It's confusing me, now, too. Now that Maurice is here, maybe he can check my logic: I think the implication is that the satellite can "see" 1500 miles to its horizon. Thus, if a satellite is in just the right place between a boat in the Atlantic and a gateway, that boat might be 2500 miles from the gateway and the call would go through.
But of course, the satellite won't be there for very long, so make it a quick call!
Pulling our Rocket's compass, I'd draw a circle 1500 miles in radius around the gateway, and 1000 miles around the user's location. The area of intersection of those circles is where a sat would have to be to get coverage. The difference in circle size is because the user's terminal is not so strong. It won't pick up the signal from the same distance as the gateway. So, the user's radius would be smaller than 1500 miles. Whether it would be 1000 miles, or 1500, or 500 I do not have a feel. (It's got to be fairly big for the "path diversity" issue to be helpful, so that several sats are in range at any given time).
As you get closer to the gateway, say 2000 miles, the angles give the phone more of a chance to find a satellite that is in the range of a gateway. And satellites will continuously be passing within range, so your coverage when slightly closer will be much better.
At least that's how I understand it.
RS, Maurice, Do I have it?
Best,
JS |
