globalstar is a bad joke and not a viable option for maritime services (or over-ocean aviation services) because unlike iridium or inmarsat, its satellite terminal-to-earth-station architecture is a bent pipe.
there is zero globalstar mid ocean coverage.
there is a reason you will see lots of competing options for people integrating the iridium embedded modems into things designed to go on top of $40 million business jets and just about zero globalstar.
An Iridium embedded modem is one of the things we came across in the wreckage of a small plane we were recovering the pilot's remains from[0].
It was for his Spidertracks[1] flight tracking system. (Which, with the ADSB track, helped us hone in on the possible location. The wreck ended up being right in line with the last few pings.
there's iridium SBD modems for low data rate/non-realtime comms (like position trackers) and full featured iridium voice/data modems integrated into a vast array of products now, in the land mobile, aviation and maritime segments.
one thing iridium has actually done really well is provide the developer documentation to make this fairly straightforward, there's a set of 600 page PDF files with every detail you could possibly need to make a very tiny embedded linux system talk to an iridum modem over a UART.
The Garmin inReach[0] line of satellite communicators are another example of a 3rd party Iridium partnership. Given the size/form factor, I wonder if they're using more custom hardware than just an off-the-shelf module for their integration.
They're another example of exorbitant fees for tiny bits of data. (Though, being able to text pretty much anywhere on the globe on a tiny device is really nice - even with a 20minute RTT.)
Is Iridium really competitive for business jets? The bandwidth of even their next-generation satellites does not seem competitive with the GEOs, and I'd guess bizjets should be mostly fine with their latitude limitations.
I'd expect most of them to go with one of the Ka band these days; they have pretty small antennas available these days as far as I know.
a small to medium sized business jet can easily mount an iridium terminal on top of it, where even the smallest/least capable geostationary vsat cannot.
you can fairly easily integrate iridium into something as small as a cessna 172...
at the minimum iridium will provide the ability to make phone calls to/from the PSTN while in the middle of an ocean on its smallest terminal. go up in terminal size a bit and you get something good for 500kbps of data.
for very large business jets that would be crossing the atlantic or pacific, that's a different market (overlaps somewhat with the same aviation VSAT terminals you would see on a 737-900 MAX)
