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dnick t1_j38c90i wrote

Reply to comment by doxx_in_the_box in Qualcomm partners with Iridium to bring satellite messaging to Android phones by thebelsnickle1991

I would assume that the time it takes to broadcast between satellites is negligible in the overall process (milliseconds?). If you could somehow save a second or two in overall connection time (on ground relays, finding a site that could route it more seemlessly, whatever), it wouldn't matter if you had to beam it back and forth between satellites 100 times to get it there, it could still be faster.

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you could be right that the overall service might be way worse, but doubtful that 'beaming between satellites' vs direct ground retransmission would make any difference except in slight audio quality vs 'speed of emergency services being services being dispatched'.

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doxx_in_the_box t1_j38drfl wrote

I agree - but I’ve always heard Iridium is slower because of the processing time or whatever occurs when linking satellites. I could have misheard

But if you read Iridium’s statement they say: faster than globalstar because we don’t require ground stations. That part makes zero sense.

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dnick t1_j38z7hm wrote

Hmm, maybe Iridium can only transmit straight back down, and it has to go through terrestrial switching stations to get to a central processing location, that then goes back out and activates EMS, rather than one or two steps through line-of-site satellites and directly to a central location?

Not sure, but if their claim is that ground stations are a bottleneck, getting more information on that seems like the question rather than just saying 'hmm, I don't know about that...'.

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doxx_in_the_box t1_j392fr9 wrote

> if ground stations are the bottleneck

You’re half way right and I think this is why Iridium is claiming speed - they’re reusing marketing material without specifying which conditions hold true.

Ground stations are the bottleneck in two situations:

  • example: customer is in Australia tracking a product on other side of planet. It needs to somehow get the data back to Australia.
  • example: a user wants to send an emergency message to another user, like using Garmin SOS device.

But with emergency SOS the ground station nearest you will be the one handling your request, so beaming across multiple satellites is pointless.

Also iridium has less total number of ground stations, so less coverage on earth, they just make up for it with better satellite-to-satellite coverage

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