I think the ~$100k+ wifi solutions for King Airs and above tend to be gyro stabilised also. Those are for geostationary satellites. Probably Inmarsat?
Satellite is a bit easier to do on a ship, though. Someone who installs the gear for a living on ships did a talk at our hack space a couple of years ago, and the antennas are typically gyrostabilised dishes in big domes and can swivel 360 degrees with quite a lot of azimuth freedom. Not hard to find a place to put one on a ship, rather harder to put one on a plane!
172driver wrote:
There are only so many ships, exploration teams and other remote area users with the money to need and use satellite comms.
The number of ships on the ocean at any one time is largely underestimated. The 2-3 worldwide leaders in ocean shipping have multi-billion $ businesses, and definitely have the money and need for communications. Each parcel being shipped today is tagged and tracked 24/7 globally, and the only way to do that is via satellite. I believe shipping companies is one of the primary markets for the new Iridium satellites going up now, as well as ADS-B reception to track airliners. The satellites all have Aireon payload for the latter.
I could not sit through the whole 1.5hr video. Most of it shows nothing happening 
GSM encryption is trivially easy to break in real time, but you may be right about the microwave links.
I bet you this was driven by MH370 and the realisation of the implications for national security.
Peter wrote:
The NSA seems to have no issue picking up mobile phones from space, so this is probably just a matter of whether it is worth doing.
What they are capable of doing in reality probably is intercepting the microwave links of the telco’s internal network through which the mobile phone conversations are transported.
Peter wrote:
Hence I wonder what the drive was behind using the Iridium sats for ADS-B IN.
In the video I linked just above he shows about how big the ADS-B payload is on the actual satellite.
Peter wrote:
The NSA seems to have no issue picking up mobile phones from space
The NSA also have a massively larger budget! (and if they are using satellites to monitor cellphones, rather than the easier step than just asking AT&T and others for a simple feed from their datacentres), then they are probably doing it from an LEO constellation rather than geostationary orbit.
The NSA seems to have no issue picking up mobile phones from space, so this is probably just a matter of whether it is worth doing.
However I recall seeing an ADS-B demo at EDNY where a single antenna (a vertical rod) was picking up ADS-B over a radius of some 500-1000nm, so a few such stations would cover all of Europe. Not all the way down to surface of course; the curvature of the earth limits that, so it would depend on the objective (e.g. jet transports enroute and maybe in terminal areas). I can’t see anyone doing it to pick up GA given that almost nobody is radiating it and GA traffic is generally of little interest given that most of it is OCAS and ADS-B OUT is never likely to be mandated for OCAS.
Hence I wonder what the drive was behind using the Iridium sats for ADS-B IN. Maybe it was a cheap thing to add, and there may be oddball factors e.g. U.S. national security / worldwide traffic surveillance, plus whatever fallout came out of the MH370 event which was a huge scandal, with a 777 simply vanishing into thin air (which itself has huge national security implications if it can be done easily).
Peter wrote:
Monitoring ADS-B should surely be possible with a geostationary satellite?
Not easily, I would have thought, at least without a purpose built system. The antennas on planes for ADS-B aren’t designed to be radiating straight up into space, the received signals will be extremely feeble, and you’d be seeing half the world’s ADS-B transmissions on top of each other at the same time (unless you could scan with a very directional antenna). From LEO the job’s got to be a lot easier – signal strength much higher and each individual satellite in the constellation will only be seeing a relatively small number of ADS-B transmitters at a time.
Peter wrote:
Monitoring ADS-B should surely be possible with a geostationary satellite? Just rent a low bandwidth channel on one of the many sitting out there in orbit…
Problem is how do you get to them to install the ADS-B receiver… you can’t economically get to them once they are floating out in space.
Then picking up ADS-B from 35,000 km away (geostationary) is perhaps a bit much too ask? Iridium NEXT is at an altitude of 780 km from which they expect to achieve global ADS-B coverage.
That will be pretty revolutionary. It’s basically like an ATC radar environment… everywhere!?
Yes, I know….being in the marine business…
