LEO Internet was mentioned in another post so decided to do another search, as been awhile since I looked it up. Came across this article thought I'd share for those interested.
Keeping things relevent to the discussion in Tech Support: Lowering the orbit to 700km still doesn't get you below 100mS.
I built a spreadsheet for the J2 calculation. Lowering J2 from 35785km to 700km would still only give me a time-to-internet latency of 112.8mS. It's a vast improvement, but I'm sure LEOs bring other problems such as how to network them effectively at ground stations, how to gain maximum beam coverage, how do you reach polar regions, dealing with power levels, etc.
And if reach to Northern locations is an issue from the equator, I don't even want to think about how you would deal with non-geostationary orbits like Sirius does.
Certainly an interesting problem. Just thought I'd throw that out there.
I think I heard something on TV AD the other day about Directv having NO DISH now .... think it could be this?
From the Article:
Consumer ground-stations will also be small, cheap and easy to install "pizza boxes." Since the signals will be weak, the antennae will have to be outside, but end users will be able to install them because, unlike today's TV and Internet dishes, they will not have to be aimed precisely at a single, geostationary satellite. Modern phase-shift array antennae will follow a satellite as it moves and switch to another in microseconds or a few milliseconds when it goes out of site. Similarly, satellites will be able to transmit a beam that is fixed on one area on the ground as it moves over it.
It's that "follow a satellite as it moves" part that scares me... a lot.
That works well for receive only most of the time but still has periods where it drops out, so you buffer in advance and hopefully it covers the dropout.
Acquiring and transmitting back is a whole 'nother ballgame with elliptical Molniya orbits.
Ok, my original mindset was focused on using parabolic dishes such as what we use now - this is apparently not the case. LEOs would use antennas with a more omnidirectional pattern, since antenna gain is not vital.
Regarding the handoff protocols: I understand that would be similar to handoffs used with mobile phone towers, but in reverse. You would be stationary and the satellites would be moving.
Now, the only question I have is how large a constellation you have... possibly three orbits (East Coast, Central, and West Coast) with 3 birds each? Unsure how many satellites you can actually put in an elliptical orbit (they call it elliptical, but it's actually a figure-8) before they crash into each other on the cross-over portion.