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Galileo satellite system (merged thread)

Peter wrote:

Surely one would launch from near the equator?

“GPS” satellites are not on equatorial orbits, so I don’t think an equatorial launch is particularly useful.
My understanding is that equator:
- has a a boost (for eastward launches)
- can access any orbit, especially equatorial (most of which are, I presume, geostationary) without having to change inclination, which can be a costly manoeuvre in terms of energy (delta V)

GPS satellite constellation:
https://www.gps.gov/systems/gps/space/

EKRK, Denmark
EKRK, Denmark

Noe wrote:

“GPS” satellites are not on equatorial orbits, so I don’t think an equatorial launch is particularly useful.

Still Scotland is not the best place, assuming easterly launch to gain from earth velocity
The Danish will not be happy with a launch fail, especially after Brexit

ESSEX, United Kingdom

What does all this mean? We all know what “GPS” is Does it mean that launching a complete constellation is out of reach of the UK (as I suspect it probably is)?

But Russia (GDP 1.5T USD) did it, well eventually, and the UK has a GDP of 2.6T USD. Not many people know that the UK is almost twice as big an economy as Russia! There is no doubt whatsoever that the UK could do it technologically.

But, as with Galileo, and Glonass, nobody of relevance will use it – simply because everybody will use the American system, and if there is a “WW3” and the US shuts it down, the other players will all shut theirs down at exactly the same time, or the US will shoot down their satellites, as they have said they would, and they would be fully entitled to do so.

Administrator
Shoreham EGKA, United Kingdom

By that time I hope we still keep some of the old VOR stations at a safe storage ready to be reinstated.

EKRK, Denmark

Peter wrote:

But, as with Galileo, and Glonass, nobody of relevance will use it – simply because everybody will use the American system, and if there is a “WW3” and the US shuts it down, the other players will all shut theirs down at exactly the same time, or the US will shoot down their satellites, as they have said they would, and they would be fully entitled to do so.

I mostly agree (putting technological expertise asides), and mostly playing devil’s advocate here:
Do the US provide the “precise” data to allies?
What if a european ally decides not to follow the US into some war (e.g. France and Iraq), and the US has a much more capricious administration than the Bush one, and decides to cut off access?

By that time I hope we still keep some of the old VOR stations at a safe storage ready to be reinstated.

I doubt it because in all major conflicts GA is immediately grounded. Airliners use INS with DME/DME corrections so they don’t need any navaids except DME.

In 2008 I went to a Eurocontrol “navigation workshop” (a rather politicised event, with almost everybody doing preening and posturing) and this topic came up. The answer given by the head honcho (who was not only an ATCO but also a 737 “pilot” (part-time FO I am sure) and thus untouchable because he knew everything, and spoke accordingly) was that Plan B for a loss of GPS was ATC radar (so any talk of removing radar and using ADS-B was just wishful thinking) and 500 new DMEs would be deployed around Europe.

GA doesn’t count.

Do the US provide the “precise” data to allies?

Yes; since the earliest days of GPS the British military got the keys. In the original Iraq conflict they got military receivers (Magellan, according to some book I read) which picked this up. That was in 1991.

What if a european ally decides not to follow the US into some war (e.g. France and Iraq), and the US has a much more capricious administration than the Bush one, and decides to cut off access?

An interesting situation

The US cannot deny access to a specific country, for the civilian signal which, with SA gone in 2002, as accurate enough for almost any practical military purpose. AFAIK they can do a large area denial but it is quite coarse and would have undesirable political side effects.

They can deny the military signal keys but that would be relevant only if the civilian signal was shut down, which is really problematic.

AFAIK GPS denial is done with area jamming, which is much easier to target where needed. You jam the civilian signal only.

Administrator
Shoreham EGKA, United Kingdom

“Not many people know that the UK is almost twice as big an economy as Russia!”
The way the GDP is calculated is interesting. I’m surprised that the UK Exchequer has made no response to the recent death of their Economic Guru. (Robert Mugabe.)

Maoraigh
EGPE, United Kingdom

Peter wrote:

But Russia (GDP 1.5T USD) did it, well eventually, and the UK has a GDP of 2.6T USD

Not a good comparison – cost of design and manufacturing (hourly rates) is much lower in Russia, comparing to UK.

EGTR
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