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===Yet Another===
<del>
The only thing we are doing is defining the distance from satellite i to the receiver. Therefore there is no need for radical changes to the Problem description section which obscure the equations to be solved. Therefore I propose the following for the Problem description section which adds the definition without further changes:</del>
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<del>The receiver uses messages received from satellites to determine the satellite positions and time sent. The ''x, y,'' and ''z'' components of satellite position and the time sent are designated as [''x<sub>i</sub>, y<sub>i</sub>, z<sub>i</sub>, s<sub>i</sub>''] where the subscript ''i'' denotes the satellite and has the value 1, 2, ..., ''n'', where ''n'' ≥ 4. When the time of message reception indicated by the on-board receiver clock is ''t̃'', the true reception time is {{nobreak|1=''t'' = ''t̃'' - ''b''}}, where ''b'' is the receiver's clock offset from the much more accurate GPS system clocks employed by the satellites. The receiver clock offset is the same for all received satellite signals (assuming the satellite clocks are all perfectly synchronized). The message's transit time is {{nobreak|1=''t̃'' - ''b'' - ''s<sub>i</sub>''}}<!--, where ''s<sub>i</sub>'' is the satellite time-->. Assuming the message traveled at [[Speed of light|the speed of light]], ''c'', the distance traveled is {{nobreak|1=(''t̃'' - ''b'' - ''s<sub>i</sub>'') ''c''}}. <!--(''t~<sub>i</sub> - b − t<sub>i</sub>'')''c''.--></del>
<del>For n satellites, the equations to satisfy are:</del>
:<del><math>(x-x_i)^2 + (y-y_i)^2 + (z-z_i)^2 = \bigl([ \tilde{t} - b - s_i]c\bigr)^2, \; i=1,2,\dots,n</math></del>
<del>or in terms of ''pseudoranges'', <math> p_i = \left ( \tilde{t} - s_i \right )c</math>, as</del>
:<del><math>\sqrt{(x-x_i)^2 + (y-y_i)^2 + (z-z_i)^2} + bc = p_i, \;i=1,2,...,n</math> .<ref name=GPS_BASICS_Blewitt>section 4 beginning on page 15 [http://www.nbmg.unr.edu/staff/pdfs/Blewitt%20Basics%20of%20gps.pdf GEOFFREY BLEWITT: BASICS OF THE GPS TECHNIQUE]</ref><ref name=Bancroft>{{cite web|url=http://www.macalester.edu/~halverson/math36/GPS.pdf|archiveurl=http://web.archive.org/web/20110719232148/http://www.macalester.edu/~halverson/math36/GPS.pdf|archivedate=July 19, 2011|title=Global Positioning Systems|format=PDF|accessdate=October 15, 2010}}</ref></del>
<del>We define :<math> r_i(x,y,z) = \sqrt{(x-x_i)^2 + (y-y_i)^2 + (z-z_i)^2}, \;i=1,2,...,n</math>, the distance from the satellite i to the receiver for later use.</del>
<del>Since the equations have four unknowns [''x, y, z, b'']—the three components of GPS receiver position and the clock bias—signals from at least four satellites are necessary to attempt solving these equations. They can be solved by algebraic or numerical methods. Existence and uniqueness of GPS solutions are discussed by Abell and Chaffee.<ref name="Abel1"/> When ''n'' is greater than 4 this system is overdetermined and a fitting method must be used.</del>
<del>With each combination of satellites, GDOP quantities can be calculated based on the relative sky directions of the satellites used.<ref>{{cite web|url=http://www.colorado.edu/geography/gcraft/notes/gps/gps.html#Gdop|title=Geometric Dilution of Precision (GDOP) and Visibility|first=Peter H.|last=Dana|publisher=University of Colorado at Boulder|accessdate=July 7, 2008}}</ref> The receiver ___location is expressed in a specific coordinate system, such as latitude and longitude using the [[WGS 84]] [[datum (geodesy)|geodetic datum]] or a country-specific system.<ref>{{cite web|url=http://www.colorado.edu/geography/gcraft/notes/gps/gps.html#PosVelTime|title=Receiver Position, Velocity, and Time|author=Peter H. Dana|publisher=University of Colorado at Boulder|accessdate=July 7, 2008}}</ref></del>
____________________________________________________________________________________
<del>[[User:RHB100|RHB100]] ([[User talk:RHB100|talk]]) 04:03, 5 July 2015 (UTC)</del>
<del>Woodstone made the statement,</del>
:<del>Then the receiver would have to be located somewhere on each of the spheres given by:</del>
:<del><math>r_i(x,y,z) = (t_i - s_i) c </math> above. This is a terrible statement which could only be true if the clock bias, b, were zero and that were no other errors. Therefore we should avoid these types of changes. [[User:RHB100|RHB100]] ([[User talk:RHB100|talk]]) 04:12, 5 July 2015 (UTC)</del>
====Comment====
{{reply|RHB100}} I'll ignore the long new section above; I'll only consider specific changes, not complete rewrites. I'll not make an undue effort to understand your proposal. Only if you decide to abide by the [[Wikipedia:Talk page guidelines]], including threading and sectioning, I'll engage in discussion. Otherwise, the article will remain as it is, given the edit lock in effect. This discussion is restarting all too often, and I'm losing hope of convergence. [[User:Fgnievinski|Fgnievinski]] ([[User talk:Fgnievinski|talk]]) 05:10, 5 July 2015 (UTC)
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*''Before'' anyone adds anything to the article be forewarned that if it is not agreed upon here (by which I mean if there is no consensus to move forward with the idea) and/or the change results in another round of reverting the article will be placed back on lockdown and the time for which you will all be unable to edit it will be extended. Therefore, it would be in everyone's best interest to discuss this to death to make certain that whatever you are going to do to the article is done with the majority consensus and that the disagreeing minority does not start or cause to be continued an edit or revert war. [[User:TomStar81|TomStar81]] ([[User talk:TomStar81|Talk]]) 17:57, 6 July 2015 (UTC)
{{reflist-talk}}
=="Main article: GNSS positioning calculation" should be removed==
"Main article: GNSS positioning calculation" at the beginning of the Navigation section should be removed. Saying "GNSS positioning calculation" is the main article for GPS is like saying the United Nations is the main government for the United States of America. There appears to be no justification whatsoever for calling "GNSS positioning calculation" the main article. GPS is an American developed system. The GPS article Navigation section was written without any reliance on "GNSS positioning calculation". "GNSS positioning calculation" is not very clearly written. It uses very terse notation which is more likely to confuse the reader rather than to enlighten him or her. [[User:RHB100|RHB100]] ([[User talk:RHB100|talk]]) 18:43, 15 July 2015 (UTC)
:I've changed it to a "Further" as I think you're right that "Main" is inappropriate. [[User:Kendall-K1|Kendall-K1]] ([[User talk:Kendall-K1|talk]]) 21:14, 15 July 2015 (UTC)
Alright, thank you [[User:Kendall-K1|Kendall-K1]]. [[User:RHB100|RHB100]] ([[User talk:RHB100|talk]]) 21:27, 15 July 2015 (UTC)
Is there any need for the proposed merger message, "It has been suggested that this section be merged into GNSS positioning calculation. (Discuss) Proposed since April 2015" near the beginning of the Navigation section. There has been no expression of support for this at the link provided. GPS is an American system. This proposal should be removed. [[User:RHB100|RHB100]] ([[User talk:RHB100|talk]]) 01:33, 17 July 2015 (UTC)
:I suggest you discuss this at [[Talk:GNSS positioning calculation]] as the template says. I don't understand what "GPS is an American system" has to do with the merge proposal. [[User:Kendall-K1|Kendall-K1]] ([[User talk:Kendall-K1|talk]]) 14:28, 17 July 2015 (UTC)
I have discussed it at [[Talk:GNSS positioning calculation]]. But since the template suggests merging the two articles, it is appropriate to discuss here on the talk page for GPS in addition to the other talk page. The fact that GPS is an American developed system is important because merging the two articles would have the effect of suppressing the fact that GPS was developed by the government of the United States of America funded by American taxpayers. [[User:RHB100|RHB100]] ([[User talk:RHB100|talk]]) 20:02, 17 July 2015 (UTC)
== Trying To Track A Deletion: Pre-launch clock adjustment calculation ==
As I remember this GPS page used to have a section on how the satellite clocks were adjusted so as to run at the same rate as the earthbound clocks. Part of it went something like:
1) GPS used the velocity of the satellite clocks with respect to the ECI frame to determine how much each satellite clock has slowed relative to a (virtual) clock at rest in the ECI frame.
2) GPS used the velocity of the earthbound clocks with respect to the ECI frame to determine how much each earthbound clock has slowed relative to a (virtual) clock at rest in the ECI frame.
3) GPS used the results of 1) & 2) to compute the expected difference in satellite clocks rates vs the earthbound clock rates due to velocity.
And equations were included. Anyway, I don't see that section anymore. I'd like to see the "old" description in that section. Can you help? - as in providing the approximate date of the deletion and/or who made the deletion or anything that would help locate the deletion. Also, I'd be interested in the "Why?" in a few words and anything else you think might be relevant.
Thanks![[User:HarvPhys|HarvPhys]] ([[User talk:HarvPhys|talk]]) 22:28, 20 July 2015 (UTC)
When did you last see the section and what was it called? [[User:RHB100|RHB100]] ([[User talk:RHB100|talk]]) 01:07, 21 July 2015 (UTC)
Have you looked at the article, {{Main|Error analysis for the Global Positioning System}}? [[User:RHB100|RHB100]] ([[User talk:RHB100|talk]]) 01:16, 21 July 2015 (UTC)
RHB, Thanks very much for your suggestion. I had not looked at the referenced article and, in fact, was unaware of its existence. I reviewed the article. I found a section that covered the topic I was interested in and was asking about. Note that it was NOT a case of a section being moved from the GPS article to this article.
In the section entitled, “Calculation of time dilation”, it discusses computing the special relativistic velocity effect of the satellite clocks versus the (theoretical) clock rate of a NON-ROTATING clock at rest at the center of the earth. That part I remember, but instead of using the approximation, I remembered the main article as using the full equation. However, this article then did NOT describe what I referred to as steps 2 & 3 (i.e., It does NOT then do a similar calculation for the special relativistic velocity effect on the GPS ROTATING ground based clocks versus the (theoretical) clock rate of a clock at rest at the center of the earth and, hence, does NOT then use the result of those two calculation of the two clocks with different rotation rates to determine the net special relativistic velocity effect of the satellite clocks versus the rotating earth bound clocks on the surface of the earth.)
I then re-read the section to see if steps 2 & 3 were covered implicitly. I focused on this section in the article:
“Note that this speed of 3874 m/s is measured relative to Earth's center rather than its surface where the GPS receivers (and users) are. This is because Earth's equipotential makes net time dilation equal across its geodesic surface.[19] That is, the combination of Special and General effects make the net time dilation at the equator equal to that of the poles, which in turn are at rest relative to the center. Hence we use the center as a reference point to represent the entire surface.”
Well, after reading it twice and thinking about it, I noted that the article has said the satellite clock adjustment has two components, one for the velocity effect and one for the difference in gravitational potential effect. The above paragraph notes that the net adjustment for all points on the surface of the earth is the same and that for two of those points, the poles of the axis of rotation, there is no rotation so the net velocity effect is the same as for the non-rotating center and, hence, the calculation used to compute the velocity effect vs a clock at rest at the center of the earth would also apply to clocks at the two poles. Hence, by IMPLICATION, the reader should figure out that for all other points on the earth, the physics would require the difference between the rotating satellite effect and the rotating earth bound clock effect and by further IMPLICATION that would mean doing steps 2 & 3 which were never explicitly mentioned.
So I guess one could say that the article implies that steps 2 & 3 are needed to understand the physics for all clocks on earth except for those at the poles. However, for me, who knew the effect and was looking for it, it took quite a bit to see that it was there by implication.
Further, when the article discussed the gravitational potential effect, a single calculation was made based on the “earth’s radius”. So I think some of the physics gets lost especially for a GPS naïve reader.
Two other points: 1) Personally, I do NOT think of this pre-launch satellite clock adjustment procedure as part of “Error Analysis”, but rather as an integral part of the basic GPS design and 2) I always thought the main purpose of Time Dilation adjustment was to sync the satellite clocks with the GPS earthbound clocks and not so much as syncing them with what the article specifies as “GPS receivers (and users)” and I must confess that if I’m wrong on that point, I have a fundamental misunderstanding, so please let me know. ( For GPS receivers’ clocks, their velocity and gravitational potential can vary especially for those used in planes and in many cases rather than tending to cancel the two effects can be additive for receiver clocks.)
Sorry if the above seems picky as I know that when you, the authors, know a topic really well, it can be difficult to see it from the reader’s perspective. Hopefully, a reader’s perspective can be helpful.
While the cited section deals in implications, it does help me a lot! However, if the original section on this topic from the GPS article can be found, I’m still interested. The best I can do is say I thought it was there in 2014 and if not, definitely in 2013. It was in the main GPS article, but I don’t remember what the section was called – maybe “Synchronization” would have been in the title, or, looking at the current index, it could have been something more general like “More Detailed Description”. Before my original post, I had scanned History to no avail.
If anyone has additional comments, they’re appreciated . However, don’t spend an inordinate amount of time as the above has indeed helped a lot.
Thanks [[Special:Contributions/32.212.188.124|32.212.188.124]] ([[User talk:32.212.188.124|talk]]) 19:25, 22 July 2015 (UTC)
==Spheres subsection of Geometric interpretation is misleading and= confusing==
The Spheres subsection of Geometric interpretation is misleading and confusing. '''This subsection should be completely removed.''' In this subsection, there is a statement that the solution is at the intersection of three sphere surfaces. This is completely misleading and is incompatible with the need for four or more spheres as concluded in the Langley paper and as we have tried to make clear in the Problem description section.<ref name="Langley"></ref> It is also stated in the paper,,<ref name="Abel1">Abel, J.S. and Chaffee, J.W., "Existence and uniqueness of GPS solutions", ''IEEE Transactions on Aerospace and Electronic Systems'', vol:26, no:6, p:748-53, Sept. 1991.</ref> that "GPS fixes are found as the point of intersection of four spheres centered on the satellites with radii given by the PRs corrected for user clock bias". This discussion of the solution being at the intersection of three sphere surfaces should be completely eliminated. [[User:RHB100|RHB100]] ([[User talk:RHB100|talk]]) 17:42, 20 July 2015 (UTC)
Does anyone have any objection to the deletion of this subsection? If so present your argument. Reading the Langley paper will help you understand why this subsection as it is currently written is confusing and misleading.<ref name="Langley"></ref> [[User:RHB100|RHB100]] ([[User talk:RHB100|talk]]) 01:11, 21 July 2015 (UTC)
:I see no harm in showing an idealised case with synchronised clock first. It gently brings the reader on board. −[[User:Woodstone|Woodstone]] ([[User talk:Woodstone|talk]]) 10:59, 22 July 2015 (UTC)
::I hesitate to wade into this discussion, but I would first describe the case where the receiver clock is synchronized, since that's a three dimensional problem and can benefit from geometric analogies. Then I would generalize to the (real world) case where the receiver clock bias in unknown, and not attempt to make any geometric analogies, because that's hard to do and of limited benefit when you have four unknowns. [[User:Kendall-K1|Kendall-K1]] ([[User talk:Kendall-K1|talk]]) 22:31, 26 July 2015 (UTC)
Well this subsection is certainly pathetic and confusing as it is currently written. Hopefully the more intelligent readers will have enough sense to ignore this pathetic and confusing subsection and rely on the equations in the Problem description section and the Solution methods section. Also readers should look at other publications such as the Langley paper rather than rely exclusively on Wikipedia.<ref name="Langley"></ref> [[User:RHB100|RHB100]] ([[User talk:RHB100|talk]]) 21:11, 28 July 2015 (UTC)
{{reflist-talk}}
==Geometric interpretation section is a disaster==
The Geometric interpretation section is a disaster and should be removed. It would be
more correctly titled if it were called the Geometric misinterpretation section. It
looks like a forum for people to enter their favorite shape. All we need to have in the
Navigation equations section is a statement of the equations to be solved as in the
Problem description section and methods for solving these equations as in the Solution
methods section. In the Spheres subsection of Geometric interpretation, there is a
statement that the solution is at the intersection of three sphere surfaces. This is a
completely misleading statement which is incompatible with the need for four or more
spheres as concluded in the Langley paper and as we have tried to make clear in the
Problem description section.<ref name=Langley>Richard Langley, The Mathematics of GPS, [http://gauss.gge.unb.ca/gpsworld/EarlyInnovationColumns/Innov.1991.07-08.pdf], 1991</ref>
It is also stated in the paper,,<ref name="Abel1">Abel, J.S. and Chaffee, J.W., "Existence and uniqueness of GPS solutions", ''IEEE Transactions on Aerospace and Electronic Systems'', vol:26, no:6,
p:748-53, Sept. 1991.</ref> that "GPS fixes are found as the point of intersection of four spheres centered on the satellites with radii given by the PRs corrected for user clock bias".
The Hyperboloids sub-section does not in any way enhance the understanding of GPS. The
paper by Abel and Chaffee referenced does not even mention the word, hyperboloid, in any
form.<ref name="Abel1"></ref> The Langley paper talks about the intersection of four or
more spheres and does not mention hyperboloids.<ref name="Langley"></ref>
For gaining an understanding of GPS, the concept of four dimensional spherical cones
contributes nothing but instead only adds confusion. You don't need to know anything
about four dimensional spherical cones to understand GPS and you should not waste your
time on this unrelated topic. [[User:RHB100|RHB100]] ([[User talk:RHB100|talk]]) 20:12, 6 August 2015 (UTC)
. .
:We have discussed this several times already. See [[Talk:Global Positioning System/Archive 8]]. [[User:Kendall-K1|Kendall-K1]] ([[User talk:Kendall-K1|talk]]) 20:39, 6 August 2015 (UTC)
Well what I have said before is absolute truth and what I say now is absolute truth. Although I clearly understand the incorrect and misleading nature of this section, there are some who don't seem to understand. I am here presenting the great disregard for honesty and integrity which characterizes the writing of this section. No one has ever presented good arguments why this section should be retained. I am a licensed professional engineer. I hold advanced engineering degree from both the University of Arkansas and UCLA. When you say, "We have discussed this", that is a very vague and ambiguous statement. There are several points that are made in what I have said above, you don't say whether you are talking about hyperboloids, three spheres, spherical cones or what. [[User:RHB100|RHB100]] ([[User talk:RHB100|talk]]) 03:57, 7 August 2015 (UTC)
{{reflist-talk}}
== User RHB100 and GPS article/topic ==
Please weigh in here: [[Wikipedia:Administrators' noticeboard/Archive273#User RHB100 and GPS article/topic]]. [[User:Fgnievinski|Fgnievinski]] ([[User talk:Fgnievinski|talk]]) 13:34, 7 August 2015 (UTC)
== External links modified ==
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== History ==
It seems odd to me that the relativistic effects on the clock are discussed in the first paragraph of the Predecessors section. [[User:Kendall-K1|Kendall-K1]] ([[User talk:Kendall-K1|talk]]) 20:49, 12 February 2016 (UTC)
Me too. I moved the text above the predecessors section. It may deserve its own design section. I also broke text into more paragraphs. I think the section needs more sequencing and organization. [[User:CuriousMind01|CuriousMind01]] ([[User talk:CuriousMind01|talk]]) 02:39, 13 February 2016 (UTC)
:Yes it does but that's a great start. Thanks. Personally I would like to see more about the ground based predecessors like LORAN but I suspect I'm more of an historian than our general readers. [[User:Kendall-K1|Kendall-K1]] ([[User talk:Kendall-K1|talk]]) 16:42, 13 February 2016 (UTC)
== What is meant by satellites_nominal and satellites_current? ==
Could we get some agreement on what is meant by satellites_nominal (=Total Satellites in the infobox) and satellites_current (=Satellites in Orbit in the infobox)? To me, satellites_nominal aka "Total Satellites" is meant to indicate the full constellation size, i.e. 32, while satellites_current aka "Satellites in Orbit" is meant to indicate how many total GPS satellites are currently orbiting, which is 70. Meanwhile, the other number that's been tossed around, 31 - which represents how many ''active'' GPS satellites there are currently - doesn't belong - nor does 39, which is the total number of ''active'' and ''reserve'' satellites. The infobox has been changed multiple times because we cannot seem to agree on these items' meanings. [[User:Jtrevor99|Jtrevor99]] ([[User talk:Jtrevor99|talk]]) 13:31, 15 June 2016 (UTC)
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*Added archive https://web.archive.org/web/20070104191143/https://www.metaresearch.org:80/cosmology/gps-relativity.asp to http://metaresearch.org/cosmology/gps-relativity.asp
*Added archive https://web.archive.org/web/20111022020714/https://www.gmat.unsw.edu.au:80/snap/gps/gps_survey/chap2/222sats.htm to http://www.gmat.unsw.edu.au/snap/gps/gps_survey/chap2/222sats.htm
*Added archive https://web.archive.org/web/20080216041650/https://spot.colorado.edu/~kristine/gpsrep.pdf to http://spot.colorado.edu/~kristine/gpsrep.pdf
*Added {{tlx|dead link}} tag to http://igs.bkg.bund.de/root_ftp/IGS/mail/igsmail/year2005/5209
*Corrected formatting/usage for http://www.allanstime.com/Publications/DWA/Science_Timekeeping/TheScienceOfTimekeeping.pdf
*Corrected formatting/usage for http://www.usace.army.mil/publications/eng-manuals/em1110-1-1003/toc.htm
*Corrected formatting/usage for http://www.usace.army.mil/publications/eng-manuals/em1110-1-1003/entire.pdf
*Added archive https://web.archive.org/web/20111230195946/https://ion.org/search/view_abstract.cfm?jp=p&idno=7517 to http://www.ion.org/search/view_abstract.cfm?jp=p&idno=7517
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== External links modified ==
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*Added archive https://web.archive.org/web/20120503181621/http://www.losangeles.af.mil/library/factsheets/factsheet.asp?id=18676 to http://www.losangeles.af.mil/library/factsheets/factsheet.asp?id=18676
*Added archive https://web.archive.org/web/20130224065525/http://www.darpa.mil/WorkArea/DownloadAsset.aspx?id=2565 to http://www.darpa.mil/WorkArea/DownloadAsset.aspx?id=2565
*Added archive https://web.archive.org/web/20110611205433/http://www.schriever.af.mil:80/library/factsheets/factsheet.asp?id=4045 to http://www.schriever.af.mil/library/factsheets/factsheet.asp?id=4045
*Added archive https://web.archive.org/web/20071116230801/http://www.losangeles.af.mil:80/library/factsheets/factsheet.asp?id=5325 to http://www.losangeles.af.mil/library/factsheets/factsheet.asp?id=5325
*Added archive https://web.archive.org/web/20120908003700/http://www.losangeles.af.mil/shared/media/document/AFD-070803-059.pdf to http://www.losangeles.af.mil/shared/media/document/AFD-070803-059.pdf
*Added archive https://web.archive.org/web/20080705134550/http://www.xilinx.com/support/documentation/application_notes/xapp217.pdf to http://www.xilinx.com/support/documentation/application_notes/xapp217.pdf
*Added archive https://web.archive.org/web/20110306051358/http://www.gmat.unsw.edu.au/snap/gps/gps_survey/chap6/633.htm to http://www.gmat.unsw.edu.au/snap/gps/gps_survey/chap6/633.htm
*Added archive https://web.archive.org/web/20110306051809/http://www.gmat.unsw.edu.au/snap/gps/gps_survey/chap6/635.htm to http://www.gmat.unsw.edu.au/snap/gps/gps_survey/chap6/635.htm
*Added archive https://web.archive.org/web/20110306051924/http://www.gmat.unsw.edu.au/snap/gps/gps_survey/chap6/636.htm to http://www.gmat.unsw.edu.au/snap/gps/gps_survey/chap6/636.htm
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== What potential monitoring? ==
Need some details about monitoring potential (and sources!). GPS is one-way; the receivers are ''only'' receivers so as far as I can figure there is no potential for monitoring... <!-- Template:Unsigned IP --><small class="autosigned">— Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/165.225.36.79|165.225.36.79]] ([[User talk:165.225.36.79#top|talk]]) 16:55, 16 March 2017 (UTC)</small> <!--Autosigned by SineBot-->
:Monitoring what? [[User:Fgnievinski|fgnievinski]] ([[User talk:Fgnievinski|talk]]) 20:05, 21 April 2017 (UTC)
::I have [//en.wikipedia.org/w/index.php?title=Global_Positioning_System&diff=776631277&oldid=776566383 removed] the material in question. [[User:Burninthruthesky|Burninthruthesky]] ([[User talk:Burninthruthesky|talk]]) 07:36, 22 April 2017 (UTC)
== Visual GPS ==
Is there potential for a visible GPS using geostationary satellites that are visible to the naked eye. Anyone could then measure the relative angles to work out their approximate position. [[Special:Contributions/86.143.210.142|86.143.210.142]] ([[User talk:86.143.210.142|talk]]) 09:26, 25 March 2017 (UTC)
:See [[Astrolabe]] - [[User:MrOllie|MrOllie]] ([[User talk:MrOllie|talk]]) 21:59, 22 April 2017 (UTC)
== Do regional systems qualify as "similar to" the Global Positioning System? ==
I have temporarily reverted the removal of references to [[IRNSS]] and other, similar, systems that provide a user's global position within a limited region. At issue is whether a system must span the entire globe to be considered similar to the US's "Global Positioning System", or merely be capable of providing a global position. My opinion is that if they are satellite-based and able to provide GPS-like positioning data anywhere on the globe - even in limited areas - then they are "similar to" the GPS system. Other thoughts? [[User:Jtrevor99|Jtrevor99]] ([[User talk:Jtrevor99|talk]]) 22:20, 24 January 2017 (UTC)
Hi, {{u|Jtrevor99}} No, regional Systems aren't similar to Global Systems, US GPS is globally (all continents)
indian regional system IRNSS is only "Regional" isn't capable to have a Global coverage .
Indian Regional Navigation Satellite System is only a Regional System similar to The European Geostationary Navigation Overlay Service (EGNOS) .[[User:LuigiPortaro29|LuigiPortaro29]] ([[User talk:LuigiPortaro|talk]]) 00:25, 25 January 2017 (UTC)
: I understand that IRNSS etc. only have "regional" coverage. However, within that region, they are able to provide a global position - information identical to what GPS provides. [[User:Jtrevor99|Jtrevor99]] ([[User talk:Jtrevor99|talk]]) 18:22, 25 January 2017 (UTC)
:: I am inclined to agree with INRSS and the Japanese systems be mentioned here. Not because they are global but the article is about GPS which is a satellite navigation system. It is cleared stated that they are regional and helps the user understand that there are other systems out there. Also, FYI the article is about GPS a satellite based navigation system not a Global navigation system. In the Future please try to build consensus before trying to remove information. Most of this info has been debated and thus added. Wikipedia is a collective effort not a place for POV pushing. Thanks. [[User:Adamgerber80|Adamgerber80]] ([[User talk:Adamgerber80|talk]]) 21:59, 27 January 2017 (UTC)
::" If I want to change the added of the unknown , I need to Discuss in the Talk Page "? But Honestly the last version was added by ME and since 2 months that was here, Today the unknown have changed it , and then I had make a Good version of the section of GPS " GLOBAL - (G.L.O.B.A.L.) ("P-O-S-I-T-I-O-N") SYTEMS " for not make confusion Between "GPS " and other Global Systems with regional systems. , then you Have delete it without Talk in the Page , and You say me that I need to talk in the Talk page? and with no consensus you changed it?.... Why you still Believe that regional Indian deserves to be mentioned here in the same range of Beidou , Galileo and GLONASS?, I know that you are very Patriotic , But Honestly you can't say " I add Regional System of India" without consensus, AND Only because the regional system of India is a "Satellite navigation" here we are Talking about the GPS not about " satellite Navigation" ... please , C'mon , I assume that you can put a Tata car in the group of Ferrari or Mclaren saying that Tata is in the SAME group of Ferrari and Maclaren only because Tata is a " Car" , Can you understand that ? regional system of India don't deserves to be here and Believe me I don't have nothing against India, I like the legality, so what we make , we list ALL the regional systems that exist along with GPS and with the others Global Systems only because they are "Satellite navigation"?? Regional Systems like the Indian one, there's so many in every Continent and they aren't important , as well isn't true that we have talked here about the GPS , We had talked about the "Satellite navigation" ,You are confusing a Global system with a navigation system just because only here on Wipedia there is no a page about Global Systems and there's no the right Classifacation on here . we had an agreemend not here in the other section of Satellite navigation , so ins't true that we have talked about the GPS. So who has right ? You or I ? I'm educate so I don't want to change the version of today from part of the unknown to my Version that was here since 2 monts, waiting for a convincing reply.--[[User:LuigiPortaro29|LuigiPortaro29]] ([[User talk:LuigiPortaro29|talk]])-21:27, 22 April 2017 (UTC)
::: {{u|LuigiPortaro29}} Firstly, IP editors have same rights as registered users on Wikipedia since is a community effort. IRNSS has been added multiple times on this page (by different users) and has been removed by you. Thus, this merits a discussion, similar to one we had on the [[Talk:Satellite_navigation]]. Wikipedia is a community effort and you thus there needs to be a broad consensus and no uni-laterally decisions. Now coming to the discussion at hand, no one is disputing the fact that IRNSS is not a global system. It is clearly stated on that page and its mention on this page as well that it is regional. On Wikipedia, the ""See Also"" section refers to other pages which might interest the reader and have some relation to the existing page. It does not mean that they are equivalent. There is a definite connection between GPS and IRNSS is that both of them are satellite navigation systems. Thus, it is okay to mention IRNSS in the See Also section. Similarly, the section header at the very end clearly mentions Other Systems. This is to point the user to other satellite navigation systems. The word regional again is mentioned clearly here. There is no attempt to equate these systems. I believe that your argument about cars is flawed here since there are many different car types and each car type has many examples. There are not many satellite navigation systems out there thus there is only a single page on Wikipedia, not a Global or a Regional one. It does make sense other systems are mentioned across pages since this list is not too long. If you like you can add the Japanese system here as well. Lastly, I have warned you in the past and do so again, that we are all here is editors and work together. It does not matter what our nationality is as long as we are fair in our analysis. Please refrain from bringing that in these discussions or basing your arguments on these irrelevant arguments. Thanks [[User:Adamgerber80|Adamgerber80]] ([[User talk:Adamgerber80|talk]]) 22:15, 22 April 2017 (UTC)
== Intersection of three spheres is misleading ==
{{Archive top|result=[[WP:SNOW]] close. This has been repeatedly discussed before, and rejected. I remind the poster to carefully re-read {{u|EdJohnston}}'s 2015 warnings on their talk page. [[User:Burninthruthesky|Burninthruthesky]] ([[User talk:Burninthruthesky|talk]]) 09:03, 5 May 2017 (UTC)}}
Here is a quote from the current section 6.1 called Spheres, "In a simplified idealization in which the ranges are synchronized, these true ranges represent the radii of spheres, each centered on one of the transmitting satellites. The solution for the position of the receiver is then at the intersection of the surfaces of three of these spheres".
These synchronized ranges never occur unless we have the intersection of the surfaces of four or more spheres. Therefore speaking of a solution occurring at the intersection of the surfaces of three spheres is misleading and confusing. A correct statement is to say a solution is found when we have found the intersection of the surfaces of four or more spheres. For further clarity it could also be stated that a necessary and sufficient condition for a solution is that we have found the intersection of the surfaces of four or more spheres. [[User:RHB100|RHB100]] ([[User talk:RHB100|talk]]) 20:00, 4 May 2017 (UTC)
: Not again... [[Wikipedia:Administrators' noticeboard/Archive274#User RHB100 and GPS article/topic]]. [[User:Fgnievinski|fgnievinski]] ([[User talk:Fgnievinski|talk]]) 03:45, 5 May 2017 (UTC)
{{Archive bottom}}
==Still have misleading and confusing writing==
The closing of discussion below by [[User:Fgnievinski|fgnievinski]] was somewhat premature. There are still important issues to be discussed. [[User:Fgnievinski|fgnievinski]] says this has been discussed before. This does not mean all problems have been solved. We still have misleading and confusing writing in the current section 6.1 called Spheres. No one should be allowed to protect misleading and confusing writing from criticism. Let's make sure [[User:Fgnievinski|fgnievinski]] does not get away with it.
Again quoting from the current section 6.1 called Spheres, "In a simplified idealization in which the ranges are synchronized, these true ranges represent the radii of spheres, each centered on one of the transmitting satellites. The solution for the position of the receiver is then at the intersection of the surfaces of three of these spheres".
This is misleading and confusing, these synchronized ranges never occur unless we have the intersection of the surfaces of four or more spheres. Therefore speaking of a solution occurring at the intersection of the surfaces of three spheres is misleading and confusing. A correct statement is to say a solution is found when we have found the intersection of the surfaces of four or more spheres. For further clarity it could also be stated that a necessary and sufficient condition for a solution is that we have found the intersection of the surfaces of four or more spheres. [[User:RHB100|RHB100]] ([[User talk:RHB100|talk]]) 02:19, 6 May 2017 (UTC)
This brings up the question why would anyone want to write anything so confusing and misleading as the above quote from section 6.1? While you might say it results from good intentions but failure to understand how GPS works, it is now becoming undeniable that something else is at work. Although I hate to say it, it is now becoming so obvious that it cannot be overlooked that some editors are almost certainly deliberately attempting to confuse and mislead readers. It is all but certain that some editors feel that their livelihood is threatened by providing a clear and unambiguous explanation of GPS on Wikipedia. Thus we have [[User:Fgnievinski|fgnievinski]] madly rushing to close any discusion of any criticism of this all but obvious attempt to confuse the understanding of how GPS works. [[User:RHB100|RHB100]] ([[User talk:RHB100|talk]]) 18:41, 6 May 2017 (UTC)
: Why I'm not surprised we got into conspiracy theories. [[User:Fgnievinski|fgnievinski]] ([[User talk:Fgnievinski|talk]]) 20:17, 6 May 2017 (UTC)
::{{re|RHB100}} Aren't you topic banned from GPS articles? —[[User:JJBers|<span style="color:red;">JJ</span>]][[User Talk:JJBers|<span style="color:green;">Be</span>]][[Special:Contributions/JJBers|<span style="color:blue;">rs</span>]] 13:21, 7 May 2017 (UTC)
I don't waste my time getting into edit wars with these people who make confusing and misleading statements regarding GPS. I limit my valuable time only to criticizing and pointing out what is wrong with the GPS article. [[User:RHB100|RHB100]] ([[User talk:RHB100|talk]]) 00:42, 8 May 2017 (UTC)
This is being discussed at [[WP:ANI#RHB100 and GPS article (again)]]. [[User:Burninthruthesky|Burninthruthesky]] ([[User talk:Burninthruthesky|talk]]) 08:08, 8 May 2017 (UTC)
==The good news is that the current section 6.2 Geometric interpretation can be improved==
A wonderful paper by Richard B. Langley called "The Mathematics of GPS" can be found at
http://gauss.gge.unb.ca/gpsworld/EarlyInnovationColumns/Innov.1991.07-08.pdf .
This paper explains how the intersection of three spheres is inadequate to determine the ___location of a GPS receiver. The paper goes on to show that the intersection of four spheres is generally sufficient to determine the ___location of a GPS receiver. The explanation of GPS in this paper is far superior to that found in the current section 6.2 of the GPS article. But the good news is that section 6.2 can be improved to the level of that found in this Langley paper. This can be done by ditching the current contents of section 6.2 and replacing it with an explanation which follows that found in the Langley paper. [[User:RHB100|RHB100]] ([[User talk:RHB100|talk]]) 21:32, 9 May 2017 (UTC)
== External links modified ==
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*Added archive https://web.archive.org/web/20110817001221/http://www.afspc.af.mil/heritage/chronology.asp to http://www.afspc.af.mil/heritage/chronology.asp
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*Corrected formatting/usage for http://www.allanstime.com/Publications/DWA/Science_Timekeeping/TheScienceOfTimekeeping.pdf
*Corrected formatting/usage for http://www.gpsworld.com/gnss-system/news/data-shows-disastrous-gps-jamming-fcc-approved-broadcaster-11029
*Added archive https://web.archive.org/web/20120113093239/http://www.lightsquared.com/documents/FCC%20Julius%20Genachowski%20letter%20to%20Senator%20Grassley%20-%20May%2031%2C%202011.pdf to http://www.lightsquared.com/documents/FCC%20Julius%20Genachowski%20letter%20to%20Senator%20Grassley%20-%20May%2031%2C%202011.pdf
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== External links modified ==
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== External link is spreading lies ==
This link 11:
http://www.astronomy.ohio-state.edu/~pogge/Ast162/Unit5/gps.html
is claiming wrongly, that:
The engineers who designed the GPS system included these relativistic effects when they designed and deployed the system. For example, to counteract the General Relativistic effect once on orbit, the onboard clocks were designed to "tick" at a slower frequency than ground reference clocks, so that once they were in their proper orbit stations their clocks would appear to tick at about the correct rate as compared to the reference atomic clocks at the GPS ground stations. Further, each GPS receiver has built into it a microcomputer that, in addition to performing the calculation of position using 3D trilateration, will also compute any additional special relativistic timing calculations required [3], using data provided by the satellites.
In reality, there was only one short experiment described here:
http://www.phys.lsu.edu/mog/mog9/node9.html
At the time of launch of the first NTS-2 satellite (June 1977), which contained the first Cesium clock to be placed in orbit, there were some who doubted that relativistic effects were real. A frequency synthesizer was built into the satellite clock system so that after launch, if in fact the rate of the clock in its final orbit was that predicted by GR, then the synthesizer could be turned on bringing the clock to the coordinate rate necessary for operation. The atomic clock was first operated for about 20 days to measure its clock rate before turning on the synthesizer. The frequency measured during that interval was parts in faster than clocks on the ground; if left uncorrected this would have resulted in timing errors of about 38,000 nanoseconds per day. The difference between predicted and measured values of the frequency shift was only parts in , well, within the accuracy capabilities of the orbiting clock. This then gave about a validation of the combined motional and gravitational shifts for a clock at earth radii.
My comment:
To sum it up, general relativity is not needed to run GPS, it could be possible to use it as confirmation for general relativity, but this are two separate things.
Another citation from the second link:
At present one cannot easily perform tests of relativity with the system because the SV clocks are actively steered to be within 1 microsecond of Universal Coordinated Time (USNO). <!-- Template:Unsigned IP --><small class="autosigned">— Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/212.5.215.61|212.5.215.61]] ([[User talk:212.5.215.61#top|talk]]) 12:09, 19 June 2017 (UTC)</small> <!--Autosigned by SineBot-->
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