Visualyse GSO User Guide

Contact Information

You can contact us at:

Address Transfinite Systems Ltd, Suite 24 (5th Floor), AMP House, Dingwall Road, Croydon, CR0 2LX U.K

Phone +44 20 3904 3220

Fax +44 20 3904 3211

Email info@transfinite.com

Web www.transfinite.com

Transfinite Systems reserves the right to change features and screen layouts without notice.

©Transfinite Systems Ltd

Introduction

Visualyse GSO V3 is a collection of software tools that control and guide the process of coordination between geostationary satellite networks that share the same frequency bands. The coordination process is split into two parts:

Determine which systems you need to coordinate with
Undertake interference analysis to support the detailed coordination process

The number of networks that are submitted to the ITU bi-weekly complicates the first part. New networks are published once every two weeks in a database known as the International Frequency Information Circular (IFIC), which replaced the paper and microfiche formats of the Weekly Circular (WIC) and Special Sections with effect from 1 January 2000.

Visualyse GSO V3 works seamlessly with these databases, automatically flagging filed networks that may need to be coordinated. This removes a large amount of the work needed to screen the publications.

The coordination triggers used are based on worst case ΔT/T calculations and coordination arc definitions. Both or either measure can, in certain situations, trigger detailed coordination.

Further analysis is performed in terms of C/I ratios. C/Is are calculated and compared to a threshold value - the resulting margin is displayed and the C/I calculation can be inspected in detail.

Quick Overview

If you've only got 5 minutes to spare, then this is the section to read. Once you have installed the software then go ahead and run it up. The rest of this section provides a quick overview of the software and what it can do.

Coordination Check

The first step is to look at whether there might be a requirement for coordination between your networks and networks in an ITU IFIC. We call this a Coordination Check.

New Coordination Check

Analysis

Visualyse GSO V3 will load the IFIC and begin analysing each of the networks. The networks are shown on the left-hand side of the application.

At the top is the Satellite Map. This shows the networks arranged along the GSO arc. Labels for your networks are shown above the arc line and labels for the other, coordinating networks, are shown below the line. Purple areas show where networks would have no geographical overlap with yours.

Analysis

The full analysis may take a few minutes but as soon as the calculations for a particular network are complete (indicated by a change in colour from grey to red or green) you can click on it to see the results without waiting for all the other networks to finish.

Analysis Complete

Results

When you click on a network, the right-hand side of the application changes to show the results of the analysis.

Results

Coordination Trigger

Visualyse GSO V3 makes it easy to determine whether coordination is required. Results can be examined in detail making verification a simple process

Coordination Trigger

Data can be easily copied and pasted into other applications.

Detailed Coordination

Once you have excluded any beam pairs (based on beam contour overlap) the next step is to take the included ones across to Detailed Coordination.

Detailed Coordination

Software Features

We'll now look at all the features of the software in more detail. In order to highlight the various options, tools, and views available we'll make use the sample data that is provided with the software. This data is based upon the scenario of a spectrum manager who is responsible for two Fixed Satellite Service (FSS) GSO satellite networks:

IMPROSAT, located at 134 $^{\circ}$ E
TSLSAT, located at 130 $^{\circ}$ E

In this document, and in the software, these will be referred to as My Networks.

Scenario

Both of these satellites are currently under coordination and have not been brought into use. Bi-weekly, the spectrum manager must check that other systems (notified to the BR and then distributed via IFIC) would not present issues:

either by being likely to cause unacceptable interference into the spectrum manager's networks
or by being likely to suffer unacceptable interference from the spectrum manager's networks

A key aspect in assessing what should be done in these situations is to know which network (the spectrum manager's or those in the IFIC) has regulatory priority. This is typically based upon which network was filed first. This is far from a clear cut decision because, while the original submission might have priority, modifications could have been made at a later stage. In this situation some beams (or IFIC Groups) will have priority while others don't. One powerful aspect of Visualyse GSO V3 that will be demonstrated is the ability to deal with Regulatory Priority and the automatic detection of cases where coordination may be needed.

In addition Visualyse GSO V3 could be used for other tasks involved in GSO satellite spectrum management, for example:

During design phase, to check the complexity of coordination and hence feasibility of a proposed new system, including searching the GSO arc for suitable locations
When submitting Advance Publication Information (API), to determine which administrations are likely to indicate they have an interest in protecting their system
When submitting Coordination Requests (CR), to determine which administrations for which coordination will be required
To check other systems during the API or CR phase, to ensure they will not cause an interference problem, and that any necessary regulatory steps are made to register interests where required
When Detailed Coordination is required, to perform the analysis based upon C/I calculations, including tools to show the impact of varying specific system parameters in the ability to share, and where each system has priority.

Demo Version Limitations

If you're using the demo version of the software then please be aware that this is subject to the following restrictions:

While you can edit or redefine you own network assets, these changes cannot be saved
You are limited to the use of the demonstration data provided for your networks. However, you can use any IFIC or the SRS database.
You will not be able to save or print.
You will not have access to certain additional features such as the Priority Map tool.

Apart from these limitations, the demo version shows as much as possible of the complete program. If you have any further questions please do not hesitate to contact us (info@transfinite.com).

Sample Data

Please note that the satellite antenna gains in the supplied demonstration networks and sample IFIC are un-realistic. This results in many DT/T levels being much lower than worst case analysis would indicate.

Getting Started

So let’s get begin then.

If you have a desktop shortcut, double click on it. Alternatively, click your PC's Start menu and select VisualyseGSO from the Visualyse GSO V3 program group. You are presented with two options: either create a new coordination check or open an existing one.

Main GSO Window

Across the top of the window is the toolbar. You can access various application features from here but in particular you can access the software settings.

Software Settings

Click the Settings button. The key thing to spot is the default directions of interference.

Visualyse GSO V3 can be used to calculate interference from either or both of:

Coordinating Networks into My Networks
My Networks into Coordinating Networks

In this example we will be analysing the former, namely interference into our networks.

My Networks can be configured by clicking on the My Networks button

My Networks Button

We will look at this at a later stage.

The settings should not be changed at this point, though it is useful to identify what defaults could be changed.

Close this dialog to return to the start screen.

Coordination Check

The Coordination Check is one of the main features of Visualyse GSO V3. It is used to determine whether coordination is required, based upon one of two forms of coordination trigger:

DT/T - using a threshold, typically 6%
Coordination Arc - using a maximum orbital separation

Starting a Coordination Check

To start a coordination check click New Coordination Check on the start screen.

New Coordination Check Button

The New Coordination Check dialog will appear:

New Coordination Check Dialog

To undertake a coordination check you need a set of Coordinating Networks and in Visualyse GSO V3 there are two options for defining these

IFIC - this will use all the networks in an IFIC
Select Networks - here you can define subset of networks selected from any number of different IFICs or the SRS

By default the sample ific.mdb database is selected.

Sample IFIC

Click Go. Visualyse GSO V3 will now examine each network in this sample IFIC against both of the two networks defined in My Networks.

Note: All data in the sample IFIC and those in "My Networks" has been created for this demo and does not have any particular significance.

Calculation of DT/T

The DT/T is calculated from the data in the chosen IFIC or SRS using standard ITU-R approaches such as those identified in Appendix 8 of the Radio Regulations.

The software takes each network in turn and calculates the worst case DT/T to, or from each of your own networks. To do this, for the interfering network the emission with the highest e.i.r.p spectral power density is used and for the victim network the highest receive gain and lowest noise temperature are used. A worst-case geometry is assumed.

Frequency and geographical overlaps are also considered and if none are found for a particular network then the software will show this.

Calculation of DT/T

As soon as calculations are complete on a network it is possible to examine the results. When CHAINSAT 35A is complete, select it to show the coordination details.

CHAINSAT 35A

Network List

This shows the 7 networks in the IFIC including their administration, notification reason (API, CR etc.) and date.

Selecting a network updates the other windows with data related to that network.

Network List

Satellite Map

The Satellite Map provides a graphical representation of the satellite positions on the GSO arc.

It allows you to easily determine the relative orbital proximity of satellites and see whether they lie within any coordination arc(s).

Satellite Map

Focus Network

By default the purple ‘no geographical overlap’ area shows where coordinating networks would have no geographical overlap with any of your networks.

If you double-click on a coordinating network you can ‘focus’ on that network and instead show where there’s no geographical overlap with only that network.

A small eye icon will appear above the label and another in line with the network location.

Focus Network

You can also double-click to focus on one of your own networks. The ‘no geographical overlap’ area will change to show the area that applies only to that network.

In addition the entire network list will update to show the coordination status based on looking at overlaps with the focused network only.

To reflect this the focused network will be highlighted with a purple border.

Purple Border

To exit Network Focus double-click on an empty area of the Satellite Map background.

Overlap List

This window shows the interference paths between My Networks and the network selected from the Network List.

These are broken down into frequency overlaps and grouped by network, link direction (up/down) and then beam pair.

Selecting a beam pair will display the beams and coordination trigger calculation on their respective windows (we’ll talk about these next).

Overlap List

Overlap Diagram

The Overlap Diagram provides a graphical representation of the selected frequency overlap(s).

Frequency assignments are shown together with the group bandwidth to illustrate how the spectrum is occupied for each network.

Overlap Diagram

Beam Overlaps

The Map View is used to perform an initial visual inspection and eliminate cases based on beam overlap.

Beam contour data is automatically loaded from GIMS when available.

When you click on a Beam Pair in the Overlap List you should see the contours on the Beam Overlaps window.

As our example uses fictional networks, there is no beam data in GIMS so we’ve added some to the here just for illustration purposes.

If there is a sufficient overlap not to discount the beam pair you would next look at the coordination trigger calculations.

Beam Overlaps

Coordination Trigger

This shows a detailed breakdown of the Coordination Trigger.

It gives more detailed information about the networks concerned including the coordination arc, and how the calculation of DT/T was arrived at based on the parameters of the selected networks.

For our example we see the following:

Interfering network CHAINSAT-35A
Victim network IMPROSAT
Orbital separation 2.5°
Inside coordination arc Yes
DT/T 164.8%

From both triggers we see that coordination would be required so we can proceed and include this beam pair in our detailed coordination.

Coordination Trigger

Maximise Pane

If you’re working on a laptop or with a small display then you'll have limited space to see all the application panes in detail at the same time.

To help with this we have added the ability to temporarily maximise any of the panes.

You can easily flick between maximised panes using the number keys. You can also configure the maximised panes so that you can show two or three panes at a time.

Simply adjust the pane splitters while a pane is maximised. The software will then remember this configuration for you.

Maximise Pane

Detailed Coordination (DC)

REQUIREMENTS

The previous section described how to identify which networks require coordination, by considering the DT/T and the coordination arc. This can be used by operators and administrations to decide which notices they could have an issue with and hence which require a notification to be sent requesting coordination to the BR and other operators and administrations.

Having entered into detailed coordination with another operator a different approach is required – not looking at a range of systems in an IFIC or SRS, but considering one or a small number of systems in detail, to see how interference could be managed so that both could operate. This will involve negotiation between the parties, which must take into account which network has regulatory priority. However there is a provision in Article 9.53 that both parties should make every possible mutual effort to overcome any difficulties, which is intended to facilitate the entry of the newer system.

These negotiations must take account of details of each system, their beams, service areas, polarisations, emission codes, e.i.r.p.s, frequencies, and earth station characteristics. Detailed discussions therefore must consider a large number of combinations of interfering and victim carriers plus link characteristics for each in great detail.

A successful outcome requires a good understanding of where the main problems are, why there are problems and what could be done to facilitate sharing. This can be achieved using the Visualyse GSO V3 Detailed Coordination tool.

Calculation of C/I

The basis of our Detailed Coordination tool is the C/I between the victim and the wanted network. This will depend upon the data in the Group pair selected – such as frequency, polarisation and associated earth station. The C/I threshold can either be directly entered or is derived based upon a calculated C/N, using the approach given in Recommendation ITU-R S.741-2:

C/I = C/N + 12.2

By default the C/I calculations use the worst case geometry. However, during analysis, specific locations can be included and hence the antenna directivity can be used to decrease interference.

Examining a Network in Detail

The Detailed Coordination tool can either be launched from Visualyse GSO V3 (by pressing one of the ‘Detailed Coordination’ buttons) or independently (by pressing the ‘DC’ button on the toolbar in Visualyse GSO V3) or by launching from the Start Menu or file system.

If launched independently the application will launch into the start screen. This is very similar to Visualyse GSO V3 and allows you to load up previously saved files.

Detailed Coordination Main Window

We're going to launch from inside Visualyse GSO V3. Click the ‘Detailed Coordination’ button next to beam pair CDN (from CHAINSAT-35A) and HD (from IMPROSAT) i.e. ‘CDN → HD’.

The Detailed Coordination tool will appear.

Detailed Coordination

Interference Cases

The Detailed Coordination tool looks at interference cases. To create these the software looks at all the combinations of emission pairs, powers, frequencies and earth stations that could occur. It then calculates the interference.

The frequency producing the worst C/I for each combination is then taken and forms one interference case. Each is represented by a row in the list.

Detailed Coordination Interference Cases

Group Bar

The Group Bar allows you to organise the interference cases into logical collections. You can group by beam, emission or earth station and by doing so, see how the interference cases are spread across a particular set of assets.

Group Bar

Grouping

Calculations

When you select an interference case, a full breakdown of all the components of the calculation are shown in the Calculations pane.

You can click the Copy button to copy the contents so that you can paste into applications like Microsoft Excel for further analysis.

Calculations

Beam Overlaps

In the Detailed Coordination tool the Beam Overlaps pane has extra analysis tools. These allow you to look at how parameters such as interference, EIRP or Required Dish Size vary as you move the Earth station across some defined area.

Beam Overlaps

Network Editor

The Network Editor shows the full network definition for the both interferer and victim. You can use it to trace exactly which network parameters are contributing to a particular interference case. However, its real value is in the ability to change those parameters in order to explore ways of reducing the interference.

Network Editor

Constraints

When you make a change to a network asset you are not changing it permanently but merely exploring what might happen if the asset were altered. We call this kind of change a Constraint and these are collected in the Constraints pane.

By compiling a list of constraints you can go into a coordination meeting with a set of proposed solutions. Constraints can be toggled on and off for easy comparison or deleted completely. What’s more, because they apply to the asset, all interference cases that use the asset will be updated whenever a constraint is applied or removed.

Constraints

Antenna Modelling

One of the best ways to mitigate interference is to use accurate antenna gain modelling.

If the software was not able to locate your beam data in GIMS then it will automatically use the worst case scenario of peak gain across the whole service area. Obviously if the interference levels are below the desired threshold then all is well. However, if that’s not the case then you can get a more realistic picture by either using an appropriate ITU gain pattern or by providing antenna gain contours

ITU Gain Patterns

To show you how to use an ITU gain pattern for a beam let’s change the one for CHAINSAT-35A in the example we’ve been looking at. In the Network Editor, click on CHAINSAT-35A

ITU Gain Patterns

You should see the beam footprint on the Beam Overlaps pane. If you don’t then it could be that you have this switched off on the display options.

Display Options

One other option you have with the ITU gain pattern is to change the pointing direction. Click and drag the boresight for CDN over to central China as shown.

Move Boresight

You should see that this immediately improves the interference picture as the off-axis gain for the interfering signal is significantly reduced

Try changing the gain pattern for the victim beam HD in the same way but this time choose ‘App 30 Space FR’.

Changing the Gain Pattern

Antenna Gain Contours

The other option for antenna modelling is to supply gain contour data. If you have this in a GIMS format .gxt file then you can easily load them into the software. To do this follow the same steps as for the ITU Gain Patterns but from the pop-up menu choose ‘Import from .gxt file…’.

Import from .gxt file

You can also choose the option to extract directly from GIMS if you have the data there.

Shaped Beam Editor

If you don’t have your gain contour data in GIMS format then you can use our Shaped Beam Editor (SBE) tool to capture this. Choose Shaped Beam Editor from the Tools menu or click the Shaped Beam Editor button on the toolbar.

Shaped Beam Editor button

For information on the Shaped Beam Editor see here.

Area Analysis

The interference cases show the C/I for one particular Earth Station arrangement. On the Beam Overlaps pane you can drag the Earth Station(s) to a different location and see all the calculations update as you drag. This is great for looking at individual ES locations in isolation, but what if you wanted to get an overview across a whole coverage area? What you need is Area Analysis.

Creating an Area Analysis

All you need to do is define the area and choose the plot parameter. The software then generates a coloured plot of the parameter across the area for every possible Earth Station location.

Creating an Area Analysis

Try clicking on the GRID button. The cursor will change and a message will appear to show that you’re now in area definition mode.

GRID button

You can see instantly that almost all Earth Stations in Australia meet the required threshold and that interference levels become a problem as the position moves towards China.

GRID button

If you add any constraints then these will be reflected in the area analysis automatically. The analysis updates independently so you can drag a slider in the Network Editor and see the analysis update in real time, as you drag

Changing the Plot Parameter

In addition to C/I, there are five other parameters you can plot on an Area Analysis. These are: C/(N+I), C/N, DT/T, I EIRP and Required Dish Size.

Changing the Plot Parameter

The parameters are self explanatory except for Required Dish Size. In this case we look at the dish size that would be required in order to reduce the C/I enough to meet the required threshold. Mostly this will be the victim Earth Station but for uplinks you can choose to look at the interfering Earth Station instead.

Try selecting Required Dish Size. In our example the plot is a uniform colour and the colour key tells us this is because the interference is so high that a dish size in excess of 5 metres would be required to meet the threshold.

Required Dish Size

If we change the network parameters slightly you can see more variation.

Changing Network Parameters

You’ll see now that within the 3 dB beam there’s an area where an Earth Station dish size of around 3m would be all that’s needed to mitigate the interference. You can get more explicit figures for required dish size by switching from a GRID to a CONTOUR plot.

If you drag the reference Earth Station to different points on the plot you should see the required dish size change accordingly on the Interference Cases pane

Drag the Reference Earth Station

In the example above, we’ve dragged the reference Earth Station to the 3.0m contour and, as expected, the required dish size changes to 3.0m in the Interference Case.

Modifying an Area Analysis

There are a few ways you can alter an Area Analysis after it has been created. First off are detail level and transparency. These can be adjusted using the two sliders on the Analysis toolbar

Modifying an Area Analysis

As well as the appearance, you can also change the size and shape of the Area Analysis. You can do this by moving, deleting or adding to the points that define the analysis boundary.

To Move a point

Hover the mouse near the point you want to move until the point is highlighted and the mouse pointer changes.
Click and hold. Drag the point to the new position and release the mouse button.

To Delete a point

Hold the CTRL key and hover the mouse near the point you want to delete until the point is highlighted in red and the mouse pointer changes.
Click the mouse button to delete the point

To Add a point

Hover the mouse near where you want to add a point until the segment and potential new point are highlighted and the mouse pointer
Click and hold. Drag the point to place it.
Release the mouse button to finish.

Removing an Area Analysis

If you only want to hide the analysis temporarily then you can just switch it off. It can then be recalled later by selecting a plot parameter or by clicking the ‘Grid or ‘Contours’ buttons.

Removing an Area Analysis

If you want to remove an area analysis permanently then click on the delete button in the top-right corner of either the ‘Grid’ or ‘Contours’ buttons

Removing an Area Analysis Button

Maximise Pane

The Maximise Pane feature is also available in Detailed Coordination. See here for details on how this works.

Maximise Pane

Data Output

Pane Copy

All the Visualyse tools have some way of getting data out of the software. The two main tools, Coordination Check and Detailed Coordination implement a system called Pane Copy. This is easy to use. Just choose Copy from the Edit menu or press CTRL + C.

Pane Copy

Graphical panes like the Satellite Map or Network Editor (in Detailed Coordination) will have their contents copied to the clipboard as an image. You can then paste these into reports or e-mails just like any other image.

PaClipboardne Copy

Panes that contain data like the Overlap List or Calculations Pane (in Detailed Coordination) will have their contents copied to the clipboard as formatted text. This is prepared in a format that will paste easily into spreadsheet applications like Microsoft Excel.

Excel Copy

Reporting

In Visualyse GSO V3, when you select a beam pair for one of the overlaps you can choose to generate a report for the Coordination Trigger. This is created as a formatted Microsoft Word document.

Reporting

Defining a Network

My Networks

There are two ways to get your networks into the software. You can either import them from an existing ITU format database (an IFIC or the SRS) or you can enter your data using the Network Editor. With both methods the first step is the same. Launch Visualyse GSO V3. From the Tools menu select Define My Networks. You can also click the My Networks button on the toolbar.

My Networks

The My Networks dialog will be displayed. The dialog shows all the networks you have created or imported into your database. In the case of imported networks, the IFIC reference is also shown. Each network has a check box next to it. Checked networks will be included in the IFIC and Custom coordination checks.

Importing From an ITU Format Database

To import a network from an ITU format database such as an IFIC or the SRS, open the My Networks dialog and click the Import button. The Select Networks dialog will be shown.

Select Networks

Editing Networks

You can create your networks from scratch using the Network Editor. You can also use the Network Editor to modify networks that you have imported from other databases. None of these features are available in the demo version.

On the My Networks dialog, select IMPROSAT and then click Edit to open the Network Editor.

Editing Networks

Application Settings

The Settings and Defaults dialog was mentioned at the beginning of this document. You’ll recall that this can be invoked by selecting Settings from the Tools menu in Visualyse GSO V3.

The Settings and Defaults dialog can also be accessed by clicking on the Settings button on the toolbar.

Application Settings

Aside from the option to check for software updates, the Settings are broken down into two different sections - those that affect the Coordination Check and those that affect Detailed Coordination.

Coordination Check

Coordination Check Settings

Detailed Coordination

These settings are only used in the Detailed Coordination (DC) tool. They govern how the Interference and C/I required level (threshold) are calculated.

Detailed Coordination Setting

The final option is to calculate the C/I threshold based on the carrier class (extracted from the emission code). Click the “Edit” button and you’ll be able to select the option used for each carrier class pair.

When the Interferer is Analogue (TV-FM) and the victim is Digital or Analogue (Other) the equations used by ITU-R S. 741 option are as follows:

Interferer Analogue (TV-FM), Victim Digital

DeNeBd $\leq ln EqB d \dots \to C / I = C / N + 5.5 + 3.5 \times lo g (De N e B d)$

DeNeBd $\geq ln EqB d \to C / I = C / N + 12.2$

Interferer Analogue (TV-FM), Victim Analogue (Other)

$C / I = 11.4 + 2 lo g (DeNeBd$ in $MHz)$

DeNeBd = Necessary bandwidth of the desired carrier in $MHz$

$lnEqBd =$ Equivalent bandwidth of the interfering carrier (equal to Total Power to Power Density ratio)

When you launch the Detailed Coordination tool you can access all of these settings from the toolbar at the top of the Interference Cases pane.

Detailed Coordination Settings Toolbar

Shaped Beam Editor

The Shaped Beam Editor (SBE) allows you to edit or create shaped beams which can then be used as part of the detailed coordination process. The tool allows you to load GIMS format .gxt files. You can also export to GIMS format so anything you create can be exchanged with ITU software.

Launching

The Shaped Beam Editor is a separate tool from the main application. To open it choose Shaped Beam Editor from the Tools menu or click the Shaped Beam Editor button on the toolbar.

Launching SBE

The Shaped Beam Editor window opens with a new shaped beam file by default. You can either proceed and start creating a beam from scratch or load in a GIMS .gxt file and work on that.

SBE

Setting Network Details

Use the controls at the top to set the name, admin and notice id for the network that the beam is to be a part of.

Setting Network Details

The orbital position of the satellite is set from the toolbar at the bottom of the window. When you change this you’ll see that the highlighted area of map representing the satellite field of view will change accordingly.

Satllite Longitude

Adding Boresights

Click the Add Boresight button, then click on the map to add a boresight (hold SHIFT while clicking to add more than one).

Adding Boresights

Editing Boresights

You can move a boresight by clicking on it, holding the mouse button and dragging it to a new location.

To edit a boresight, first click to select it. You’ll see a small toolbar appear below the selection rectangle. This is called the Selection Toolbar

Editing Boresights

From here you can set the relative gain and the exact location in latitude and longitude coordinates. A boresight can also be duplicated and deleted from the selection toolbar.

Adding Contours

You then need to set the relative gain for the contour. This is shown in the label on the contour itself. By default it’s set to zero. To change it simply click on it then type in the relative gain you want and either click away or press ENTER.

Add Contour Gain

Adding Open Contours

Editing Contours

Click on a contour to select it. Just like boresights, contours have their own selection toolbar

Editing Contours

Editing contour points is described in the next section. Reducing the number of points will intelligently reduce the number of points by around half. Smoothing on the other hand will re-sample the contour and add extra points to smooth out any sharp edges.

Resize Contours

Edit Contour Points

To edit a Contour (be it Closed or Open), either double-click on it or select it and then press the Edit Points button on the Selection Toolbar or press ENTER.

Edit Contour Points

You can click on a point and drag it to a new position. You can also use the cursor keys to move the selected point by small amounts up, down, left or right. Hold SHIFT while doing this to move the point by a larger amount each time. The same applies to selections containing multiple points.

Pressing the TAB key will select the next point in the contour and SHIFT + TAB will select the previous point.

To finish editing either click on the Map or another item or alternatively press ESC.

Detaching from the Field of View

As we mentioned earlier, open contours should start and end on the satellite field of view. If you drag an open contour then the end points will always remain on the field of view.

If you want to detach the end points from the field of view there are a couple of ways to do this. If you want to move the whole contour then simply click and drag it but hold SHIFT as you do this. The end points will then detach.

Detaching from the Field of View

To re-attach the end points do exactly the same thing. Once an end point gets close to the Field of View both end points will re-attach at the nearest intersection.

HOVER MOUSE OVER CONTOUR HOLD SHIFT & CLICK AND DRAG If you only want to move the end points then first edit the contour. Click and drag an end point while holding SHIFT. The point will switch between being unattached or detached. Note that reattaching will only happen when you drag close to the field of view

Detaching from the Field of View

Warnings and Errors

You may notice that as you start to construct your shaped beam an orange panel will appear in the bottom-right corner of the application window. This shows any warnings or errors. These are mostly advisory so that you can check your beam will conform to GIMS requirements as you go along.

If there are no errors or warnings you’ll see this:

If there are any warnings or errors you’ll see something like this Errors

Multiple Selections

You can select multiple contours and boresights and then move, duplicate or delete all of them in one go. There are two ways to do this. You can click on an empty area of the map and then drag out a selection rectangle. Any contours or boresights that are caught in the rectangle will be selected. Alternatively just hold SHIFT and click to add or remove items from the selection.

Multiple Selections

Multiple selections have their own Selection Toolbar. If you have a combination of boresights and contours then you will only get options to Duplicate or Delete.

However, if your selection only contains contours then you’ll get all the options that are available to you when just a single contour is selected. This allows you make changes like smoothing or point reduction to several contours at once. You can also resize the selection when it only contains contours. All contours will size proportionally and maintain the same relative spacing from each another.

Copy and Paste

You can copy any selected contour or boresight, or any selected combination by using the standard keyboard shortcut CTRL+C. To paste the copied selection use the standard keyboard shortcut for paste, CTRL+V.

Copy and Paste

Display Options

There are several options for controlling the way that items are displayed. Click the Contour Colours button to choose one of eight built in colour schemes for displaying contours. Click on the map to finish.

Display Options

Contour and Boresight gain labels can be switched on and off independently.

Gain Labels

You can also hide contour point labels.

SBE

Saving Changes

When you’ve finished making changes to a shaped beam you can save it to GIMS .gxt format.

SBE

NOTE: Whilst the Shaped Beam Editor tool is available in the demo version, saving to .gxt file is disabled. You can still open and modify existing files and you can also create new ones, they just can’t be saved

Slot Finder

The Slot Finder (SF) is a separate tool for use in the design of new satellite networks. It can be used to locate the best orbital slot for a new satellite, one that will minimise the coordination process later down the line. All you need to do is define a network and a range of orbital slots.

For each slot, the software will calculate the number of co-frequency networks that would be within the coordination arc. The software also calculates the DT/T for each network and displays the number of networks that would fail to meet the 6% interference threshold.

For any given slot you can then go automatically to Visualyse GSO V3 and examine the interference in more detail.

Launching

The Slot Finder is launched from Visualyse GSO V3 by clicking The SF button on the toolbar or by selecting Slot Finder from the Tools menu.

Alternatively, you can click your PC’s Start menu and select Slot Finder from the Visualyse GSO V3 program group

Launching Slot Finder

Defining the Analysis

When the Slot Finder starts for the first time you will see the Start Screen. This allows you to define your analysis.

Defining the Analysis

Search Network

If you have already defined a network or you know all the system parameters choose ‘One of My Networks’ then click on the currently selected network to choose a different one.

Search Network

If you haven’t created any networks yet, click the My Networks button. The My Networks dialog will appear. This dialog is similar to the one in Visualyse GSO V3 and lists all the networks you have created.

Click Add to add a new network to the list, then click Edit. This will take you to the Network Editor (see the chapter on Defining a Network for information on how to use this).

My Networks

If you are at the early stages of design, you may only have a few system parameters. If this is the case, you can still use this information to perform an analysis. All you need is a frequency range. The software will use the system defaults for everything else.

To do this choose the ‘Specified Band and System Parameters’ option. Enter the frequency range

Specified Band and System Parameter

Database and Filters

Choose a database to search against. This can be the complete SRS or any other ITU format database containing networks. You can apply filters to select only specific notice types.

Slot Range

The slot range is defined by an upper and lower bound in degrees running eastward from the first longitude to the next. Longitudes West of zero degrees should be entered as negative values. Hence 30 deg West would be represent by a value of –30.

Calculations

You can define the coordination arc here. This will determine how many other networks are identified as being potential interferers. The Slot Finder will look at all networks within X degrees of a particular orbital slot where X is the size of the coordination arc that you are using.

Having determined the networks that may cause interference you can then say whether the actual interference is to be calculated. If you only want to see how many networks are within range then make sure that the Calculate box is not checked.

Once all the parameters have been filled in, click Start to begin the calculations.

Results

As soon as you click the start button the results will begin to be displayed. First the Slot Finder will calculate the number of networks that are within the coordination arc of each slot. You will see all this update in real time. The histogram bars will grow as new networks are added and the progress bar will extend.

Slot Finder Initial Results

Once all the networks have been identified, if you chose to calculate the interference this process will begin. The progress bar will reset and, just as before, the results will be updated as they are calculated. A red portion on a bar indicates a network that fails to meet the interference threshold. A grey portion represents a network that does meet the threshold.

Slot Finder Progress

You can see from the image above that, part way through calculating the interference for the slot at 34 E, the Slot Finder has so far identified 20 bad networks and 8 good ones with 70 still to check.

When the calculations are complete the results can then be examined as a whole. Slots where less coordination is required can be identified visually. These slots can then be examined in more detail by double-clicking on them or by selecting them and clicking the Detailed Analysis button. This will take the complete analysis for this slot to Visualyse GSO V3.

Slot Finder Results

You can copy the chart data by clicking the Copy Data button. This can then be pasted into a spreadsheet like Microsoft Excel. You can also copy the chart as a picture by clicking the Copy Pic button

Priority Map

The Priority Map (PM) tool can be used to determine where one or more networks have regulatory priority over another set of networks. Priority is determined individually for each frequency band and polarisation.

The results can be used during the coordination process to try and get the best possible result for your systems during any negotiations. Having a clear picture of everybody’s assets is essential in these circumstances.

Launching

The Priority Map is launched from Visualyse GSO V3 by clicking the PM button on the toolbar or by selecting Priority Map from the Tools menu.

Alternatively, you can click your PC’s Start menu and select Priority Map from the Visualyse GSO V3 program group.

Launching Priority Map

Defining the Analysis

When the Priority Map starts for the first time you will see the Main Screen.

You’ll notice this window looks exactly like the top part of the new coordination check dialog. It works exactly the same too, the purpose being to select two sets of networks to compare

Priority Map Defining the Analysis

If you choose to select specific networks (by pressing the Select Networks button then the Select Networks dialog will appear. This allows you to hand pick a set of networks from one or more databases.

Priority Map Select Network

Results

Priority Map Results

Areas where one or more networks have transponders are shown as horizontal bars. The bars are colour coded as follows:

White - only other networks operate here

Grey - only My Networks operate here

Green - My Networks and other networks operate here and My Networks have priority

Red - My Networks and other networks operate here but My Networks do not have priority

Blue - My Networks and other networks operate here but no priority data is supplied for either and so priority cannot be determined

Outputs

If you click the Copy button, a picture of the visible contents of the main window will be copied to the clipboard. This can then be pasted into a report.

If you click the Export button, you can transfer the complete analysis to Microsoft Excel or a text file for further manipulation or analysis.

Priority Map Outputs

Keyboard Shortcuts

GSO

Key	Description
CTRL +C	Copy pane
1-6	Maximise pane
0 or ESC	Reset Maximise pane

Detailed Coordination

Key	Description
CTRL +C	Copy pane
1-6	Maximise pane
0 or ESC	Reset Maximise pane

CONSTRAINTS (DC)

Key	Description
DELETE	Delete selected constraint
PGDN	Select last item in current grouping
CURSOR KEYS	Left and Right switch selection off or on
CURSOR KEYS	Up and Down moves between items

MAP VIEW (DC & GSO)

Key	Description
ESC	Cancel Area Analysis creation
CTRL + L	Toggle beam labels
CTRL + K	Toggle Area Analysis contour labels
CTRL + F	Show/hide satellite field of view
CTRL + B	Toggle show beam contours
CURSOR KEYS	Rotate globe
HOME	Reset view to default position
I	Zoom in
O	Zoom out
C	Start or finish creating Area Analysis
P	Set view position explicitly

INTERFERENCE CASES (DC)

Key	Description
PGUP	Select first item in current grouping
PGDN	Select last item in current grouping
CURSOR KEYS	Up and Down moves between items

SHAPED BEAM EDITOR

Key	Description
ESC	Cancel current operation or deselect
TAB	Select next point in contour
SHIFT + TAB	Select previous point in contour
CURSOR KEYS	Move selection
CURSOR KEYS + SHIFT	Move selection by larger amount
HOME	Reset view zoom and scroll position
DEL	Delete current selection
0	Reset zoom
1	Cycle through contour colour options
T	Smooth selected contour(s)
R	Reduce contour points
I	Insert intermediate points
CTRL + S	Save shaped beam
CTRL + D	Duplicate selection
CTRL + A	Select all
CTRL + C	Copy selection
CTRL + V	Paste
CTRL $+ Z$	Undo
CTRL + Y	Redo
CTRL $+ " + "$	Zoom in
CTRL $+ "$ "	Zoom out

Contact Information

TRANSFINITE SYSTEMS LTD

Suite 24 (5th Floor)

AMP House

Dingwall Road

Croydon, Surrey

CR0 2LX

United Kingdom

Phone: +44 (0)20 3904 3220

Fax: +44 (0)20 3904 3211

Email: info@transfinite.com

Web: www.transfinite.com

We Want To Hear From You

If you have any suggestions about this document or Visualyse GSO V3, please do not hesitate to contact us.

Disclaimer

Our products are constantly evolving and so features may change or be removed in the future. Contents of the demo version including system parameters might vary from those described in this document.

The supplied sample data may contain parameters that are unrealistic from an operational perspective. The sample IFIC and networks are provided only for the purpose of demonstrating the features of the software.

Technical Annex

APPLICATION OF APPENDIX 8 AND COORDINATION ARCS

The following excerpt is taken from a paper presented at the BR Seminar in Mexico 2001. It provides details of how the approaches to coordination triggering are (or should be) applied by Administrations.

For any new or modified GSO network the need for coordination exists with other 'existing' GSO networks which have already initiated the coordination process. For collecting information about the existing GSO networks and their technical parameters required, Administrations may check the CD-ROM on SRS (Space Radiocommunication Stations) for:

all 'existing' GSOs under status $C$ (Coordination) or $N$ (Notification) having overlap with the frequency bands for the incoming satellite network.

details of orbital position; service area; earth station geo-coordinates; space station, earth station transmitting and receiving antenna gain characteristics; transmission gains; Noise temperatures $T_{E}$ , and $T_{S}$ Precise frequency overlaps are established in either uplinks or downlinks.

Whether the process of coordination between the new and the "existing" GSO networks is necessary or not, may be determined by the following approach:

$Δ T / T$ shall be calculated by treating the uplinks and downlinks of the wanted (or affected) satellite network, separately in accordance with the procedures mention in paragraphs 2.2.1.2 & 3.2 of Appendix 8.

The results can be categorised as follows:

If the Value of $Δ T_{E} / T_{E}$ or $Δ T_{S} / T_{S}$ is greater than $6%$ and the existing GSO network lies within the coordination arc, coordination with the incoming network is necessary.

If the Value of $Δ T_{E} / T_{E}$ or $Δ T_{S} / T_{S}$ is greater than $6%$ and the existing GSO network lies outside the coordination arc, the responsible administration for the existing network may request the BR for inclusion in the process of coordination with the incoming network.

The above approach works in those bands that have coordination arcs defined. For other bands, it is still, in theory, necessary to consider the frequency strapping information i.e. the way uplinks and downlinks are connected - and to look at the overall link performance. However, this is not considered necessary, and a separate comparison of the uplink and downlink DT/T to the 6% criterion is applied (see Section 2.2.1.2 for a discussion).

BASIC CALCULATIONS

This section describes the fundamental calculations that Visualyse GSO V3 performs when assessing whether coordination is needed between two networks.

The calculations are based on information taken from BR-IFIC and SRS databases, which is the method used to publish data submitted under Appendix 4 of the Radio Regulations.

$Δ T / T$ Method

The basis of the $Δ T / T$ method is that every radiocommunications link has inherent noise on it which can be expressed as a temperature value $(T)$ . Think of the noise as caused by electrons moving around and as the temperature rises the electrons become increasingly energized. Therefore a higher noise temperature means more noise on the link.

In $Δ T / T$ analysis, the interference is characterised by calculating the rise in the noise temperature of the link that the interfering signal causes $(Δ T)$ and comparing this with the noise temperature of the link without interference. The method is equivalent to looking the ratio of $I / N$

The calculated value of $Δ T / T$ is compared to a threshold criterion of $6%$ . Values above $6%$ act as a trigger for detailed analysis.

The basic calculation method, taken from Appendix 8 of the Radio Regulations, is given below.

Let $A$ be a satellite link of network $R$ associated with satellite $S$ and $A^{'}$ be a satellite link of network $R^{'}$ associated with satellite $S^{'}$ . The symbols relating to satellite link $A^{'}$ bear primes, those relating to satellite link $A$ do not bear primes.

The parameters are defined as follows:

$T_{S}$ the receiving system noise temperature of the space station, referred to the output of the receiving antenna of the satellite $(K)$

$T_{E}$ the receiving system noise temperature of the earth station, referred to the output of the receiving antenna of the Earth station (K)

$Δ T_{S}$ apparent increase in the receiving system noise temperature of the satellite $S$ , caused by an interfering emission, referred to the output of the receiving antenna of this satellite (K)

$Δ T_{E}$ apparent increase in the receiving system noise temperature of the earth station $e_{R}$ , caused by an interfering emission, referred to the output of the receiving antenna of this Earth station (K)

maximum power density per $Hz$ delivered to the antenna of satellite $S$ (averaged over the worst $4 kHz$ band for a carrier frequency below $15 GHz$ or over the worst $1 MHz$ band above $15 GHz) (W / Hz)$

$g_{3} (η)$ transmitting antenna gain of satellite $S$ in the direction $η$ (numerical power ratio)

nA angle, from satellite $S$ , of the receiving earth station $e^{'}_{R}$ of satellite link $A$

$η e^{'}$ angle, from satellite $S$ , of the receiving earth station $e^{'}_{R}$ of satellite link $A^{'}$

$P_{e}$ maximum power density per $Hz$ delivered to the antenna of the transmitting earth station $e_{T}$ (averaged over the worst $4 kHz$ band for a carrier frequency below $15 GHz$ or over the worst $1 MHz$ band above $15 GHz$ (W/Hz) $\partial_{A}$ angle, from satellite $S$ , of the transmitting earth station $e_{T}$ of satellite link $A$

$\partial_{e^{'}}$ angle, from satellite $S$ , of the transmitting earth station $e^{'}_{T}$ of satellite link $A^{'}$

$θ_{t}$ topocentric angular separation in degrees between the two satellites

$θ_{g}$ geocentric angular separation in degrees between the two satellites, taking the longitudinal station-keeping tolerances into account

$g_{1} (θ_{t})$ transmitting antenna gain of the earth station $e_{T}$ in the direction of satellite $S^{'}$ (numerical power ratio)

$g_{4} (θ_{t})$ receiving antenna gain of the earth station $e_{R}$ in the direction of satellite $S^{'}$ (numerical power ratio)

k Boltzmann's constant $(1.38 \times 1 0^{- 23} J / K)$

$I_{d}$ free-space transmission loss on the downlink (numerical power ratio), evaluated from satellite $S$ to the receiving earth station $e_{R}$ for satellite link $A$

Iu free-space transmission loss on the uplink (numerical power ratio), evaluated from the earth station $e_{T}$ , to satellite $S$ for satellite link $A$

Based on the above parameters the uplink and downlink $Δ T$ are given by:

$Δ T_{S} = \frac{p ^{'} _{e} g ^{'} _{1} ( θ _{t} ) g _{2} ( \partial _{e^{'}} )}{k l _{u}} Δ T_{e} = \frac{p ^{'} _{s} g ^{'} _{3} ( η _{e} ) g _{4} ( θ _{t} )}{k l _{d}}$

WORST CASE CALCULATION

When assessing a $Δ T / T$ value for a specific overlap, it is important that we are sure to be looking at the worst case that can occur for that overlap.

The worst case can be influenced by geometric and RF factors.

For each frequency assignment within a network filing there are often associated multiple carrier parameters and power levels. In other places, you may see reference to Most Sensitive Most Interfering (MSMI) analysis. The idea is that you find the wanted assignment with the lowest value of $T$ , and the interfering carrier with the highest EIRP density. This pair is then assumed to produce the largest $Δ T / T$ value.

In Visualyse GSO V3, for each overlap all possible values of $Δ T / T$ are calculated for all possible pairs and the highest value is displayed. This eliminates the need for MSMI analysis.

In combination with assumptions about worst case geometry', this produces a better estimate of the highest $Δ T / T$ that might be found.

SEPARATE UPLINK AND DOWNLINK CALCULATIONS

The methods of Appendix 8 and Recommendation ITU-R S. 738 are based on the premise that uplinks and downlinks are combined and that DT/T calculations for the overall link take this into account.

This requirement has lead to a proliferation of data required for the analysis - the so-called strapping tables.

Each strapping i.e. each possible pair of uplinks and downlinks has an associated parameter called the processing gain, and noise on the uplink is propagated through to the downlink.

1 Visualyse GSO V3 assumes that the topocentric angle $= 1.1$ times geocentric angle as per Recommendation ITU-R S. 728

The requirement to link the uplink and downlink for "simple frequency-changing transponders" results in a large number of permutations in the filing and in a large amount of review work for the BR.

Many proposals have been made to eliminate the need for this strapping information and to treat uplinks and downlinks separately in all cases.

This is what is implemented in Visualyse GSO V3. It can be shown that this separate treatment of uplinks and downlinks has little impact on the effectiveness of the coordination process, whilst greatly simplifying the filing and the data analysis.

In particular, it can be shown that separately comparing uplink and downlink $Δ T / T$ values against the $6%$ criterion will identify all the necessary cases for coordination just as thoroughly as comparisons done with the $△ T / T$ for each uplink and downlink combination.

In some cases, calculations using only separate uplink and downlink parameters may cause networks to be brought into the coordination process that would not be included on the basis of the combined link calculations. However, the extra analysis is not too much of burden when compared to the simplification it brings.

A study by the BR has indicated that:

"Treatment of uplinks & downlinks separately for calculating increases by about 5-6%, the number of administrations involved in coordination and by about $10%$ the number of networks involved in coordination. Number of networks omitted, when compared to the overall $Δ T / T$ approach, is marginal."

Coordination Arcs

Coordination Arcs are an attempt to simplify the coordination triggering process. The idea is that spatial separation of the satellites can provide sufficient advantage to ensure that no interference will be seen. Therefore coordination is triggered if two systems operate via satellites that are within a predefined orbital separation.

WRC-2000 implemented a coordination-arc approach to replace the Appendix 8 (∆T/T) coordination threshold, in certain frequency bands. The coordination-arc approach affects the 6/4, 14/11, and 30/20 GHz “commercial” satellite bands.

The coordination arcs are shown in the table

It remains possible to call for coordination with systems outside these arcs, provided you can demonstrate by calculation that the DT/T values due to a new network exceeds the 6% trigger.

A co-frequency GSO FSS satellite network within the coordination arc may also be excluded from the coordination when the increase in system noise to the network is less than 6%.

Visualyse GSO V3 can be used to check which systems are within the coordination arc relevant to the frequency band in question.

CASE	BANDS (MHz)		ARC
1	3400 - 4200 5725 - 5850 5850 - 6725 7025 - 7075	(Region 1)	$\pm 7^{\circ}$
2	10950 - 11200 11450 - 11700 11700 - 12200 12200 - 12500 12500 - 12750 12700 - 12750 13750 - 14800 14500 - 14800	(Region 2) (Region 3) (Regions 1 & 3) (Region 2) SRS or FSS	$\pm 6^{\circ}$
2bis	13400 - 13650	SRS	$\pm 6^{\circ}$
3	17700 - 20200 17300 - 20200 27500 - 30000	(Regions 2 & 3) (Region 1)	$\pm 8^{\circ}$
3bis	19700 - 20200 29500 - 30000		$\pm 8^{\circ}$
4	17300 - 17700	(Regions 1 & 2)	$\pm 8^{\circ}$
5	17700 - 17800		$\pm 8^{\circ}$
6	18000 - 18300 18100 - 18400	(Region 2) (Regions 1 & 3)	$\pm 8^{\circ}$
6bis	21400 - 22000	(Regions 1 & 3)	$\pm 1 2^{\circ}$
7	17300 and above	except those in (3) and (6) for FSS-FSS only	$\pm 8^{\circ}$
8	17300 and above	except those in (4), (5) and (6bis) and for non FSS-FSS only	$\pm 1 6^{\circ}$
-	13400 - 13650	in Region1 as indicated in Article 5.499A for SRS	$\pm 2 0^{\circ}$

Acronyms and Abbreviations

Acronym / Abbreviation	Description
BR	Radio Communication Bureau (of the ITU)
CR	Coordination Request
DC	Detailed Coordination
e.i.r.p.	Equivalent Isotropic Radiated Power
GSO	Geostationary Orbit
IFIC	International Frequency Information Circular
ITU	International Telecommunication Union
PC	Personal Computer
PM	Priority Map
SBE	Shaped Beam Editor
SF	Slot Finder
SNS	Space Network System
SRS	Space Radio Communication Stations

Visualyse GSO Maintenance History

This document describes the changes that have been made to Visualyse GSO for each maintenance release. If an existing feature has been modified, or a new feature has been added, information on how to use it can be found in the online user guide. To access this, select User Guide from the Help menu within the application.