Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > sci.physics > #634501 > unrolled thread
| Started by | Ckeho Baùkora <unukn@owyqar.og> |
|---|---|
| First post | 2017-05-27 10:37 +0000 |
| Last post | 2017-06-09 13:35 -0700 |
| Articles | 20 on this page of 115 — 26 participants |
Back to article view | Back to sci.physics
This discussion starts older than the indexed window; earlier articles aren't shown. The article labeled Started by
below is the oldest one visible, not the original post.
Re: GPS Again. Ckeho Baùkora <unukn@owyqar.og> - 2017-05-27 10:37 +0000
Re: GPS Again. Tom Roberts <tjroberts137@sbcglobal.net> - 2017-05-30 09:57 -0500
Re: GPS Again. Helmut Wabnig <hwabnig@.- --- -.dotat> - 2017-05-30 20:52 +0200
Re: GPS Again. Ernest Rivers <erwm@weicnne.ac> - 2017-05-30 19:17 +0000
Re: GPS Again. Tom Roberts <tjroberts137@sbcglobal.net> - 2017-05-30 15:23 -0500
Re: GPS Again. Helmut Wabnig <hwabnig@.- --- -.dotat> - 2017-05-30 22:53 +0200
Re: GPS Again. Ernest Schwanenflügel <erwm@wanenf.oa> - 2017-05-30 20:59 +0000
Re: GPS Again. Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-05-31 00:42 +0200
Re: GPS Again. Tom Roberts <tjroberts137@sbcglobal.net> - 2017-05-30 19:03 -0500
Re: GPS Again. Serg io <invalid@invalid.com> - 2017-05-30 21:30 -0500
Re: GPS Again. Serg io <invalid@invalid.com> - 2017-05-30 19:01 -0500
Re: GPS Again. Ernest Rivers <erwm@weicnne.ac> - 2017-05-30 19:15 +0000
Re: GPS Again. Sylvia Else <sylvia@not.at.this.address> - 2017-06-09 11:37 +1000
Re: GPS Again. Jim Limey <eeug@dnne.ri> - 2017-06-09 14:32 +0000
Re: GPS Again. Serg io <invalid@invalid.com> - 2017-06-09 12:51 -0500
Re: GPS Again. Kitubu Nkyaku <akntuu@buwkau.kk> - 2017-06-09 18:52 +0000
Re: GPS Again. "HGW..." <hgw@....> - 2017-06-10 09:23 +1000
Re: GPS Again. Sylvia Else <sylvia@not.at.this.address> - 2017-06-10 11:23 +1000
Re: GPS Again. Sylvia Else <sylvia@not.at.this.address> - 2017-06-10 11:21 +1000
Re: GPS Again. Kitubu Nkyaku <akntuu@buwkau.kk> - 2017-06-10 10:42 +0000
Re: GPS Again. Serg io <invalid@invalid.com> - 2017-06-10 19:38 -0500
Re: GPS Again. Nými Icelulózy <ejienm@wzsfwe.ul> - 2017-06-16 11:30 +0000
Re: GPS Again. Sегgi о <iinvalid@invalid.com> - 2017-06-16 10:40 -0500
Re: GPS Again. Sylvia Else <sylvia@not.at.this.address> - 2017-06-11 11:11 +1000
Re: GPS Again. Serg io <invalid@invalid.com> - 2017-06-10 21:20 -0500
Re: GPS Again. Sylvia Else <sylvia@not.at.this.address> - 2017-06-11 12:31 +1000
Re: GPS Again. Tom Roberts <tjroberts137@sbcglobal.net> - 2017-06-10 22:40 -0500
Re: GPS Again. Serg io <invalid@invalid.com> - 2017-06-10 23:20 -0500
Re: GPS Again. "HGW, DSc." <HG@....> - 2017-06-11 05:14 +1000
Re: GPS Again. "Paul B. Andersen" <relativity@paulba.no> - 2017-06-10 22:16 +0200
Re: GPS Again. "HGW, DSc." <HG@....> - 2017-06-11 07:19 +1000
Re: GPS Again. "Paul B. Andersen" <relativity@paulba.no> - 2017-06-11 22:35 +0200
Re: GPS Again. Serg io <invalid@invalid.com> - 2017-06-11 15:44 -0500
Re: GPS Again. Serg io <invalid@invalid.com> - 2017-06-11 18:03 -0500
Re: GPS Again. Serg io <invalid@invalid.com> - 2017-06-11 19:00 -0500
Re: GPS Again. "HGW..." <hgw@....> - 2017-06-12 11:39 +1000
Re: GPS Again. moroney@world.std.spaamtrap.com (Michael Moroney) - 2017-06-12 02:33 +0000
Re: GPS Again. "hanson" <hanson@quick.net> - 2017-06-12 10:15 -0700
Re: GPS Again. Serg io <invalid@invalid.com> - 2017-06-12 13:40 -0500
Re: GPS Again. "hanson" <hanson@quick.net> - 2017-06-12 14:19 -0700
Re: GPS Again. Tom Roberts <tjroberts137@sbcglobal.net> - 2017-06-11 22:42 -0500
Re: GPS Again. Serg io <invalid@invalid.com> - 2017-06-11 23:27 -0500
Re: GPS Again. jimp@specsol.spam.sux.com - 2017-06-12 04:47 +0000
Re: GPS Again. Serg io <invalid@invalid.com> - 2017-06-12 08:20 -0500
Re: GPS Again. jimp@specsol.spam.sux.com - 2017-06-12 17:18 +0000
Re: GPS Again. benj <benj@nobody.net> - 2017-06-12 18:15 -0400
Re: GPS Again. jimp@specsol.spam.sux.com - 2017-06-12 22:32 +0000
Re: GPS Again. benj <benj@nobody.net> - 2017-06-12 20:48 -0400
Re: GPS Again. jimp@specsol.spam.sux.com - 2017-06-13 01:52 +0000
Re: GPS Again. benj <benj@nobody.net> - 2017-06-13 19:57 -0400
Re: GPS Again. jimp@specsol.spam.sux.com - 2017-06-14 00:46 +0000
Re: GPS Again. Tom Roberts <tjroberts137@sbcglobal.net> - 2017-06-12 09:58 -0500
Re: GPS Again. Selina Dieter <uiueeits@wlwtwstd.ci> - 2017-06-12 15:08 +0000
Re: GPS Again. Serg io <invalid@invalid.com> - 2017-06-12 10:37 -0500
Re: GPS Again. jimp@specsol.spam.sux.com - 2017-06-12 17:21 +0000
Re: GPS Again. Selina Dieter <uiueeits@wlwtwstd.ci> - 2017-06-12 17:40 +0000
Re: GPS Again. jimp@specsol.spam.sux.com - 2017-06-12 18:05 +0000
Re: GPS Again. Selina Dieter <uiueeits@wlwtwstd.ci> - 2017-06-12 18:19 +0000
Re: GPS Again. jimp@specsol.spam.sux.com - 2017-06-12 19:16 +0000
Re: GPS Again. moroney@world.std.spaamtrap.com (Michael Moroney) - 2017-06-12 19:43 +0000
Re: GPS Again. pcardinale@volcanomail.com - 2017-06-12 12:22 -0700
Re: GPS Again. jimp@specsol.spam.sux.com - 2017-06-12 20:01 +0000
Re: GPS Again. Serg io <invalid@invalid.com> - 2017-06-12 18:32 -0500
Re: GPS Again. jimp@specsol.spam.sux.com - 2017-06-13 01:54 +0000
Re: GPS Again. Serg io <invalid@invalid.com> - 2017-06-12 22:28 -0500
Re: GPS Again. benj <benj@nobody.net> - 2017-06-13 19:59 -0400
Re: GPS Again. jimp@specsol.spam.sux.com - 2017-06-14 00:48 +0000
Re: GPS Again. benj <benj@nobody.net> - 2017-06-13 21:35 -0400
Re: GPS Again. jimp@specsol.spam.sux.com - 2017-06-14 02:11 +0000
Re: GPS Again. Mahipal <mahipal7638@gmail.com> - 2017-06-13 19:50 -0700
Re: GPS Again. benj <benj@nobody.net> - 2017-06-13 23:53 -0400
Re: GPS Again. jimp@specsol.spam.sux.com - 2017-06-14 05:27 +0000
Re: GPS Again. Sегg iо <invalid@invalid.com> - 2017-06-14 09:10 -0500
Re: GPS Again. benj <benj@nobody.net> - 2017-06-14 17:10 -0400
Re: GPS Again. jimp@specsol.spam.sux.com - 2017-06-14 21:33 +0000
Re: GPS Again. benj <benj@nobody.net> - 2017-06-14 18:19 -0400
Re: GPS Again. jimp@specsol.spam.sux.com - 2017-06-14 22:33 +0000
Re: GPS Again. benj <benj@nobody.net> - 2017-06-15 17:01 -0400
Re: GPS Again. jimp@specsol.spam.sux.com - 2017-06-15 23:09 +0000
Re: GPS Again. benj <benj@nobody.net> - 2017-06-13 23:49 -0400
Re: GPS Again. jimp@specsol.spam.sux.com - 2017-06-14 05:29 +0000
Re: GPS Again. Sегg iо <invalid@invalid.com> - 2017-06-13 20:29 -0500
Re: GPS Again. pcardinale@volcanomail.com - 2017-06-13 12:33 -0700
Re: GPS Again. Серг ио <invalid@invalid.com> - 2017-06-13 16:39 -0500
Re: GPS Again. benj <benj@nobody.net> - 2017-06-12 18:25 -0400
Re: GPS Again. Serg io <invalid@invalid.com> - 2017-06-12 18:45 -0500
Re: GPS Again. "HGW..." <hgw@....> - 2017-06-12 10:35 +1000
Re: GPS Again. Sylvia Else <sylvia@not.at.this.address> - 2017-06-12 11:05 +1000
Re: GPS Again. Serg io <invalid@invalid.com> - 2017-06-11 23:29 -0500
Re: GPS Again. "HGW..." <hgw@....> - 2017-06-12 20:12 +1000
Re: GPS Again. Poutnik <poutnik4nntp@gmail.com> - 2017-06-12 13:54 +0200
Re: GPS Again. Selina Dieter <uiueeits@wlwtwstd.ci> - 2017-06-12 12:47 +0000
Re: GPS Again. "HGW, DSc." <HG@....> - 2017-06-13 04:13 +1000
Re: GPS Again. Sylvia Else <sylvia@not.at.this.address> - 2017-06-13 12:59 +1000
Re: GPS Again. "HGW, DSc." <HG@....> - 2017-06-13 04:22 +1000
Re: GPS Again. Sylvia Else <sylvia@not.at.this.address> - 2017-06-13 13:00 +1000
Re: GPS Again. Tom Roberts <tjroberts137@sbcglobal.net> - 2017-06-13 13:32 -0500
Re: GPS Again. "HGW..." <hgw@....> - 2017-06-14 10:09 +1000
Re: GPS Again. "HGW..." <hgw@....> - 2017-06-14 09:34 +1000
Re: GPS Again. Серг ио <invalid@invalid.com> - 2017-06-13 18:42 -0500
Re: GPS Again. "HGW..." <hgw@....> - 2017-06-14 12:40 +1000
Re: GPS Again. moroney@world.std.spaamtrap.com (Michael Moroney) - 2017-06-14 04:06 +0000
Re: GPS Again. "hanson" <hanson@quick.net> - 2017-06-13 23:01 -0700
Re: GPS Again. Sегg iо <invalid@invalid.com> - 2017-06-13 23:19 -0500
Re: GPS Again. Sегg iо <invalid@invalid.com> - 2017-06-13 23:46 -0500
Re: GPS Again. "HGW, DSc." <HG@....> - 2017-06-14 20:07 +1000
Re: GPS Again. Sегg iо <invalid@invalid.com> - 2017-06-14 09:17 -0500
Re: GPS Again. "HGW..." <hgw@....> - 2017-06-17 08:26 +1000
Re: GPS Again. benj <benj@nobody.net> - 2017-06-16 20:40 -0400
Re: GPS Again. Ecembre Abin <umueuu@eibbwaw.ee> - 2017-06-17 08:05 +0000
Re: GPS Again. "HGW, DSc." <HG@....> - 2017-06-17 22:20 +1000
Re: GPS Again. Sегgi о <iinvalid@invalid.com> - 2017-06-17 07:58 -0500
Re: GPS Again. benj <benj@nobody.net> - 2017-06-14 17:06 -0400
Re: GPS Again. "HGW..." <hgw@....> - 2017-05-31 09:58 +1000
Re: GPS Again. pcardinale@volcanomail.com - 2017-06-09 13:35 -0700
Page 5 of 6 — ← Prev page 1 2 3 4 [5] 6 Next page →
| From | jimp@specsol.spam.sux.com |
|---|---|
| Date | 2017-06-14 05:29 +0000 |
| Message-ID | <t5u61e-pgr.ln1@mail.specsol.com> |
| In reply to | #636332 |
benj <benj@nobody.net> wrote: > On 6/13/2017 10:11 PM, jimp@specsol.spam.sux.com wrote: >> benj <benj@nobody.net> wrote: >>> On 6/13/2017 8:48 PM, jimp@specsol.spam.sux.com wrote: >>>> benj <benj@nobody.net> wrote: >>>>> On 6/12/2017 9:54 PM, jimp@specsol.spam.sux.com wrote: >>>>>> Serg io <invalid@invalid.com> wrote: >>>>>>> On 6/12/2017 3:01 PM, jimp@specsol.spam.sux.com wrote: >>>>>>>> pcardinale@volcanomail.com wrote: >>>>>>>>> Your link actually supports what Serg io said. The article describes SS as being either frequency hopping, or direct sequence (which is what Serg io was describing). >>>>>>>> >>>>>>>> Upon rereading the article, it describes SS as FHSS, DSSS, THSS, CSS and >>>>>>>> combinations of these techniques, which has what the fuck to do with GPS >>>>>>>> which operates on fixed, well defined frequencies? >>>>>>>> >>>>>>>> >>>>>>> >>>>>>> nope. What you are calling a 'well defined frequency' is only the >>>>>>> center of the GPS SS band, and it extends more than 10Mhz on each side. >>>>>> >>>>>> Idiot. >>>>>> >>>>>> *PLONK* >>>>>> >>>>>> >>>>> Hey Sergio! >>>> >>>> The resident troll chimes in yet again with the usual ad hominems and >>>> blather. >>>> >>>> >>> Chimp >> >> The resident troll continues in the desperate search for attention. >> >> > Funny. The troll continues his ad hominems and useless blather. <snip useless troll droppings> -- Jim Pennino
[toc] | [prev] | [next] | [standalone]
| From | Sегg iо <invalid@invalid.com> |
|---|---|
| Date | 2017-06-13 20:29 -0500 |
| Message-ID | <ohq3hq$nee$1@gioia.aioe.org> |
| In reply to | #636294 |
On 6/13/2017 6:59 PM, benj wrote: > On 6/12/2017 9:54 PM, jimp@specsol.spam.sux.com wrote: >> Serg io <invalid@invalid.com> wrote: >>> On 6/12/2017 3:01 PM, jimp@specsol.spam.sux.com wrote: >>>> pcardinale@volcanomail.com wrote: >>>>> Your link actually supports what Serg io said. The article >>>>> describes SS as being either frequency hopping, or direct sequence >>>>> (which is what Serg io was describing). >>>> Upon rereading the article, it describes SS as FHSS, DSSS, THSS, CSS >>>> and >>>> combinations of these techniques, which has what the fuck to do with >>>> GPS >>>> which operates on fixed, well defined frequencies? >>>> >>>> >>> >>> nope. What you are calling a 'well defined frequency' is only the >>> center of the GPS SS band, and it extends more than 10Mhz on each side. >> Idiot. >> >> *PLONK* >> >> > Hey Sergio! There is a spread spectrum signal coming in from Chimp! > <Chimp sticks fingers in his ears> > "LA LA LA LA! I CAN'T HEAR YOU!!!!" yep, jimp-um got-um caught in area-um he dosent know anything about, and *had to withdraw*, the best way-um he knows how... but, Isn't jimp simply projecting with this one; "The resident troll chimes in yet again with the usual ad hominems and blather." ?
[toc] | [prev] | [next] | [standalone]
| From | pcardinale@volcanomail.com |
|---|---|
| Date | 2017-06-13 12:33 -0700 |
| Message-ID | <64e528eb-3130-4f5d-928c-adfdb30aa84b@googlegroups.com> |
| In reply to | #636168 |
On Monday, June 12, 2017 at 1:16:04 PM UTC-7, ji...@specsol.spam.sux.com wrote: > pcardinale@volcanomail.com wrote: > > Your link actually supports what Serg io said. The article describes SS as being either frequency hopping, or direct sequence (which is what Serg io was describing). > > Upon rereading the article, it describes SS as FHSS, DSSS, THSS, CSS and > combinations of these techniques, which has what the fuck to do with GPS > which operates on fixed, well defined frequencies? > > > -- > Jim Pennino GPS uses DSSS. Sure, the carrier frequencies are well defined, but that has nothing to do with the modulation scheme.
[toc] | [prev] | [next] | [standalone]
| From | Серг ио <invalid@invalid.com> |
|---|---|
| Date | 2017-06-13 16:39 -0500 |
| Message-ID | <ohpm3g$4ab$1@gioia.aioe.org> |
| In reply to | #636270 |
On 6/13/2017 2:33 PM, pcardinale@volcanomail.com wrote: > On Monday, June 12, 2017 at 1:16:04 PM UTC-7, ji...@specsol.spam.sux.com wrote: >> pcardinale@volcanomail.com wrote: >>> Your link actually supports what Serg io said. The article describes SS as being either frequency hopping, or direct sequence (which is what Serg io was describing). >> >> Upon rereading the article, it describes SS as FHSS, DSSS, THSS, CSS and >> combinations of these techniques, which has what the fuck to do with GPS >> which operates on fixed, well defined frequencies? >> >> >> -- >> Jim Pennino > > GPS uses DSSS. Sure, the carrier frequencies are well defined, but that has nothing to do with the modulation scheme. > the really nice thing about DSSS or spread spectrum is that you get "corrolation gain" or processing gain, which is roughly the ratio of your spread signal bandwidth to modulation signal bandwidth. (10 or 20 *log(SSBw/MBw) it can be 30 to 40 dB, which is huge! so if your signal path from a transmitter to receiver is a -100 dB loss, the extra gain allows you to go farther, another 40 dB's worth of distance (hit shadowed areas), and/or reduce antenna size, and/or reduce transmitter power (which reduces battery size enabling cellphones to be small) instead of 100 watt transmitter, you use a 1 watt transmitter. and with DSSS you can detect below the noise floor. Qualcomm is big in SS, makes $$ from licensing its technology worldwide.
[toc] | [prev] | [next] | [standalone]
| From | benj <benj@nobody.net> |
|---|---|
| Date | 2017-06-12 18:25 -0400 |
| Message-ID | <593f14d2$0$54429$b1db1813$e2fc9064@news.astraweb.com> |
| In reply to | #636151 |
On 6/12/2017 1:40 PM, Selina Dieter wrote: > jimp wrote: > >>> GPS is classic SS, was develped in the early 70s, >> >> Spread spectrum was actually developed in the 40's. > > Rather purposed, as an idea. You don't know. You don't know what it is. > Explain the clocking of data in such an arrangement. You don't know. I was > right all the time. > Chimp is an idiot and Selina has him backed into a corner since Selina knows that clock extraction from BPSK modulation is not such a simple task!
[toc] | [prev] | [next] | [standalone]
| From | Serg io <invalid@invalid.com> |
|---|---|
| Date | 2017-06-12 18:45 -0500 |
| Message-ID | <ohn920$1uj$1@gioia.aioe.org> |
| In reply to | #636188 |
On 6/12/2017 5:25 PM, benj wrote:
> On 6/12/2017 1:40 PM, Selina Dieter wrote:
>> jimp wrote:
>>
>>>> GPS is classic SS, was develped in the early 70s,
>>>
>>> Spread spectrum was actually developed in the 40's.
>>
>> Rather purposed, as an idea. You don't know. You don't know what it is.
>> Explain the clocking of data in such an arrangement. You don't know. I
>> was
>> right all the time.
>>
> Chimp is an idiot and Selina has him backed into a corner since Selina
> knows that clock extraction from BPSK modulation is not such a simple task!
BenjJi! you are right again, not simple at all! many tradeoff's there,
bit sync, code sync, tracking loop bandwidths, SNR etc.
now that most of it is settled for GPS, and there are chipsets out
there, I would love to see how they did all the sync up.
take code sync, you have 12 sattilites sending SS to you with different
codes, and you have to corrolate with each of them, would you put 12 in
yoru design, like Motorola would do? (they not a SS house)
http://www.navipedia.net/index.php/Correlators
Pseudo-Random Noise (PRN) Codes - also called ranging codes - are a
sequence of pulses that are used to spread the spectrum of the
transmitted signal. For this purpose, several types of codes are used,
and some examples are given here (for further information on the codes
used by each system, refer to the respective SIS ICDs):
GPS L1 C/A uses Gold codes[1] that are actually a combination of
two maximum length codes[2].
[toc] | [prev] | [next] | [standalone]
| From | "HGW..." <hgw@....> |
|---|---|
| Date | 2017-06-12 10:35 +1000 |
| Message-ID | <ohknkf$1v06$1@gioia.aioe.org> |
| In reply to | #636085 |
On 12/06/17 06:35, Paul B. Andersen wrote: > Den 10.06.2017 23.19, skrev HGW, DSc.: > >>> It would indeed be very interesting to see how Ralph >>> would count "the number of wavelengths between satellite >>> and receiver" without using "ct". >>> >>> But we won't see the explanation of how that "IN fact" >>> is done, will we Henry? :-D >> >> No we wont...because as Wiki points out, it is top secret.... >> >> ...but the answer is pretty obvious. Each wavelength is actually >> 'labelled' so that its number can be matched against the label of the >> wave received at the instant the second one was sent....simple, eh? It >> gives the number of absolute wavelengths in the signal directly. > > Quite. Pretty obvious indeed! :-D > > (Lurkers: No, he is not joking!) Too hard for you , eh, Paul? It shouldn't be. It is actually very simple and clever. Of course the waves aren't all actually numbered. As long as some are marked at regular intervals the electronics can do the rest. I gather from the Wiki article that phase differences are used. The hardest part might be in knowing the receiver's clock error but since that will affect all four paths equally, a small time discrepancy will only cause a navigation error in height. Since wavelengths are absolute and virtually invariant over 85 msecs, the idea is much smarter than using light speeds, which wander all over the place. It appears that BaTh wins yet again. --
[toc] | [prev] | [next] | [standalone]
| From | Sylvia Else <sylvia@not.at.this.address> |
|---|---|
| Date | 2017-06-12 11:05 +1000 |
| Message-ID | <eq67mnFu2r3U1@mid.individual.net> |
| In reply to | #636107 |
On 12/06/2017 10:35 AM, HGW... wrote: > On 12/06/17 06:35, Paul B. Andersen wrote: >> Den 10.06.2017 23.19, skrev HGW, DSc.: >> >>>> It would indeed be very interesting to see how Ralph >>>> would count "the number of wavelengths between satellite >>>> and receiver" without using "ct". >>>> >>>> But we won't see the explanation of how that "IN fact" >>>> is done, will we Henry? :-D >>> >>> No we wont...because as Wiki points out, it is top secret.... >>> >>> ...but the answer is pretty obvious. Each wavelength is actually >>> 'labelled' so that its number can be matched against the label of the >>> wave received at the instant the second one was sent....simple, eh? >>> It gives the number of absolute wavelengths in the signal directly. >> >> Quite. Pretty obvious indeed! :-D >> >> (Lurkers: No, he is not joking!) > > Too hard for you , eh, Paul? > > It shouldn't be. It is actually very simple and clever. Of course the > waves aren't all actually numbered. As long as some are marked at > regular intervals the electronics can do the rest. I gather from the > Wiki article that phase differences are used. The hardest part might be > in knowing the receiver's clock error but since that will affect all > four paths equally, a small time discrepancy will only cause a > navigation error in height. > > Since wavelengths are absolute and virtually invariant over 85 msecs, > the idea is much smarter than using light speeds, which wander all over > the place. > > It appears that BaTh wins yet again. > > > The Wiki article is not very well expressed. Carrier phase tracking is just a method of determining more precisely (down to small fractions of a nano-second) the difference between the receiver's clock (which is accurate enough in the short term) and the satellite's clock. The result is still multiplied by the fixed speed of light to convert it to a distance. Sylvia.
[toc] | [prev] | [next] | [standalone]
| From | Serg io <invalid@invalid.com> |
|---|---|
| Date | 2017-06-11 23:29 -0500 |
| Message-ID | <ohl5af$eto$2@gioia.aioe.org> |
| In reply to | #636108 |
On 6/11/2017 8:05 PM, Sylvia Else wrote: > On 12/06/2017 10:35 AM, HGW... wrote: >> On 12/06/17 06:35, Paul B. Andersen wrote: >>> Den 10.06.2017 23.19, skrev HGW, DSc.: >>> >>>>> It would indeed be very interesting to see how Ralph >>>>> would count "the number of wavelengths between satellite >>>>> and receiver" without using "ct". >>>>> >>>>> But we won't see the explanation of how that "IN fact" >>>>> is done, will we Henry? :-D >>>> No we wont...because as Wiki points out, it is top secret.... >>>> >>>> ...but the answer is pretty obvious. Each wavelength is actually >>>> 'labelled' so that its number can be matched against the label of the >>>> wave received at the instant the second one was sent....simple, eh? >>>> It gives the number of absolute wavelengths in the signal directly. >>> >>> Quite. Pretty obvious indeed! :-D >>> >>> (Lurkers: No, he is not joking!) >> Too hard for you , eh, Paul? >> >> It shouldn't be. It is actually very simple and clever. Of course the >> waves aren't all actually numbered. As long as some are marked at >> regular intervals the electronics can do the rest. I gather from the >> Wiki article that phase differences are used. The hardest part might be >> in knowing the receiver's clock error but since that will affect all >> four paths equally, a small time discrepancy will only cause a >> navigation error in height. >> >> Since wavelengths are absolute and virtually invariant over 85 msecs, >> the idea is much smarter than using light speeds, which wander all over >> the place. >> >> It appears that BaTh wins yet again. >> >> > The Wiki article is not very well expressed. Carrier phase tracking is > just a method of determining more precisely (down to small fractions of > a nano-second) the difference between the receiver's clock (which is > accurate enough in the short term) and the satellite's clock. The result > is still multiplied by the fixed speed of light to convert it to a > distance. > > Sylvia. yes with several corrections for ionosphere, etc, etc...
[toc] | [prev] | [next] | [standalone]
| From | "HGW..." <hgw@....> |
|---|---|
| Date | 2017-06-12 20:12 +1000 |
| Message-ID | <ohlpdu$1e20$1@gioia.aioe.org> |
| In reply to | #636108 |
On 12/06/17 11:05, Sylvia Else wrote: > On 12/06/2017 10:35 AM, HGW... wrote: >> >> It shouldn't be. It is actually very simple and clever. Of course the >> waves aren't all actually numbered. As long as some are marked at >> regular intervals the electronics can do the rest. I gather from the >> Wiki article that phase differences are used. The hardest part might be >> in knowing the receiver's clock error but since that will affect all >> four paths equally, a small time discrepancy will only cause a >> navigation error in height. >> >> Since wavelengths are absolute and virtually invariant over 85 msecs, >> the idea is much smarter than using light speeds, which wander all over >> the place. >> >> It appears that BaTh wins yet again. >> >> >> > The Wiki article is not very well expressed. Carrier phase tracking is > just a method of determining more precisely (down to small fractions of > a nano-second) the difference between the receiver's clock (which is > accurate enough in the short term) and the satellite's clock. The result > is still multiplied by the fixed speed of light to convert it to a > distance. There is no point in arguing. It is obvious hat the developers have woken up to the fact that light speed is variable and the system is much much better using absolute wavelengths. > > Sylvia. --
[toc] | [prev] | [next] | [standalone]
| From | Poutnik <poutnik4nntp@gmail.com> |
|---|---|
| Date | 2017-06-12 13:54 +0200 |
| Message-ID | <ohlv6b$mqj$1@dont-email.me> |
| In reply to | #636130 |
Dne 12.6.2017 v 12:12 HGW... napsal(a): > On 12/06/17 11:05, Sylvia Else wrote: >> On 12/06/2017 10:35 AM, HGW... wrote: > >>> >>> It shouldn't be. It is actually very simple and clever. Of course the >>> waves aren't all actually numbered. As long as some are marked at >>> regular intervals the electronics can do the rest. I gather from the >>> Wiki article that phase differences are used. The hardest part might be >>> in knowing the receiver's clock error but since that will affect all >>> four paths equally, a small time discrepancy will only cause a >>> navigation error in height. >>> >>> Since wavelengths are absolute and virtually invariant over 85 msecs, >>> the idea is much smarter than using light speeds, which wander all over >>> the place. >>> >>> It appears that BaTh wins yet again. >>> >>> >>> >> The Wiki article is not very well expressed. Carrier phase tracking is >> just a method of determining more precisely (down to small fractions >> of a nano-second) the difference between the receiver's clock (which >> is accurate enough in the short term) and the satellite's clock. The >> result is still multiplied by the fixed speed of light to convert it >> to a distance. > > There is no point in arguing. It is obvious hat the developers have > woken up to the fact that light speed is variable and the system is much > much better using absolute wavelengths. > Even if the vacuum light speed had been variable, absolute constant wavelength would have been impossible due requirement of constant frequency because of principle of continuity. -- Poutnik ( The Pilgrim, Der Wanderer ) A wise man guards words he says, as they say about him more, than he says about the subject.
[toc] | [prev] | [next] | [standalone]
| From | Selina Dieter <uiueeits@wlwtwstd.ci> |
|---|---|
| Date | 2017-06-12 12:47 +0000 |
| Message-ID | <ohm2gc$1v0d$1@gioia.aioe.org> |
| In reply to | #636134 |
Poutnik wrote: > Even if the vacuum light speed had been variable, absolute constant > wavelength would have been impossible due requirement of constant > frequency because of principle of continuity. Are there any info during that paragraph, I'm not able to catch. Why such nonsense.
[toc] | [prev] | [next] | [standalone]
| From | "HGW, DSc." <HG@....> |
|---|---|
| Date | 2017-06-13 04:13 +1000 |
| Message-ID | <ohmlgk$1444$1@gioia.aioe.org> |
| In reply to | #636135 |
On 12/06/17 22:47, Selina Dieter wrote: > Poutnik wrote: > >> Even if the vacuum light speed had been variable, absolute constant >> wavelength would have been impossible due requirement of constant >> frequency because of principle of continuity. > > Are there any info during that paragraph, I'm not able to catch. Why such > nonsense. He always writes nonsense...doesn't know anything else....
[toc] | [prev] | [next] | [standalone]
| From | Sylvia Else <sylvia@not.at.this.address> |
|---|---|
| Date | 2017-06-13 12:59 +1000 |
| Message-ID | <eq92ogFjauoU1@mid.individual.net> |
| In reply to | #636135 |
On 12/06/2017 10:47 PM, Selina Dieter wrote: > Poutnik wrote: > >> Even if the vacuum light speed had been variable, absolute constant >> wavelength would have been impossible due requirement of constant >> frequency because of principle of continuity. > > Are there any info during that paragraph, I'm not able to catch. Why such > nonsense. > The frequency has to remain constant because otherwise either the receiver would receive more cycles than had been transmitted, or it would receive fewer. Given that the frequency is constant, and wavelength is velocity divided by frequency, if the velocity varied then so would the wavelength, so if there's varying velocity, then there cannot be absolute wavelength. Sylvia.
[toc] | [prev] | [next] | [standalone]
| From | "HGW, DSc." <HG@....> |
|---|---|
| Date | 2017-06-13 04:22 +1000 |
| Message-ID | <ohmm1k$1524$1@gioia.aioe.org> |
| In reply to | #636134 |
On 12/06/17 21:54, Poutnik wrote: >> >> There is no point in arguing. It is obvious hat the developers have >> woken up to the fact that light speed is variable and the system is >> much much better using absolute wavelengths. >> > Even if the vacuum light speed had been variable, > absolute constant wavelength would have been impossible > due requirement of constant frequency > because of principle of continuity. There is a slight slowing in the atmosphere and that reduces the absolute wavelength by a very small amount. For civilian use, that kind of error is irrelevant because it only results in a small height error. Note, the ECI coordinates are the same along any particular radius vector from the Earth's centre so height doesn't matter much because true surface height is already known at every point on the planet. The same applies to receiving clock error. If the number of wavelengths in each of the four signal paths is out by about the same proportion, that only results in a height error.
[toc] | [prev] | [next] | [standalone]
| From | Sylvia Else <sylvia@not.at.this.address> |
|---|---|
| Date | 2017-06-13 13:00 +1000 |
| Message-ID | <eq92poFjauoU2@mid.individual.net> |
| In reply to | #636155 |
On 13/06/2017 4:22 AM, HGW, DSc. wrote: > On 12/06/17 21:54, Poutnik wrote: > >>> >>> There is no point in arguing. It is obvious hat the developers have >>> woken up to the fact that light speed is variable and the system is >>> much much better using absolute wavelengths. >>> >> Even if the vacuum light speed had been variable, >> absolute constant wavelength would have been impossible >> due requirement of constant frequency >> because of principle of continuity. > > There is a slight slowing in the atmosphere and that reduces the > absolute wavelength by a very small amount. > For civilian use, that kind of error is irrelevant because it only > results in a small height error. > Note, the ECI coordinates are the same along any particular radius > vector from the Earth's centre so height doesn't matter much because > true surface height is already known at every point on the planet. The > same applies to receiving clock error. > If the number of wavelengths in each of the four signal paths is out by > about the same proportion, that only results in a height error. > Oh, shifting ground. Either the wavelength is absolute, or it's not. You cannot have a moderately absolute wavelength. Sylvia.
[toc] | [prev] | [next] | [standalone]
| From | Tom Roberts <tjroberts137@sbcglobal.net> |
|---|---|
| Date | 2017-06-13 13:32 -0500 |
| Message-ID | <y9mdnemoYpoxst3EnZ2dnUU7_8zNnZ2d@giganews.com> |
| In reply to | #636222 |
On 6/12/17 6/12/17 - 10:00 PM, Sylvia Else wrote: > On 13/06/2017 4:22 AM, HGW, DSc. wrote: >> There is a slight slowing in the atmosphere and that reduces the >> absolute wavelength by a very small amount. >> For civilian use, that kind of error is irrelevant because it only >> results in a small height error. >> Note, the ECI coordinates are the same along any particular radius >> vector from the Earth's centre so height doesn't matter much because >> true surface height is already known at every point on the planet. The >> same applies to receiving clock error. >> If the number of wavelengths in each of the four signal paths is out by >> about the same proportion, that only results in a height error. >> > > Oh, shifting ground. Either the wavelength is absolute, or it's not. You cannot > have a moderately absolute wavelength. Yes, Wilson does not have a theory, he just has a bunch of rather vague feelings and fantasies that change with his whim. Elsewhere it suited him to claim "wavelength is absolute", and here it suited him to claim otherwise. Of course his notion "wavelength is absolute" is solidly refuted experimentally: if it were true then astronomically distant objects would not have redshifts measured with wavelength-sensitive spectrometers. Also, most of what he said above is just plain wrong, and in the GPS atmospheric effects affect more than just "height error" -- they affect the computed position and its errorbars in all four dimensions (not just height). But Wilson is clueless about errorbars. And about how the GPS actually works. Tom Roberts
[toc] | [prev] | [next] | [standalone]
| From | "HGW..." <hgw@....> |
|---|---|
| Date | 2017-06-14 10:09 +1000 |
| Message-ID | <ohpure$gss$1@gioia.aioe.org> |
| In reply to | #636265 |
On 14/06/17 04:32, Tom Roberts wrote: > On 6/12/17 6/12/17 - 10:00 PM, Sylvia Else wrote: >> >> Oh, shifting ground. Either the wavelength is absolute, or it's not. >> You cannot have a moderately absolute wavelength. > > Yes, Wilson does not have a theory, he just has a bunch of rather vague > feelings and fantasies that change with his whim. Elsewhere it suited > him to claim "wavelength is absolute", and here it suited him to claim > otherwise. Tom, whether you like it or not, the GPS system now uses wave count rather than light speed because the former improves accuracy by about an order of magnitude. That is to be expected since, in the absence of an aether, signal speed is obviously source dependent whilst wavelength is pretty well constant. > Of course his notion "wavelength is absolute" is solidly > refuted experimentally: if it were true then astronomically > distant objects would not have redshifts measured with > wavelength-sensitive spectrometers. All lengths are absolute. Wavelength is absolute....but that does not mean it is invariant. Gawd! I thought any real physicist would know that. > Also, most of what he said above is just plain wrong, and in the GPS > atmospheric effects affect more than just "height error" -- they affect > the computed position and its errorbars in all four dimensions (not just > height). But Wilson is clueless about errorbars. And about how the GPS > actually works. I know perfectly well what error bars are and know they are hardly needed for civilian usage.. The length of each signal's path through the atmosphere is easy to calculate from its clock's ephemeris...and it is the same correction that was used previously for light speed variations. We are talking about only a wavelength or two at most because air's RI is only about 0.0003 even at sea level and most speed change occurs in only the lowest 10000 metres....and as I pointed out, if the four satellites are well away from the horizon, a similar error in all four wave counts results in only a height error...which is easy to fix in civilian usage. Do you not agree that points on an particular Earth radius vector have the same ratio ECI coordinates...apart from distance along that vector? > Tom Roberts --
[toc] | [prev] | [next] | [standalone]
| From | "HGW..." <hgw@....> |
|---|---|
| Date | 2017-06-14 09:34 +1000 |
| Message-ID | <ohpsr1$eb8$1@gioia.aioe.org> |
| In reply to | #636222 |
On 13/06/17 13:00, Sylvia Else wrote: > On 13/06/2017 4:22 AM, HGW, DSc. wrote: >> >> There is a slight slowing in the atmosphere and that reduces the >> absolute wavelength by a very small amount. >> For civilian use, that kind of error is irrelevant because it only >> results in a small height error. >> Note, the ECI coordinates are the same along any particular radius >> vector from the Earth's centre so height doesn't matter much because >> true surface height is already known at every point on the planet. The >> same applies to receiving clock error. >> If the number of wavelengths in each of the four signal paths is out by >> about the same proportion, that only results in a height error. >> > > Oh, shifting ground. Either the wavelength is absolute, or it's not. You > cannot have a moderately absolute wavelength. The absolute wavelength will very slightly decrease to a new absolute length as the signals slow in the atmosphere. The changes are easy to calculate from each satellite's ephemeris. > Sylvia. --
[toc] | [prev] | [next] | [standalone]
| From | Серг ио <invalid@invalid.com> |
|---|---|
| Date | 2017-06-13 18:42 -0500 |
| Message-ID | <ohpta1$euo$1@gioia.aioe.org> |
| In reply to | #636288 |
On 6/13/2017 6:34 PM, HGW... wrote:
> On 13/06/17 13:00, Sylvia Else wrote:
>> On 13/06/2017 4:22 AM, HGW, DSc. wrote:
>
>>>
>>> There is a slight slowing in the atmosphere and that reduces the
>>> absolute wavelength by a very small amount.
>>> For civilian use, that kind of error is irrelevant because it only
>>> results in a small height error.
>>> Note, the ECI coordinates are the same along any particular radius
>>> vector from the Earth's centre so height doesn't matter much because
>>> true surface height is already known at every point on the planet. The
>>> same applies to receiving clock error.
>>> If the number of wavelengths in each of the four signal paths is out by
>>> about the same proportion, that only results in a height error.
>>>
>>
>> Oh, shifting ground. Either the wavelength is absolute, or it's not.
>> You cannot have a moderately absolute wavelength.
>
> The absolute wavelength will very slightly decrease to a new absolute
> length as the signals slow in the atmosphere. The changes are easy to
> calculate from each satellite's ephemeris.
wavelength also changes due to its orbitle velocity and relitivity
effects.
additionally;
https://en.wikipedia.org/wiki/Error_analysis_for_the_Global_Positioning_System
source Effect (meters)
Signal arrival C/A ±3
Signal arrival P(Y) ±0.3
Ionospheric effects ±5
Ephemeris errors ±2.5
Satellite clock errors ±2
Multipath distortion ±1
Tropospheric effects ±0.5
3 σ R {\displaystyle \ 3\sigma _{R}} \ 3\sigma_R C/A ±6.7
3 σ R {\displaystyle \ 3\sigma _{R}} \ 3\sigma_R P(Y) ±6.0
>
>> Sylvia.
>
>
[toc] | [prev] | [next] | [standalone]
Page 5 of 6 — ← Prev page 1 2 3 4 [5] 6 Next page →
Back to top | Article view | sci.physics
csiph-web