Final Results In this chapter all the results collected after the upgrades announced in the previous part of this work are shown, particularly as regard as statistics on sample carriers

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5. Final Results

In this chapter all the results collected after the upgrades announced in the previous part of this work are shown, particularly as regard as statistics on sample carriers.

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5.1 – Rambouillet_1 final architecture

Main interventions on the original structure can be listed as follow:

• Each ADM input was not connected directly to the waveguides, but Divider Units have been added. Each of them is a 4x32 matrix and for each input we have 8 identical outputs. The first of them is always connected to the correct ADM, while the following 3 are necessary for localization and backup systems. Doing this, for each polarization, 4 copies are available, in order to be connected to future ADMs or Monitoring Devices.

• Removing interference localization systems from ADMs outputs led to make 2 port of them free, so ASA5 and ASA6 were able to receive, through new ETL™

switches, signals from the 12 original antennas.

• Measuring signal powers at divider units output, it have been noted that maximum 5 dB of loss are present, but this has been considered acceptable for system performances. Remember also that at the end of the work a new initial and full calibration was scheduled, in order to make “transparent” the new architecture.

For best understanding all changes, look at the following scheme.

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(Image 5.1 – Final Rambouillet_1 architecture)

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5.2 – Rambouillet_1 actual performance

In order to make comparison possible, we’ll analyze statistics on the same carriers of the previous chapter; these have been analyzed from November 20^th at 14:22:00 to November 27^th at 13:00:00, that is a period of 7 days like the one on which previous statistics were based.

5.2.1 – Final data for Carrier #1

Here are statistics for “Noorsat” on AB2-B1.

Index Value for

Carrier #1 Total Number of Background measures in the selected period (One week) 623 Minimum value of minutes between two consecutive measures 6 [Min]

Maximum value of minutes between two consecutive measures 75 [Min]

Average value of minutes between two consecutive measures 15.14 [Min]

Standard deviation value of minutes between two consecutive measures 7.32 Percentage of two consecutive measures within 10 minutes 11.72 [%]

Percentage of two consecutive measures within 15 minutes 70.63 [%]

(Table 5.1 – Final statistics for carrier #1)

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(Image 5.2 – Final PDF for carrier #1)

(Image 5.3 – Final CDF for carrier #1)

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Here are statistics for carrier “M6” on AB3-KA01.

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Finally, we show same statistics for the last carrier on EB4-B1

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5.3 – Rambouillet_2 final architecture

Rambouillet_2 has been totally re-planned concerning its architecture. Main interventions can be listed as follow:

• The two originally independent subsystems have been grouped into a single one, in order to use more efficiently available resources. So, the final configuration permits to monitor signal coming from 10 antennas with 3 Agilent® Spectrum Analyzers.

• Like Rambouillet_1, Amplifier Divider Units have been added near the ends of waveguides and monitoring devices, in order to add more free ports.

• All the old switches have been replaced by new ETL® ones, directly controlled via an Ethernet port.

The most important aspect of the new architecture is that Rambouillet_2 is very scalable, that is lots of new devices can be added in the future; just looking at the following scheme, we can observe that for each higher Amplifier Divider Unit 7 ports are available, while for the lower ones at least one output can be connected directly to another monitoring device without great efforts.

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(Image 5.8 – Final Rambouillet_2 architecture)

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5.4 – Images of installed equipment

Here some pictures of installed components are shown.

(Image 5.9 – The CSC Room, where operators use the Monitoring System)

(Image 5.10 – Front view of ETL™ switches and SA on Rambouillet_1)

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(Image 5.11 – Agilent™ Spectrum Analyzers on Rambouillet_2)

(Image 5.12 – Front view of Amplifier Divider Units)

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(Image 5.13 – Rear view of Amplifier Divider Units)

(Image 5.14 – Rear view of ETL™ switches)

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5.5 – Future perspectives

At the end of this work, Eutelsat’s monitoring system is without any doubt upgraded, but other interventions could take place in order to get it better.

The first problem that would have to be solved is the calibration on Rambouillet_2.

We’ve already spoken about the importance of getting a precise measure on a downlinked carrier, but accuracy can’t be possible if a manual calibration isn’t often made in the second subsystem. It means that periodically (really as often as possible) measures collected need to be compared to calibrated ones; using a calibrated antenna (if it’s available!), a technician can periodically scan all the monitored fleet to look at uncalibrated measures and to correct them if it’s necessary. But, the greatest problem is that a human being needs to dedicate lot of time to do this operation. The easiest, but most expensive, way to provide a solution to this problem would be the installation of the calibration system on Rambouillet_2, but signal synthesizers, powerheads, powermeters and injection systems would have to be installed.

According to us, the best solution should be the integration of a module in SIECAMS® which, disposing of only one calibrated antenna, would automatically point, measure and provide corrections for the rest of the system.

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(Image 5.16 – A possible solution for calibrating antennas)

For each path on each spectrum analyzer a simple comparison between EIRP values of a same carrier would align the wrong measures to the correct ones.

We can also compare which is the usage of ASA2 as we’ve done before the intervention. Taking into account Image 4.1, we can observe that the instrument dedicates more time to background operations, and this fact justifies improvements about statistics mentioned before.

As we’ve done for Rambouillet_1, we can evaluate performance on the second subsystem; we’ll adopt the same criteria, selecting a carrier and analyzing statistics.

We focused our attention on “OVERON” ON AB1-B3 and Table 5.3 show us the results:

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(Image 5.17 – ASA2 usage after upgrade)

Carrier on RMB2 Total Number of Background measures in the selected period (One week) 612 Minimum value of minutes between two consecutive measures 4 [Min]

(Table 5.3 – Final statistics for selected carrier on RMB_2)

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Since values as similar between various carriers, we can observe that average quantities are quite the same of Rambouillet_1, even though they are more dispersed, that is standard deviation is generally greater. Next images confirm these assumptions.

(Image 5.18 – PDF for carrier on RMB_2)

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(Image 5.19 – CDF for carrier on RMB_2)

So, we think that at least one Monitoring Device more would be necessary to improve performance on Rambouillet_2, also because it’s very scalable in the future, in the sense that lots of free ports are available to be connected to new antennas in order to look after more satellites.