«

»

Tracking Software

APRS Tracking

At the heart of our ballooning program is our tracking system. After all, what goes up must come down, and if we don’t have a tracking system we’ll never recover our payloads! For the past few years we have used a system called APRS, or Automated Packet Reporting System. APRS is a widely used standard in the ham radio community that (roughly speaking) defines a data protocol, a packet protocol and a wavelength. Ham enthusiasts use the APRS standard for many things, but one of the most common is reporting GPS position from a moving station (car, boat etc.). APRS is so popular that many ham radio operators have set up automatic radios that automatically receive  APRS packets and forward them to databases on the internet where they can be freely plotted and followed on a map. We use this to follow our flights on http://aprs.fi/ when we are not in the chase vans.

The tracking system for our ballon system has two parts. On the balloon end we have a commercially available BeeLine APRS system from Big Red Bee. The BeeLine contains a GPS system, a Terminal Node Controller (TNC) and a radio transmitter. The TNC is essentially  modem for the radio, translating the GPS data, once a minute, into a series of audio tones that are transmitted via the radio transmitter.

On the ground, in the chase vans we have a Kenwood radio with a built in TNC. Tuned to the right frequency (in this case 144.390MHz), it will interpret the incoming radio signals and output a serial port stream of characters for each packet. To extract the position from this packet and plot it on a map, we rely on a laptop running two programs: UI-View and Precision Mapping. UI-View reads the serial port and translates the APRS packets into a set of positions. It then requests a map from Precision Mapping and plots the balloon position on this map.

Plotting Positions

The set of these two programs has been very useful and has allowed us to make dozens of successful  flights, but they are very frustrating to use and lack many features that we really would like to have:

  • The map interface is quite old and navigating it is difficult and unintuitive. The interface also shows only the most recent position. Finally, the only map available is a street map. Satellite views are unavailable.
  • Only a single person can use the software at a time.
  • There is no ability to do a live prediction for the landing location

What we would really like is a system that is as easy to use and intuitive as Google Maps, can be used by everyone in the van, and allows us to “crunch” the APRS data to produce predictions, plots, etc. The current system isn’t extendable so we have decided to go ahead with the development of an entirely new tracking software based on a more modern web-app paradigm.

What we would really like is a system based on a single server attached to the receiving radio in the van. This server would read the serial port, decode the APRS packets and create a database of flight positions. It would act as a wireless access point and html and map server for any laptop, smartphone or tablet in the van. Tracking the balloon wouldn’t require any special software: simply point your browser at the correct URL and a javascript page would load that would implement a “google maps” style interface with the balloon positions plotted. With a little tweaking of the code we could implement predictions, plot telemetry stored in the “comment” fields of the APRS packets, or compare current locations and path to the predictions from before the flight. We think this would make  the tracking experience much better, especially for larger groups of participants. Everyone could follow along and make comments.

Ted Freeman is leading the Far Horizons Tracking Software efforts. If you have any questions or would like to contribute, just give a shout. We need help in programming, design and testing. A good tracking software system would be a major improvement for our program.

Hack Day

This weekend the Adler is hosting Hack Day Chicago so the place will be crawling with hundreds of programmers, tinkerers, hackers and just generally fun folks. If you missed your chance to register for the events you can still come in to the lab and enjoy a day of hacking on Far Horizons!

NATO Summit

Don’t forget that next weekend the Adler will be closed for the NATO summit. So no Lab Saturday on May 19th!

Permanent link to this article: https://farhorizonsproject.com/blog/tracking-software/

2 comments

  1. Mick

    There’s no need to reinvent the wheel; I’m fairly sure we could get a free license for the google maps API here.

    https://developers.google.com/maps/

    Microsoft launched a Lumina 900 into space and it reported back data at normal rates. I think we should just buy a used smartphone, and put tracking software on it a la, ‘where’s my iPhone?’ and distribute the tracking number. However, we would need to pay the data fees.

    1. gezagyuk

      Absolutely! Reinventing would take forever and we’d end up with a worse product in the end. Openstreetmap has a nice set of map tiles that are free for us to download (within reason in terms of load on their servers). There are a bunch of readily available javascript libraries (OpenLayers) that let us put together “slippy” maps with the standard intuitive drag and click type interface in just a few calls. From these we could then layer on functionality. We will have to download the maps tiles since we need to be able to run this out in the field where internet coverage is spotty. Some good javascript coding skills are what we chiefly need to get this going.

      As for using a cell/smart phone, we’ve thought about this, and would really like to do it, but unfortunately putting a cell phone on a balloon is actually illegal! FCC (not FAA) regulations prohibit airborne cell phones. While I don’t think we’d get into much trouble with the occasional flight, better safe than sorry…

Leave a Reply

%d bloggers like this: