Eutelsat OneWeb: Constellation - General Thread

[TorenAltair]

I would take any study (co-)authored by companies with an interest of selling their product with some grain of salt. That is, I would not make any decisions or opinions based on such studies. They might be completely correct, they might be false, they might be made to look pretty or advantageous.

[john smith 19]

Though to be honest, if the chip-scale atomic clocks plus daily sync really is enough, the barrier to entry has dropped a lot. Extreme cases being something in the 9U/12U flat pack sizing being possibly enough, especially with some of the new compact reflector antenna designs.

Indeed, which again begs the question what does OneWeb offer?

Frequency allocation? All existing GNSS run in L band around 1.5-2.0GHz and it took a lot of negotiation to ensure they run without mutual interference (some of theory of which was worked out by the UK engineers on the Galileo programme).  OW's are AIUI in the Ku band around 10x that frequency.  So using those allocations avoids any interference and makes your ground receivers useless for any other GNSS.

From your comments it looks like if the UK wanted just GNSS they could have fielded a network of cubesats to do it.

[john smith 19]

I assume it's due to raw number of visible satellites improving the geometry of the calculation at the receiver (you want a nice wide spread over the whole sky, not clustered in one area)(generally you would like a sat nearly directly overhead to avoid concrete canyon issues), maybe distances as well. GNSS designers previously did not have the luxury of using a very large fleet of satellites, so minimizing total satellite count was an attempt to reduce cost balanced with visibility and orientation (plus primary areas of operation). Also, they were pretty big too. A lot has changed since early GPS/NAVSTAR sats hardware-wise.

All systems that depend on constellations of satellites to work are optimization problems.

GPS gave maximum coverage with minimum number of sats and spares at target accuracy.

Note also GPS is a military sytem that was designed during the Cold War.  Those orbits just inside the Van Allan radiation belt were not viewed as major disadvantage. They made them much harder to hit with anti satellite weapons.

AFAIK all the on board digital electronics was done in mil spec TTL so today boards full of logic would be integrated onto an FPGA.

[soltasto]

I would take any study (co-)authored by companies with an interest of selling their product with some grain of salt. That is, I would not make any decisions or opinions based on such studies. They might be completely correct, they might be false, they might be made to look pretty or advantageous.

This, this and this.

That company literally wants to sell the same thing that OneWeb would do for PNT. You bet they would say it works if they want to keep their company alive.

I also really don't get this concept from a political point of view. I mean, what they want it as an alternative to GPS and Galileo, but if any of those stop providing the public signals they would be out of service as well, so they might as well just use the public signals directly. So while there could be slight technical advantages like stronger signal as the satellites would be closer, it doesn't make any sense to me from a national security point of view, which generally is the main reason to develop a GNSS network.

[ChrisWilson68]

I would take any study (co-)authored by companies with an interest of selling their product with some grain of salt. That is, I would not make any decisions or opinions based on such studies. They might be completely correct, they might be false, they might be made to look pretty or advantageous.

This, this and this.

That company literally wants to sell the same thing that OneWeb would do for PNT. You bet they would say it works if they want to keep their company alive.

I also really don't get this concept from a political point of view. I mean, what they want it as an alternative to GPS and Galileo, but if any of those stop providing the public signals they would be out of service as well, so they might as well just use the public signals directly. So while there could be slight technical advantages like stronger signal as the satellites would be closer, it doesn't make any sense to me from a national security point of view, which generally is the main reason to develop a GNSS network.

It makes it harder to jam locally if there is another frequency that also provides positioning data.

[MikeAtkinson]

Here is a direct link to the paper : https://pdfs.semanticscholar.org/487e/24483f22b43d57da78772dac9d20a948ec23.pdf

Although I agree with the comments expressing skepticism about this study it looks reasonable technically, though I am surprised at how much better GDOP is for the LEO constellations. It may be due to the angle above the horizon above which satellites are used. Modern receivers can use a combination of GNSS systems that give will give better GDOP than used in the paper (which was GPS only). The weakest section is building the hosted payload, there are many things not covered there.

There is no doubt that a LEO constellation can be used for navigation. The debate is about whether it is practical to add as a payload to OneWeb, and whether it will deliver any benefits for users over the existing GNSS systems. Commercial users would want services that are not available from GPS or Galileo (what might they be), UK government users (mainly military) would want anti-jamming, anti-spoofing, robustness, resistance to anti-satellite weapons, not relying on other GNSS systems.

I doubt that OneWeb satellites can be used by just adding a payload to the existing bus, a redesigned second generation satellite could perhaps include a navigation payload, but there are likely to be conflicts in the requirements for navigation and communications, particularly those for military use.

[gongora]

For those who may have lost track, OneWeb is a communications constellation and the new owners fully intend to build it out as a communications constellation.  Some sort of PNT functionality may be added to a small subset of the satellites in the future.

[Asteroza]

Though to be honest, if the chip-scale atomic clocks plus daily sync really is enough, the barrier to entry has dropped a lot. Extreme cases being something in the 9U/12U flat pack sizing being possibly enough, especially with some of the new compact reflector antenna designs.

Indeed, which again begs the question what does OneWeb offer?

Frequency allocation? All existing GNSS run in L band around 1.5-2.0GHz and it took a lot of negotiation to ensure they run without mutual interference (some of theory of which was worked out by the UK engineers on the Galileo programme).  OW's are AIUI in the Ku band around 10x that frequency.  So using those allocations avoids any interference and makes your ground receivers useless for any other GNSS.

From your comments it looks like if the UK wanted just GNSS they could have fielded a network of cubesats to do it.

There may be a method to the madness, in so much that PNT functions embedded in OneWeb comms functionality may be the point (software will eat the world, or at least make japanese radio hardware makers weep, if the stories regarding Apple and their early software modems are any indication). From a user terminal perspective, as many consumer systems move towards SDR hardware using generic chips and/or cheaply licensible semiconductor IP (ASIC or FPGA), going all software means you could potentially reduce the footprint of the chips and onboard hardware. Many GNSS receivers at this point are full ARM SoC's  running an SDR internally anyways, which consumes additional power and real estate on a board.

Now, due to economies of mass production, using a 4G/5G Qualcomm fully integrated SoC for android phones as the basis of a user terminal is conceivable, so you get current GNSS system access "for free" in a sense. This assume a UT operating as a user mobile router, with wifi AP capability and possibly 4g LTE access when available (OneWeb augmenting their coverage by being a data MVNO and negotiating a lot of roaming). Similar to those Android TV or mobile router setups.

But again, the alleged public face is completing OneWeb as a comms constellation. The fact that previously there was a serious startup planning to use OneWeb sat buses for an earth observation payload, possibly using OneWeb intersat links for backhaul, I think is the core value proposition for the UK. The factory is ready, just needs the payload (primary or as secondary). Every major space power wants the all seeing gorgon stare eye of a full 24/7 observation constellation, but the technologies for really miniaturizing it only recently came together (on government timeline scales). Putting up such an observation constellation would have cost big money, even today. But sneaking it in onto the deployment of an existing comms constellation that can provide backhaul is the key to making it happen.

I previously stated that the Iridium NEXT secondary payload opportunity was a potential goldmine for an earth observation capability, as it would have provided backhaul and substantially reduced launch costs. To the level that a civilian company could have made the attempt to buy most of the secondary slots and suddenly gain a big market advantage. Think Planet Labs' Doves on a traversing mount on the side of on a NEXT sat. Frankly it's within the range of of something a big financial company like Goldman Sachs could have paid for (and they do pay for it now in a sense, as useful observation metadata purchased from Planet Labs).

Think back to DARPA project Blackjack, that preferred existing buses for their payload experiments, preferably those planned for use on comm constellations. One could make a case that this may result in a barter arrangement, of the UK as a Five Eyes/NATO partner with the US, as the US desires an all seeing orbital eye but doesn't want to pay for it directly.

[Robotbeat]

For those who may have lost track, OneWeb is a communications constellation and the new owners fully intend to build it out as a communications constellation.  Some sort of PNT functionality may be added to a small subset of the satellites in the future.

This, plus OneWeb has long been trying to sell people these secondary capabilities. It's nothing new. Still, it's secondary to the main purpose of OneWeb.

[MikeAtkinson]

http://www.mit.edu/~portillo/files/Comparison-LEO-IAC-2018-slides.pdf Page 6

This shows the number of satellites in Line of Sight (although I think this is the number of satellites that have a beam pointed at a user). This is less than 2 for much of the Earth's surface, and so is not suitable for navigation. Beams are slewed (by turning the satellite) and some beams are turned off to avoid interference with GEO sats.

So it looks like OneWeb could not use existing antenna and beam forming, but would need a completely new non-beam formed antenna and signal path.

For GNSS they would probably have to use a low power spread spectrum signal to avoid interference with GEO satellites using the same frequencies.

If they used the same encoding and similar data stream as GPS/Galileo but at a multiple of the L1 band, a simple mixer could be used as a front-end to a Galileo receiver, which would almost work except that the satellites are moving much faster and hence would probably have Doppler shifts outside of what a GNS/Galileo receiver can cope with. Details of the ephemeris encoding would probably need to be different as well.

[Rondaz]

.@OneWeb received permission from the bankruptcy court to pay @OneWebSatellit1 to resume building its satellites allowing to "preserve its supply chain". Number of built sats was not specified. Contracts to be modified as part of acquisition.

https://twitter.com/Megaconstellati/status/1283331562436730880

[Rondaz]

Celebrating the one year anniversary of our Florida factory inauguration! Thank you so much to all of the teams at @OneWeb, @AirbusSpace and @OneWebSatellit1.  We could not have done it without you!

https://twitter.com/OneWebSatellit1/status/1285893619430326276

[Robotbeat]

My first thought was "why is no one wearing a mask??" Then I saw the date on the photo LOL

[Rondaz]

"Investing in OneWeb allows the U.K. to capitalize on the company's wealth of knowledge and technological advancement," writes Betty Bonnardel-Azzarelli @AtomicBettyBA of https://bit.ly/39pah2d Alliance.

https://twitter.com/Via_Satellite/status/1286791276592013315

[alanr74]

Quick question for you guys on the PNT side of things.   
 
Obviously it could only be added on a subset of satellites yet to be build, but the current talk is about piggybacking onto existing GNSS atomic clock signals. 
 
 Could these signals be generated from the Skynet 6 constellation once up and running?

[Swedish chef]

https://spacenews.com/uk-parliament-to-scrutinize-oneweb-purchase/

A U.K. parliamentary committee said it will review the steps that led to the government’s bid for struggling megaconstellation startup OneWeb, arguing that the $500-million investment decision was rushed and jeopardizes British taxpayer dollars.

Darren Jones, chair of the Business, Energy and Industrial Strategy Committee in Parliament, said Wednesday that the decision to take a 45% stake in OneWeb appears to have been hurried through before the government could fully evaluate whether it was a smart move.

“This whole decision-making process seems unusual and doesn’t have the transparency that it requires,” he said in a video posted to Twitter. “Therefore, my committee will be holding an inquiry to understand the decision making behind this purchase.”

[alanr74]

https://spacenews.com/uk-parliament-to-scrutinize-oneweb-purchase/

A U.K. parliamentary committee said it will review the steps that led to the government’s bid for struggling megaconstellation startup OneWeb, arguing that the $500-million investment decision was rushed and jeopardizes British taxpayer dollars.

Darren Jones, chair of the Business, Energy and Industrial Strategy Committee in Parliament, said Wednesday that the decision to take a 45% stake in OneWeb appears to have been hurried through before the government could fully evaluate whether it was a smart move.

“This whole decision-making process seems unusual and doesn’t have the transparency that it requires,” he said in a video posted to Twitter. “Therefore, my committee will be holding an inquiry to understand the decision making behind this purchase.”

Standard UK politics. Government does something that Parliament didn't discuss, parliament find a way to discuss it. The end result will be split amongst party lines. 
 

[russianhalo117]

OneWeb plans to resume its launches from Russia:
http://russianspaceweb.com/oneweb.html#2020_0726

Several hurdles to clear before resumption of flights including a required Russian vaccination of foreign personnel because the vaccine is not yet easily available in the USA and EU. New launch dates will be announced at a later date partly as launches are to be shifted to Vostochny Cosmodrome.

[Welsh Dragon]

<snip>
Standard UK politics. Government does something that Parliament didn't discuss, parliament find a way to discuss it. The end result will be split amongst party lines.

Almost like it's supposed to be a parliamentary democracy. Who'd have thought?

[kessdawg]

OneWeb plans to resume its launches from Russia:
http://russianspaceweb.com/oneweb.html#2020_0726

Several hurdles to clear before resumption of flights including a required Russian vaccination of foreign personnel because the vaccine is not yet easily available in the USA and EU. New launch dates will be announced at a later date partly as launches are to be shifted to Vostochny Cosmodrome.

What vaccine? I hadn't heard of a COVID-19 vaccine that was available yet.