Radiation Belt Storm Probes Ion Composition Experiment

(RBSPICE)

 

 

 

 

 

 

 

 

 

Science Operations Center (SOC)

RBSPICE Science Data Handbook

 

Revision: c

 

 

 

 

 

 

 

 

 

Written by

Jerry W. Manweiler, Ph.D.

and

Heather Mull

 

 

 

 

August 18, 2015

 

 

 

 

Lou Lanzerotti, RBSPICE Principal Investigator

Don Mitchell, RBSPICE Instrument Scientist

Jerry W. Manweiler, RBSPICE SOC Lead Engineer


 

Document Change Log

Date

Version Number

Reason for Change

September 18, 2013

 

Original Draft

January 29, 2014

Rev a

Added Field Name Descriptions Table for the Calibration Tables

February 28, 2014

Rev  b

Revised L3 pitch angle quality flags

August 18, 2015

Rev c

Added section for Pitch Angles and Pressures (PAP), and Table of Acronym Definitions

 


 

 

 

 

RBSPICE Data Handbook

1       Introduction. 5

1.1        Document Purpose. 5

1.2        Document Scope. 5

1.3        Applicable Documentation. 5

RBSPICE Instrument Paper. 5

2       Links to Data files, calibration tables and software. 5

2.1        RBSPICE A and B data files. 5

2.2        RBSPICE A and B calibration tables. 56

2.3        Software required and recommended to use RBSPICE data. 6

3       RBSPICE SOC Archive Data Products. 7

3.1        RBSPICE Data Categories. 7

3.2        RBSPICE Data Products Specification. 7

3.3        RBSPICE Data Product Production Specifications. 8

3.4        RBSPICE Data Products and related Instrument Data Modes. 9

3.5        RBSPICE Data Product Production Steps (High Level Overview) 11

3.6        RBSPICE Data Product Production Steps (Detailed Processing Algorithms) 12

3.6.1         Level 0 Processing Algorithms. 12

3.6.2         Level 1 Processing Algorithms. 17

3.6.3         Level 2 Processing Algorithms. 2019

3.6.4         Level 3 Processing Algorithms. 22

4       RBSPICE SOC Data Repository Directory Structure. 2623

4.1        Van Allen Probes MOC Data Directory structures. 2623

4.2        RBSP Spacecraft Data Organization. 2624

4.3        EMFSIS Data Organization. 2725

4.4        RBSPICE Data Organization. 2725

4.5        Product Directory Naming. 2826

5       Production Filename Convention. 2926

5.1        RBSP CDF Filenames. 2926

5.2        RBSPICE Specific File Name Conventions. 3128

5.3        RBSPICE Data Release Plans. 3229

5.3.1         Publicly Accessible RBSPICE Data. 3229

5.3.2         Release of data to NSSDC archive. 3229

5.3.3         Web Services Access. 3229

6       RBSPICE Data Product Field Descriptions. 3330

6.1        RBSPICE Level 1 Product Field Descriptions. 3330

6.2        RBSPICE Level 2 Product Field Descriptions. 4442

7       References. 6462

           


 

1                   Introduction

1.1            Document Purpose

This is the Data Analysis Handbook for the Van Allen Probes’ Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE).  This handbook is intended to guide RBSPICE data users in locating, identifying and understanding the content of the RBSPICE data files maintained by the RBSPICE Science Operations Center (SOC). As data products are added or changed, or other changes are made to the system for storing and accessing the RBSPICE data, this document will be updated accordingly.

1.2            Document Scope

This document contains lists, descriptions and/or explanations pertaining to the following RBSPICE data assets:

Data directory structure and file naming convention;

Data products produced and utilized by the RBSPICE SOC data processing system and data publication system;

Produced and published data products for the RBSPICE instrument aboard each Van Allen Probes satellite, A and B, which are available to the general public; and

Processes used to convert the data and generate data products according to specifications from Level 0 through Level 4.

 

Users who wish to work with either telemetry or commanding data or who have other questions not addressed in this document concerning data maintained by the RBSPICE SOC should contact RBSPICE SOC Lead Engineer Jerry W. Manweiler, Ph.D. at Manweiler@ftecs.com.

 

1.3            Applicable Documentation

Originally named the Radiation Belt Storm Probes (RBSP), the mission was re-named the Van Allen Probes, following successful launch and commissioning. For simplicity and continuity, the RBSP short-form has been retained for existing documentation, file naming, and data product identification purposes. The RBSPICE investigation including the RBSPICE Instrument SOC maintains compliance with requirements levied in all applicable mission control documents.

1.4            Acronym Definitions

[Insert table of data products, with acronyms,  and explain what the data products are and how they are used. Maybe organize the table by protons, non-protons, ions, etc.]

RBSPICE Instrument Paper

One key document that every user of the RBSPICE data should read is the RBSPICE Instrument Paper. The abstract can be found at http://link.springer.com/article/10.1007%2Fs11214-013-9965-x, along with a link to the full paper.

2                   Links to Data files, calibration tables and software

2.1            RBSPICE A and B data files

Publicly accessible data files for spacecraft A are found at http://rbspicea.ftecs.com.

 

Publicly accessible data files for spacecraft B are found at http://rbspiceb.ftecs.com.

 

 

 

2.2            RBSPICE A and B calibration tables

 

Calibration Tables – Field Name Descriptions

SC

Name of spacecraft either RBSPA or RBSPB

ProductType

One of the product types listed in the beginning of the cal file

Telescope

Identifies which of the six telescopes the cal information corresponds

StartUTC

The starting time for this calibration record in UTC string format (CCYY-MM-DDTHH:MM:SS:hhh)

StartET

The starting time for this calibration record in Ephemeris Time using the J2000 epoch

StopUTC

The ending time for this calibration record in UTC string format (CCYY-MM-DDTHH:MM:SS:hhh)

StopET

The ending time for this calibration record in Ephemeris Time using the J2000 epoch

Species

The primary species for which this calibration record is responsive – note that this does not identify all species that this channel will detect but the species that it is designed to detect, some channels are responsive to multiple species and depending upon the situation the primary species differs from time to time. E.g. TOFxPH products are generally responsive to protons but some of the channels are responsive to Oxygen or Helium although when those species are not present the channel will detect background proton rates

Channel

The energy channel number for this calibration record

E_Low

The bottom energy of the passband in MeV

E_High

The upper energy of the passband in MeV

E_Mid

The calculated midpoint energy of the passband in MeV. Note that this is not always the geometrical mean since some passbands are more sensitive to lower energies even though they allow for higher energy ranges

G_Small

The small pixel geometrical factor in cm^2*sr. See the RBSPICE Data Handbook for more information about pixel sizes

G_Large

The large pixel geometrical factor in cm^2*sr. See the RBSPICE Data Handbook for more information about pixel sizes

Eff

The efficiency of the energy channel.

Notes

Any specific notes about this energy channel.

 

 

Calibration tables for spacecraft A are found at http://rbspice.ftecs.com/RBSPICEA_Calibration.html.

 

Calibration tables for spacecraft B are found at http://rbspice.ftecs.com/RBSPICEB_Calibration.html.

 

2.3            Software required and recommended to use RBSPICE data

CDF Files

Access and use of the RBSPICE data requires the most recent version of NASA’s common data format (CDF) software, CDF V3.6.0, which supports the CDF_TIME_TT2000 variable and properly handles the new leapsecond added on June 30, 2015. This software is available for download at http://cdf.gsfc.nasa.gov.

 

CSV Files

CSV files can be opened with PKZip, which can be found at this website: http://www.pkware.com/software/pkzip.

 

Data visualization

MIDL is used and recommended by the RBSPICE team to visualize RBSPICE data. This software is available for download at http://sd-www.jhuapl.edu/rbspice/MIDL.

 

3                   RBSPICE SOC Archive Data Products

The RBSPICE SOC data system contains data products derived from other RBSP mission-related data sources, as well as that data which is produced by the RBSPICE SOC, both intermediary and final.  Organizationally this can be viewed as a collection of data categories, data product specifications, and data production specifications. Each of the following sections provides details of these organizational perspectives on the RBSPICE data.

3.1            RBSPICE Data Categories

Table 3‑3‑1Table 3‑3‑1 lists the various RBSPICE data categories representing the highest level perspective on the data that is to be contained by the RBSPICE SOC Data Repository system.  These categories do not necessarily represent a directory structure, but do drive the final structure presented in Section 4.

 

 

Table 3‑31 Top level list of RBSPICE Data Categories

Data Category

Data Source

Publication/Access Level

MOC Data Products – not instrument specific

MOC

RBSPICE team only

EMFISIS Mag Data Products

MOC/EMFISIS SOC

RBSPICE team only

RBSPICE Instrument Data (telemetry/Level 0)

MOC

RBSPICE team only

RBSPICE Level 1, 2, 3 Data

RBSPICE SOC

General Public

RBSPICE Level 3 PAP data

RBSPICE SOC

General Public

RBSPICE Level 4 Data – modeling data

RBSPICE Science Team

RBSP

RBSPICE Level 4 Data – results data

RBSPICE Science Team

General Public

RBSPICE Intermediate Data

RBSPICE SOC

RBSPICE SOC only

 

3.2            RBSPICE Data Products Specification

Table 3‑3‑2Table 3‑3‑2 lists the collection of data products contained in the RBSPICE SOC Data Repository that are specific to the RBSPICE Instrument measurements, as well as any other data elements required to process and understand/interpret the RBSPICE data.  The Level 0 data products are downloaded directly from the Mission Operations Center (MOC), stored locally within the RBSPICE SOC Data Repository, and used for production of the higher level data products. This table provides a high level characterization of the important variables defining the various data products and drives the final structure of the RBSPICE SOC Data Repository.

 

For a more complete discussion of each of the higher level data products and the controlling variables, see http://link.springer.com/article/10.1007%2Fs11214-013-9965-x for the abstract and a link to the full paper.

 

Table 3‑32 RBSPICE SOC Data Products  

Product

Species

Energy Bins

L0 Data Type

L1 Data Type

L2 Data Type

L3 Data Type

L4 Data Type

Ion Basic Rate

Ions

NA

Count

Rate

Electron Basic Rate

Electrons

NA

Count

Rate

Low Energy Resolution High Time Resolution Electron Species Rate1

Electrons

14

Count

Spectra

Spectra Flux

PAD, Aggregates

PSD, 2nd, 3rd Adiabat,

 

High Energy Resolution Low Time Resolution Electron Species Rate1

Electrons

64

Count

Spectra

Spectra Flux

PAD, Aggregates

PSD, 2nd, 3rd Adiabat,

 

High Energy Resolution Low Time Resolution Ion Species Rate1

Ions

64

Count

Spectra

Spectra Flux

PAD, Aggregates

PSD, 2nd, 3rd Adiabat,

 

High Energy Resolution Low Time Resolution TOFxPH Proton Rate

Protons

32

Count

Spectra

Spectra Flux

PAD, Aggregates

PSD, 2nd, 3rd Adiabat,

 

TOFxE Proton Rate

Protons

14

Count

Spectra

Spectra Flux

PAD, Aggregates

PSD, 2nd, 3rd Adiabat,

 

TOFxE non Proton Rate

Heavy Ions

28

Count

Spectra

Spectra Flux

PAD, Aggregates

PSD, 2nd, 3rd Adiabat,

 

Low Energy Resolution High Time Resolution TOFxPH Proton Rate

Protons

10

Count

Spectra

Spectra Flux

PAD, Aggregates

PSD, 2nd, 3rd Adiabat,

 

TOFxE Ion Species

Ions

64

Count

Spectra

Spectra Flux

PAD, Aggregates

PSD, 2nd, 3rd Adiabat,

 

Space Weather Rates

All

NA

Count

Rate

Flux

Ion Species Basic Rate

Ions

NA

Count

Rate

Priority Events

NA

NA

Event

Ion Energy Diagnostic Rate

Ions

NA

Count

Rate

Ion Species Diagnostic Rate

Ions

NA

Count

Rate

Raw Ion Species Events

Ions

NA

Event

Raw Electron Energy Events

Electrons

NA

Event

Raw Ion Energy Events

Ions

NA

Event

Auxiliary Data

NA

NA

Aux

Critical Housekeeping Data

NA

NA

HSK

Magnetometer Data and Pointing Information

Mag

Pitch Angles


1: Use of the term “species” in these products descriptions is misleading since these three data products utilize the energy collection mode of the RBSPICE instrument, rather than the species collection mode. See below for more details about which products use which instrument modes.

3.3            RBSPICE Data Product Production Specifications

Table 3‑3‑3Table 3‑3‑3 lists the various data products that exist within the RBSPICE SOC Data Repository and are either produced or used by the RBSPICE SOC Processing System and stored within the RBSPICE SOC Data Repository.  This table provides the critical variables that drive the final storage solution including the expected requirements on the final data volume. These requirements drive not only the size of the file system but also characterize the performance of the database where the data resides for quick access and use by the publication system.

 

Table 3‑33 RBSPICE SOC Data Product Production Specifications

Data Level

Product Title

Contents

Volume  

Format

Latency

Frequency

L0

Raw telemetry

Raw de-commutated telemetry received at RBSPICE-SOC

414 MB / day  - TBR

Binary

from Receipt (T0)

daily

 

 

L1

Count Rates

Sorted, time-tagged, instrument separated cts/sec

750 MB / day - TBR

ISTP Compliant CDF &
ASCII (CSV

T0­ + < 14 days

daily

L2

Calibrated Flux

Calibrated and corrected physical units

1200 MB / day - TBR

ISTP Compliant CDF &
ASCII (CSV

T0­ + < 1 month

daily

L3

Pitch Angle and Moments

Pitch angle distributions, plasma moments

1500 MB / day - TBR

ISTP Compliant CDF &
ASCII (CSV

T0­ + < 3 months*

daily

L4

Phase Space Density

PSD units, adiabatic invariants, mag coordinates

30 MB / day

ISTP Compliant CDF &
ASCII (CSV

T0 + < 1 year

daily

3.4            RBSPICE Data Products and related Instrument Data Modes

RBSPICE Flight Software spin-based sectoring is used to break each spin into 36 sectors.  The sectoring information is then used to drive the accumulation periods for each of the counting data products.  Table 3-4 identifies the various data products collected by the RBSPICE instrument on each spacecraft.  The accumulation time of each measurement is dependent upon the frequency strings shown in the table.  

 

The Frequency column uses the following key phrases:

As needed

This product is only produced at certain times and is not a regular product

On Demand

This product is only produced at certain times and is not a regular product

On Demand

This product is like the “On Demand” but has a 1 record per second default frequency

Commandable

The frequency of this product is configurable

Every Second

A record is produced every second the instrument is on

Every Spin

A record is produced once per spin

S Sectors

A record is produced every S sectors;
S is a configurable number in the flight software (fsw)

S*N1 Sectors

A record is produced every S*N1 sectors where S and N1 are configurable in the fsw

S*N1*N2 Sectors/Spins

Accumulation occurs over multiple spins for every S*N1*N2 sectors where the actual number of Spins and the values of S, N1, and N2 are all configurable in the fsw.

180 Seconds

A record is produced every 180 seconds.

 

The Mode column uses the following key phrases:

NA

Not Applicable to a data mode collection pattern

Ion Species

Data is collected using the Ion Species Instrument mode1

Ion Energy

Data is collected using the Ion Energy Instrument mode1

Electron Energy

Data is collected using the Electron Energy Instrument mode1

1 – See the instrument paper for a description of the various instrument modes.

 

Certain strings in the Product Names relate to the accumulation time and resolution of the energy spectra.  These strings are best interpreted as:

LEHT  

Low Energy Resolution High Time Resolution

HELT

High Energy Resolution Low Time Resolution

 

Table 3‑4 RBSPICE Data Products and Instrument Modes

APID

Product

ProductName

Frequency

Mode

301

Command Echo

Commands

As needed

NA

302

Alarm

Alarms

As needed

NA

303

Memory Checksum

MemoryChecksum

On Demand

NA

304

Memory Dump

MemoryDump

On Demand, 1/sec

NA

305

Status

Status

Commandable

NA

306

Boot Status

BootStatus

Commandable

NA

307

Macro Dump

MacroDump

On Demand, 1/sec

NA

308

Macro Checksums

MacroChecksums

On Demand

NA

309

Monitor Limits

MonitorLimits

On Demand

NA

30A

Parameters

Parameters

On Demand

NA

30B

Text

Text

On Demand

NA

30C

Pixel Parameters

PixelParameters

On Demand

NA

30D

NA

30E

NA

30F

NA

310

Critical Housekeeping

CHSK

Every Second

NA

311

Space Weather

SW

Every Spin

Ion Species

312

Electron Energy Basic Rates

EBR

S Sectors

Electron Energy

313

Ion Energy Basic Rates

IBR

S Sectors

Ion Energy

314

Ion Energy Diagnostic Rates

IEDR

S Sectors

Ion Energy

315

Ion Species Basic Rates

ISBR

S Sectors

Ion Species

316

Ion Species Diagnostic Rates

ISDR

S Sectors

Ion Species

317

LER-HTR Electron Spectra

ESRLEHT

S Sectors

Electron Energy

318

HER LTR Ion Spectra

ISRHELT

S*N1*N2 Sectors/Spins

Ion Energy

319

HER LTR Electron Spectra

ESRHELT

S*N1*N2 Sectors/Spins

Electron Energy

31A

TOFxEnergy Ion Energy Spectra

TOFxE_Ion

S*N1*N2 Sectors/Spins

Ion Species

31B

TOFxEnergy Proton Rates

TOFxE_H

S Sectors

Ion Species

31C

TOFxEnergy Non-Proton Rates

TOFxE_nonH

S*N1 Sectors

Ion Species

31D

LRHTR TOFxPH Proton Rates

TOFxPH_H_LEHT

S Sectors

Ion Species

31E

HRLTR TOFxPH Proton Rates

TOFxPH_H_HELT

S*N1*N2 Sectors/Spins

Ion Species

31F

Raw Electron Energy Events

REEE

S Sectors

Electron Energy

320

Raw Ion Energy Events

RIEE

S Sectors

Ion Energy

321

Raw Ion Species Events

RISE

S Sectors

Ion Species

322

Priority Events

Priority

S Sectors

Ion Species

323

Auxiliary

Aux

Every Spin

NA

324

ERM Data

ERM

180 seconds

NA

 

3.5            RBSPICE Data Product Production Steps (High Level Overview)

 

The RBSPICE automation system performs the following processing steps, in the order listed:

1)      Download Processing
Nightly, a set of download scripts is triggered to bring down data that require processing.

a.       SPICE Files

b.      Mission Operations Center (MOC) Telemetry Files

c.       EMFISIS Level 2 Magnetic Field Files

d.      ECT Level 2 Magnetic Ephemeris Files

 

2)      SPICE Processing
Key XML scripts are modified in this step to integrate new SPICE kernels into the overall system.

 

3)      MOC Data Organization
RBSPICE data downloaded from the MOC is moved to a final directory within the overall repository directory structure, based upon the APID of the data product. 

 

4)      Data Characterization
The system does a full file read to provide a detailed characterization of each file including the actual start and stop times of the data, the total number of records, and other relevant information.  This information is entered into a processing control database, which is the primary driver for subsequent data processing.

 

5)      Level 0 Processing – Daily Files in which each record start time occurs in the specified day/year
A Processing Script is read, identifying which Level 0 Data Products are to be produced.

a.       Telemetry data files for each product are then read.

b.      The data is extracted into the database.

c.       A Comma Separated Values (CSV) text-based Level 0 data file is produced.

d.      A Common Data Format (CDF) Level 0 data file is produced.

 

6)      Level 1 Processing
A Processing Script is read, identifying which Level 1 Data Products are to be produced.

a.       Counting data files for each product are then read.

b.      The counts for each record are then converted into a rate, in units of Counts/Second.

c.       A CSV text-based Level 1 data file is produced.

d.      A CDF Level 1 data file is produced.

7)      Level 2 Processing
A Processing Script is read, identifying which Level 2 Data Products are to be produced.

a.       Rate data files for each product are then read.

b.      The rates for each record are then converted, using the RBSPICE calibration data, into particle intensities (flux) in units of counts/(sec*sr*cm2*MeV).

c.       A CSV text-based Level 2 data file is produced.

d.      A CDF Level 2 data file is produced.

 

8)      Level 3 Processing
A Processing Script is read, identifying which Level 3 Data Products are to be produced.

a.       Intensity data files for each product are then read.

b.      The Magnetic Field data for the time frame is then loaded.

c.       The Magnetic Ephemeris data for the time frame is then loaded.

d.      Pitch Angles for each telescope look direction are calculated, using the SPICE system.

e.       A CDF Level 3 data file is produced.

 

9)      Level 3 Pitch Angle and Pressure (PAP) Processing
A Processing Script is read, identifying which Level 3 PAP Data Products are to be produced.

a.       Level 3 data files for each product are then read

b.      The intensity data is binned according to a specified pitch angle binning schema

c.       The aggregate data (pressures, density, omnidirectional flux, integrated flux) are calculated

d.      A CDF Level 3 PAP data file is produced

3.6            RBSPICE Data Product Production Steps (Detailed Processing Algorithms)

 

The RBSPICE SOC software system is comprised of a set of processing workflows (see previous section) in which the underlying software system triggers different processing code for each workflow.  The following sections detail the algorithms used in the creation of the Level 0 Count Files, the Level 1 Rate files, the Level 2 Intensity (flux) files, and the Level 3 Pitch Angle files.  Details presented for each of these steps are sufficient to allow other software developers to write their own translation workflow.  (Note that only the RBSPICE SOC data files are considered the Official release of the data, and any files produced by outside agents using these algorithms are considered unofficial even though they might be identical in content.)

3.6.1     Level 0 Processing Algorithms

Level 0 data is generated by directly decoding telemetry into binary data values.  The encoding is described completely in the RBPSICE Instrument Flight Software and needs no additional description. Specific aspects of the telemetry to Level 0 processing are explained below.

 

The data fields described are used throughout the various workflows to generate products for Level 0 through Level 3.

 

Timing values

Field Name

Type

Description

Allowed Values

SCLOCK

UInt32

The value of the SCLOCK at the beginning of the spin

0…4294967295

Fine SCLOCK

UInt16

The value of the RBSPICE high resolution clock at the beginning of the spin units of (1/216) seconds
One tick of the Fine SCLOCK value is equivalent to 15.25855624… microseconds

0…65535

Spin

UInt16

The current spin number as received from the SC in the 1 PPS signal

0…65535

Spin Duration

UInt32

The value of the spin period in milliseconds used by the RBSPICE flight SW in units of milliseconds

5000…20000

 

Accumulation Mode values – used in the calculation of accumulation duration to convert counts to rates (see below)

Field Name

Type

Description

Values

Integration Sectors –S

Byte

Number of sectors used in the RBSPICE fast accumulation mode

1-36

Integration Multiplier 1 – N1

Byte

Multiplication factor used to control the number of sectors accumulation in medium modes

1-36

Integration Multiplier 2 – N2

Byte

Multiplication factor used to control the number of sectors accumulated in slow modes

1-36

Integration Spin - SpinI

Byte

Number of spins to include in the slow accumulation mode

1-20

 

Pixel Size Values – used in the calculation of intensity (flux)

Field Name

Type

Description

Values

Electron Pixel - epixel

Bool

Identifies whether we are using the small pixel (0) or the large pixel (1) size in electron energy mode

0-1

Ion Energy Pixel - IEpixel

Bool

Identifies whether we are using the small pixel or the large pixel in ion energy mode

0-1

Ion Species Pixel - ISpixel

Bool

Identifies whether we are using the small pixel or the large pixel in ion species mode

0-1

 

 

Data Collection Pattern - used in the calculation of accumulation start/stop times and duration to convert counts to rates

Field Name

Type

Description

Values

Subsector 1 – DCP[0]

Byte

Identifies what accumulation mode is used in the first half of the sector
0=Electron Energy, 1=Ion Energy, 2=Ion Species

0-2

Subsector 2 – DCP[1]

Byte

Identifies what accumulation mode is used in the third quarter of the sector

0-2

Subsector3 – DCP[2]

Byte

Identifies what accumulation mode is used in the fourth quarter of the sector

0-2

 

Spin Data – used in the calculation of pitch angles

Field Name

Type

Description

Values

Spin Data Valid – validspin

Bool

Identifies if the spin value from the SC is valid or not, 0=invalid, 1=valid

0-1

Mag Data Valid - validmag

Bool

Identifies if the magnetic field value from SC is valid or not

0-1

Mag Phase Valid - validphase

Bool

Identifies if the magnetic field phase value from SC is valid or not

0-1

Time Stamp Generation

The telemetry product X323 (Auxiliary) is the only component of the received RBSPICE telemetry that provides the ability to create a high time resolution conversion from spacecraft clock (SCLOCK) plus the RBSPICE instrument internal timer (Fine SCLOCK), which is used for data accumulation in the counters, to ephemeris time (ET) representing the real time on a clock.  The X323 packets are generated by the RBSPICE instrument at the end of each spin. The packets include a time stamp derived from the timing information provided by the spacecraft in the “1 PPS (Pulse Per Spin) SC to Instrument” data packet.  The SCLOCK value cycles from 0 to 4294967295 and then repeats. The Fine SCLOCK value cycles from 0 to 65535 and is in units of (1/216) seconds. In general, each tick of the SCLOCK is approximately 1 second, although this relationship can drift depending upon the heating and cooling of the spacecraft.  The SCLOCK value is not a unique value, but repeats every 136.19 years.  Since the Van Allen Probes Mission is a nominal two-year mission, it is expected that the SCLOCK value never repeats over the life of the mission.  However, environmental factors could trigger a reset of the SCLOCK.

 

Because the Van Allen Probes spacecraft orbit through extreme radiation environments, it is expected that at some time a Single Event Upset (SEU) will occur, causing the SCLOCK to reset on one or both of the spacecraft.  One of the mission requirements assigned to the Mission Operations Center (MOC) is to ensure the SCLOCK value is unique and monotonic throughout the life of the mission, including extended mission phases, even in the event of an SEU.  The RBSPICE SOC has written the processing software with the assumption that the SCLOCK value provided to the RBSPICE instrument is unique and will never repeat.  When combined with the Fine SCLOCK value, the resulting time value provides RBSPICE scientists the ability to meet the 2-3 millisecond resolution requirement definition specified for inter-instrument calculations, as specified in the instrument requirement documents.

 

The X323 telemetry record time stamps are decoded by the RBSPICE SOC software system and the resulting SCLOCK and Fine SCLOCK values are converted into a time stamp using the following algorithm:

1. The Fine value is converted into seconds as fine*(1/216) and then converted into SPICE fine seconds (1/5x104) i.e. in units of 20 milliseconds per tick. 

2. The SCLOCK data value from telemetry along with the Fine SCLOCK value (see step 1) is converted into a timestamp by use of the JPL SPICE software system and the MOC-provided RBSP (A/B) SPICE SCLOCK kernels.  (Note that the SPICE system has a high resolution mapping kernel that relates SCLOCK values to ET, which is defined in the J2000 EPOCH.) 

3. The next step in the process is to get the ET value at the start of each sector.  The RBSPICE flight software divides a spin into 36 sectors. At the end of the spin, the spin duration value of the just finished spin is reported in the X323 telemetry record.  With the ET value (from step 2) of the start of the spin and the spin duration in milliseconds, it is possible to directly calculate the ET value at the start of each sector:





Most other telemetry packets received from the RBSPICE instrument contain the spin and sector numbers at the start of the telemetry packet, so that ET at the start of an accumulation can be easily calculated.

Duration of Measurement and Start/Stop Times

During the process of generating the timestamp for each measurement, the level 0 processing system also calculates the duration of each measurement.  This is not as simple as merely calculating the start time of each measurement and subtracting it from the start of the previous measurement since the RBSPICE instrument has three possible measurement modes which can be assigned to one of the three available subsector measurement time frames. 

To understand this fully, it is necessary to understand how the RBSPICE instrument takes measurements.  Each sector is divided into three subsectors. Subsector 0 spans the first half of the sector; subsector 1 spans the third quarter of the sector, and subsector 2 spans the fourth quarter of the sector. 

 

Figure 31 Sector and subsector scheme used by RBSPICE also showing inter-subsector dead times.

 

 

The RBSPICE instrument can be commanded to use one of the three measurement modes (electron energy, ion energy, and ion species) during each of the subsectors, providing the ability to simultaneously measure electrons and ions within a sector or, alternatively, to use a single type of measurement for higher resolution science. Also shown in the diagram is the instances of “dead time” which occur at the end of each subsector due to the instrument must reconfiguring itself for the next subsector. This portion of the subsector time must be subtracted from the overall time of the subsector to properly calculate the total duration of the measurement. The response of the RBSPICE electronics shows that a transition from subsector 2 to subsector 0 takes 4.04 milliseconds and a transition from subsector 0 to 1 or subsector 1 to 2 takes 3.95 milliseconds.

The key values required to properly calculate the measurement duration are found in the X323 telemetry packet (see above): Spin Duration (in seconds), Accumulation Mode Values (S, N1, N2, and Spin) and Data Collection Pattern (DCP).  For each time measurement, the timing system queries the Auxiliary data from the RBSPICE database for the current running value of each of these variables.  The timing system also identifies the type of data product being processed. By using the following table, the system understands the frequency of the measurement for the product and which DCP mode applies to the measurement.

 

Table 34 Data Collection Pattern and Frequency by APID

APID

Product

Product Name

Frequency

DCP mode

301

Command Echo

Commands

As needed

NA

302

Alarm

Alarms

As needed

NA

303

Memory Checksum

MemoryChecksum

On Demand

NA

304

Memory Dump

MemoryDump

On Demand, 1/sec

NA

305

Status

Status

Commandable

NA

306

Boot Status

BootStatus

Commandable

NA

307

Macro Dump

MacroDump

On Demand, 1/sec

NA

308

Macro Checksums

MacroChecksums

On Demand

NA

309

Monitor Limits

MonitorLimits

On Demand

NA

30A

Parameters

Parameters

On Demand

NA

30B

Text

Text

On Demand

NA

30C

Pixel Parameters

PixelParameters

On Demand

NA

30D

NA

30E

NA

30F

NA

310

Critical Housekeeping

CHSK

Every Second

NA

311

Space Weather

SW

Every Spin

Ion Species

312

Electron Energy Basic Rates

EBR

S Sectors

Electron Energy

313

Ion Energy Basic Rates

IBR

S Sectors

Ion Energy

314

Ion Energy Diagnostic Rates

IEDR

S Sectors

Ion Energy

315

Ion Species Basic Rates

ISBR

S Sectors

Ion Species

316

Ion Species Diagnostic Rates

ISDR

S Sectors

Ion Species

317

LER-HTR Electron Spectra

ESRLEHT

S Sectors

Electron Energy

318

HER LTR Ion Spectra

ISRHELT

S*N1*N2 Sectors/Spins

Ion Energy

319

HER LTR Electron Spectra

ESRHELT

S*N1*N2 Sectors/Spins

Electron Energy

31A

TOFxEnergy Ion Energy Spectra

TOFxE_Ion

S*N1*N2 Sectors/Spins

Ion Species

31B

TOFxEnergy Proton Rates

TOFxE_H

S Sectors

Ion Species

31C

TOFxEnergy Non-Proton Rates

TOFxE_nonH

S*N1 Sectors

Ion Species

31D

LRHTR TOFxPH Proton Rates

TOFxPH_H_LEHT

S Sectors

Ion Species

31E

HRLTR TOFxPH Proton Rates

TOFxPH_H_HELT

S*N1*N2 Sectors/Spins

Ion Species

31F

Raw Electron Energy Events

REEE

S Sectors

Electron Energy

320

Raw Ion Energy Events

RIEE

S Sectors

Ion Energy

321

Raw Ion Species Events

RISE

S Sectors

Ion Species

322

Priority Events

Priority

S Sectors

Ion Species

323

Auxiliary

Aux

Every Spin

NA

324

ERM Data

ERM

180 seconds

NA

 

The timing system calculates the duration of the measurement using the following algorithm:

1)      Use the current Spin Duration and calculate:

a.       Accumulation time of a sector – acc­sector

b.      Duration of Ό of a sector (or a subsector) - dursubsector

2)      Identify the Product Accumulation Factor (S, S*N1, S*N1*N2, S*N1*N2/Spins) from the above table

a.       Use the values of S, N1, N2, and SpinI to calculate the multiplication factor

                                                              i.      factor = S;

                                                            ii.      factor = S*N1; or

                                                          iii.      factor = S*N1*N2

b.      If this measurement is done over multiple spins, i.e. (S*N1*N2/Spins), then we also need to query the database for the spin duration of each spin included in the measurement so that the timing can be calculated as precisely as possible for each spin in the measurement, i.e. accsector and dursubsector are recalculated for each value of spin duration.

3)      For the current product, identify which subsectors (0, 1, or 2) are involved in this measurement for the DCP mode derived from the table.
Note that this measurement mode could be used in all possible combinations of subsectors (0, 1, and/or 2), but since we are working with a particular product with real data, there has to be at least one subsector involved (otherwise we wouldn’t have data for the product!)

4)      Create two variables to capture the durations:  

a.       AccumTime – to capture the total amount of sector/subsector time available in the measurement

b.      DeadTime – to capture the amount of dead time involved in the measurement

5)      For each spin that is involved in the measurement, calculate the sector and subsector times based upon the spin duration for each spin:

a.       For each DCP that is involved in the measurement

                                                              i.      Add the subsector time (sub0=2*dursubsector, sub1=dur­subsector, sub2=dursubsector) to the current AccumTime

                                                            ii.      Add the specific DeadTime to the DeadTime duration

1.      In going from subsector 2 to subsector 0, the DeadTime is 4.04 millseconds

2.      In going from subsector 0 to 1 or 1 to 2, the DeadTime is 3.95 milliseconds

6)      Calculate the duration of the measurement (Duration) as: (AccumTime – DeadTime)*factor for each spin.

7)      Calculate the start/stop time for the accumulation  

a.       The start time is the start of the accumulation at the start of the first subsector involved in the measurement.

b.      The stop time is the end time of the last subsector involved in the measurement.

                                                              i.      For products accumulated over a single spin, this becomes simply
endET = startET + duration + DeadTime; or endET = startET + AccumTime;

                                                            ii.      For products accumulated over multiple spins

1.      For the first spin, add in the time from the start of the measurement to the end of the last subsector of the last sector measured in that spin.

2.      For each subsequent spin (except the last), add in the total time of the spin.

3.      For the last spin, add in the time to go from the start of the spin to the end of the last subsector of the last sector of the measurement.

8)      Calculate the Midpoint time for the accumulation:

a.       For single spin measurements, this is startET + (endET-startET)/2

b.      For multiple spin measurements, this is a very complex problem since the midpoint from startET to endET would not necessarily occur in the middle of the sectors that are participating in the accumulation.
This can be seen most clearly in the following table in which we are starting our accumulation in sector 0 and accumulating over 4 sectors and 10 spins, i.e. S = 1, N1 = 2, N2 = 2, and SpinI = 10.  The sectors involved in the measurement are identified in the table as green with two white squares in the middle; the location of the start and end times are obvious.  The red square outside the actual accumulation time is the false midpoint time taken as simply the startET + (endET – startET)/2, showing that this algorithm does not work correctly.  The actual midpoint time is shown in the middle of the two white squares and is based upon the correct calculation of the midpoint time. This table (and others) were used to generate an algorithm to properly calculate what the actual midpoint of the measurement is, based upon the starting sector, the number of sectors involved, and the number of spins involved.

 

Table 35 Sample multi-spin accumulation showing the false (red) and true (white) midpoint times of the accumulation.

Start ET

SpinDur

Sector

SubSec

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

410270537.6

10.884

0.302333333

0.075583333

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

410270548.4

10.883

0.302305556

0.075576389

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

410270559.3

10.882

0.302277778

0.075569444

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

410270570.2

10.882

0.302277778

0.075569444

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

410270581.1

10.883

0.302305556

0.075576389

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

410270592

10.882

0.302277778

0.075569444

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

410270602.9

10.882

0.302277778

0.075569444

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

410270613.7

10.882

0.302277778

0.075569444

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

410270624.6

10.883

0.302305556

0.075576389

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

410270635.5

10.883

0.302305556

0.075576389

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

RBSPICE Status Control information

The telemetry product X305 (Status) includes a small number of values that are necessary to one or more of the workflows as the data is processed from Level 0 to Level 3. These fields are described below:

Field Name

SoftName

Description

Values

TOFxPH Deprecation

TOFxPH

Identifies how the TOFxPH events are collected:
0-disabled (TOFxPH isn’t used)
1-Enable All
2-Enable 1 of 2 (i.e. collect 1 out of every 2)
3-Enable 1 of 4
4-Enable 1 of 8
5-Enable 1 of 16
6-Enable 1 of 32
7-Enable 1 of 64

0-7

 

RBSPICE Basic Rate Information (EBR, IBR, and ISBR)

There are three telemetry products related to collection of basic rate statistics that are critical in processing RBSPICE data from Level 0 to Level 1, and are part of the Rin versus R­out algorithms described in the Level 1 Processing Algorithms section (3.6.2).

 

The fields from each of these three telemetry products are as follows:

 

Electron Basic Rates (X312) and Ion Energy Basic Rates (X313) – Ancillary Data Values

Field Name

SoftName

Description

Units

Type

Values

SSD Counters

SSD[0..5]

Counts events above the SSD energy threshold for each telescope

Counts

UINT32[6]

SSD Dead Time

SSDDead[0..5]

Integrates the amount of dead time in each SSD for each telescope

100ns

UINT32[6]

State Machine Idle

SMI

Event State Machine Idle Time

100ns

UINT32

Multiple Hit Reject

MHR

Counts number of events rejected due to simultaneous energy channel events

Counts

UINT32

Valid Energy Events

VEE

Counts the number of valid energy events

Counts

UINT32

Valid Events Queued

VEQ

Counts the number of valid energy events placed in the FIFO

Counts

UINT32

Valid Events Processed

VEP

Counts the number of valid energy events processed by the flight software

Counts

UINT32

 

 

Ion Species Basic Rates (X315) – Ancillary Data Values

Field Name

SoftName

Description

Units

Type

Values

Start 0 Anode

Start0

Counts the number of events above the start0 anode threshold

Counts

UINT32

Stop 0 Anode

Stop0

Counts the number of events above the stop0 anode threshold

Counts

UINT32

TOF Coincidence

TOF

Counts the number of events where the start and stop are within the 200ns window

Counts

UINT32

Pulse Height

PH

Counts the number of events above the TOF pulse height threshold

Counts

UINT32

Start Counters

Start[0..5]

Counts the number of events calculated to be at the given start position per telescope

Counts

UINT32

SSD Counters

SSD[0..5]

Counts the number of events above the SSD threshold

Counts

UINT32[6]

SSD Dead Time

SSDDead[0..5]

Integrates the amount of dead time in each SSD for each telescope

100ns

UINT32[6]

State  Machine Idle

SMI

Event State Machine Idle Time

100ns

UINT32

Multiple Hit Reject

MHR

Counts the number of events rejected due to simultaneous energy channel events

Counts

UINT32

Valid TOFxPH Events

TOFxPH

Counts the number of valid TOFxPH events

Counts

UINT32

Valid TOFxE Events

TOFxE

Counts the number of valid TOFxE events

Counts

UINT32

Valid Events Queued

VEQ

Counts the number of valid energy events placed in the FIFO

Counts

UINT32

Valid Events Processed

VEP

Counts the number of valid energy events processed by the flight software

Counts

UINT32

 

3.6.2     Level 1 Processing Algorithms

The primary activity in processing the Level 0 data into Level 1 data is to convert the count data into rate data.  This is done in a series of algorithmic steps in which the Level 0 count data is read into memory, the duration of the measurement is loaded from the Level 0 file, the counts themselves are adjusted according to the Rin vs Rout algorithm, and the rate data is then written to a Level 1 file.  The following constants and variables are used throughout the subsequent sections:

Name

Description

Type

Value(s)

MaxIDLE

Maximum number of 100ns intervals for which data can be accumulated

UInt32

969938

ClkPeriod

Number of nanoseconds in the RBSPICE DPU clock period

UInt32

100

STDead

Start counter dead time due to synchronization logic

UInt32

2

SPDead

Stop counter dead time due to synchronization logic

UInt32

2

SPVeto

Interval in which additional stop pulses cause the event to be discarded

UInt32

2

RDTVeto

Interval for inhibiting start and stop counter during chip TOF reset

UInt32

1

PKDReset

Interval for resetting the peak detector

UInt32

4

PURVeto

Interval during which a second SSD pulse causes the event to be discarded

UInt32

7

 

Rin vs Rout Algorithm and Formulae

Basic Rates

EBR (X312), IBR(X313), and ISBR(X315) telemetry includes the measured counts (SSD) and dead time (SSDDead) for each telescope. These values are converted to a rate value using the following algorithm:

For each telescope (where “tele” goes from 0 to 5)



 

Energy Rates

Conversion of the counts obtained for the ESRLEHT(X317), ISRHELT(X318), and ESRHELT(X319) telemetry is somewhat more complicated, because the algorithm requires an understanding of the spin information (X323) and the basic rate data (EBR for ESRLEHT and ESRHELT, IBR for ISRHELT) to fully convert the count data into a rate. For purposes of this algorithm, the count values in the telemetry are called hij, where i refers to the telescope number and j refers to the energy channel of the measurement.  Following is the algorithm used in the RBSPICE SOC software for each telescope and each energy channel:

1)      If the count is zero, return a rate of 0.0

2)      Identify the number of sectors involved in the measurement, based upon the frequency of the product (S, S*N1, S*N1*N2/Spins) – for an example see table 3-5.

3)      Calculate the default rate as:

4)      If the measurement spans a single spin
Get the basic rate energy data object (erd) for the current SCLOCK, Spin, and Sector

5)      If the measurement spans multiple spins
Get a conglomerate basic rate energy data object (erd) for the current SCLOCK, Spin, and Sector for each involved spin

6)      If erd = null, return the defaultrate (i.e. we cannot do R vs R correction without the basic rate data)
(Note that there are some scenarios in which this is possible, but they are extremely rare.)

7)      Get the following variables from the erd object:
vee = valid energy events
vep = valid events processed
idle = state machine idle
ssd = basic count for the current telescope
ssddead = basic count dead time for the current telescope

8)      Calculate the basic rate, brate, (see section above) using the values returned in the erd object

9)      Calculate each of the following terms (cipkdreset and cipurveto) using the following formula:


This algorithm can produce rates that are smaller than the default rate at somewhat low counting times.  The SOC software tests for this condition and returns the default rate if the calculated rate is smaller. Note that the SOC software has conditions on the level of failure built into the processing, such that if the percent error of the calculated rate versus the default rate (in an error condition) is significantly high, then a particular file will fail so that more investigation can be made to better understand the situation.  Eventually the file will be allowed to succeed, once it has been understood and recognized that no significant processing issue is involved.

 

Species TOFxPH Rates

The conversion of the species mode TOFxPH measurements for products TOFxPHHLEHT (X31D) and TOFxPHHHELT (X31E) follows a similar algorithm as discussed for the calculation of Energy Rates (see above).  The key difference is in the values used from the Ion Species Basic Rate data object (erd) and the formulas of step 9:

7)      Get the following variables from the erd object:
vtofxe = valid TOFxE events
vtofxph = valid TOFxPH events
vep = valid events processed
idle = state machine idle
ssd = basic count for the current telescope
ssddead = basic count dead time for the current telescope
stop0 = number of events above the Stop 0 threshold

9)      Calculate each of the following terms (efact)



 

Species TOFxE Rates

The conversion of the species mode TOFxE measurements for products TOFxEIon (X31A), TOFxEH (X31B), and TOFxEnonH (X31C) follows a similar algorithm as discussed above for Energy Rates and Species TOFxPH rates (see above). Again the key difference is what values are acquired in Step 7 and the formula in Step 9.

7)      Get the following variables from the erd object:
vtofxe = valid TOFxE events
vtofxph = valid TOFxPH events
vep = valid events processed
idle = state machine idle
ssd = basic count for the current telescope
ssddead = basic count dead time for the current telescope
stop0 = number of events above the Stop 0 threshold

9)      Calculate each of the following terms (efact)





 

Error Calculations for Rate Files

As counts are converted into rates, the Level 1 files capture the statistical Poisson error so that the information can be used in understanding and calculating the error propagation for scientific publications.  The errors placed in the Level 1 files are done for each telescope and energy channel measured.  Given a count, n, the calculated values are the percent error calculated as:

3.6.3     Level 2 Processing Algorithms

The primary activity in processing the Level 1 data into Level 2 data is to convert the rate data into particle intensity (flux) data.  This is done in a series of algorithmic steps in which the Level 1 rate data is read into memory, the calibration data for the SC and product are loaded, the intensities are calculated, and the intensities are then written to a Level 2 file.  Additional fields are added to the Level 2 file to match the Panel on Radiation Belt Environmental Modeling (PRBEM) standards for such data.  See http://craterre.onecert.fr//prbem/home.html for a complete specification of this standard. Note that the Level 2 files do not include all required variables to meet the PRBEM standard, but instead those variables are added to the files to create the Level 3 final data products.

Conversion of Field Names into PRBEM standards

The PRBEM standards require all variables to fit specific field name guidelines.  The RBSPICE SOC team has made every effort to utilize these guidelines.  The Level 1 rate files contain variables of rate data with a CSV common name of T#_R where # represents the telescope, and a CDF common name of T#_Rates.  The Level 2 PRBEM standard requires a variable that is species-specific, so the standard Intensity (Flux) variables contained in the Level 2 files are of the standard for F?DU, where “?” is a character representing the species of the variable. The individual characters have the following meaning:

 

Character

Interpretation

RBPSICE Values

F

Represents an Intensity or Flux

 

?

Identifies the Species

I=Ion, H=Proton(Hydrogen), He=Helium, O=Oxygen, E=Electron

D

Identifies that the intensities are Differential in energy

 

U

Identifies that the intensities are unidirectional and not omni-directional

 

It should be noted that several RBSPICE products contain multiple intensity variables, because some of the products energy channels are responsive to different species of particles.  While the variable names match the PRBEM standard, the variable sizes do not.  When creating the intensity variables, it was prudent to create a two-dimensional array that contains the intensity for each telescope and channel combination. Energy channels that are NOT responsive to the particular species are written with a fill value in the CDF files and an empty field value in the CSV files.

Calculation of Intensities (Flux)

RBSPICE calibration data can be found at the following locations:
http://rbspice.ftecs.com/RBSPICEA_Calibration.html and http://rbspice.ftecs.com/RBSPICEB_Calibration.html.

The data is organized by product type and contains the necessary information needed to convert RBSPICE rate data into intensity (flux) data.  The calibration data fields are described in the following table.

 

Name

Description

Type

Units

Values

SC

Identifies the SC for this record

String

NA

RBSPA or RBSPB

Product Type

Identifies the applicable product

String

NA

ESRHELT, ISRHELT, ESRLEHT, TOFxEIon, TOFxEH, TOFxEnonH, TOFxPHHHELT, and TOFxPHHLEHT

Telescope

Allows the values to vary per telescope as the instrument starts degrading

Integer

NA

0 … 5

StartUTC

Identifies when this calibration record is applicable

String

Time

Standard format of CCYY-MM-DDTHH:MM:SS.hhh

StartET

Identifies the Ephemeris Time when this record is applicable

Real

Seconds

315576066.183925 … 788961666.183928

StopUTC

Identifies when ending time when this record is applicable

String

Time

Standard format of CCYY-MM-DDTHH:MM:SS.hhh

StopET

Identifies the ending ET when this record is applicable

Real

Seconds

315576066.183925 … 788961666.183928

Species

Identifies the primary species of the measurement

String

NA

e=electron, Ion(Ions)=ion, H=proton, P=proton,
He=Helium, O=Oxygen, X=not used

Channel

Energy channel

Integer

NA

0 … total number of energy channels – 1

E_Low

Low end of the energy passband

Real

MeV

 

E_High

High end of the energy passband

Real

MeV

 

E_Mid

Midpoint of the energy passband

Real

MeV

 

G_Small

Geometrical factor when the small pixels are used (See X323 data)

Real

cm2

 

G_Large

Geometrical factor when the large pixels are used (See X323 data)

Real

cm2

 

Eff

Efficiency of the passband

Real

NA

 

Notes

Relevant information about channel

String

NA

 

 

Rates are converted into Intensities using the following equation:

 

The specific value used of the geometrical factor, G, is based upon the current pixel value (small or large) contained in the X323 auxiliary data packet (see Level 0 processing for more information).  The final CDF variable that is created to contain the intensities is a two-dimensional variable of type Real and sized as F?DU[tele,ch] so that it contains the data for each telescope and channel combination.

Additional Variables Added to Level 2 Data

A number of additional variables are added to the Level 2 data file during conversion.  The following paragraphs and tables describe these variables and how they are calculated. Note the following notations: Real[ch] indicates a Real array with a size equivalent to the number of energy channels, Real[tl] indicates a Real array with a size equivalent to the number of telescopes, and Real[tl,ch] indicates a Real two-dimensional array with a size equivalent to the number of telescopes and energy channels.

Field

Description

Type

Units

Limits

Algorithm

L

Value of the McElwain L Shell for a Dipole Field

Real

RE

0.0 to 10.0

Position_SM

Position of SC in Solar Magnetospheric Coordinates

Real[3]

RE

-10.0 to 10.0

SPICE

F?DU_Error

The Poisson statistical percent error (see Level 1 error)

Real[tl,ch]

%

0.0 to 100.0

F?DU_Crosscalib_RMS

This variable is not used in the Level 2 files but exists for consistency with the PRBEM standards.  Once inter-instrument calibration is finished this variable might be used to contain that information

Real[tl,ch]

NA

 

 

F?DU_Energy

Midpoint energy for each energy channel

Real[tl,ch]

MeV

0.01 to 10

 

F?DU_Energy_Range

The high and low energy values for the Channel
Note that this variable does NOT follow the standard which asks for the delta low and high values

Real[tl,2,ch]

MeV

0.01 to 10

 

FEDU_Quality

The data quality flag using the PRBEM standard.
Note that currently the automation system only sets the value to 10 which is that the quality is unknown.  As algorithms are developed to clarify the quality of the data this value will be changed.

Integer[tl,ch]

NA

0 to 10

 

Inter-Instrument Calibration

The RBSPICE energy measurements have been cross-calibrated with the MagEIS and HOPE energy measurements for similar energy channels.  These calibration activities have resulted in adjustments to the efficiencies in the calibration table. At some time in the future the details of these calibration activities will be presented in this section.

RBSPICE Background

The current data files produced by the RBSPICE SOC are NOT background corrected for contamination due to energetic electrons and cosmic rays.  At some time in the future this section will be completed with steps that describe the process required to background correct the RBSPICE intensity data.

3.6.4     Level 3 Processing Algorithms

The primary activity in processing the Level 2 data into Level 3 data is to calculate the pitch angles of the six telescopes, based upon the measured magnetic field received from the EMFISIS instrument.  This processing is done in a series of algorithmic steps in which the EMFISIS magnetic field data is loaded, the ECT Magnetic Ephemeris data is loaded, the Level 2 intensity data file is copied, and the pitch angles are calculated and placed into the copied Level 2 file, creating a Level 3 file.  Additional fields are added to the Level 3 file to fulfill the full standards of the PRBEM for such data.  See http://craterre.onecert.fr//prbem/home.html for a complete specification of this standard.

Note that the Level 3 files are only created as CDF files.  It was determined that the number of fields in the Level 2 CSV files was becoming excessive and that the additional fields added to the Level 3 files would make this even more cumbersome.  The RBSPICE SOC can provide a CSV equivalent file for a small specific set of days, if a scientist does not have software to read-in the CDF files. These queries should be emailed to the RBSPICE SOC Lead.

EMFISIS Magnetic Field Data

The Level 2 UVW EMFISIS 60 hertz magnetic field data files were chosen to be used to calculate the RBSPICE pitch angles.  These files contain data sampled at 60 Hz, so contain around 5 million samples per data file.  In order to reduce the overall memory utilization and to reduce the overall processing requirements, these files were deprecated by a specific programmable number before being used to calculate Pitch Angles. .  Currently the deprecation is set at a factor of 8.  There is no filtering used during the deprecation stage of loading the magnetic field data into the database, but instead every 8th value was included.

ECT Magnetic Ephemeris Data

Some of the additional fields included in the RBSPICE Level 3 CDF files have data taken directly from the ECT Magnetic Ephemeris data files.  The definitive Olsen Pfitzer 1977 quiet time files were used in this processing. The data fields chosen from these files are deemed relevant to understanding the RBSPICE energetic particle data.

Calculation of Pitch Angles

The pitch angle calculation uses the following algorithms in the order listed:

1)      Verify that magnetic field data and magnetic ephemeris data exist; otherwise fail processing.

2)      Verify that SPICE C-Kernels are available for the time frame to be processed.

3)      For each record of the Level 2 intensity variable, do the following:

a.       Get spin segment that applies to this record

                                                              i.      This recognizes data products that accumulate over multiple spins

b.      Create an array of start and stop times based upon the accumulation sectors for each spin involved and the available magnetic field data, i.e. this is start/stop for the actual B vectors, not for the accumulation time point.

c.       Get a set of magnetic field vectors for each time point contained in the time segments defined in b.

d.      Calculate the look direction for each telescope and each time point contained in the time segments defined in b.

e.       Calculate a pitch angle for each look direction/magnetic field vector combination

f.       Average all pitch angles to get a final pitch angle representative of the accumulation for this measurement

g.       Set the pitch angle quality flag, as follows:

                                                              i.      Quality = 0 (good)

                                                            ii.      Quality = 1 (bad – poorly defined virtual spin period)

                                                          iii.      Quality = 2 (bad – no magnetic field data available)

h.      Set the minimum and maximum pitch angle values from the list of pitch angles as calculated above.
Note that the pitch angle range data is written in the F?DU_AlphaRange variable for each species in the file.

i.        Write the pitch angle data, as well as the other new variables for this measurement

Additional Level 3 Variables

A number of additional variables are added to the Level 3 data file while the pitch angles are being calculated.  The following paragraphs and tables describe these variables and how they are calculated. Note the following notations: Real[ch] indicates a Real array with a size equivalent to the number of energy channels, Real[tl] indicates a Real array with a size equivalent to the number of telescopes, and Real[tl,ch] indicates a Real two-dimensional array with a size equivalent to the number of telescopes and energy channels.

Field

Description

Type

Units

Limits

Algorithm

Position

Position of SC in GSE coordinates

Real

RE

-10.0 to 10.0

SPICE

Position_GSM

Position of SC in GSM Coordinates

Real[3]

RE

-10.0 to 10.0

SPICE

Position Quality

PRBEM position quality flag, 0=good, 1=bad

Integer

NA

0 to 1

Always 0

Alpha