Status of Delta-DOR interoperability Colorado Springs April 20 th , - - PowerPoint PPT Presentation

Status of Delta-DOR interoperability

Colorado Springs April 20th, 2009 Mattia Mercolino E SA/ E SOC,

Summary

Results of ESA ΔDOR support to Hayabusa ESA-JAXA ΔDOR tracking on VEX Status and plans of ESA enhanced Wideband ΔDOR for

future supports to JPL

ESA-JPL wideband ΔDOR interoperability testing Way forward to ESA possible ΔDOR support to MSL

Results of ESA ΔDOR support to Hayabusa

Hayabusa observations (1)

Acquisitions: 2 acquisitions of Hayabusa were made during 2008 During the first tracking there were problems in DSN

antenna pointing for the uplink of ranging tones to the S/C, therefore only quasar and carrier signal were acquired

The second tracking was successful Data translation: JAXA translated some sample of quasar data of the first

acquisition in VSR format

Such Quasar data were successfully correlated with ESA

data

JAXA provided all data of the second acquisition translated

into both VSR and MK-V formats

Hayabusa observations (2)

• Data processing – S/C

The two datasets (JAXA-VSR and JAXA-MKV) were translated, for

each acquisition, in the ESA-CDF format and processed with the ESA - ΔDOR s/w correlator.

The S/C correlation of the S/C acquisition produced a correlation

peak at 0Hz, with a phase of about -1.5 rad different from the expected value of 0 rad.

Hayabusa observations (3)

Data processing – Quasar (1) The two datasets were translated, for each acquisition, in the

ESA-CDF format and processed with the ESA - ΔDOR s/w correlator.

The quasar correlation produced a correlation peak of 0.82

for both acquisition Q1 and Q3

This value is lower than expected, since the two samples

streams, representing the same signal, should almost equal

Hayabusa observations (4)

• Data processing – Quasar (2)

Direct comparison between the CDF samples obtained from the

JAXA VSR file and those obtained from the JAXA VLBI file was made.

The I streams were almost the same (only 1.000 samples over

2.000.000 differ, i.e. the 0.05%)

The Q streams differed by more than 1.000.000 samples over

2.000.000, i.e. more than 50% of samples.

JAXA VSR data were also translated in VLBI format using the ESA-

ΔDOR format converter. Again a comparison wrt the VSR samples was performed.

The I streams were almost the same (only 1.000 samples over

2.000.000 differed).

The Q streams differed by about 233.000 samples over

2.000.000 (11%). This amount of noise is consistent with what has been measured up to now, and is due to the quantization error affecting the reconstruction process of the analytic signal during the VLBI CDF translation.

Hayabusa observations (5)

• Data processing – Quasar (3)

Finally, a direct comparison of the JAXA VLBI file with the ESA

VLBI file obtained with the ESA-ΔDOR format converter. The result was that the two real streams differed by more than 1.000.000 samples over 4.000.000.

Looking this difference more in details, it was discovered that the

differences between the JAXA and DIAA VLBI quasar files involved the odd samples.

The I samples of the JAXA VLBICDF translation derive from the

VLBI real stream, which is under-sampled by taking one every two samples (i.e. the even samples).

On the contrary, the Q samples of the JAXA VLBICDF translation

are obtained by a signal reconstruction process involving all the VLBI real stream.

Since the stream includes also the odd samples, the Q-samples

cannot be reconstructed in a proper way. This might explain why the correlation process produced a low correlation peak on the Quasar files, and an unexpected non-zero correlation phase on the S/C files.

ESA-JAXA ΔDOR tracking on VEX

VE X observations

VEX is currently being observed monthly (once per month) by ESA in

• rder to provide JPL with plane-of-the-sky measurement of the S/C

ESA provided JAXA with the dates for a VEX tracking in the 2009

timeframe

JAXA to identify suitable dates for the support

Status and plans of ESA enhanced Wideband ΔDOR

E SA enhanced wideband ΔDOR (1)

From Phoenix support experience, the limiting factor of ESA ΔDOR

accuracy is the total spanned bandwidth at the receiver (maximum 28 MHz) that allows the reception of only one of the ΔDOR tones at X-band (19 MHz wrt the carrier)

ESA is undergoing an activity to upgrade its ΔDOR receiving

capabilities for wideband ΔDOR (i.e. use of both 19 MHz tones and/or 2nd harmonics of such tones)

The activity foresees some rewiring of the back-end at both

Cebreros and New Norcia DSA plus some new developments for the correlator in order to be able to cope with such modifications

E SA enhanced wideband ΔDOR (2)

In order to be able to acquire the spectrum The wiring will be upgraded as follows

E SA enhanced wideband ΔDOR (3)

The cabling will be installed in Cebreros during week 18, but not

connected to the L-band downconverter due to station freeze for the launch of Herschel-Planck.

Once the freeze is over, the new wiring will be connected and

validated.

For New Norcia the installation is foreseen for weeks 23/24,

depending on H-P launch.

By the end of June the system should be ready for operational

validation (with VEX since passes are already foreseen for the remaining of 2009).

ESA-JPL wideband ΔDOR interoperability testing

MRO observations

• In order to fully validate the ESA wideband Delta-DOR functionality the

following options are foreseen:

First functional validation of the acquisition with one station only First end-to-end validation on ESA S/C (VEX in the frame of th eactivity

already foreseen)

Real-scenario validation using a S/C with DOR tones at X-band

candidate MRO. Is this feasible in the frame of the mutual agreement between JPL and ESA for Delta-DOR operations? Any other S/C that could be used?

Two are the configuration to be tested: Delta-DOR from ESA stations only Delta-DOR in mixed-baseline mode

• Since data translation from/to VSR has already been proven, the
• bservations on MRO would:

Validate ESA wideband raw data capture Validate ESA capability of correctly correlate data acquired in wideband

at its stations

Validate ESA capability of correctly correlate data acquired in wideband

in mixed-baseline mode

Tentative schedule

ESA-JPL MRO Delta-DOR tentative schedule: JPL to confirm whether a ESA is allowed to track MRO

• Sept. 09

March 10 TBD 10 HW upgrades readiness SW upgrades readiness April 2009 Tracking and data processing and validation

Way forward to ESA possible ΔDOR support to MSL

ΔDOR support to MSL?

Results of Phoenix Delta-DOR tracking by ESA were not as

accurate as expected due to bandwidth limitations

This could be seen as a potential problem for future Delta-DOR

support by ESA

ESA is undertaking an upgrade to wideband Delta-DOR in order to

be able to support recordings up to 100 MHz wide (the limitation in this case is the diplexer) in the band 8.4 – 8.5 GHz

This should enhance the Delta-DOR accuracy of the ESA system to

the same level of the JPL system

Once the capability is installed, verified and tested in a real-case

scenario (i.e. with MRO), JPL and ESA could jointly produce and distribute to the MSL project a Memo outlining the obtained results