Let it go already! Nobody here cares about this satellite stuff. It's the market action thread and the market is open. Create your own thread FFS
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Let it go already! Nobody here cares about this satellite stuff. It's the market action thread and the market is open. Create your own thread FFS
The Starlink antenna will be roughly the size of a pizza box.
Highly unlikely this will work for passenger vehicles. Nor is it especially necessary.
It's possible this will be deployed on the Tesla Semi, as a selling point.
But, remember this?
Starlink will come to Tesla Superchargers sometime late next year or early 2020. (Aggressive goal is Christmas 2019)
Tesla will create a local Wi-Fi network with the signal.
And your car will have Netflix/YouTube/video access while charging.
Version 10 of software. Version 1 of Starlink.
Bye bye AT&T.
Highly unlikely this will work for passenger vehicles. Nor is it especially necessary.
It's possible this will be deployed on the Tesla Semi, as a selling point.
But, remember this?
Starlink will come to Tesla Superchargers sometime late next year or early 2020. (Aggressive goal is Christmas 2019)
Tesla will create a local Wi-Fi network with the signal.
And your car will have Netflix/YouTube/video access while charging.
Version 10 of software. Version 1 of Starlink.
Bye bye AT&T.
Per https://licensing.fcc.gov/myibfs/download.do?attachment_key=1190019
LEO satellites will have a spot beam size of ~550 km^2, VLEO spot beam size ~52 km^2. Unless already on the edge of a spot beam, the satellite will not even have to try to follow the car with any more difficulty than normal. I would imagine the reverse would be true too, with the possible exception of excessively quick changes vehicle direction. But if you're batting the user terminal around like they're on an ASDS, or at an Autocross event, well, you should expect some dropouts.
omgwtfbyobbq
Active Member
I have no clue how well they work, but there are at least patents for optically transparent phased array antennas.
US6388621B1 - Optically transparent phase array antenna - Google Patents
Buckminster
Well-Known Member
Taking specific discussion out of the longer threads is a win - win. The main thread is improved immeasurably and the new subject somehow becomes much more interesting.
SpaceX board member says Starlink prototype satellites "are working wonderfully"
Apparent success with phased array system being very adaptable.
Apparent success with phased array system being very adaptable.
mspohr
Well-Known Member
Within hours of landing, Musk had fired at least seven members of the program's senior management team at the Redmond, Washington, office, the culmination of disagreements over the pace at which the team was developing and testing its Starlink satellites, according to the two SpaceX employees with direct knowledge of the situation.
Musk reportedly shakes up SpaceX in the race to make a satellite launch window
Musk reportedly shakes up SpaceX in the race to make a satellite launch window
Favorite quote from the article: "There had to be a much bigger idea for generating cash to basically realize the Mars plans," said one of the SpaceX employees. "What better idea than to put Comcast out of business?"
Reviving this thread, since I didn't know about it when discussing on the trading thread.
You all seem to be very knowledgable about satellite communications, and ggr especially.
But aren't you making the problem much harder than it needs to be? Why does it have to be 2-way high-bandwidth mobile communications like with cell phones in a car?
Why not:
- stream map updates unidirectionally from the sky
- broadcast encrypted autopilot data up to the sky
- and a separate low-bandwidth frequency/antenna for tasks like locking/unlocking the car? (or maybe keep the 3g cell service)
As has been pointed out already, the gps antenna is tiny, since it only needs to receive, and the iridium satellite phones are a lower frequency/bandwidth signal, but they also work without needing large antennas. Or did I miss something?
You all seem to be very knowledgable about satellite communications, and ggr especially.
But aren't you making the problem much harder than it needs to be? Why does it have to be 2-way high-bandwidth mobile communications like with cell phones in a car?
Why not:
- stream map updates unidirectionally from the sky
- broadcast encrypted autopilot data up to the sky
- and a separate low-bandwidth frequency/antenna for tasks like locking/unlocking the car? (or maybe keep the 3g cell service)
As has been pointed out already, the gps antenna is tiny, since it only needs to receive, and the iridium satellite phones are a lower frequency/bandwidth signal, but they also work without needing large antennas. Or did I miss something?
Antenna size is inversely proportional to frequency for the same beam width/ gain. Antenna receive performance is identical to transmit ability (reciprocity).
Yeah, with the replacement of some of the upper management, has it been an improvement or has morale suffered? I'd love to ask for more technical info, but would probably run into NDA issues with those questions.
If you're going to send AP data up, and receive map data down, even if you magically knew which data to send down separately, you'd still be doing 2-way comms. And you'll need the same antenna regardless.
In fact, because the satellites are whipping across the sky, steering spot beams along the ground, in order to send or receive you must have yourself a steerable beam phased array antenna to receive much less send. Basically, you electronically "point" the antenna at the satellite, just as it is doing to you.
Because of constraints when no / poor line of sight (garages, built up downtown areas with skyscrapers, valleys, tunnels, etc), you'd need to keep cellular service anyways, plus there's only so many terminals that can be served in a given area (polarization (left circular / right circular) * some number of max frequencies per spot beam * some number of max multiplexing of time slots or whatever).
so while in theory they could save money (or at least pay another Musk entity) by using starlink preferentially to or in replacement of cellular service, you still need the cellular service for many scenarios.
It doesn't make sense to sell terminals to Tesla when they won't want to pay more than cellular, when they can instead sell the limited number per area to those they can charge more (such as cellular backhaul, or internet backhaul, big companies that want dedicated high bandwidth private links between offices, etc).
I expect few if any individuals to be sold the service in populous areas, though I expect them to price it very competitively in rural areas, and perhaps practically give it away free to places in Africa or wherever that don't even have utilities (send in a "care package" container/crate of solar panels, battery, water purifier, starlink terminal with wifi bridge, etc).
I'm trying to get around the need to track a specific satellite. Much like how GPS signals are received omni-directionally.
As for knowing which data to send down, doesn't each satellite know its position around the earth and relative to each ground station? Then couldn't the satellite broadcast the map data just for the region that it's flying over, followed by the map data for the next region that it flys over, and then the one after that, etc? A sort of TDMA but spanning arc-seconds as it flys over the earth.
The receiver then stays tuned to the specific part of the sky where its portion of the broadcast is expected to come from different satellites as they fly through.
Something like collecting water from a rotating lawn sprinkler by placing a cup on the lawn. You're not going to collect every drop, but you'll definitely catch something. Map info isn't private, so it shouldn't be treated that way with transmission spot beams.
The same in reverse with the encrypted AP info.
You can't get around tracking, this is how starlink is intended to work. If the receiver is not aimed at the transmitter, it is not receiving anything. You can have a GEO sat painting the whole of North America, but if you don't aim your stationary dish at it, you won't receive anything.
Also, terminals may be moving (they're likely to sell them to airlines and cruise ships and so on), though the movement of the terminals is tiny compared to the movement of the satellites, so the necessary error correction for misalignment of beams combined with even the VLEO spot beams not being particularly small (~52 km^2) will solve the problem.
Now, you can certainly support some kind of "broadcast" mode where any terminal can receive the data for that time slot, and you could feed map data through this, but even then it's probably more efficient to just send map data as requested. Keep in mind, while a Starlink sat will know approximately where all terminals it's talking to are on the ground (it must, so that it can point the spot beam accordingly), it doesn't have any kind of idea of what these terminals are used for. It would be silly to have special Tesla map server logic flying onboard the Starlink satellites to feed map data via a broadcast method. So you'd have to broadcast all this Tesla map data to all user terminals, not just those on Tesla vehicles, and that would be wasteful and not ideal for various IP/competitive reasons.
As for sending up AP info, it is far more efficient and easier to actually aim at the actual satellite and send the data directly on your timeslice, than to blindly blast it into space where a satellite will eventually be. You'd have to keep looping the upload until you were guaranteed a satellite had passed by, and if it's too big to be picked up during that brief moment it was in your uplink beam, you'd be screwed. Using beam steering from the user terminal to track the satellite is needed to ensure the entire upload can get through, and to not waste time repeating it, and at that point you may as well be doing proper 2-way communication.
Have a read at how Starlink is intended to operate via the docs SpaceX submitted to FCC : https://licensing.fcc.gov/myibfs/download.do?attachment_key=1190019
As I posted above, I doubt the cars will be getting Starlink. There's nowhere to put the antenna, especially with the glass roof models.
I suspect Tesla's plan is to put a Starlink receiver at superchargers and share the signal via local Wi-Fi, where cars will just auto-connect. And then in V10 of the software you'll be able to watch YouTube/Netflix while charging.
I suspect Tesla's plan is to put a Starlink receiver at superchargers and share the signal via local Wi-Fi, where cars will just auto-connect. And then in V10 of the software you'll be able to watch YouTube/Netflix while charging.
There's not nowhere to put it, just the additional expense (place in frunk lid, eating up ~1" of depth for the area of the antenna, and use RF transparent materials for frunk lid, which is both more expensive and one more different material to match paint on) isn't really worth it for something that would almost never have any use (nearly always in cellular coverage).
I do think that Supercharger "free" internet for Tesla vehicles is an obvious move though.
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