Long range, low bitrate, small data transceiver unit for telemetry data

There are many regulations in many countries. Also the air regs vary from place to place in the same country. You need to consult the air maps.

You may be able to do "anything" where you live but try flying anything over the residence of your local head of state and see what happens. (survivors may like to re-tell their experiences here :-)

What may be fine for photoing an archaeological sight is a field will get you arrested (at best) when you balloon strays a km and finds itself over an unmarked military installation. Some places are more sensitive than others and they don't always tell you beforehand.

This all stems from a surveying trip I was going on the ruins of the fort were, we discovered, not to far from a "secret" military staging area. We were foreigners in the country :-)

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\/\/\/\/\ Chris Hills  Staffs  England     /\/\/\/\/
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Start with the AIP (Aeronautical Information Publication) of your own country.

In my country, Finland, the current aerial photographing regulations are pretty liberal. The most important prohibited photo targets are military installations and penitentiary units. When I started the aerial photographing (a couple of tens of years ago) all negatives had to be given in for inspection before copying. Also, the list of prohibited targets was much longer.

AFAIK, the same targets are banned in all ICAO countries.

You may be surprised to notice that most maps are else accurate, but there are things that are not mapped for public distribution.

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Tauno Voipio
tauno voipio (at) iki fi

Another low bitrate satellite service that is available worldwide is Inmarsat D+. This provides bi-directional communication to small mobile terminals most places more that 5 degrees away from the poles. The smallest terminal available is the SAT-201 which is around 4.5 inches in diameter and 2 inches tall. More info from

Ian

Thank you for the link and information. It is very intereting. On their brochures

they say data transmission rate from terminal to satellite is ~10bits per second and receive bitrate is 9 bits per second. They also say "By pressing a panic button, the message transmission frequency can be dramatically increased - for example, to every few minutes, to provide Search and Rescue authorities with rapidly updating position reports." which is very good for the applications given in their web site.

I'm afraid our applications requires almost continious communication between ground station and balloon at 1200-19200 baud and that's why Satamatics's terminals would not be appropriate for our application. But it is good for me to learn the existance of such an alternatives. Thank you.

How they charge their services? Does cost defined by the amount of data communicated ? Do you know how much it cost?

Thank you

Leo

Thanks - Magnus pointed me to Skywave's Inmarsat-D+ products, and that kind of opened the funnel for me, I've been looking at all sorts of options. They basically fall into three categories:

• Argos - restricted use (my application is probably eligible), 256 bits uplink only, low power requirements.

• Inmarsat D+ SMS - bidirectional telemetry and command information. It would also be possible to use a prepaid [voice] satphone's SMS capabilities to do the same thing, possibly cheaper (Skywave hasn't returned my emails asking for pricing info).

• Other satellite data services (R-BGAN, Inmarsat mini-C, etc etc). Would allow full uplink of image data as well as low-bandwidth telemetry. I would never need to recover the vehicle if it had this fat a satellite pipe.

The eye-opener for me is that all this stuff is really COTS and really cheap (compared to what I thought it would cost, anyway); it looks as if