Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Flightradar24 – how it works

habr.com

Post reply on HN
Print view View original

71–80 of 160 posts

Re: Flightradar24 – how it works

#71

Post by godelski »

jacobreg wrote: post #15
fergbrain wrote: post #3

“Every civilian airliner is equipped with a special device — the so-caller ADS-B (Automatic Dependent Surveillance-Broadcast) transponder” Not true actually: in the US, ADS-B isn’t required until January 1, 2020 [1]. Also, FR24 uses radar data in the US (probably because not all aircraft has ADS-B) [2]. There are also sites, such as ADS-B Exchange [3] that provide unfiltered flight data...very helpful for tracking mi…

Even after 2020 ADS-B out won't be required in much of the airspace in the US. Only within 30 nautical miles of a class B airport, within the lateral limits of a class C airport, within class D airspace, and above 10k feet (but not below 2500 AGL I think). Even then, its only required for aircraft originally equipped with an alternator and electrical system (except in class B). Basically, it's optional in most uncont…

To be fair, that's going to include the vast majority of aircraft. Most people will be above 2500AGL if they're not flying for very short distances. That said, there's always people that just like to fly in an unsafe manner.

Re: Flightradar24 – how it works

#72

Post by netsharc »

phkahler wrote: post #50

Is there a simple solution to get a basic offline map (OSM maybe) and use a pi without internet as a radar display at my local non-towered airport?

If you're only showing the area around the airport, even a static PNG of the map would work, would it not? Obviously you'd need to figure out the offsets, etc to draw the planes "on top" of the image (if we're talking about an HTML page).

Re: Flightradar24 – how it works

#73

Post by upofadown »

heavenlyblue wrote: post #70
remus wrote: post #64

Earlier quoted context omitted.

That seems very odd. Somewhat similar to putting up a billboard then saying it's illegal for people to read it, as the billboard wasn't intended for them.

Someone putting a car in the middle of nowhere doesn’t leave it there for anyone ti pickup.

But it is pretty OK to look at the license plate...

Re: Flightradar24 – how it works

#74

Post by tialaramex »

heavenlyblue wrote: post #70
remus wrote: post #64

Earlier quoted context omitted.

That seems very odd. Somewhat similar to putting up a billboard then saying it's illegal for people to read it, as the billboard wasn't intended for them.

Someone putting a car in the middle of nowhere doesn’t leave it there for anyone ti pickup.

But we are not "picking up" the car. The car is still there for its owner. We only recorded the presence of the car (radio transmission) for our own purposes and it is unmolested.

Re: Flightradar24 – how it works

#76

Post by jacobreg »

godelski wrote: post #71
jacobreg wrote: post #15

Earlier quoted context omitted.

Even after 2020 ADS-B out won't be required in much of the airspace in the US. Only within 30 nautical miles of a class B airport, within the lateral limits of a class C airport, within class D airspace, and above 10k feet (but not below 2500 AGL I think). Even then, its only required for aircraft originally equipped with an alternator and electrical system (except in class B). Basically, it's optional in most uncont…

To be fair, that's going to include the vast majority of aircraft. Most people will be above 2500AGL if they're not flying for very short distances. That said, there's always people that just like to fly in an unsafe manner.

Sorry, I may have worded that confusingly. The important number is 10,000 MSL. If you don't go above that you don't need ADS-B (as long as you stay out of the other airspace mentioned). They make an exception for people flying around high terrain, so if you are above 10,000 MSL but below 2,500 AGL then you are also exempt.

Re: Flightradar24 – how it works

#77

Post by natch »

Bait and switch app. They convinced me to fork out for the fully paid version, then switched to a subscription model that froze current features for those who had supported their work, adding a nag and an implied threat of end of life. Stay away.

Re: Flightradar24 – how it works

#78

Post by bicubic »

Rebelgecko wrote: post #44
RivieraKid wrote: post #22

Not a big fan of "data monopolies" like Flightradar24. It's as if OpenStreetMaps was a private company that capitalizes on being first into the space and having a community of contributors willing to supply data to a private company for free. I hope an open data project such as https://www.adsbexchange.com/ wins in the long-term.

There's also https://opensky-network.org/ Their API is actually a bit more open than adsbexchange's

How is the data coverage compared to flightradar?

Re: Flightradar24 – how it works

#79

Post by wbl »

theyinwhy wrote: post #53
loeg wrote: post #51

Earlier quoted context omitted.

Do you have more detail on how collection messes with MLAT calculations? It seems like for triangulation purposes, each device should produce some precise timestamp that is not affected by store-and-forward transmission.

Unfortunately, there is no good solution for this. Either you rely on the time settings of the sender or on the time needed to transmit the data and on the time the data gets transmitted.

A radio receiver with a GPS time base doesnt seem that tricky.

Re: Flightradar24 – how it works

#80

Post by pard68 »

ronsor wrote: post #69
pard68 wrote: post #65

Earlier quoted context omitted.

I want[ed] to get one but the options are overwhelming. I dislike buying not-the-best product. I also dislike eBay, which seems to be one of the main methods of purchasing a setup (have been burned too many times by sellers).

Buy the kit from rtl-sdr.com -- no need to use ebay and they are the best option for a beginner

Thanks! Bought one for myself and a second for my Ham radio enthusiast father.
Post reply on HN