ARHAB - Amateur Radio High Altitude Ballooning
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 the country gather for the Great Plains Super Launch (GPSL) and multiple high-altitude balloon flights are conducted. This happened on Aug. 5, 2006 near Hutchison, KS. Many photos and other information from this year's GPSL are [here]. The 2007 GPSL will be held near Grand Island, Nebraska.
View ARHAB Flights on findU
A well-kept list of [upcoming ARHAB launches] is available, and a good way to monitor these launches is to use the tracking and maps available in findU. Open these four findU links, each in a different instance of your browser,
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.
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 become 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 Page can be reached by two different and totally redundant URLs,
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 [here].
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.