Methods of sending GPS position
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.