Home Automatic Packet Reporting System (APRS) APRS Use Cases APRS and High Altitude Ballooning (ARHAB)

APRS and High Altitude Ballooning (ARHAB)


  • Introduction
  • ARHAB Announcements
  • Observing ARHAB Flight
    • Tracking ARHAB Flights with APRSISCE/32
    • View ARHAB Flights on findU
    • View ARHAB Flights via aprs.fi
  • Country Specific Information
    • United States of America
      • Interfacing with the FAA
      • APRS/EOSS/FAA Balloon Report Page
    • Canada
      • Canadian Regulations
    • United Kingdom


The ability of APRS to provide three-dimensional locating and tracking is a key component of high-altitude ballooning.

A very thorough web site describing the many facets of Amateur Radio High Altitude Ballooning and how APRS is used to track balloons is the Edge of Space Sciences -EOSS web site; well worth the time spent looking through it.

Each summer, many of the balloon groups from around North America gather for the Great Plains Super Launch (GPSL) where multiple high-altitude balloon flights are conducted.

GPSL provides a forum for exchange of ideas, and sharing of information between the many groups involved in high altitude balloon experimentation.

ARHAB Announcements

The ARHAB.org website is an excellent resource for anyone interested in High Altitude Balloon projects. A current list of all know upcoming flights is maintained on the ARHAB launch list page. If you are going to be flying an ARHAB flight, you can enter information about your group and flight through this link to the launch form. Many members of the ARHAB community enjoy observing flights by others, and this page allows everyone to know what events are upcoming. A YahooGroups mailing list is maintained that is used to send out email announcements about upcoming flights as well. There is also an automated script running that scans the APRS-IS data stream for APRS activity that looks like a balloon flight by S3 Research This system can also send email alerts to notify you of a flight currently underway.

Observing ARHAB Flight

Many ARHAB flights use the APRS tracking gear to report location information to ground tracking stations. Most chase and recovery teams listen to the information from the balloon directly on RF using radios and computer based tracking software such as APRSISCE/32 and UI-View. A ground based network of stations also gather the information and forward it to the APRS-IS where it can be observed using web based tools. FindU.com, aprs.fi, db0anf.de, and OpenAPRS.net among others can show you not only maps indicating the location of the payload, but other information as well.

Tracking ARHAB Flights with APRSISCE/32

APRSISCE/32 is a Windows based APRS client that runs under Windows on desktops, laptops, or notebooks, or Windows Mobile running on Smartphones or other mobile devices. APRSISCE/32 can interface with just about all of the available hardware that supports APRS operations. Live data received from the payload will be displayed on screen without the need for any outside infrastructure. A number of features are built into APRSISCE/32 that help with the observation of ARHAB flights, such as radio range circles (based on reported altitude), and projected payload location dead reckoning derived from last reported course and speed. Using APRSISCE/32 for ARHAB support is covered in more detail on the APRSISCE/32 Wiki.

View ARHAB Flights on findU

A good way to monitor balloon launches is to use the tracking and maps available in findU. Open these four findU links, each in a different instance of your browser,

[Location of Balloon] – [Track of Balloon] – [Altitude of Balloon] – [Nearby APRS Stations]

You will need to change the callsign of the balloon in the URLs to match the callsign of the balloon you are interested in if it is not AE0SS-11. In the location link, change to the USGS maps and zoom in or out to see aerial photos of the area beneath the balloon current location. In the track link, you can change the degree viewed parameter to zoom in or out. In the altitude link, you can change the number of hours by changing the last parameter. In the nearby stations link, go to the bottom and select the map option and you’ll see the locations of nearby stations and often these will be the tracking and recovery vehicles chasing the balloon. Since each of these is in a different instance of your browser, you’ll be able to have all four windows open and on the screen at the same time to make it easier to follow what’s going on. Some of the links have to be updated manually to see the current data.

View ARHAB Flights via aprs.fi

Heikki Hannikainen runs and maintains the aprs.fi server in Helsinki, Finland. You can quickly get a map of the station in question by using a shortcut such as http://aprs.fi/va6tny-11. This will bring up a map centered on the last known location for the station specified. You can limit the display to only the station of interest, or you can have all known current stations shown on the map display as well.

You can tell aprs.fi to track multiple stations at a time by using a comma separated list in the URL. http://aprs.fi/ve6sve-3,ve6sve-5 This can be handy when sending out an email notification as you can put all the callsigns to be tracked in the URL, including all payloads, as well as the chase crews if desired. You have the ability to change to terrain maps, as well as satellite maps anywhere in the world, as well as to have the site provide a KML file for use with Google Earth to observe the flight in a live 3D observational medium. Historical data can be downloaded via the aprs.fi site as well, allowing for post flight data gathering.

If your payload is sending telemetry information, aprs.fi can display properly scaled and labeled telemetry provided that the appropriate telemetry definitions have been sent.

Country Specific Information

United States of America

Interfacing with the FAA

If you are going to become involved in Ballooning (or balloonacy, as it is sometimes called), it is important to realize that the airspace is shared among different users and that the Federal Aviation Administration (FAA) has responsibility for making this sharing arrangement work. The [Federal Aviation Regulations PART 101] is the main FAA document relating to Moored Balloons, Kites, Unmanned Rockets and Unmanned Free Balloons and is one of the ways that balloonacy is kept from becoming lunacy.

Mike, W5VSI, has written several very helpful items on how to interface with the FAA regarding amateur ballooning. An important ballooning/FAA subject is [payload weight] and what has to be done when [payloads exceed 6 lbs]. Another important thing to master is knowing [how to speak the FAA language]. Also important, is [what EOSS does] to reduce the risk of an air-to-air collision.

APRS/EOSS/FAA Balloon Report Page

APRS can also be used to interface with the FAA and to inform Air Traffic Controllers on the position of a balloon as it traverses the controlled Airspace. If the balloon payload includes an APRS tracker and if the position reports from that tracker get to APRS-IS, the FAA controllers can be made aware of the current balloon position and altitude in near real-time. This is what EOSS has done since 2003 and it has worked very well and received high praise from Denver FAA personnel.

The APRS/EOSS/FAA Balloon Position Report

– [Balloon Report Page Entry 1] – [Balloon Report Page Entry 2]

These two pages both provide identical entry set-up pages for tracking the balloon through findU and providing this tracking information relative to VORs, which is the way that commercial aircraft are tracked by the FAA (more explanation in the link on how to speak the FAA language in the previous paragraph). The FAA ARTCC personnel can look at the Balloon Report Page and see the bearing and range to the balloon from two different (and selectable) VORs in near real-time and relay this information to pilots. A controller or other user simply selects the balloon and two VORs and presses “submit” and then selects the standard findU location page, the track page, the altitude page or the page that shows the location relative to VORs. The choice can be either by IP address or by DNS selection. The displayed Balloon Report page updates automatically every 60 seconds.

Usually, in the preflight period, the APRS tracker position is not on findU. So, there are usually one or more available test sites, with callsign CWxxxx, that can be used to test the Balloon Report Page capability. The latitude and longitude of the test site can be found by entering the callsign into the search box located.

To see a list of registered balloons or of VORs available, just leave that selection blank and press “submit” and the current list of VORs and their location will be shown. You can check the location of a particular VOR by entering the latitude and longitude into the URL of this [aerial photo of EMP VOR] and check that the image shows the VOR.

Upcoming balloon flights can be registered by sending a request to russ at wxqa dot com. New VORs can be entered into the list, but that takes 1-2 weeks to find, enter and verify VOR location and get that information updated on the two Entry Points and on findU.

A key part of the Balloon Report Page is the participating amateur radio opperators who operate I-Gates and relay the position information that they receive from the balloon to APRS-IS and findU. There is a more detailed [explanation of I-Gating for balloon flights] that gives some of the reasons for I-Gating. An import reason is to use redundant I-Gates to improve reliability. There are four items that have to function for the Balloon Report Page to work. They are: 1)the Balloon Report Page Entry point; 2)the APRS tracker on the balloon; 3)the I-Gate link to findU; and 4)the findU server. Imagine that there is no redundancy and that each of these four items is independent and is 99% reliable. Then, the overall probability of working is (0.99)^4 or about 0.961. However, in reality, there is redundancy that improves this reliability. As pointed out above there are always two entry points. Often, there are two APRS trackers on the balloon. Usually there are two (or more) I-Gate operators and the findU server is actually two independent servers. Two items, each with 0.99 reliability, have reliability of 0.9999 when used redundantly. With this redundancy, the overall probability of working is (0.9999)^4 or 0.9996. So, in reality, the Balloon Report page is quite reliable due to the redundancy that is part of the system.


Canadian Regulations

The Canadian regulations pertaining to ARHAB flights appears to be a partial copy of the United States Regulations. The Canadian Aviation Regulations (CARs) Part VI – General Operating and Flight Rules Part VI – General Operating and Flight Rules 602.42 describes ARHAB Balloons in Canada.

Large Unoccupied Free Balloons

602.42 No person shall release an unoccupied free balloon having a gas-carrying capacity of more than 115 cubic feet (3.256 m3) except in accordance with an authorization issued by the Minister pursuant to section 602.44.

Authorization by the Minister

602.44 The Minister may issue an authorization referred to in section 602.42 or 602.43 where the release of the balloon or the launch of the rocket is in the public interest and is not likely to affect aviation safety.

A call to your local Flight Service Station (FSS) well before the flight advising them of your intention to fly a large unmanned balloon is a good idea. Be prepared to give the location, date and time of the flight along with the proposed rate of climb, maximum altitude, and area where the payload will end up. Just before launch, call the FSS to advise them of the imminent launch. This information will allow the FSS to issue a Notice to Airmen (NOTAM)for the day of the flight, and also to ensure that air traffic does not come into conflict with the balloon payload.

United Kingdom

Amateur radio operators in the United Kingdom are prohibited from operating an airborne station, and thus all HAB communications take place on frequencies outside of amateur regulations.