Extended timeout for Inmarsat data (JAERO)

The "to-do" list for Virtual Radar Server is as long as my arm, but if you want to pile more work onto it then this is for you.
dsfh2992
Posts: 156
Joined: Tue Oct 06, 2015 9:57 pm

Re: Extended timeout for Inmarsat data (JAERO)

Post by dsfh2992 » Thu May 12, 2016 3:20 am

If a ModeS and JAERO feed are merged into a "merged feed" and sent to another VRS server via JSON, does the JAERO/non-JAERO flag get passed along for each aircraft?

dsfh2992
Posts: 156
Joined: Tue Oct 06, 2015 9:57 pm

Re: Extended timeout for Inmarsat data (JAERO)

Post by dsfh2992 » Thu May 12, 2016 5:18 am

agw wrote:I've uploaded a new preview today that changes the timeout handling for JAERO.

There are now two sets of timeouts, one for Mode-S / ADS-B feeds and one for JAERO feeds. The JAERO timeouts are measured in minutes, not seconds. The defaults might be a bit iffy, I'm not sure of the normal period between transmissions for those.

The receiver settings have a new checkbox that you can use to indicate that the feed is coming from JAERO. All aircraft on a feed with that box ticked will use the JAERO timeouts, if it's not ticked it'll use the normal timeouts.

When a JAERO feed is merged with a Mode-S feed the program will keep track of whether messages that gets used come from a JAERO source or not. If an aircraft is seen by a JAERO feed and then later on by a Mode-S feed then both timeouts will apply. VRS keeps track of the times of the last JAERO and last Mode-S messages and applies each timeout to the appropriate "last time seen" value.
So, should this work acceptably for planes flying from Mode S coverage to JAERO, and vice-versa? I am seeing some odd behavior that seems to normalize when I restart VRS (ie. planes under JAERO coverage appear/disappear/reappear, etc. - all well within the JAERO timeouts, so it's not that).

When you say "both timeouts will apply" what exactly does that mean? The shorter timeout will take precedence and remove the aircraft from the display?

agw
Posts: 2146
Joined: Fri Feb 17, 2012 3:20 am

Re: Extended timeout for Inmarsat data (JAERO)

Post by agw » Fri May 13, 2016 12:11 am

When you say "both timeouts will apply" what exactly does that mean? The shorter timeout will take precedence and remove the aircraft from the display?
No, there's no precedence, the timeouts are both applied independently.

VRS is keeping track of the last message time for both kinds of feeds, with the default last message time being the beginning of time. The JAERO timeouts are applied against the last JAERO message time and the Mode-S timeouts against the last non-JAERO message time. Once both timeouts expire it removes the aircraft from the display / tracking list.

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