PE Traffic Output Data Format

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NameCoin
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PE Traffic Output Data Format

Post by NameCoin »

Hi there. I was recently thinking about the PE client link to ForeFlight, which sends traffic information via one of the X-Plane data messages. I was wondering if anybody happens to know where that data is coming from and what the data format is. I'd like to use it in a few personal MATLAB tools (e.g. simple TCAS / traffic display).

Thanks!
Keith Smith
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Re: PE Traffic Output Data Format

Post by Keith Smith »

This is the protocol that I used to integrate the PE client with ForeFlight:
https://www.foreflight.com/support/network-gps/

If you'd like to drive something other than ForeFlight, just point to the IP that's bound by your own application and you'll receive that data on the port that's listed in the specification.
NameCoin
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Re: PE Traffic Output Data Format

Post by NameCoin »

Great, thanks Keith. I've successfully collected and decoded the data from the PE plugin. Truth be told, I was extremely confused by the ForeFlight post on the data format. I figured that the initial part of the message would be the 'XTRAFFICMy Sim' string, and the rest would be a numerical format like singles. This even seemed to be implied when they referred to position data as floats. I then couldn't understand why I was seeing five or so bytes per field, as that isn't a standard floating point representation. It wasn't until I looked at the packets in Wireshark that I realised the whole message was just a string.

It's kind of curious that they wouldn't just take the values as singles, as they would just take up four bytes each and you could have better than just two or three decimal places of precision. (Not that you can really tell the difference on a moving map anyway, for application to ForeFlight.) I think the .001 degree resolution in longitude translates to about 350 feet, or a 175-foot uncertainty. Hopefully that's more than enough for my application.

Thanks again!
barcman1967
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Joined: Wed Oct 07, 2015 12:29 pm

Re: PE Traffic Output Data Format

Post by barcman1967 »

Forgive me if if this has been asked before. I use ForeFlight but I am wondering if there is a way to have the native TCAS in X-Plane provide PE traffic.
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