WAAS reception

[Taxman003]

OK, I'm asking this because I just got my Legend back from service. I saw something in GPS Units and Software about WAAS recently, but I want to ask you Canucks.

 

Is anyone from the Kitchener to Mount Forest area not receiving regular WAAS locks anymore?

 

I barely picked up Satellite 33 yesterday (if we all see the same numbers) but it didn't last and my accuracy never improved from 5 metres. I used to get an accuracy down to 2 metres before I sent it in.

 

We used to have Satellite 35 too, didn't we?

 

Any comments would be greatly appreciated.

 

Mike

 

Even though you enter the wrong waypoint....you're still in the right spot!

[+mrcpu]

I seem to get WAAS pretty well everywhere I go in S/Ontario, depending on overhead cover and southern exposure. I've had WAAS in Hamilton and Oshawa.

 

Rob

Mobile Cache Command

[+Hard Oiler]

No problem getting WAAS on a Meridian in Petrolia today but 2 metres EPE sounds optimistic. Occasionally 3, usually 5 which is what I was getting this evening.

 

"If you don't know where you are going, then it doesn't much matter where you are." - Lewis Carroll in Through the Looking Glass

[+Solar Max]

I was getting both 35 (Atlantic) and 47 (Pacific) WAAS satellites today, with resolution of 3 meters on my Legend.

 

How much intelligence does it take to sneak up on a piece of tupperware?

[+MedicP1]

I don't get the WAAS sats but I do regularly get 3 meter EPE with it going down to 2 meters about 5 % of the time. I have a MAG315 and am in the London/Stratford area.

 

GPSr's...A step in the right direction!

[+EraSeek]

If I understand this link correctly, it show the WAAS service area well into Canada. A handy active map. http://www.nstb.tc.faa.gov/vpl.html

 

 

"See the wonderous works of Providence! The uncertainty of human things!" Geo.Washington

[+PDOP's]

quote:

---

Originally posted by EraSeek:

If I understand this link correctly, it show the WAAS service area well into Canada. A handy active map. http://www.nstb.tc.faa.gov/vpl.html

 

http://img.Groundspeak.com/user/4497_300.jpg

 

_"See the wonderous works of Providence! The uncertainty of human things!" Geo.Washington_

---

This would seem to indicate a vertical accuracy of 20 metres at best and the horizontal accuracy should be roughly twice as good - say 10 metres over a large part of southern Canada. There's still the question of how far you can be from a ground reference station and still be getting valid corrections.

 

I wish some of you that have GPSr's with WAAS would visit Canadian Base Networksurvey monuments and let us know what the results are. The EPE shown on your GPSr is just an estimate which is probably biased to show better than actual by the manufacturers.

 

PDOP's GPS Pages

[ChiefPig]

Can I get WAAS as far north as Edmonton, AB?

[+Olar]

quote:

---

Originally posted by PDOP's:

 

I wish some of you that have GPSr's with WAAS would visit http://www.geocaching.com/seek/cache_details.asp?ID=17841 survey monuments and let us know what the results are. The EPE shown on your GPSr is just an estimate which is probably biased to show better than actual by the manufacturers.

---

Hey PDOP's! There is one near me that I will visit again and try WAAS. When I did the original cache visit I got 2 metres (actual) with my GPS V. I'll do it with and without WAAS in order to compare. I'll let you know soon.

 

Cheers, Olar

 

"You are only young once but you can stay immature forever"

[+PDOP's]

That's great Olar. Maybe we can start a separate forum topic to post your results and others can join in. Or one of us can put up a page on their website.

 

It will be nice to have some real data from across the country to compare.

 

PDOP's GPS Pages

[gm100guy]

test your gps

 

here's the cache Olar is talking about.

 

I read through the logs and there are few with waas on and off that you can compare.

 

 

gm100guy

http://members.rogers.com/gm100guy/cachepage.htm

Ontario geocachers http://groups.msn.com/GeocachinginOntario/homepage

[+EraSeek]

Found a few things of interest:

 

FAA: "Planned expansion of the U.S. network will include Canada, Iceland, Mexico, and Panama, and has the potential to expand to other countries as well. Additionally, Japan and Europe are building similar systems which are planned to be interoperable with the U.S. WAAS. The merging of these systems will create a worldwide seamless navigation capability similar to GPS, but with greater accuracy, availability and integrity.''

 

Also a third sat is planned for as soon as possible to make up for the weak link in the system. That being NO redundancy. If one WAAS sat goes down, so does much of it's coverage area. After they get the third one up as soon as possible, then their longer term plan is to get a forth up to make it a full system.

 

Here is the current coverage:

 

Here's with the 3rd WAAS bird:

 

 

[This message was edited by EraSeek on September 03, 2003 at 09:17 PM.]

[+EraSeek]

double post

[Taxman003]

Thanks for all the comments and such. Nothing's really changed, but I have good WAAS connections now and do actually get down to 2 metres EPE regularly.

 

I was concerned because my Legend came back from service and I was afraid there was something wrong with it.

 

Happy Caching,

 

Mike

 

Even though you enter the wrong waypoint....you're still in the right spot!

[Boromir]

quote:

---

Originally posted by ChiefPig:

Can I get WAAS as far north as Edmonton, AB?

---

 

I just (this week) got a new WAAS enabled receiver, and on my one driving trip so far (between Athabasca and the Legal area, both north of Edmonton) it reported a WAAS connection pretty much constantly. The answer seems to be yes, but keep in mind that answer is based on limited data. I will check it out again tomorrow on an Athabasca - Edmonton trip.

 

In Athabasca the satellites appear right on the edge of the outer circle on the screen that shows the satellite fixes, so I think they are pretty low on the horizon by this point. In fact when just doing a quick test of it in Athabasca I did not get a WAAS fix. I suspect the WAAS signal would quickly be lost in a low spot or in a poor reception situation this far north.

[Boromir]

Based on a few trips into Edmonton WAAS seems to be consistently available around Edmonton, although sometimes it takes a while before I get the WAAS fix.

[+MrPeabody]

Does anyone know of a reference for all of the survey markers in Canada? Preferably on the web?

 

----

Mr Peabody and his fabulous WABAC Machine.

[Boromir]

quote:

---

Originally posted by MrPeabody:

Does anyone know of a reference for all of the survey markers in Canada? Preferably on the web?

 

----

Mr Peabody and his fabulous WABAC Machine.

---

 

Canadian Base Network

http://www.geod.nrcan.gc.ca/index_e/products_e/passiveNetworks_e/cbn_e/cbn_e.html

Spaced every 200-1000km. Very accurate position in 3 dimensions, the one I looked up was +/-0.001m horizontally, and +/-0.003m vertically.

 

Canadian Spatial Reference System

http://www.geod.nrcan.gc.ca/index_e/products_e/online_data_e/online_data_e.html

This covers pretty much every little survey marker you can find (including CBN). It includes all the small disks on the sides of buildings or bridge foundations. These are all over the place, there are about a dozen within 10km of Athabasca. You do need to sign up for an account (still free I think) if you want this information.

[ChiefPig]

Hmm...I have changed from an etrex Legend to a GPS V but I have not seen WAAS correction so far in Edmonton. Maybe I just need to go somewhere open and high?

[Boromir]

quote:

---

Originally posted by ChiefPig:

Hmm...I have changed from an etrex Legend to a GPS V but I have not seen WAAS correction so far in Edmonton. Maybe I just need to go somewhere open and high?

---

 

I have been able to get my WAAS signal in and around Edmonton fairly regularly (although it can take several minutes some times). I am using a Magellan Meridian Gold, which recently replaced my much loved eTrex.

 

I think somewhere in this thread someone had asked about accuracy of the WAAS corrections this far from the ground stations. On the weekend I visited one of the Canadian Base Network markers (+/- 1mm horizontal accuracy) about an hour west of Edmonton (near Gainford). I used the GPS for the last few miles and when I got there I had no WAAS yet. I set the unit on the marker and was told it was 3m away, when WAAS finally hit it dropped to 2m, and after another minute or two of averaging it dropped to 1m, so the corrections seem to be valid up here (based on a single test, YMMV). Elevation was out by about 1m, also a pretty good result.

 

NOTE: Elevation info corrected 03-09-29

 

[This message was edited by Boromir on September 29, 2003 at 09:11 PM.]

[+PDOP's]

quote:

---

Originally posted by Boromir:

 

I think somewhere in this thread someone had asked about accuracy of the WAAS corrections this far from the ground stations. On the weekend I visited one of the Canadian Base Network markers (+/- 1mm horizontal accuracy) about an hour west of Edmonton (near Gainford). I used the GPS for the last few miles and when I got there I had no WAAS yet. I set the unit on the marker and was told it was 3m away, when WAAS finally hit it dropped to 2m, and after another minute or two of averaging it dropped to 1m, so the corrections seem to be valid up here (based on a single test, YMMV). Of course the altitude was out by about 20m.

---

 

Boromir

 

I'm the one who was asking - thanks for your post. Are these figures you're giving the EPE from your GPS or have you actually plotted the waypoint and calculated the difference? The latter is what I'm interested in and is what will give an accurate idea if WAAS is doing anything.

 

PDOP's GPS Pages

[+PDOP's]

Here's a great little piece of freeware written by a cacher FizyMagic that will calculate the distance between two points. This will tell you exactly how far off your waypoint is from a benchmark. GeoCalc can be downloaded at this web page

 

You can post your findings in this thread started by Olar.

 

PDOP's GPS Pages

[ChiefPig]

Hmm, I guess I have to try one CBN marker here in Edmonton, perhaps the one on Highway 16 just east of Edmonton. I think it is pretty open there so my GPS V does not have any excuse for not finding the WAAS satellites.

[Boromir]

quote:

---

Originally posted by PDOP's:

Are these figures you're giving the EPE from your GPS or have you actually plotted the waypoint and calculated the difference? The latter is what I'm interested in and is what will give an accurate idea if WAAS is doing anything.

---

 

I set the known coordinates of the marker as a waypoint and navigated to the waypoint. The numbers I gave (1-3m) are the distance from the waypoint (which is essentially the error since the GPS was on the waypoint) as determined by the GPS. My GPS (Magellan Meridian Gold) does not seem to show EPE when I get a WAAS fix (the display just changes from 'EPE XXm' to 'WAAS').

 

Using the GeoCalc software the final horizontal error after WAAS & a bit of averaging was 0.925m, which is consistent with the 1m offset reported by the GPS. Not bad at all.

[+PDOP's]

Boromir

 

Thanks for the info. Here's a web pageabout the BrassCap cache which travels around to survey monuments across Alberta. You can download a GPX file of all the locations visited to date.

 

I'm not sure how the BrassCaps compare in accuracy to CBN monuments but they should be good enough to check out WAAS at the various locations.

 

PDOP's GPS Pages

[Boromir]

Corrected my previous post, my elevation was only out by just over 1m, rather than the 20m I had reported previously. User problem on my end, read the wrong value off the CBN report.