Issue with coordinates

[Michael Schwartz 1143713]

I've had an issue with coordinates. It was first noticed when setting up the CRDA. I took the rw data for the necessary points but when I displayed the qualification zones they were way off. I was able to visually amend the coordinates until things were lined up correctly. Now I'm working on the volumes and when I tested things out the same issue appears to persist. Any ideas on why the coordinates are working?

[Ross Carlson]

You'll need to give a lot more detail ... screenshots of what you're seeing AND some indication of what you're expecting, would be helpful.

[Michael Schwartz 1143713]

Apologies for the delayed reply. Hopefully the below details shed some light on the issue. I feel like I must have just made a mistake somewhere but i'm definitely confused as to where it is.

 

This first picture shows the qualification zone for runway 10 at TJSJ aligned correctly. The coordinates in the CDRA can also be seen. However, in the following picture you will notice these coordinates I used to get the qualification zone to work do not reflect what vSTARS or Google Show.

https://prnt.sc/jgsimx

 

Based on what I entered into CDRA to get things aligned this is where the actual target point is.

https://prnt.sc/jgsjgn

 

Last image shows what vSTARS indicates the coordinates should be. As you can see they don't match what is actually inputted.

https://prnt.sc/jgsjwu

[Ross Carlson]

Can you post the facility file somewhere for me to download?

[Michael Schwartz 1143713]

Facility File:

 

https://www.dropbox.com/s/tsg1dniioq8l7di/vSTARS%20Facility%20-%20San%20Juan%20Approach%20%28SJU%29.gz?dl=0

[Ross Carlson]

As far as I can tell, everything is working correctly. I think you may not be realizing that the qualification region starts 3.0 NM away from the target reference point. I'm guessing you were adjusting the target reference point such that the qualification region starts right at the runway threshold. If that's the case, what you want to do is change your target reference point to be right at the threshold, and then set the "Near Side Distance" to 0.0 instead of 3.0.

 

Does that make sense?

[Michael Schwartz 1143713]

Thanks for taking a look at the file. You are indeed correct that I wasn't setting the near side distance to 0. I went ahead and made that change. Unfortunately, when I put in the coordinates for the threshold it still placed the qualification zone to the southwest. I'm not sure what I'm doing incorrectly. I've had the same issue with volumes, I believe everything with the volumes is set up correctly but when i've run tests the MSAWs are never detected and no alert goes off.

 

I'm I correct that the proper format for a polygon would be something along the lines of:

18.50748,-66.68424

18.56385,-66.67763

18.41742,-66.32832

18.41488,-66.25654

18.40376,-66.12274

18.44150,-66.12988

18.47124,-66.32044

18.54421,-66.58172

18.56465,-66.67339

18.50748,-66.68424

I've also tried the above with a space after the comma but no luck.

[Ross Carlson]

Go ahead and send me a new facility file with your changes and I'll take a look.

[Michael Schwartz 1143713]

Thanks for the help. I've linked the file where I changed back to what I think should be the correct target point coordinates for runway 10 and set the near side distance to 0.

 

https://www.dropbox.com/s/yga5kgly1db67ju/vSTARS%20Facility%20-%20San%20Juan%20Approach%20%28SJU%29.gz?dl=0

[Ross Carlson]

You've got the target reference point too far south. You want it at the runway threshold, which is at the following coordinates:

 

18.43358, -66.01316

 

Looks like maybe you're trying to enter the coordinates in degrees and minutes ... you need to use decimal degrees.

[Michael Schwartz 1143713]

Yeah, that will do it. Not sure why I didn't pick up on that. Just grabbed the point myself in decimal degrees and it worked perfectly. Apologies for the trouble and thanks again for the help!

[Ross Carlson]

No problem.

 

Note that I don't think they have the qualification region extend right up to the threshold in the real systems ... it's kinda too late to adjust spacing when the aircraft is that close to touchdown. I'm not sure about that, but the examples I've seen have the qual region start 3 miles out or so. You mentioned you took real world data ... are you referring to real world CRDA RPC data?

[Michael Schwartz 1143713]

It makes sense that the zone is set a few miles off the threshold. I simply meant coordinates not the actual CRDA. I don't have much knowledge on STARS just ERAM, simply trying to put together an updated file for the facility. I'll amend those zones based on you guidance. Thanks again for the help!