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I thought this was interesting "The GOMX-3 satellite orbits the earth approximately every 90 minutes at a speed of 27440 kilometers per hour" - https://blog.fli
by deutronium 10y ago
I thought this was interesting "The GOMX-3 satellite orbits the earth approximately every 90 minutes at a speed of 27440 kilometers per hour" - https://blog.flightradar24.com/blog/tracking-flights-with-satellite-based-ads-b-receivers/ https://blog.flightradar24.com/blog/tracking-flights-with-sa...
I was assuming it would be a geostationary satellite they would be using.
- 8bitben 10y agoDoes that mean they can only get ADS-B data from the tracker every 90 minutes?
- deutronium 10y agoI would assume so yeah. I'd be interested to know if there's any reasonably affordable satellite system that you could use for closer to real-time data.
- mirashii 10y agoMy company, Spire, is doing fundamentally the same type of tracking as is described here, except for ships using AIS. By building a constellation of satellites with different orbits, and using a network of groundstations, you can achieve near-real time data. These would be no exception, it's just a matter of scaling up from one to n satellites and having the coverage of a groundstation network to support them.
- lorenzhs 10y agoOh I read about your company in the Economist recently, I thought that was really cool! Here's the article, for anyone interested: http://www.economist.com/technology-quarterly/2016-25-08/space-2016 http://www.economist.com/technology-quarterly/2016-25-08/spa... (the bit on Spire is in section 3). That you're also doing atmospheric measurements for weather forecasting seems pretty neat.
- fbender 10y agoThe Iridium NEXT satellites to be launched by SpaceX soon (well, we'll see about that ...) are equipped with ADS-B receivers, see e.g. http://aireon.com/resources/iridium-next/ http://aireon.com/resources/iridium-next/
- JshWright 10y agoNo, the boat doesn't talk to the satellite. They're two different methods they're using to improve coverage.
- CPLX 10y agoGeostationary orbit is a lot further away. Presumably that's an issue for acquiring ADS-B signals.
- deutronium 10y agoSorry I'm not sure what you mean, as I understand it, the ADS-B signals are just being acquired with a receiver on the 'boat' and then relayed via satellite.
- jpalomaki 10y agoThey have two different things. One is the boat that is relaying the signals via satellite. Another one is a satellite that is directly capturing the signals (if I understood the link below correctly). https://blog.flightradar24.com/blog/tracking-flights-with-satellite-based-ads-b-receivers/ https://blog.flightradar24.com/blog/tracking-flights-with-sa...
- deutronium 10y agoOh gotcha sorry, I misunderstood that link
- CPLX 10y agoMy understanding was that those were two distinct methods they were evaluating not one combined method.
- deleted 10y ago[deleted]
- fbender 10y agoYou can use any of the LEO/MEO Satcomm services that support simplex and/or duplex data transmission, which currently are Globalstar or Iridium. These are far easier to target since you don't need as much transmitter power resp. precise pointing like you need when talking to GSO satellites. Though, bandwidth is a trade-off, but I suppose the amount of data acquired by ADS-B receivers is less than the available bandwidth, especially in (relatively) low-traffic regions like the oceans. Edit: To be clear, that only covers the data transmission part from the vessel and not picking up ADS-B signals. For the latter, the Iridium NEXT satellites will be equipped with ADS-B receivers directly.