Frequently Asked Questions

The OpenSky Network was initiated in 2012 by researchers from armasuisse (Switzerland), University of Kaiserslautern (Germany), and University of Oxford (UK). The objective was (and still is!) to provide high quality air traffic data to researchers. By 2015, the OpenSky Network transitioned into a non-profit association based in Switzerland. OpenSky has taken part in two Horizon grants and is supported by a number of volunteers from industry government and academia. Researchers from different areas are using the data that is provided by people from all around the world.

Due to limited resources, our association's policy therefore is to grant free access to the full data set only to research institutions, aviation authorities, governmental organizations, and other non-profit organizations. This does typically not include personal learning and research purposes by private individuals, instead we have made many datasets available for such use cases (see below). We further preserve the right to control this access and in particular, to refuse access if we think the application is for example not ethical. You can apply for access here by giving us a brief description of how you will use the data and what data you need. If you are from an eligible institution, please use an affiliated email address! Please note that in any case, you need an account for our platform to get access to the data. Access to the full dataset is currently only supported via a Trino interface and can be used to calculate statistics or perform direct searches with small result sets. Beyond this, we release many pre-curated datasets, see our dataset page.

The OpenSky network collects raw air traffic control communication. We monitor the 1090 MHz SSR Mode S downlink channel, including ADS-B and also collect FLARM data and VHF/Voice. This means that we can provide on the one hand low-level data (down to single transponder transmissions) and on the other hand high-level tracking data of the form "at date and time T, aircraft A was at position X and altitude Y and moved into direction D at a speed of V".

Furthermore, we derive origin and destination of a flight from this track data where possible. The process is described in this paper. While we have began to integrate some route information into the live view of the OpenSky Explorer, we do not currently map this to commercial flight schedules. This means that we cannot give any information on, for example, scheduled flights, cancellations, delays, flight numbers, or passenger counts! While more information may be inferred by combining our data with other data sources, this is beyond the scope of our services. For crowdsourced aircraft metadata, you can use our aircraft database.

Generally, we don't have any data at all from before 2013 and have the best coverage in Europe and the US. Regarding our day-to-day coverage, you can check it on our Coverage & Facts page.

The technology which is used by the OpenSky Network is the Automatic Dependent Surveillance-Broadcast (ADS-B). The ADS-B allows airplanes to determine their position and velocity using GPS. Airplanes then periodically broadcast this and other information on the 1090 MHz radio frequency. To obtain this valuable information at a large scale, we operate a network of ADS-B receivers around the globe and harvest the data via the Internet. Our receivers are sponsored or hosted by private people, industrial partners, and academic/governmental organizations. If you would like to support the project by becoming a contributor or receiver host, please refer to this page.

The first thing you need is an ADS-B receiver. At the moment, we support the following devices: Radarcape and dump1090-based receivers (mutability and antirez forks) plus FLARM / OGN. In case you do not own such a device but you have access to a location with power supply, permanent Internet connection, a good line of sight in all directions and you are willing to host one of our devices for free, please refer to this page for more information. Once you obtain one of the listed devices, you need a free account for this website. You can simply create one by registering here. After logging in, you can add your receiver in the My OpenSky>Receiver Profile. After approval by one of our admins, your receivers automatically starts streaming the data to our servers. In case it remains offline, please check the receiver's setup, Internet connection, or contact us for further support.

We store all the data which is received by your receiver on our servers. The data includes reception timestamps, the position of the receiver, and the raw ADS-B message. We use this data to generate live views and calculate statistics. In addition, we share the data with researchers, and other networks. For examples on how they use they use the data, see the list of publications. Please note: if you do not tick the Anonymize-box in your receiver settings (see My OpenSky>Receiver Profile), the receiver's location will appear in the raw shared data. For more details, please check the data sample provided on github and have a look at our Terms of Use. If you have a different receiver device or your organization wants to share any other data with us, please contact us and we can work on a solution with you.

Yes there is! You can find it here: OpenSky API Documentation. Also read this as a starting point. We have language bindings for Python and Java. The API also supports retrieving historical data (within some limits though!). You can freely use the API for personal and non-profit applications but any commercial use requires our consent. Such commercial use includes, but is not limited to, selling applications using the API, advertisements on a web page/application using the API, and also internal use by any commercial for-profit entity that goes beyond testing and evaulating the quality of the data. If you have any problems, questions, bug reports, or ideas regarding the API, please use our forum and let us know.

Absolutely! We are happy to see and share the value of our Network. Please note that if you used our data, you must credit us by referencing us as the data source according to our Terms of Use. Also, in case you published your results in form of a scientific publication, we would like to add it to our publications list.

Yes you can, as long as your colleagues work in the same organization and only assist you with working on the project you mentioned in your application for the data. In case your colleagues want to use the data for a different project or organization, they also have to apply for the data (see "How can I get access to OpenSky's data?"). Please refer to our Terms of Use for more information. If your case remains unclear, we are happy to answer additional questions.

Yes! Sharing is caring and the OpenSky Network's philosophy is to give back as much as possible to the world. If you use any information of the OpenSky network, we would highly appreciate being credited with providing the information.

This can have many reasons. One common cause is that most Internet providers reset connections once during the night. This results in a short disruption of the receiver's connection to our servers. However, this distruption should not last longer than a couple of minutes. In case you observe longer outages, please contact us and we will help you to identify and resolve the problem.

If your receiver is up and running, this display can have several reasons. There could be connection issues for example. However, most likely there are simply no aircraft in range of the receiver at that point in time. If there are no aircraft messages send to OpenSky for an extended period of time, this receiver is then also shown as "offline".

Some airplanes transmit false or erroneous positions. Since we rely on the airplanes position reports for determining the range of a receiver, such erroneous position reports can result in wrong measurements for certain directions. The result is spikes in the ranges. Although we perform a lot filtering and reasonableness tests already, some of the bad position reports pass anyway.

We infer flights for both our Rest API and our Trino database in a nightly batch procedure from the ADS-B tracks collected for the finished day (UTC). For some more information on how they are derived, you can refer to this publication.

This also means that we only have historical flight data for previous days, no live flights and no commercial data about schedules, delays or cancellations etc (definitely no passenger numbers!).

We source our airports from the open source option ourairports.com. If your airport is not in the downloadable CSV or has an issue such as incorrect data, we might not be able to add them. We suggest you add it on their webpage and let us know about it in this forum thread.

We source our aircraft details such as transponder ID, registration, type or owner from various available sources. Besides such sources, we rely on your crowdsourced knowledge! As many countries do not make this information accessible, you can update missing or wrong information or add new aircraft in our aircraft database. Click "Edit airframe" on the respective aircraft page or go to this page to add a new airframe.

The OpenSky REST API is provided “as is”. We may change access policies or apply rate limits as needed to protect system performance.

To use the API, authenticate via the OAuth2 client credentials flow (recommended for all programmatic access):

1. Log in to your OpenSky account and create an API client to get your client_id and client_secret.
2. Use these credentials to obtain an access token:

   export CLIENT_ID=your_client_id
   export CLIENT_SECRET=your_client_secret
   
   export TOKEN=$(curl -X POST "https://auth.opensky-network.org/auth/realms/opensky-network/protocol/openid-connect/token" \
     -H "Content-Type: application/x-www-form-urlencoded" \
     -d "grant_type=client_credentials" \
     -d "client_id=$CLIENT_ID" \
     -d "client_secret=$CLIENT_SECRET" | jq -r .access_token)

3. Include the token in your API requests:

   curl -H "Authorization: Bearer $TOKEN" https://opensky-network.org/api/states/all

Rate limits and API credits

Rate limits currently apply to: /states/all, /flights/*, and /tracks/all.

🔥 For full details, please refer to the official API documentation.

Special access for researchers

Institutional (typically academic) researchers can request unlimited API access, including historical data. For non-profit causes with significant impact, please create an account and raise a data request.

If you think an aircraft should be there but isn't, there are two main reasons. a) It might be outside our coverage (too low, no sensor close by). b) It might not support ADS-B or FLARM but only Mode S, which does not provide a position but only the altitude. In this case, it should show up in the search box of the Explorer but naturally can't be displayed on the map. As we currently do not offer multilateration (MLAT), this affects also some military planes. Please note that those military planes that *really* do not want to be tracked will switch their entire transponders off. Either way, they are not being filtered.