Payload Tracking – Radio or Satellite? Both!

A quick post with lots of pictures. If you backed the previous Starduster project, you may already know this.

One way we track the balloon and payload is using a GPS tracking device. This particular piece has lots of positives and just a few negatives.

For one, it’s SIMPLE to use. We turn it on, punch the tracking button and because it’s satellite based, we are virtually guaranteed to get a series of location reports as long as it can see the sky to communicate with the GPS constellation overhead. It’s not the cheapest option but I own one already and I pay the monthly subscription for these projects and hiking/backpacking/international travel to keep family up to date with [exactly] where I am.

They have a great website tailored to my device and there’s a proven iPhone app that tells me where this thing is located down to 5 or 6 decimal places. Screen shots below.

The downside to using this device is that it’s built for backpacking which more-or-less takes place on a 2-dimensional map and doesn’t take altitude into account for reporting. It also only reports movements every 5 minutes as long as it’s below ~24,000ft. What this means for the project is that we’ll get 10-12 points of location data on the way up and 3-5 points of location data on the way down; and none of that data shows altitude. So technically we don’t even know we’ve landed until we get 2-3 reports over 10-15 minutes from the same location.

One of the main objectives for this project of course is partner with the BARC and use the APRS system for real-time tracking at 5-10 second[!] intervals including lat/long and altitude up to 275,000ft. Jacob posted about that last week and testing is going well.

Jacob and the radio guys feel like their equipment is good enough from launch to landing for tracking and I think we’ll get reports that will be awesome to see in real-time BUT we need to experiment more with what happens the last 1000-3000 feet when the radios disappear from our line-of-sight. I’m REALLY excited about this part of testing and maybe it’ll prove to work perfectly or maybe we need some improvement with a DF (direction finding) radio.

As it stands, I think including this little ‘proven’ 1/4 pound device into the payload is a solid backstop for payload recovery and worth every gram.

Stayed tuned!





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