check BM2 CDF – extracts and plots summary information on CDF packet sizes, timing and angles (U. Sheff.)

5. Software status
All the U. Iowa software is now installed and working at Sheffield.
This has required porting from Sun to Mac platforms.
Normally this was achieved with only minor bug fixes, usually array bounds problems, and the change in the size of the ‘long’ type from 4 to 8 bytes.
Further changes were however needed to the CDF archiving and validation processes, handling special cases not apparent in earlier test data. Eg.:
Noisy antenna angle data in a small number of cases (high B field regions, and when B field aligned with spin axis). The WBD waveform data were not effected.
Part of data frames spanning hour boundaries were missing.
Problems processing observations that span date boundaries.
The Ephemeris database is installed, but not the software process to update it. As the identical database is also used at Prague, it was agreed that Sheffield could update their database by mirroring the Prague copy.
An attempt was made to install the CAA software to convert CDF files to CEF. However we could not make this work, so it was agreed that for now we will deliver CDF files and the CAA will convert them.

6. Data processing status
The ‘level one’ data is processed monthly, usually soon after the TCOR data for that month is available.
‘level one’ data for January to June 2015 are processed and validated (earlier years processed at Iowa).
The GIF Plots and Overview Plots are processed as part of the validation process for the ‘level one’ data, and are also processed for January to June 2015 (earlier years processed at Iowa, and online at CSA).
The CDF archive data are processed and validated for January to May 2015.
Earlier years CDF data are not processed, except for one test from 2001.

7. Data delivery status
Some delays gaining access to WBD drop zone at CAA, but working now after resetting password.
CDF archive data for January 2015 delivered (one observation on ).
CDF data for February to May 2015 are ready to be delivered as soon as we have confirmation that January has been ingested with no problems.
Overview plots and GIF plots for January to June 2015 ready for delivery.

8. Future plans Short term activities.
Deliver the overview and GIF plots for January to June 2015.
Deliver the CDF data for February to May 2015.
Process and validate ‘level one’ data for July 2015 onwards, and deliver the associated overview and GIF plots.
Process, validate and deliver CDF data for June 2015 onwards.
Medium term activities.
Process, validate and deliver CDF data for previous years.