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Galileo Now Tells UTC Time



 
 
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  #1  
Old April 30th 13, 08:27 PM posted to sci.geo.satellite-nav
Sam Wormley[_2_]
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Posts: 775
Default Galileo Now Tells UTC Time

Galileo Now Tells UTC Time
http://www.gpsworld.com/galileo-now-tells-utc-time/





Europe’s four Galileo satellites are now working as clocks accurate
to a few billionths of a second, disseminating the exact time through
their signals expressed as the UTC Universal Coordinated Time global
standard, reports the European Space Agency.


“A billionth of a second equals a nanosecond, a time interval far
beyond our own human capacity of appreciation,” explains Marco
Falcone, ESA’s Galileo System Manager.

“A single lightning flash across the sky during a thunderstorm lasts
about ten milliseconds, which is already 10 000 000 nanoseconds. But
for high-tech applications, as well as navigation services,
nanosecond accuracy is essential.”


The replacement for Greenwich Mean Time, UTC is part of all our daily
lives: it is the timing used for Internet, banking and aviation
standards as well as precise scientific experiments, maintained by
the Paris-based Bureau International de Poids et Mesures (BIPM).


  #2  
Old April 30th 13, 09:34 PM posted to sci.geo.satellite-nav
oriel36[_2_]
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Posts: 144
Default Galileo Now Tells UTC Time

On Apr 30, 9:27*pm, Sam Wormley wrote:
Galileo Now Tells UTC Time







http://www.gpsworld.com/galileo-now-tells-utc-time/
Europe’s four Galileo satellites are now working as clocks accurate
to a few billionths of a second, disseminating the exact time through
their signals expressed as the UTC Universal Coordinated Time global
standard, reports the European Space Agency.
“A billionth of a second equals a nanosecond, a time interval far
beyond our own human capacity of appreciation,” explains Marco
Falcone, ESA’s Galileo System Manager.


“A single lightning flash across the sky during a thunderstorm lasts
about ten milliseconds, which is already 10 000 000 nanoseconds. But
for high-tech applications, as well as navigation services,
nanosecond accuracy is essential.”
The replacement for Greenwich Mean Time, UTC is part of all our daily
lives: it is the timing used for Internet, banking and aviation
standards as well as precise scientific experiments, maintained by
the Paris-based Bureau International de Poids et Mesures (BIPM).


Tell me Sam - how many times does the Earth rotate,to the nearest
rotation, in proportion to its four orbital circuits ?.

I will show you the most disruptive scandal the world has ever known
when you give your answer.
  #3  
Old April 30th 13, 11:35 PM posted to sci.geo.satellite-nav
Greg Troxel
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Posts: 14
Default Galileo Now Tells UTC Time


Sam Wormley writes:

Europeā€™s four Galileo satellites are now working as clocks accurate
to a few billionths of a second, disseminating the exact time through
their signals expressed as the UTC Universal Coordinated Time global
standard, reports the European Space Agency.


So is Galileo really using UTC as the system timescale? That seems
odd, compared to using TAI, which seems like the obvious-in-hindight
choice (given what now seems like an odd decision to create a new
timescale without any interesting properties).

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  #4  
Old May 1st 13, 12:16 AM posted to sci.geo.satellite-nav
Alan Browne
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Posts: 1,339
Default Galileo Now Tells UTC Time

On 2013.04.30 19:35 , Greg Troxel wrote:

Sam Wormley writes:

Europeā€™s four Galileo satellites are now working as clocks accurate
to a few billionths of a second, disseminating the exact time through
their signals expressed as the UTC Universal Coordinated Time global
standard, reports the European Space Agency.


So is Galileo really using UTC as the system timescale? That seems
odd, compared to using TAI, which seems like the obvious-in-hindight
choice (given what now seems like an odd decision to create a new
timescale without any interesting properties).


Whatever the internal system used, they will speak UTC to promote the
public use and integration of the system (telecoms, industry, banking
and so on).

The up/downlink time might indeed be TAI (or something else altogether),
but with the receiver correcting to UTC. (just as GPS receivers need
an offset in the GPS messages to allow the receiver correct it to UTC
for output).

IOW: as long as the ICD is clear the desired output should be UTC along
with the usual "leap second" signalling - regardless of what time base
is used.

--
"A Canadian is someone who knows how to have sex in a canoe."
-Pierre Berton

  #5  
Old May 1st 13, 06:47 AM posted to sci.geo.satellite-nav
oriel36[_2_]
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Posts: 144
Default Galileo Now Tells UTC Time

On May 1, 1:16*am, Alan Browne
wrote:

IOW: as long as the ICD is clear the desired output should be UTC along
with the usual "leap second" signalling - regardless of what time base
is used.


You do not compete with pretension as there are always people with the
dubious talent of saying nothing worthwhile and rely on voodoo with no
physical consideration for the topic hence modern timekeeping and its
practitioners are the most imprecise people ever to be involved in
this noble discipline which meshes human innovation and invention with
the great planetary cycles as the latter provides the framework for
timekeeping.

The second was never,ever extrapolated from the rotation of the Earth
even though people imagine that it is through the 24 hour AM/PM cycle
and the further divisions into equable hours,minutes and seconds so
these 'leap second' justifications are roughly the equivalent of
saying that men have invented rulers that are so flat that they no
longer relate to the flat Earth principle - it really is that bad.

The closest that humanity can come to relating a second to the Earth's
dynamics is that a second was a fraction of the 24 hour day which is
based on the 365/365/365/366 day format which in turn amounts to a
proportion of 1461 days to 4 years,this proportion in turn can be
transferred into 1461 rotations for 4 orbital circuits to the nearest
rotation.The conceptual air gets very thin after this as the next
level of subtleties ,something which produced the Gregorian
reforms,make it very tricky to distinguish the human convenience of a
clock and its timescales from the dynamics of the planet.

It should not happen that people do not act where there is an obvious
error in judgment which tried to tie the daily and orbital motions of
the Earth to stellar circumpolar motion -

"... our clocks kept so good a correspondence with the Heavens that I
doubt it not but they would prove the revolutions of the Earth to be
isochronical (constant)... " Flamsteed to Moore

What that unfortunate man was noting is that a clock keeps pace with
stellar circumpolar motion within the 365/365/365/366 day format and
this framework cannot be used to prove the motions of the
Earth,neither daily rotation nor orbital motion.Sorting out the
problem is an exciting endeavor and prohibits the pretentious and the
plain boring but one thing is for certain - until the matter is dealt
with properly , with transparency and the fact that people like
Flamsteed did make mistakes that are not immediately obvious,it ends
with a crisis of competence which I have sought desperately to avoid.








  #6  
Old May 1st 13, 11:26 AM posted to sci.geo.satellite-nav
Greg Troxel
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Posts: 14
Default Galileo Now Tells UTC Time


Alan Browne writes:

Whatever the internal system used, they will speak UTC to promote the
public use and integration of the system (telecoms, industry, banking
and so on).

The up/downlink time might indeed be TAI (or something else
altogether), but with the receiver correcting to UTC. (just as GPS
receivers need an offset in the GPS messages to allow the receiver
correct it to UTC for output).


Sure, I understand that on the user side of the receiver people expect
UTC. But the ICD I am thinking of is about the signal in space to the
receiver, not the receiver to the user so much. In GPS, the ephemeris
etc. are expressed in GPS time, so my real question - still on the table
- is what is Galileo doing. Specifically, are their almanac/ephemeris
in some UTC(galileo) scale, or their own non-leap-second scale, GPS
time, TAI, or ?

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  #7  
Old May 1st 13, 12:46 PM posted to sci.geo.satellite-nav
oriel36[_2_]
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Posts: 144
Default Galileo Now Tells UTC Time

On May 1, 12:26*pm, Greg Troxel wrote:
Alan Browne writes:
Whatever the internal system used, they will speak UTC to promote the
public use and integration of the system (telecoms, industry, banking
and so on).


The up/downlink time might indeed be TAI (or something else
altogether), but with the receiver correcting to UTC. * (just as GPS
receivers need an offset in the GPS messages to allow the receiver
correct it to UTC for output).


Sure, I understand that on the user side of the receiver people expect
UTC. *But the ICD I am thinking of is about the signal in space to the
receiver, not the receiver to the user so much. *In GPS, the ephemeris
etc. are expressed in GPS time, so my real question - still on the table
- is what is Galileo doing. *Specifically, are their almanac/ephemeris
in some UTC(galileo) scale, or their own non-leap-second scale, GPS
time, TAI, or ?

*application_pgp-signature_part
1KViewDownload


You poor people put yourselves in such a tangle, intentionally it may
be said,that all the external references needed to streamline the
whole discipline are lost in a babble of inappropriate terms like your
counterparts in astronomy who created monsters such the now defunct
'solar vs sidereal' time and the references attached to them -

"* Sidereal Day: A sidereal day is the amount of time it takes the
Earth to rotate once on it axis relative to the stars. A mean sidereal
day is equal to 0.99727 mean solar days, or 23 hours, 56 minutes, 4.1
seconds. The mean solar day and the mean sidereal day differ due to
the fact the Earth is orbiting the sun in 365.2422 mean solar days,
resulting in the sun moving slightly across the celestial sphere
during one solar day (24 hours)"

http://www.physics.ncsu.edu/courses/astron/orbits.html

You are such strange people,there is a crisis bearing down on you and
you hardly even know it exists let alone register it.The crisis
wouldn't register with the wider population as the elements are simply
too complicated and intricate for anyone other than those who are
familiar with the area where timekeeping meshes with astronomy and
ultimately it is a question of competence.

In short,I am sure in some circles that saying nothing is a lucrative
pursuit but I assure you I know the difference between competence and
incompetence and I have yet to see one other person qualify for a
renowned status.
  #8  
Old May 1st 13, 02:57 PM posted to sci.geo.satellite-nav
Alan Browne
external usenet poster
 
Posts: 1,339
Default Galileo Now Tells UTC Time

On 2013.05.01 07:26 , Greg Troxel wrote:

Alan Browne writes:

Whatever the internal system used, they will speak UTC to promote the
public use and integration of the system (telecoms, industry, banking
and so on).

The up/downlink time might indeed be TAI (or something else
altogether), but with the receiver correcting to UTC. (just as GPS
receivers need an offset in the GPS messages to allow the receiver
correct it to UTC for output).


Sure, I understand that on the user side of the receiver people expect
UTC. But the ICD I am thinking of is about the signal in space to the
receiver, not the receiver to the user so much. In GPS, the ephemeris
etc. are expressed in GPS time, so my real question - still on the table
- is what is Galileo doing. Specifically, are their almanac/ephemeris
in some UTC(galileo) scale, or their own non-leap-second scale, GPS
time, TAI, or ?


I wish I had thought of this yesterday. Always look at the ICD.

GST is (Galileo System Time). p.46

QUOTE
5.1.2. Galileo System Time (GST)
The GST is given as 32-bit binary number composed of two parameters as
follows:
ā—¸ The Week Number is an integer counter that gives the
sequential week number from the origin of the Galileo time.

This parameter is coded on 12 bits, which covers 4096 weeks
(about 78 years). Then the counter is reset to zero to cover
additional period modulo 4096.

ā—¸ The Time of Week is defi ned as the number of seconds that
have occurred since the transition from the previous week.
The TOW covers an entire week from 0 to 604799 seconds and is
reset to zero at the end of each week.
table

The GST start epoch shall be 00:00 UT on Sunday 22nd August
1999 (midnight between 21st and 22nd August). At the start
epoch, GST shall be ahead of UTC by thirteen (13) leap
seconds. Since the next leap second was inserted at
01.01.2006, this implies that as of 01.01.2006 GST is ahead
of UTC by fourteen (14) leap seconds.
ENDQUOTE

Conversion definitions are on pages 50 and 51 for UTC and GPS.

"TAI" is not mentioned once.

http://ec.europa.eu/enterprise/polic...vision1_en.pdf


--
"A Canadian is someone who knows how to have sex in a canoe."
-Pierre Berton

  #9  
Old May 1st 13, 10:17 PM posted to sci.geo.satellite-nav
Greg Troxel
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Posts: 14
Default Galileo Now Tells UTC Time


Alan Browne writes:

Conversion definitions are on pages 50 and 51 for UTC and GPS.

"TAI" is not mentioned once.

http://ec.europa.eu/enterprise/polic...vision1_en.pdf


Thanks. I looked at that, and it seems like GST is intended to be very
close to GPS time, with the GST/UTC offset being the same as the GPS/UTC
offset. But it was really hard to be sure.

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  #10  
Old May 2nd 13, 04:47 AM posted to sci.geo.satellite-nav
oriel36[_2_]
external usenet poster
 
Posts: 144
Default Galileo Now Tells UTC Time

On May 1, 11:17*pm, Greg Troxel wrote:
Alan Browne writes:
Conversion definitions are on pages 50 and 51 for UTC and GPS.


"TAI" is not mentioned once.


http://ec.europa.eu/enterprise/polic...files/galileo-...


Thanks. *I looked at that, and it seems like GST is intended to be very
close to GPS time, with the GST/UTC offset being the same as the GPS/UTC
offset. *But it was really hard to be sure.

*application_pgp-signature_part
1KViewDownload


You would hardly suspect that the word 'atrocity' could possibly be
associated with timekeeping but given that the failed attempt to
rework the clock and the calendar system into the Earth's planetary
dynamics and subsequently its catastrophic consequences for cause and
effect ,it is fair to say that the timekeeping regime that relies on
so much voodoo for their reputations and salaries has done so much
damage to human understanding of their surroundings and the motions in
the celestial arena.This Nazi-like ability to totally filter out the
degradation caused by a silly judgment based on stellar circumpolar
motion and the Earth's rotation is second only to the promotion of so
much junk by turning the celestial arena into a junkyard for
theoretical nonsense.

I have witnessed the collapse of interpretative astronomy among men
for nothing more than speculative theoretical junk and it was done by
exploiting the links between timekeeping and the astronomical
references from which they came and that is why I have to look at
holocaust literature to discover why people show not the slightest
hint of remorse that great human insights and innovations were
destroyed to make way for the rubbish seen today and passing itself
off as astronomy -

http://www.youtube.com/watch?v=gVfFHJE0e1g

The clinical coldness can be astonishing but I assure each and every
one of you that the pretension and the voodoo that have formed much of
your endeavors is on the way out - all it takes is human kindness,a
lot of effort and much resilience.
 




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