That was an interesting read, there are about 200 ground stations that measure the GPS satellite positions with very precise radar. Then they tell the satellite where it is once an hour so it can tell us where it is all the time.
Positional error is a couple of meters. Pretty danged impressive accuracy for something that is about 12,000 miles away. Imagine if you hacked the ephermeral data uplink and told them all they were somewhere else. Talk about screwing up everything. From: Chuck McCown Sent: Thursday, November 17, 2016 12:48 PM To: af@afmug.com Subject: Re: [AFMUG] Space X, Satellite internet 1 GBPS, FCC They do have an uplink (for their own use). I think that ground based stations determine the satellite position and uplinks that data so that it can broadcast its position. Not sure if it is altitude above geoid that is the most critical bit of ephermal data or if it actually transmits 3D positional data. Never studied it hard enough. Super accurate timing info doesn’t do much for you unless you knew where it originated. From: Adam Moffett Sent: Thursday, November 17, 2016 12:36 PM To: af@afmug.com Subject: Re: [AFMUG] Space X, Satellite internet 1 GBPS, FCC ....yeah but GPS doesn't need an uplink. So if you have an antenna of similar size and shape to one of those cone shaped GPS antennas, how much tx power do you need to hit sats in LEO? That's at least a hundred miles up isn't it? ------ Original Message ------ From: "Mike Hammett" <af...@ics-il.net> To: af@afmug.com Sent: 11/17/2016 11:53:49 AM Subject: Re: [AFMUG] Space X, Satellite internet 1 GBPS, FCC They won't need to be south-facing. With 4,000 of them, they'll be everywhere going everywhere. I'd think like GPS. ----- Mike Hammett Intelligent Computing Solutions Midwest Internet Exchange The Brothers WISP ------------------------------------------------------------------------------ From: "Ken Hohhof" <af...@kwisp.com> To: af@afmug.com Sent: Thursday, November 17, 2016 10:52:04 AM Subject: Re: [AFMUG] Space X, Satellite internet 1 GBPS, FCC Article says client side antennas will be phased array to track the sats, also that the sats will communicate with each other. Seems to me even with all those sats, talking about gigabit service to customers is a bit of marketing hype. Speaking of marketing, that would seem to be the key, how will they market this? Unless the target market is the same people who bought Iridium phones. SpaceX does not have a natural existing marketing vehicle for Internet service, I assume they will need partners or resellers. That is the advantage a Verizon, AT&T or DISH has – millions of existing customers they can advertise to, and offer bundle deals to. Satellite does have a natural appeal to the “nothing on my house” people, you can stick the antenna on a short pole in the yard. Still not a great solution for the apartment and condo dwellers without south facing balconies, they want indoor wireless modems. I am assuming the LEO orbits will still be in the southern sky like GPS sats, maybe that is wrong and they will whiz overhead in all directions? From: Af [mailto:af-boun...@afmug.com] On Behalf Of Chuck McCown Sent: Thursday, November 17, 2016 10:10 AM To: af@afmug.com Subject: Re: [AFMUG] Space X, Satellite internet 1 GBPS, FCC I didn’t see what frequencies they are using. Earth stations would need to track them I would think. From: Tushar Patel Sent: Thursday, November 17, 2016 7:00 AM To: af@afmug.com Subject: [AFMUG] Space X, Satellite internet 1 GBPS, FCC http://www.businessinsider.com/spacex-internet-satellite-constellation-2016-11
