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I'm trying to figure out possible methods in sending GPS location in my project to the server and one possible option is still mystery to me. I hope someone will be able to clarify it.

The most common option as I understand is to have something like this GPS module and send gathered information via GSM module connected to this.

However, I see many travelers on Facebook use something like SPOT devices. According to the website they can send position back to user without GSM connection. So how this can be done? Are there some other GPS modules beside the ones like on Adafruit? I've checked different websites and cannot find any with transmitting capabilities. The one idea I have is suggested by one of their products - satellite phone. Maybe they just use instead of GSM signal satellite signal (I have no idea what's the name of that).

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  • \$\begingroup\$ "back to satellite without GSM connection" first of all, GSM isn't via satellite, and secondly, there are several satellite data/phone services. \$\endgroup\$
    – PlasmaHH
    Commented Nov 10, 2016 at 13:12
  • \$\begingroup\$ @PlasmaHH sorry, my mistake. I meant to write "back to user". I am aware that GSM is not satellite. \$\endgroup\$
    – sebap123
    Commented Nov 10, 2016 at 13:17
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    \$\begingroup\$ It would help to know how far and where "back to user" is. If it's across the room, Bluetooth comes to mind, if its somewhere in the house then wifi comes to mind, if it is mobile and doesn't have to work 100% then cell phone networks comes to mind, if it's in the middle of the ocean then satellites comes to mind. \$\endgroup\$
    – st2000
    Commented Nov 10, 2016 at 13:22
  • \$\begingroup\$ Indeed those SPOT devices appear to use a satellite based connection to get the GPS acquired location data onto the internet. GSM modules (for land-based data connections) exist but I have not seen any satellite based equivalent. Probably because a subscription is needed (GSM can work with pre-paid) and the market for such a module is likely to be very small and the module expensive. \$\endgroup\$
    – Bimpelrekkie
    Commented Nov 10, 2016 at 13:25
  • \$\begingroup\$ They actually have a sketch on their website, showing a satellite backhaul/uplink. They only do not disclose what satellite comms service they're using for that. findmespot.com/en/index.php?cid=115 \$\endgroup\$
    – frr
    Commented Nov 10, 2016 at 13:27

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SPOT uses the Globalstar Satellite Constellation as a back channel, specifically the TLPS service. There is a link to SPOT on Globalstars web presence, so I think there is some affiliation.

This site lists some COTS tracking devices with global coverage. Garmin seems to offer a similar service as DeLorme inReach.

I am not aware of any modules with satellite backchannel available and I am not sure if such a module would be sold unbundled from a service plan.

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Looking at the comments under my question I did some additional research and found one module that is capable of sending information to satellite: RockBlock. It can even be found on Sparkfun: https://www.sparkfun.com/products/13745

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