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Overview of the L1B Dataset, Product Baselines updates and data availability.L2 Commissioning Status.

Giuseppe Ottavianelli, Ivan Di Lodovico, Igino Coco, Antonio De La Fuente, Christian Siemes, Riccardo Mecozzi and the ESL teams.

Swarm – 4th Data Quality WorkshopSession 1

2nd-5th December 2014, GFZ Potsdam

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NEWS are published on :

https://earth.esa.int/swarm

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Dataset and Product Baseline (1/3)

The term Dataset represents a series of products presenting physical consistency and interoperability.

On the FTP:

The 'Current' folder contains the latest Dataset (composed of the applicable Product Baselines).

The 'Previous' folder contains two previous Product Baselines. This folder does not assure interoperability. Therefore in order to correctly select past interoperable Product Baselines, users should refer to the past Dataset webpage.

CDF format filename example:

SW_OPER_STRCATT_1B_20140218T000000_20140218T235959_0301_MDR_SAT_AT.cdf

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Previous folder with Dataset history

Current Dataset

Dataset and Product Baseline (2/3)

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Dataset and Product Baseline (3/3)

https://earth.esa.int/web/guest/swarm/data-access/dataset-history

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Improved L1b data: timeline

1. Improved Operational processor delivered on 28th November 2014

2. Internal PDGS testing currently on-going

3. New processor operational in mid-January 2015.

…the details of recent changes, upcoming delivery and long term changes :

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ORBATT PROCESSOR

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Recent ORBATT changes

Following the QWG recommendations:

1.Starting from the 23rd October 2014, the L1b chain is processing data with an updated version of the ORBATT processor and related CCDBs. These changes affect the GPSR L1b products and consists in:

a. Deactivating of antenna and receiver corrections.

b. Deactivating of the carrier smoothing algorithm that uses carrier range observations to smooth code range observations.

No significant impact on the MOD and POD products but changes are motivated by the user wish to access GPS observations that are closer to the original measurements.

2.On-board changes:

a. All Swarm satellites deliver since 15 July 2014 all GPSR data at a 1 Hz rate.

b. The GPSR antenna field-of-view has been increased from 80 to 83 degrees on all three satellites (22nd October 2014). (…more in ACC/GPS splinter)

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ORBATT next delivery improvements

1. MOD vs NAV (on-board) solutions: Cumulative errors in some of the MOD products are corrected (due to wrong NAPEOS configurations leading to a large number of GPSR observations being rejected).

2. Correct L1b absolute orbit number (i.e. orbit start – orbit end) computed in the L1b product header (this is applicable to all products).

3. Modified input constraints for attitude computation.The conditions for considering attitudes samples for combination are relaxed:a. The Sequence flag is no longer checked– implying that attitudes computed

on-board the spacecraft using the lost-in-space algorithm are used on equal terms as others.

b. Attitudes with BBO (“big bright object”) flag set are also considered when the difference of the inter-boresight angle(s) (IBA) between the individual CHU’s and the nominal IBA designated by CCDB.Structure.STR_q_CHU ids is within a certain threshold.

This change improves in particular attitudes based on a single camera head unit (CHU) since the number of such events will decrease with the proposed algorithm.

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ORBATT Possible future changes

Long term analysis of the STR inter-boresight angles (IBA) reveals a possible small temperature dependency of the IBA.

Models of this effect will be analysed and tested and the analysis findings may result in an update of the STR Level 1b processing algorithm using the STR temperature information and additional CCDB parameters.

Image from Peter S. Jørgensen presentation

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MAGNET PROCESSOR

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• Improvements in the next delivery :

i. dF_AOCS and dF_Other

ii. Corrections in dB_AOCS of ASM and VFM

iii. Corrections in TCF estimation

iv. Corrections in MAG_HR to MAG_LR sample reduction

v. MAG_L and H Platform flag

vi. VFM reference frame Vectorial Magnetic Field (B_VFM Errors)

MAGNET next delivery improvements

1.The cross-verification process has been finalised.

All variables are now fully aligned to the Prototype processors results.

• A minor difference in the q_NEC_CRF computation is still under investigation. This leads to a spurious discrepancy in the MAG_L.B_NEC computation (occurrance around 1%), considered as acceptable by the ESL.

2.Fix to handle the missing ASM data scenario (e.g. currently Swarm Charlie satellite missing ASM from 06 November 2014).

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MAGNET Long term updates

Long term:

• The OP/PP cross-verification efforts will be continued and any further improvement will be implemented.

• The current cubic B-spline interpolation for UTC exact computation on both OP and PP is not fully adequate when rapid changes of the magnetic field intensity occurs. Alternative methods of interpolation should be considered in the future.

• Based on the investigation results on the ASM-VFM residuals modifications might be included in the L1B.

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ACCELE PROCESSOR

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1. These sign issues are solved with the next processor version :

• Linear and angular acceleration are not in the Common Reference Frame : the x and z components have the wrong sign.

• The sign of acceleration-correction for the gravity gradient effect, a_GG, is reversed.

• The sign of acceleration-correction for the centrifugal effect, a_centr, is reversed

2.Moreover the scale factor (“SF”) of the element “p” of ACCx_PR_1B has been changed in order to enable nm resolution of the proof mass position information.

ACCELE next delivery improvements

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Instrument characterisation ongoing.

Depending on results, there is a possibility to actually follow a completely differ approach for the ACC data processing:

a. implement an “off-line” consolidation step (SIL) and only after distribute the data

b. Implement a L2 dedicated chain

ACCELE Long term updates

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PLASMA PROCESSOR

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PLASMA OP Status

1. LP:

• Cross-verification succesfull.

• Detected [0,0,0] positions and velocities in the PP, which affect the calculation of the correction to the S/C potential due to the plasma induced electric field. – source of minor discrepancies (0.06 V)

2. TII:

• Instrument characterisation on-going.

IRF and Un. of Calgary are using “sandboxes” of the prototype processors.

• Key improvements are achieved.

• Instead of distributing operational data, it was decided to prepare and distribute a “provisional” dataset based on the “sandboxes”.

• Such dataset has been made available by ESA to the Cal/Val and expert users on 18th November 2014.

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• Separate datasets for the Langmuir Probes derived parameters (plasma density, elec. temp., S/C potential) and TII derived parameters (ion velocity and temp., electric field).

• LP: daily ASCII files (.txt), EFIx_LP_1B file type, covering from EFI BOL up to mid-November 2014 for all S/C. Bi-weekly updates. Provided by Swedish Institute for Space Physics, Uppsala (IRF).

• TII: daily CDF files, EFIx_TII1B file type, currently covering about one month of data, for S/C A, between April and May 2014. Periodical updates are foreseen, data selection has to be done very carefully in order to discard periods affected by TII image anomaly. Provided by University of Calgary.

• Available at ftp://swarm-diss.eo.esa.int path: “/External/Provisional_Plasma_dataset”. Release notes and README files are also available for basic information about data content, quality and format. For more detailed information, please refer to data providers.

PLASMA Preliminary Dataset

Possibility to open the data to complete user community.

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Level 2

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Level 2 Cat-2 (integrated in PDGS)

1. ESL and ESA performed extended product validation and cross-verification that led to improvements on both the PP and OP.

2. Finalised all Product Description document.

3. OP delivery on 28th November 2014.

Processors will be uploaded on operational platform after L1B upgrade and L2 Cat-2 data will be available in mid-January 2015.

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Level 2 Cat-1 (distributed chains)

1. L2 Commissioning has been successfully initiated and go-ahead for the delivery of products has been released (on best effort basis: POD, MMA, QL)

2. L2 processing of several products has been postponed pending refinement of the L1b data quality

3. Schedule has been updated to reflect this delay, resulting in a six months shift of “1st year delivery”

4. Following deliveries depend on upcoming L1b-related decisions

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NEWS are published on :

https://earth.esa.int/swarm

MAKE IT YOUR HOME PAGE!:-)

…ALSO ON YOUR SMARTPHONE!

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Thank you