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Galileo ever come on stream?



 
 
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  #51  
Old February 22nd 18, 11:46 AM posted to uk.tech.digital-tv
tim...[_2_]
external usenet poster
 
Posts: 619
Default Galileo ever come on stream?



"Tweed" wrote in message
news
Jim Lesurf wrote:
In article , NY
wrote:


Ah, so the civilian signal was simply a full-precision signal with a
random value added to it? I'd thought that it was a value that was
truncated by masking off the more precise bits.


IIRC they pseudo-randomly 'jittered' the information to blur the time
accuracy. You needed to be able to decode the secret squirrel info to
find
out the details of the jitter pattern and get a more accurate result. Or
do
a long-term average, etc, as others have pointed out.

Jim


GPS carries two coded signals. The unencrypted signal was jittered to give
an accuracy of around 100 metres. This has since been removed and accuracy
is roughly 5 metres. The military have access to a second encrypted signal
which gives a much higher accuracy. This signal is also transmitted on a
second frequency, which allows ionospheric error to be cancelled out.
Ionospheric delays can cause offsets, as noted by an earlier poster.
(Offsets to road position can also be caused by poor road position data.
OS
have had to do a huge amount of work to align the national grid to GPS
coordinates. Not all grid squares have turned out to be as square as they
had hoped owing to original survey errors.) The jitter on the civilian
signal can now be added back on a regional basis, so accuracy can be
reduced in a war zone whilst maintaining it elsewhere. The fact that the
system can be regionally made more inaccurate at the touch of a button is
probably one reason why Europe wanted to have its own separate system.
With
so much now dependent on GPS positioning, suddenly returning to 100 metre
accuracy could have severe economic consequences.


But we were already well on the way to solving that problem with
differential GPS, Chipsets using it had be developed, many ground stations
had been created.

Paying to build/launch 30 satellites instead of adding ground stations to
fill in the gaps in the DGPS coverage seems to be overkill

tim



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  #52  
Old February 22nd 18, 11:48 AM posted to uk.tech.digital-tv
Tweed[_3_]
external usenet poster
 
Posts: 36
Default Galileo ever come on stream?

Alan White wrote:
On Thu, 22 Feb 2018 12:36:00 +0000 (UTC), Tweed
wrote:

There are many ways of messing about with GPS accuracy that do not
necessarily involve the use of satellites. Ground and aircraft based
systems can be used to locally or regionally spoof the system. In car sat
navs are reported to go haywire around the Kremlin. North Korea is reported
to have messed up GPS within South Korea.


Agreed, but in that case why bother to use jitter. Just blot it out.


Guided munitions etc that fail to see GPS will switch to other methods.
Those that see a slightly distorted but still plausible signal will likely
land in the wrong place. Shades of WW2 beam bending.

  #53  
Old February 22nd 18, 11:48 AM posted to uk.tech.digital-tv
tim...[_2_]
external usenet poster
 
Posts: 619
Default Galileo ever come on stream?



"Robin" wrote in message
...
On 22/02/2018 10:10, Tweed wrote:
The fact that the
system can be regionally made more inaccurate at the touch of a button is
probably one reason why Europe wanted to have its own separate system.
With
so much now dependent on GPS positioning, suddenly returning to 100 metre
accuracy could have severe economic consequences.


Various strategic and economic reasons were given for the EU to have its
own satellite navigation system. Including in effect "All the big
players[1] are going to have one and we're a big player."

There were possibly also reasons not articulated explicitly. Eg every
type-approved car sold in the EU will have to have Galileo-enabled kit
(for eCall) which aids safety but also EU manufacturers.


how does it aid EU manufacturers?

The eCall bit's going to be a 20 dollar box that is screwed into the car
somewhere. the world and his mother are going to have access to them

tim



  #54  
Old February 22nd 18, 11:49 AM posted to uk.tech.digital-tv
tim...[_2_]
external usenet poster
 
Posts: 619
Default Galileo ever come on stream?



"R. Mark Clayton" wrote in message
...
On Thursday, 22 February 2018 11:58:27 UTC, Robin wrote:
On 22/02/2018 10:10, Tweed wrote:
The fact that the
system can be regionally made more inaccurate at the touch of a button
is
probably one reason why Europe wanted to have its own separate system.
With
so much now dependent on GPS positioning, suddenly returning to 100
metre
accuracy could have severe economic consequences.


Various strategic and economic reasons were given for the EU to have its
own satellite navigation system. Including in effect "All the big
players[1] are going to have one and we're a big player."

There were possibly also reasons not articulated explicitly. Eg every
type-approved car sold in the EU will have to have Galileo-enabled kit
(for eCall) which aids safety but also EU manufacturers.


And more seriously be capable of being charged for congested areas,
speeding etc.


eCall cannot be used to do this

tim



  #55  
Old February 22nd 18, 11:54 AM posted to uk.tech.digital-tv
Tweed[_3_]
external usenet poster
 
Posts: 36
Default Galileo ever come on stream?

tim... wrote:


"Tweed" wrote in message
news
Jim Lesurf wrote:
In article , NY
wrote:


Ah, so the civilian signal was simply a full-precision signal with a
random value added to it? I'd thought that it was a value that was
truncated by masking off the more precise bits.

IIRC they pseudo-randomly 'jittered' the information to blur the time
accuracy. You needed to be able to decode the secret squirrel info to
find
out the details of the jitter pattern and get a more accurate result. Or
do
a long-term average, etc, as others have pointed out.

Jim


GPS carries two coded signals. The unencrypted signal was jittered to give
an accuracy of around 100 metres. This has since been removed and accuracy
is roughly 5 metres. The military have access to a second encrypted signal
which gives a much higher accuracy. This signal is also transmitted on a
second frequency, which allows ionospheric error to be cancelled out.
Ionospheric delays can cause offsets, as noted by an earlier poster.
(Offsets to road position can also be caused by poor road position data.
OS
have had to do a huge amount of work to align the national grid to GPS
coordinates. Not all grid squares have turned out to be as square as they
had hoped owing to original survey errors.) The jitter on the civilian
signal can now be added back on a regional basis, so accuracy can be
reduced in a war zone whilst maintaining it elsewhere. The fact that the
system can be regionally made more inaccurate at the touch of a button is
probably one reason why Europe wanted to have its own separate system.
With
so much now dependent on GPS positioning, suddenly returning to 100 metre
accuracy could have severe economic consequences.


But we were already well on the way to solving that problem with
differential GPS, Chipsets using it had be developed, many ground stations
had been created.

Paying to build/launch 30 satellites instead of adding ground stations to
fill in the gaps in the DGPS coverage seems to be overkill

tim





I think part of the motivation was that Europe didn’t want to be
potentially held to ransom by the US Defense department. Monopoly supplier
and all that that entails. (I’m excluding GLONASS for obvious reasons) .

  #56  
Old February 22nd 18, 12:00 PM posted to uk.tech.digital-tv
Andy Burns[_12_]
external usenet poster
 
Posts: 573
Default Galileo ever come on stream?

Tweed wrote:

I think part of the motivation was that Europe didn’t want to be
potentially held to ransom by the US Defense department.


At first they said they'd make it un-jammable (without also jamming GPS)
but soon rolled-over when USA said in that case they reserved to right
to shoot Galileo out of the sky.
  #57  
Old February 22nd 18, 12:28 PM posted to uk.tech.digital-tv
Robin[_8_]
external usenet poster
 
Posts: 506
Default Galileo ever come on stream?

On 22/02/2018 12:48, tim... wrote:


"Robin" wrote in message
...
On 22/02/2018 10:10, Tweed wrote:
The fact that the
system can be regionally made more inaccurate at the touch of a
button is
probably one reason why Europe wanted to have its own separate
system. With
so much now dependent on GPS positioning, suddenly returning to 100
metre
accuracy could have severe economic consequences.


Various strategic and economic reasons were given for the EU to have
its own satellite navigation system.* Including in effect "All the big
players[1] are going to have one and we're a big player."

There were possibly also reasons not articulated explicitly.* Eg every
type-approved car sold in the EU will have to have Galileo-enabled kit
(for eCall) which aids safety but also EU manufacturers.


how does it aid EU manufacturers?


The economies of scale of fitting kit required for your "home" market

The eCall bit's going to be a 20 dollar box that is screwed into the car
somewhere.* the world and his mother are going to have access to them

I'd like to know the source of that 20 dollar figure. That's way below
the figures used in cost-benefit analyses.


--
Robin
reply-to address is (intended to be) valid
  #58  
Old February 22nd 18, 02:20 PM posted to uk.tech.digital-tv
tim...[_2_]
external usenet poster
 
Posts: 619
Default Galileo ever come on stream?



"Robin" wrote in message
...
On 22/02/2018 12:48, tim... wrote:


"Robin" wrote in message
...
On 22/02/2018 10:10, Tweed wrote:
The fact that the
system can be regionally made more inaccurate at the touch of a button
is
probably one reason why Europe wanted to have its own separate system.
With
so much now dependent on GPS positioning, suddenly returning to 100
metre
accuracy could have severe economic consequences.


Various strategic and economic reasons were given for the EU to have its
own satellite navigation system. Including in effect "All the big
players[1] are going to have one and we're a big player."

There were possibly also reasons not articulated explicitly. Eg every
type-approved car sold in the EU will have to have Galileo-enabled kit
(for eCall) which aids safety but also EU manufacturers.


how does it aid EU manufacturers?


The economies of scale of fitting kit required for your "home" market


In that case the Japanese and Korean manufactures wouldn't be able to
compete in Europe at all,

but they do

The eCall bit's going to be a 20 dollar box that is screwed into the car
somewhere. the world and his mother are going to have access to them

I'd like to know the source of that 20 dollar figure. That's way below
the figures used in cost-benefit analyses.


I did a job working for a company who thought that they could reengineer a
product that they already had for this market

That was a target figure

(I have no idea if they achieved it)

(Of course there's installation costs to add on)

tim



  #59  
Old February 22nd 18, 02:57 PM posted to uk.tech.digital-tv
Bill Wright[_3_]
external usenet poster
 
Posts: 2,448
Default Galileo ever come on stream?

On 22/02/2018 10:22, R. Mark Clayton wrote:

A Sky box might be installed in a boat, barge, yacht, car, caravan,
motorhome, ocean-going ship, or hot air balloon.

Bill


Indeed, but you have to arrange for it to be able to phone home from time to time or it stops working.


No you don't.

Bill
  #60  
Old February 22nd 18, 02:59 PM posted to uk.tech.digital-tv
Bill Wright[_3_]
external usenet poster
 
Posts: 2,448
Default Galileo ever come on stream?

On 22/02/2018 10:43, NY wrote:

GPS tracks seem to be better in the sense of having fewer occasions when
the track drifts off the road that I'm driving on, though it still
suffers total loss of reception and lengthy periods trying to re-acquire
a lock when I'm on a cruise ship. All that metal gets in the way...
Strangely, going out on the top deck, where I then have unimpeded view
to the horizon, doesn't always help, even after I've updated the A-GPS
almanac.


Could be getting blasted by the radar.

Bill
 




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