Talk:Wide Area Augmentation System

Limitations of WAAS?

I realize this is a nit but:

"WAAS Localizer Performance with Vertical guidance (LPV) approaches with 200-foot minimums will not be published for airports without medium intensity lighting, precision runway markings and a parallel taxiway."

Hardly qualifies as a "WAAS limitation or weakness". It is a limitation of airports that simply got exposed by the low tide. — Preceding unsigned comment added by 64.2.3.194 (talk) 01:50, 27 May 2015 (UTC)

Complete Article Update

I've spent the last month working an improved version of the article in my personal sandbox. I believe it is suitable for posting into the main article at this point, with the group helping to make the final improvements. The article is not perfect (history still needs to be re-written, and the drawbacks are still in list form, etc.) but I feel it is best for the group to improved after my personal fork is re-integrated.

Since its a complete change it seems some discussion is appropriate first, so I'm posting notice here and asking those interested to review the copy in my sandbox and comment here. Here is the sandboxed article: User:Davandron/WAAS

Thank you everyone in advance for the constructive feedback and guideance! Davandron | Talk 17:27, 29 November 2006 (UTC)

The main article has been updated. Davandron | Talk 14:35, 5 December 2006 (UTC)

Identical content?

The first few paragraphs contain sentences verbatim from http://gps.faa.gov/Programs/WAAS/waas.htm; is that kosher? --R27182818 05:39, 26 September 2006 (UTC)

US Government websites are public domain. --Dual Freq 11:33, 26 September 2006 (UTC)

Merge

I suggest someone merge GPS_WAAS into this article. Ideas? --Dual Freq 01:11, 9 May 2006 (UTC)

Strong yes. They do seem redundant... -- RevRagnarok 02:24, 23 May 2006 (UTC)

Strong yes, provided that only the redundant information in GPS_WAAS is removed, and the remaining non-redundant information be remain, and the article be expanded to include key info on non-GPS WAAS systems, such as those coming online here in Europe. Dr1819 18:30, 10 June 2006 (UTC)

This article is about WAAS

In this revision, I pulled a large section out of the History/approaches section. Most of it was a bit tangent to the subject of WAAS, maybe it could be distilled to something smaller and more readable. I think this article should focus on the capabilities, limitations, history, operation and future of WAAS. Comparison of WAAS with other systems is probably acceptable as long as it's very concise and doesn't stray from the subject WAAS. We don't need to explain GPS, ILS, MLS and every other radio navigation system in this article. I suppose consumer usage of WAAS could be mentioned, but WAAS was made for aviation usage, so that should be the focus of this article. --Dual Freq 23:44, 12 June 2006 (UTC)

And if we are to re-add that section, I would suggest finding some references and cite it appropriately. --Dual Freq 23:47, 12 June 2006 (UTC)

Dual, you have now cut background information from this article twice. Both times your comment is simply that the content in question was "off topic". However, the resulting article is now far too on topic to be readable. Do you see what I mean by this? It may not be clear.

Remember, the wiki is an encyclopedia, not an aviation navigation primer. The average user coming to this page will known little or nothing about existing navigation systems. Providing this information and comparing it with similar, or older, systems allows the reader to put WAAS into it's proper context. Without this information the reader will build a false image of where WAAS fits into the navigation "world" (ie, in isolation).

The pre-cut article was just over three pages long. Three pages is not too long for a topic like this. If you add up all the background information that you removed, it only added about 1/2 of a page in total. This doesn't strike me as too much either, 1/2 a page for context seems like a very small price to pay.

I really don't see the argument for this content's removal. Maury 12:28, 13 June 2006 (UTC)

I agree that a little too much might have been taken out here, but I will try to revisit later - a lot new was also written, not just moved. -- RevRagnarok ^{Talk Contrib Reverts} 13:31, 13 June 2006 (UTC)

I may have pulled a bit much, but my initial thought remains the same. Each navaid has its own article, in fact there is an article specifically for Radio navigation. Do we need to add a history of radio navigation to every article about radio navigation systems? There was even a section in here about MLS, a system I think was killed by GPS, not really by WAAS. Additionally, there was a swipe in there about ILS providing "a rough fix". That's not correct, WAAS has only just recently, after much debate, been declared "equal" to ILS Cat I, but it can not and will not equal Cat II or III ILS systems. If I remember correctly, the FAA actually lowered the standards for Cat I to allow WAAS to replace it. (I'll look for a ref for that bit of info before adding it to the article though.) In summary, I'd suggest carefully examining what was removed, citing it and re-adding it, if it's that important to the continuity of the article. As for the LAAS link at bottom, I pulled it because it was mentioned in the article and in the GPS template at the bottom. --Dual Freq 23:02, 13 June 2006 (UTC)

Lead paragraph

I'll separately address the lead paragraph, which I deliberately removed it once, but I must have removed it along with the rest when I made the above revision. Comparison with similar systems might be OK, but is it really lead section material? I also dislike the content, compare with this and I'll explain why I removed it, point by point. DGPS is only similar to WAAS in that it corrects errors in GPS. The methodology is totally different, WAAS uses a grid covering the entire world and provides corrections for grid sections covered by its reference stations, calculating the error using data from all ref stations and using software/algorithms to approximate the error in other areas not next to a ref station. DGPS (the USCG version at least) each station is independent, transmitting corrections only for satellites within view of that one station. It's run by the USCG not broadcast from "commercial radio stations", but I may be misunderstanding the meaning of commerical radio stations. I understand that to mean Commercial broadcasting radio station, which doesn't make sense to me since the largest (I believe) DGPS system (in the US) is free, run by the USCG. USCG DGPS was primarily for ground usage, such as trucks, boats and trains, I don't think it was ever used/considered for aviation usage. USCG DGPS uses LF which covers a large area, ~200 miles from the site and does not require line of site to the transmitter. LAAS doesn't deliberately limit its coverage to the airport, but it is limited to a small area because of the VHF line-of-sight radio link it uses. Its correction would likely be just as useful as USCG DGPS in that it would degrade in accuracy the further from the airport you were. LAAS would be useless to consumers because of the VHF link used, but DGPS is useful because of the low freq used. Additionally, is LAAS/GPS used for takeoffs? I'm not a pilot, but are there instrument takeoff procedures like the instrument landing procedures? Maybe a section titled, "other GPS correction systems" or similar could address alternative systems, but the see also section and wiki-links already point to GPS and alternatives like LAAS and DGPS. Citations would be nice as well. --Dual Freq 23:02, 13 June 2006 (UTC)

Hi, Dual Freq. I am a pilot, with just over 2,300 hours in military aviation. You hit the nail on the head - WAAS was developed primarily with aviation in mind, but since Department of Transportation funding was involved, I'm sure they were considering more precise navigation for tricky intersections like like multiple-entrance/exit cloverleafs, and heavy fog harbor navigation. WAAS is the medium-accuracy alternative to Cat I ILS approaches, primarily for smaller airfields which cannot afford the expensive initial cost and maintenance of precision and non-precision navigation facilities. LAAS is the high-accuracy alternative to CAT II and CAT III ILS approaches. The most precise CAT-III equipment allows pilots to take-off and land in 0-0 vis situations. Dr1819 23:29, 13 June 2006 (UTC)

By the way, I re-added the link to the [Joint Precision Approach and Landing System] article in the See Also section, as literally hundreds of thousands of civilian contractors, and many times that many members of the military, will soon be riding aboard military airlifters and certain contracted civilian airlift aircraft. These systems will soon be deployed to many critical locations throughout the world, not just in combat zones. It's an amazing system with very close ties to WAAS, but some possessing important key elements, some of which may eventually find their way into civilian systems to deter unauthorize signal alteration. Dr1819 23:29, 13 June 2006 (UTC)

I just realized I broke my own unstated rule, and edited before checking for changes here. Bad Maury, bad! *rubs nose on keyboard*

Anyway...

- DGPS is only similar to WAAS in that it corrects errors in GPS.

Isn't that the point though? That's certainly why I mentioned it. My concern is that if someone were to arrive here from google (which is likely how they'll get here) and read the article as it was, one would be left with the impression that WAAS was the only such system. This is very bad.

I think the average reader will find DGPS, WAAS and LAAS very much comparable based on the fact that they all correct the GPS signal by comparing the measured signal with a known location. The only difference is how they distribute the signal. In fact, John Deere refers to their StarFire sat-based system as a "wide-area Differental GPS system". Perhaps I'm misunderstanding your line of reasoning, but it would seem that following your comments above, one should not mention PAL in an article about NTSC.

• Response - isn't that akin to leaving out "blood" in an article about the heart? I believe terms need context for enhanced comprehension. In WAAS, it needs to be mentioned that it piggybacks on GPS, augmenting the signal with corrections to increase accuracy. LAAS should be mentioned as "an even more precise system," but little more. Hopefully, we can clean up the Precision Approaches section in a way that correctly puts all of them into context, perhaps a GPS-based Precision Approaches subsection. Dr1819 20:13, 15 June 2006 (UTC)

I think it's even more important to mention ILS and MLS. Not only is the way GPS "came out of nowhere" and bushwacked 20 years of MLS development interesting, it also provides valuable background on why replacing ILS with WAAS is both interesting and something to be approached carefully.

• Response - Approaches are broken up as follows:

Visual Approaches

(etc.)

Instrument Approaches

Non-precision approaches (courseline and distance, but no glidepath)

Precision Approaches (courseline, distance, and glidepath)

ILS

MLS

GPS-based Approaches

Medium Accuracy

WAAS

High Accuracy

LAAS

JPALS

All three GPS-based approaches use DGPS as a technology. How it's used varies. Dr1819 20:24, 15 June 2006 (UTC)

- It's run by the USCG not broadcast from "commercial radio stations"

True today, but when the system was originally being set up they were going to use commercial AM and FM stations. These plans changed (in NA) when everyone started looking at WAAS. I should also point out that DGPS systems in other countries do use commercial radio. In Australia, for instance, it's sent out along with RDSinformation.[1]

- I don't think it was ever used/considered for aviation usage

Well I only learned about DGPS via aviation magazines I read while going for my IFR. All the GPS receivers I was looking at had DGPS inputs, specifically for this role. Yes, even the aviation ones. Most still do. Try googling "dgps aviation" and you get lots of real hits.

- Maybe a section titled, "other GPS correction systems"

Well this is certainly another way to attack the problem, and one well worth considering, but is a single paragraph in the intro section really too much? Considering the intro also points out similar systems in other countries, I really don't see this as too much of a stretch.

Now the History section is another matter entirely. It actually duplicates the comments in the intro section, so I can see an argument for removing one or the other. But to remove the history portion entirely strikes me as another very bad idea -- WAAS is the latest in a series of attempted upgrades to ILS, and talking about WAAS alone leads to that myopia again.

Maury 12:42, 14 June 2006 (UTC)

Good points for the DGPS article. Most of those DGPS Aviation real hits are about WAAS or LAAS which are DGPS, but not USCG DGPS which is what I thought we were talking about. How many DGPS systems have 6 second response time for out of tolerance conditions. I'm not sure I'd want the pilot to announce that the plane was landing using the John Deere Landing System. --Dual Freq 22:32, 14 June 2006 (UTC)

Verifiability

Generally, it is wise to add a citation or two when adding 6 paragraphs of content. Also, I think you've left out Omega, LORAN, GEE and that one with the morse code "A" and "N". And what about Canada Wide-Area DGPS (CDGPS)?[2] Don't want to leave that one out. Good job with the GPS article too, no need for references on the technical information there either, I'm sure we can trust you. --Dual Freq 22:32, 14 June 2006 (UTC)

Come now Dual, save this sort of banter for the Usenet. If you have actual complaints about the accuracy of anything I have posted, please feel free to be specific about those points. Given that all six paragraphs refer to other fully qualified articles on the wiki, your call for references is already answered. Look, I'm sorry I disagree with you about what information the article should contain, but you have yet to post a single cogent argument for the removal of this information. I asked, nicely, whether or not you felt this information would better be isolated into a separate section, and instead you responded with these two off-topic comments that could only be described as insults. I can't imagine how it is you feel this supports your case. Maury 14:29, 15 June 2006 (UTC)

I'll let you know when it's an insult. I responded with sarcasm because you already re-added the material in question. I still disagree with 5 paragraphs of radio navigation background for the reasons stated above, I can see comparison to the international standard of ILS or the VOR enroute functions that WAAS may eventually replace. MLS is a bit of a tangent, but who the hell am I. Usenet doesn't have a policy of WP:Verifiability, you can put whatever you want in Usenet. Here it is official policy to provide source material so that a third party can verify compliance with copyright and factuality. This article can get away with unsourced numbers and history because it is not a Good Article or Featured Article. If it is ever peer-reviewed, the first thing they will ask for is sources. The second will be WP:MOSNUM for all the numbers used elsewhere, but those are easy to fix. The sources are another matter, if someone ever does try a peer review, they will have to track down all the unsourced material and cite sources. It's easier to cite as you go, but what do I know. Carry on, forget I ever mentioned it. --Dual Freq 23:32, 15 June 2006 (UTC)

I agree that the article should focus on WAAS, and only briefly mention other technologies, but only if those are highly relevant to current WAAS operations. "WAAS is a form of differential GPS (DGPS)" is all that needs to be said about differential GPS. Similarly, a brief mention is in order about how WAAS is augmenting other instrument approach procedures at airfields with IAPs, but is expanding instrument approaches into airfields without other IAPs. We should leave the laundry list of IAPs to the [Instrument approach] entry. Dr1819 22:53, 29 June 2006 (UTC)

A reference for the update frequency of ionospheric information for the user's equipment could be the WAAS MOPS itself. (Minimal Operational Performance Standard for WAAS equipment). Doesn't appear to be available online. 64.52.12.172 (talk) 22:10, 13 December 2007 (UTC)

Updates and proposed changes

I made some significant updates to content and readability. I left 99.9% of the content in, but change some of the wording so as to be more precise. I would like to propose some significant reductions, namely in the content that's more appropriate elsewhere. While readers of this article do need to know that WAAS will eventually replace Category I ILS approaches, the information/criteria of Cat I, II, and III ILS approaches should not be repeated here, but should be referenced/linked to the ILS page which discusses the approaches in detail. There are several similar, and I believe unnecessary redundancies which also need to be deleted from here, but perhaps incorporated (if that's not already happened) on the appropriate pages.

What say you folks? Dr1819 19:36, 30 June 2006 (UTC)

I wouldn't be so optimistic about the "good news" of LAAS in Cat II/III situations. I expect ILS will be around for quite a while for those categories. LAAS is OK for CAT I, but I've heard "back to the drawing board" used to describe the state of II/III LAAS. There is some that doubt LAAS will ever meet CAT III. WAAS will never be CAT III either. Therefore, ILS will be around at least until the new multiple frequency GPS sats and receivers are out. I think the USCG DGPS system is still the primary differential system for rail[3] and waterways. It seems to work better for ground / water usage. --Dual Freq 21:42, 30 June 2006 (UTC)

Noted. Any opinions on the "significant reductions to content" issue and moving the material to where it's most relevant?

OwenX - some great edits on your part! Only two technical details which I'll take care of in the next few days. Nice work! Dr1819 22:06, 4 July 2006 (UTC)

Drawbacks and Limitations

There are now more than one certified receiver. Here is the yahoo copy of garmin's press release for their model series that are certified. link. Also, in some searching I've found other companies that have certified waas equipment.

I changed the article to say "limited number" of certified receiver models. If anyone has more info, please update that area. Davandron | Talk 19:44, 10 November 2006 (UTC)

Ground Station Count

I'm putting the list of ground stations here, since it doesn't seem appropriate in the article but have repeatedly goofed counting the number *laughs* These are from the source cited in the article, just refracted to make for easier reading/counting. - Davandron | Talk 16:29, 2 January 2007 (UTC)

CONUS

1. Albuquerque, NM;
2. Atlanta, GA;
3. Billings, MT;
4. Boston, MA;
5. Chicago, IL;
6. Cleveland, OH;
7. Denver, CO;
8. Fort Worth, TX;
9. Houston, TX;
10. Jacksonville, FL;
11. Kansas City, KS;
12. Los Angeles, CA;
13. Memphis, TN;
14. Miami, FL;
15. Minneapolis, MN;
16. New York, NY;
17. Oakland, CA;
18. Salt Lake City, UT;
19. Seattle, WA;
20. Leesburg, VA.

Alaska

1. Juneau, AK;
2. Anchorage, AK;
3. Cold Bay, AK;
4. Barrow, AK; (Added August 06)
5. Bethel, AK; (Added August 06)
6. Fairbanks, AK; (Added August 06)
7. Kotzebue, AK (Added August 06)

Hawaii

1. Honolulu, HI;

Puerto Rico

1. San Juan, PR;

Range Information

The article states: "The satellites also broadcast the same type of range information as normal GPS satellites, effectively increasing the number of satellites available for a position fix."

At this time (Jan 24,2007) it is my understanding that 48 and 51 do not provide ranging information yet.

I didn't want to edit the article without confirming with other knowledgeable contributors (I do not claim to be an expert), but I do think this is the case (based on discussion with FAA indicating that ranging would not be available for some period after certification of these satellites and experience with my own GPS receivers that do not seem to use 48 and 51 for ranging, but only for WAAS correction).

It add to the overall usefulness of the article if the projected dates of ranging availability could be added to the article - FAA or its contractors may be a good source of information, my ability to get this is quite limited.

(Sorry if I contributed this improperly, but the instructions for adding a comment to the discussion are pretty poor and I'm new to comments.)

Gabbothis 17:34, 24 January 2007 (UTC)

Gabbothis: you are correct. The details you mentioned on the new satellites are actually in the article, in the "Future of WAAS" section. I think the confusion is because the space segment does talk about the satellites. I'll move some of the text up to the space segment. Thanks for the help! - Davandron | Talk 17:41, 24 January 2007 (UTC)

SVN 51 / PRN 135 / Anik F1R may be integrated

While the NSTB website doesn't say its been integrated, I noticed this weekend that 51 is no longer a "hollow" on my GPS receiver. The receiver locked on and appeared to be using it for ranging (although the sirfIII chipset doesn't use it for differential corrections). The NSTB site does say that this week (4/16-4/23) they will put it back into test mode for some tests of the other new satellite, but after that I will be looking for an FAA / NSTB announcement that it is integrated. Looks like they finished on time! - Davandron | Talk 13:11, 16 April 2007 (UTC)

Questioning some info

The comparison chart shows vertical navigation figures for both Loran and DME. I have a good background in both avionics and flight. I am mystified by the inclusion of any vertical error figures for these systems since there is no vertical guidance components whatever provided by these systems. Am I just missing something obvious here? Maybe the barometric altimetry system errors are being used? No, that is not consistent either. Fubartu (talk) 14:54, 16 December 2007 (UTC)

You're right about DME; it just a linear measurement and that should change (mistake on my part).

Regarding LORAN, from my memory in creating the chart, the FAA listed it as having lateral and vertical error. And that makes sense to me; its the same differential time system that GPS uses and it can yield a 3D position. My experience with loran is limited to boating, which is always at sea level and therefore never concerned with vertical positioning, so I don't have any personal experience to confirm that aircraft equipment can yield a 3D fix. Are you sure that no modern LORAN receivers provide vertical information? - Davandron | Talk 14:07, 17 December 2007 (UTC)

Breakdown of my changes and why

After multiple edits and reverts, we're still at a back and forth. I appreciate your point by point edits, and offer a point by point retort.

• "monitor and measure" - I can understand why they are somewhat similar, but in the past editors have errantly assumed that WAAS "measured" (they meant calculated) positions in the same way as DGPS, which it does not. Two verbs explicitly states there is multiple levels of activity occurring.
• "GPS satellite" - satellite is not implied; there are many GPS signals, WAAS monitors the ones coming from the satellite.
• The network stations are located in North America... plus Hawaii. However it doesn't measure the signals in North America.
• WAAS corrections are used in the calculating process; they are NOT differential and may not improve accuracy (the information may be redundant). The data in WAAS has to do with the satellites actual parameters and atmospheric conditions, which are all variables in the GPS receiver.
• Encyclopedia articles generally begin with what something is followed by what it does since context many not have been established in the reverse order. I'm pretty sure this is documented elsewhere in the wiki guidelines.
• WAAS is used by more than aircraft, hence users is the more appropriate term.
• "generate" - The system does generate; it must before there is anything to send. Using this highlights the fact the system is not simply producing a differential position.
• "WAAS satellites" vs "geostationary satellites" - this one is debatable, and I can see why calling them WAAS satellites is better (they don't have to be geostationary, they just are right now). My preference is to more specific information here, and geostationary is more specific while being accurate. This is not a big deal to me.
• "small variations" seems extra to me; all your other changes were to remove extra stuff. And changes might not be small, but if you want this I wont argue this one.
• "during" - the sentence doesn't read correctly without this word... i'm not sure why you think it should be removed.
• "signal" and remove "the" - again, it doesn't read correctly; there is more than one signal, and it is sending something (hence the). I guess "the" is fine either way.

I'd rather work together on this, than in conflict. As a new user I'm excited that you're interested in contributing, but hope that you can with with the group towards wp:consensus. Please discuss here. Thanks - Davandron | Talk 05:38, 4 January 2008 (UTC)

I appreciate your invitation to work toward consensus. Let me address each of your points in order.

• "monitor and measure" - In the context of radio signals, I think "measure" absolutely implies "monitor". Alleged mistakes made in the past should stay in the past. If you want to describe another level of activity, I don't think "monitor" is a good choice of verb. I suggest that this particular distinction would be more properly addressed further down in the body of the article.
• "GPS satellite" - Again, in the specific context of ground-stations receiving GPS signals, I think it is absolutely implied that the signals are from satellites.
• Your reference to the station in Hawaii is absolutely irrelevant to the sentence in question. If you have a point to make about my copy edit, and why your reverted it, this isn't it. So far, you're zero for three.
• I wrote "...GPS receivers use them to improve accuracy", and you reverted it to "...GPS receivers apply the corrections while computing their position.", with the justification that some of the information received may theoretically be "redundant", and not actually help improve accuracy. For the sake of consensus, I would agree to the addition of the word "can", as in "...receivers can use them to improve accuracy".
• I strongly question your contention that encyclopedia articles should begin with what something is followed by what it does. I call your "I'm pretty sure this is documented elsewhere in the wiki guidelines" , and raise you a "I've looked, and find no Wikipedia guideline resembling your assertion." If you think this is a real Wikipedia policy, it's up to you to link to it. Furthermore, in addition to contesting the alleged guidelines you referred to, I think the reverted version is also "wrong" in the sense that WAAS is not only an aid to aircraft navigation. For the sake of consensus, I hope this is an argument you find difficult to resist, because that exactly your argument on the next point. Although I think you are wrong in that case, too, for a different reason, as I will explain in a moment, the point does apply perfectly here.
• "WAAS is used by (users other) than aircraft", is your argument here, but in the "all phases of flight" context of this sentence, the very clear implication is that all users are aircraft. So far, I've found five of your six arguments entirely unconvincing.
• Regarding "generate" - for the sake of consensus, I won't argue this one. See how reasonable I am?
• Regarding "WAAS satellites" versus "geostationary satellites", since you are offering to be so reasonable, let's compromise with "geostationary WAAS satellites". I would agree that's appropriate in an introductory paragraph.
• Regarding "small variations" - I think the phrase is helpful, and I'm glad you said you won't argue that.
• Regarding "during" - actually, I think not just the "during", but the whole "all phases of flight" phrase should be cut from this sentence. Although WAAS is technically used during all phases of flight, the only time it really matters is during a precision approach. Once again, we seem to be disagreeing about what I consider to be clearly implied information that gives the impression of having been added simply to pad the word count of the article. I was going to concede this point for the sake of politeness, but after reading the sentence again, I feel encouraged to stand up for the principal of improving the signal-to-noise ratio of Wikipedia articles by removing clearly implied or irrelevant details, most especially in the first opening paragraphs of an article.
• Regarding "signal" versus "signals" - I confess that the "correct" plural form often sounds awkward to my ear, and I may very well be wrong about this one. For the sake of consensus, I concede this point, and thank you for admitting my edit of "the" was fine.

Overall, a large majority of your justifications, for reverting eleven of my edits in a row, are weak at best. I agreed with only about three out of ten points. I'm willing to consider additional arguments, but so far, on most of your points, I'm not at all convinced. If you can link to the Wikipedia guideline you mentioned, for example, I will gladly concede that point. But, if you can not provide a link, for the sake of consensus, I would appreciate it if you would withdraw that particular assertion, along with some of your other less well founded arguments. If you agree with half of my points, we'll have about two-thirds of a consensus. Thanks - Norandav (talk) 05:09, 8 January 2008 (UTC)

Norandav, when I read what you wrote, I hear a tone that indicates you take this personally; or at least it you are taking this as a personal battle and I must convince you. Perhaps I'm "hearing" wrong, or perhaps I've been too aggressive and have trigger that response (I was pretty quick to revert without talking to you first); if so I apologize and hope we can both step back. I view consensus as us agreeing, not battle till one person gives up. If your answer or my answer is the only answer, then maybe we'll have to seek mediation, but if you really want the article to be its best, then we're already on the same goal and it might just be little differences in understanding.

OK so points we agree on, or reached agreement on:

• Monitor and measure vs Measure: your point about detail inside the body of the article makes sense to me; lets set it to measure in the lead in and make sure the details explain how the signals are monitored.
• "signal" versus "signals" and "the"
• "generate"
• "small variations"
• "geostationary WAAS satellites"

Points we're still working towards; can we just focus on a few for now?:

• GPS satellites - There are both ground and satellite signals and the addition of one word prevents confusion. I'd understand if GPS acronym already had satellite as word or something, but I don't see it as redundant nor safe to assume... I'll agree that 95% of users probably haven't even thought about signals from anywhere other than the satellites, but that one word ensures everyone is on the same page. Is there another way we can ensure that people know WAAS monitors the Space Segment, and not any other part?
• This sentence (not sure what to "label" it as):
  • "WAAS uses a network of ground-based reference stations throughout North America to measure the GPS signals" vs
  • "WAAS uses a network of ground-based reference stations to measure the GPS signals throughout North America"
  • I was trying to highlight where the stations are located, and it sounds like you're highlighting the area it monitors. Is that correct? If so, how about: "WAAS uses a network of ground-based reference stations, located in North America and Hawaii, to measure the GPS signals in the western hemisphere" ??
• "use them to improve accuracy" vs "apply the corrections while computing their position" ... how about "a GPS receiver uses the corrections while computing its position to improve accuracy." ? I did a crap job of explaining what I'm thinking / worried about, but hopefully this covers what you were worried about (the simple end result being clear).

I'm out of time at the moment, but for the guidelines I'm working from are in Wikipedia:Lead section, which in Wikipedia:Lead_section#Provide_an_accessible_overview suggests "The first sentence in the lead section should be a concise definition of the topic..." The part about what-it-is before what-it-does is just my understanding of a definition.

Please feel free to in-line reply if its easier to understand and read. Thanks! - Davandron | Talk 05:47, 9 January 2008 (UTC)

Davandron, it's almost funny how you don't like my 'tone', after I dared to disagree with you calmly and rationally. You put my name in bold, and then accused me of making our disagreement 'personal'. Again, almost funny. Your repeated 'threat' of mediation still doesn't scare me. But in the end, your deliberate mis-interpretation and mis-appropriation of Wikipedia policy to support your destructive attitude annoys me more than all of your other shenanigans combined. So, that's where I'll focus my energy, for now. If you want consensus with me and other editors, I suggest you start being a little more reasonable, and less territorial. -- Norandav (talk) 08:18, 15 January 2008 (UTC)

I'm truly sorry you feel that way. I'm going to move forward, based on WP:BRD, by implementing the agreed language and requesting third party comment / mediation. - Davandron | Talk 23:46, 16 January 2008 (UTC)

Third opinion

Hey. This is clearly a very technical article, and is a topic I'm wholly unfamiliar with, but I'm going to try to give my opinion here anyway. In particular, I'm looking at edits such as this one and this one. Basically, I think that you guys should strive to make the article as approachable to an outsider as possible. To that end, I prefer the versions that start with saying "is an air navigation aid", "monitor and measure the GPS", and so on. In particular, I like Davandron's idea of solving the use of "use them to improve accuracy" or "apply the corrections while computing their position" to "a GPS receiver uses the corrections while computing its position to improve accuracy." If one of you is pushing for more technical wording and the other for more simplistic wording, why not try to combine them both into one sentence, so that the article is approachable to people like me, but also has the information that more experienced people would want.

What do you guys think? Is there any other way I can help? — HelloAnnyong ^{(say whaaat?!)} 17:11, 21 January 2008 (UTC)

HelloAnnyong, thanks for helping out with a third opinion! - Davandron | Talk 02:35, 23 January 2008 (UTC)

contested statements removed

• Existing GPS satellites did not have any additional channels that could be used for this feature, so instead it was planned to add broadcasters to existing communications satellites.{{Fact|date=December 2006}}
• [eLORAN Repeatability] 10 m / 10 m {{Fact|date=December 2006}}
• [Local Area Augmentation System (LAAS) Specification] 1.0 m / 1.0 m {{Fact|date=December 2006}}
• This ultimately limits the operational area and accuracy due to undersampling. {{Fact|date=December 2006}}<!-- Stanford paper on waas modernization may be used as reference -->

Please do not return this information to the article without a citation.--BirgitteSB 15:22, 9 June 2008 (UTC)

Undue precision

Is there any reason why we're using nine decimal places in the coordinates on this article? Andy Mabbett (Pigsonthewing); Talk to Andy; Andy's edits 17:47, 17 January 2013 (UTC)

Agreed, 9 decimals suggests a precision on the order of 0.1 millimeters. If these are region centroids as mentioned, of such a size they serve multiple airports, e.g. Fort Worth Air Route Traffic Control Center, I think we could easily get by with 1 or 2 decimals (1-10 km precision). Maybe go nuts and use 3. -- atropos235 ✄ (blah blah, my past) 04:34, 21 September 2013 (UTC)

Oh, looking at the elevations (also given to millimeter precision over hundred-thousand-square-kilometer regions) where some are negative (Miami, Puerto Rico) makes it fairly obvious that it was the trivial average (including subaquatic locations) of everywhere within some polygon. Removing elevation and 7 decimals from all coordinates. -- atropos235 ✄ (blah blah, my past) 04:39, 21 September 2013 (UTC)

And just what do you mean by "polygon"? Those were the centroids of the triangles formed by the three receiving antennas at each WAAS reference station, not the centroids of some thousand-or-so-square-kilometre areas. By dropping the precision of each of those coordinates by seven orders of magnitude, now those coordinates are hundreds of metres away from those antennas. --  Denelson83  23:45, 22 September 2013 (UTC)

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WAAS with Android Smartphone?

I came to this article to learn about how to get WAAS corrections on my Android smartphone. I understand that a different source is probably the best, but I at least hoped that I would be directed to that source. How about including such a source? Hal9009az (talk) 00:23, 13 February 2019 (UTC)