SR/GR use absolute time to synchronize the GPS clocks with the ground clock.
in [Physics]
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From: kenseto on 26 Mar 2010 09:13 On Mar 24, 11:14 am, Sam Wormley <sworml...(a)gmail.com> wrote: > On 3/24/10 8:27 AM, kenseto wrote: > > > Sigh...the discussion was about whether observed doppler shift will > > effect the rate of a clock. The answer is no. The rate of a moving > > clock is 1/gamma at all time. > > > Ken Seto > >   Let the clock be a distant pulsar with radial velocity v with >   respect to the observer. The relativistic formula for the Doppler >   shift in pulse arrival time due to an arbitrary velocity is given >   by > >    t' = (1 + v/c) γ t > >   where v represents the velocity along the line of sight between >   source and observer and t' and t represent the time between >   pulses at the observer and at the source, respectively. Sigh....wormy t' is the cooridnate time. It tis not the rate of an observed clock. The rate of an observed clock is 1/gamma at all times. Why don't you study SR before you make a fool of yourself again.
From: kenseto on 26 Mar 2010 09:40 On Mar 24, 11:32 am, moro...(a)world.std.spaamtrap.com (Michael Moroney) wrote: > kenseto <kens...(a)erinet.com> writes: > >On Mar 23, 12:51 pm, moro...(a)world.std.spaamtrap.com (Michael Moroney) > >wrote: > >> kenseto <kens...(a)erinet.com> writes: > >> >Hey idiot time dilation got nothing to do with this discussion. > > >> Time dilation has *everything* to do with this discussion. Time dilation > >> would cause the GPS satellite to "transmit" at the wrong frequency (as > >> far as a terrestial receiver is concerned), so they adjusted the frequency > >> before launch so it would at the correct frequency on Earth. > >Sigh...the discussion was about whether observed doppler shift will > >effect the rate of a clock. The answer is no. > > The discussion is about how different physical effects cause a frequency > shift, and these frequency shifts can be calculated in advance and > compensated for so that a relatively moving target receives a correct > frequency. No idiot...accoridng to SR the rate of a moving clock is always 1/ gamma and it is independent of the direction of relative motion of the observed source....in other words, observed doppler shift does not effect the rate of a moving clcok. The redefined GPS second is make to synchronize the GPS clock with the ground clock....IOW the passage of one redefined GPS second will correspond to the passage of one ground clock second. You really need to study SR again before you make a fool of yourself again. Ken Seto >The passengers aboard the train will sense the "A" horn as > mistuned. But those on the platform will hear the correct tune due to > Doppler and some physics math. Someone riding aboard a GPS satellite will > think the cesium clock is mis-set, with an incorrect divisor. A GPS > receiver on the ground gets the correct frequency due to SR, GR and > precalculated physics math that set the "wrong" divisor before launch. > > Same effect, different causes.
From: kenseto on 26 Mar 2010 10:01 On Mar 24, 12:02 pm, moro...(a)world.std.spaamtrap.com (Michael Moroney) wrote: > kenseto <kens...(a)erinet.com> writes: > >On Mar 23, 12:57 pm, moro...(a)world.std.spaamtrap.com (Michael Moroney) > >wrote: > > >> Yes, just like the train horn. The approaching train has to sound at a > >> frequency lower than 440 Hz to be heard at the station as 440 Hz, while a > >> departing train has to sound at a higher frequency to be heard as 440 Hz. > >No it's not the same. The GPS sends a signal after N+4.15 perods of Cs > >133 radiation elapsed....no matter if it is approaching the ground > >clock or receding away from the ground clock. > > There are additional Doppler effects on the GPS signal as the satellites > approach or recede, but I'm not talking about that. Don't try to confuse > matters by mixing the Doppler of the GPS signals and the Doppler train > example. > > Consider the signal from a satellite as it passes directly overhead, so > that it is neither approaching nor receding. Doppler effect is zero. > However since the satellite is not as deep in the earth's gravity well, > there are GR effects. In addition the satellite is moving at a decent > clip so that there are SR (NOT Doppler!) effects. With the cesium clock > "mis-set" so that the divisor is N+4.15 periods of Cs, the received > signal on earth's surface is absolutely correct. (remember, no Doppler > in this case). Sigh....the title of this thread is SR/GR uses abnsolute time to synchronize the GPS clocks with the ground clock. Here you are talking about the corrections to the data received from the GPS. Ken Seto Ken Seto > >With your situation the audience at the platform will hear 440 Hz when > >the train is approaching but they will hear a different frequency when > >the train is receding away from the platform. > > Remember, I changed the concert so that the train is receding for the > entire performance, just for you. The Doppler effect on the performance > is constant. You could also argue that the SR and GR effects on the > satellites would change as the satellites speed up and slow down in their > orbits, or move into higher and lower orbits. However, the satellites > don't do that, so the SR/GR compensation factor is constant. > > Once again, same effect (frequency shift), different causes (SR/GR vs. > Doppler)
From: Sam Wormley on 26 Mar 2010 11:20 On 3/26/10 8:13 AM, kenseto wrote: > On Mar 24, 11:14 am, Sam Wormley<sworml...(a)gmail.com> wrote: >> On 3/24/10 8:27 AM, kenseto wrote: >> >>> Sigh...the discussion was about whether observed doppler shift will >>> effect the rate of a clock. The answer is no. The rate of a moving >>> clock is 1/gamma at all time. >> >>> Ken Seto >> >> Let the clock be a distant pulsar with radial velocity v with >> respect to the observer. The relativistic formula for the Doppler >> shift in pulse arrival time due to an arbitrary velocity is given >> by >> >> t' = (1 + v/c) γ t >> >> where v represents the velocity along the line of sight between >> source and observer and t' and t represent the time between >> pulses at the observer and at the source, respectively. > > Sigh....wormy t' is the cooridnate time. It tis not the rate of an > observed clock. The rate of an observed clock is 1/gamma at all times. > Why don't you study SR before you make a fool of yourself again. In the equation I posted, Seto, t' is the observed time between pulses of the distant pulsar. t' = (1 + v/c) γ t where v represents the velocity along the line of sight between source and observer and t' and t represent the time between pulses at the observer and at the source, respectively.
From: Michael Moroney on 26 Mar 2010 12:43
kenseto <kenseto(a)erinet.com> writes: >On Mar 24, 11:32 am, moro...(a)world.std.spaamtrap.com (Michael Moroney) >wrote: >> kenseto <kens...(a)erinet.com> writes: >> >On Mar 23, 12:51 pm, moro...(a)world.std.spaamtrap.com (Michael Moroney) >> >wrote: >> >> kenseto <kens...(a)erinet.com> writes: >> >> >Hey idiot time dilation got nothing to do with this discussion. >> >> >> Time dilation has *everything* to do with this discussion. Time dilation >> >> would cause the GPS satellite to "transmit" at the wrong frequency (as >> >> far as a terrestial receiver is concerned), so they adjusted the frequency >> >> before launch so it would at the correct frequency on Earth. >> >Sigh...the discussion was about whether observed doppler shift will >> >effect the rate of a clock. The answer is no. >> >> The discussion is about how different physical effects cause a frequency >> shift, and these frequency shifts can be calculated in advance and >> compensated for so that a relatively moving target receives a correct >> frequency. >No idiot...accoridng to SR the rate of a moving clock is always 1/ >gamma and it is independent of the direction of relative motion of the >observed source....in other words, observed doppler shift does not >effect the rate of a moving clcok. The redefined GPS second is make to >synchronize the GPS clock with the ground clock....IOW the passage of >one redefined GPS second will correspond to the passage of one ground >clock second. Are you really too stooopid to understand what's going on? Ground clock senses GPS clock as running too fast due to (mostly) GR effects. If it transmitted an "A" tune, it would be heard as a bit sharp. Designers know of this, can calculate the exact amount, and deliberately detune the clock (make it "flat" by the right amount) so the receiver receives the right tune. No "redefinition" of a second, as far as the GPS designer is concerned, instead of designing a satellite producing 1 pulse per second, for example, it produces 1 pulse per 1.0000000000001 seconds or something. In particular, the onboard frequency standard is 10.22999999543 MHz, which the ground receiver senses as running at 10.23 MHz. >You really need to study SR again before you make a fool of yourself >again. Speak for yourself. Obviously you have little comprehension of SR or GR. |