Insufficient Visibility Coverage for Large Airspace

[Rob Killins 897126]

The Edmonton FIR (CZEG) in Canada covers a geographical area in excess 2 million square nautical miles, with a perimeter close to 7000 NM.

Centre controllers are capped with 600NM visibility ranges, theoretically covering 1,130,400 NM (3.14x600x600) of geographically. With positions entitled to a maximum of four vis points, CZEG's area should be able to be adequately covered with four vis points.

 

Here is a Google Earth projection of CZEG with the vis points plotted in. Each yellow circular polygon (visibility range) represents an area from is drawn from a 600NM radii (1200NM circomeference). The FIR boundary is in green.

 

 

The 4 vis point centres are coded into the ESE position for CZEG_CTR, an individual centre controller for the entire FIR. They login with a defaulted 600NM visibility range for centre positions.

 

This is how Euroscope depicts the 600NM range circles. With the ES measurement tool, they measure 1200NM across.

 

 

Look at the huge areas without visibility! Why is there such a difference between Euroscope and the exact same projection on Google Earth? (my guess is projection deficiencies) The FIR is no bigger in Euroscope than it is in Google Earth (the exact same co-ordinates for the FIR boundary were applied to both ES and GE).

 

I would be grateful for any advice on where I may have went wrong in perhaps my math, my application of visibility points, the writing of the sector file. We would be extremely grateful for any advice on how we can overcome this inability to get full coverage of our FIR. Mathematically, it should be no problem ... but even with 4 coded vis points in ES, we are not getting near the coverage expected, whereas in GE, the same vis points with the same radii demonstrate that it should be doable.

[Halldor Bui Jonsson]

isnt CZEG allowed to use FSS , and therefore have 1500nm visbility for each ring?

[Jake Saw]

Rob,

 

Whilst I can't really explain why there is a difference between ES and GE (I'm sure someone else can), do you realise that the server hardcoded pilot radio range is 400NM for CTR positions?

 

That is, even though you have set the range to 600, pilots will not be able to "see" you as a controller in their pilot clients outside of 400NM from each visibility point.

 

We had to work around this limitation when implementing the YMMM and YBBB FIR super sectors in Australia. We could not cover the entire area required due to this limitation and ended up getting permission from VATSIM to use FSS logins. This may be something for you guys to consider (and it sure makes picking the ideal locations of vis centres easy!).

[Rob Killins 897126]

Thanks folks for the replies.

A bit disappointed that the ES designers had no response ...

Sadly, it looks like there will be no ATC services to pilots in the north of CZEG.

[Andreas Fuchs]

Hi Rob,

 

there's nothing that the ES-team can do about it, because the ranges are hard-coded in the servers. You need to get approval to use FSS for this sector, that's all.

[Rob Killins 897126]

I suppose I was seeking confirmation as to whether it was a sector development issue, a user misunderstanding of the application, an ES issue, or VATSIM issue to help isolate the problem may have helped. I was looking for an explanation as to why the circles were so far deviated from their equivalent on the GE projection. Perhaps, ES could have said their map projection inaccurately portrays geography further north ... I can only speculate (which is unfair) until the developers clarify.

[Todor Atanasov 878664]

As far as I know G was away.

As for the vis points, as Andreas said, the range is hard coded in the servers, not in ES. ES sends the coordinates of the vis points and the servers decide which track is in that range and send it to ES. Yes there is a little distortion further North (South) and if the sector is too big, but the overall result is quite good.

 

As for the difference in Google and ES, the projection is not the same.

[Marvin Palmer]

Based on my inital look...you showed the visibility rings before you logged in...it will give you an incorrect ring size before logging in VATSIM servers.

 

Connect to the network and do a .showvis....that should give you an better picture of your visibility rings, plus you can adjust as needed to get the coverage you need.

 

Cheers

 

Marvin

[Rob Killins 897126]

Hi Marvin,

 

Thank you for for your observation and reply. I was certain I was logged in used the .showvis command to prepare the image I provided, but I with hopeful optimism, I tried again as you had suggested. Sadly, there was no change, and the image provided is indeed that of a logged in CTR controller.

 

Cheers

[Marvin Palmer]

Ok, CZEG is rather large when it's displayed as a flat map...do you have traffic in the Artic region? maybe move point four (4) down or south and move it as needed while controlling for the Artic traffic?

I know these are work arounds, just some ideas.

 

Marvin

[Rob Killins 897126]

Hi again Marvin. Outside ideas and suggestions are always welcome. Sometimes we overlook things, or are on a narrower train of thought, and it takes the creative discoveries and experiences of others to help resolve a problem.

 

Yes, we have concentrated our four vis points to the southern portion of the Arctic Sector where most traffic transits. However, we're forced to loose a lot of that coverage though when we have to share those 4 points among the remaining 3 sectors to the south when one controller controlls the entire FIR.

 

Sadly, just a limitation we have to deal with. Still a wonderful application. Thankfully there is minimal traffic to the far north.

[Marvin Palmer]

I guess it begs the question of...can you add more vis points?? is this an software constraint or server?

 

Is there a way to code 6 or 7 vispoints without bogging down VATSIM servers, or is this going to be a known problem.

 

I've engineered the Alaska region from scratch for the Euroscope client and run into similar issue of dead space. a lot of the Arctic region is not covered and the entire area west of the W180/E180 line. Small annoyance but still an easy workaround.

 

Marvin

[Kirk Christie]

You can only set 4 Vis Points

 

Maximum Radio range is 400NM, despite having 600NM as your Vis Range

 

FSS has a Radio range of 1500NM, suggest you contact your VACC and ask them to apply for a FSS position for this Sector.

 

There is no other way to work around this if you cant fully cover the sector using 400NM range rings and 4 vis Points

[Gergely Csernak]

I just would like to confirm that the distance measuring tool in ES is far too simply at the moment and uses a really general projection that can show false values when you are close to the poles. That is my job to make a better one. On the other hand I also confirm that it has no effect on visibility and radio ranges as all these are coded in the servers.