Balloon missions almost always have some sort of data collection
and image taking purpose. Who doesn't want to see the curvature of the earth
from 20 miles up taken from their own high definition camera? And of course
there is no point in launching data collection electronics or a camera if you
have no plan for recovery. Consequently, balloon missions nearly always have a
strategy to observe -- in near real-time -- the balloon’s latitude, longitude,
and altitude from launch to touchdown with web-enabled tools. Near real-time
tracking also feeds into the FAA’s interest in steering aircraft around your
operations.
There are multiple philosophies and multiple methods employed
for balloon tracking. Ultimately, the selected method is answering the question,
“How willing am I to loose the payload because of the choice of tracking
approach?”
As lift and payload costs are rarely inexpensive, the answer to
this question lends towards being conservative. Lift costs can run between $200
and $300 for a modest payload. Nice lightweight high definition cameras (e.g.,
a Go Pro) can also run a few hundred dollars. As a result, best practices are
to install two independent tracking methods – despite the added weight of a
dual system.
Two common tracking information systems are a: (1) radio beacon with
encoded GPS data and sent from an on-board ham radio transmitter to connect
with what is called the APRS network, and (2) commercial tracking device that
communicates location data with a satellite network linked to web-enable
location tools.
APRS: In the United States, a VHF transmitter is typically
broadcasting GPS packet information on 144.390 MHZ. This is the frequency
reserved for location device data and collected by a network of listening posts
called APRS. A SPOT is a commercial
tracking device that is readily available for purchase at electronics retailers
or rent by hiking gear outfitters. The SPOT’s tracking information is provided
in near real-time on on a Google-map web-site for easy visualization.
SPOT is a
satellite-enabled beacon capable of relaying GPS location data from any open
sky location around the globe up to about 25,000 feet.
