Jump to content

Waas 35


Followers 3

Recommended Posts

I had posted this over here but this might be the better thread for it.

 

On the newsgroup sci.geo.satellite-nav today.

 

QuickTime animations showing the westward move of Inmarsat 3-F4 (AOR-W)

from 54°W to 142°W have been created by the Geodetic Research Lab at

UNB. The two animations show the subsatellite point and the 0°, 30°,

and 60° elevation angle contours. The animations can be downloaded

from here:

http://gauss.gge.unb.ca/AOR-W-move.1.mov(cylindrical)

http://gauss.gge.unb.ca/AOR-W-move.2.mov(spherical)

 

Richard B. Langley

Prof. of Geodesy and Precision Navigation

Link to comment
Well I left my 60csx in the window for about 30 minutes and I now have WAAS correction from 33. I guess that moving 35 has placed it too far from my location to pick it up. At least I have one bird send WAAS corrections :laughing:

 

How can you tell which WAAS satellite you are receiving corrections from? I don't think you can; in fact, I think you are misinterpreting what your unit is showing you.

 

The ranging function of AOR-W (Garmin 35) has been disabled, but it is still sending corrections. Garmin units only show a "lock" when ranging data is being used, so it may look like you aren't receiving data from AOR-W even if you are.

 

AOR-W hasn't moved far enough yet for it to have any noticeable impact on your reception of it.

 

And 33 does not send WAAS corrections, since it is not part of the WAAS network. It is the SBAS satellite for Europe, which is called the EGNOS system. Its correction data does not work in the US. If you are seeing a "lock" on it in your unit, then it is being used for ranging data.

Edited by fizzymagic
Link to comment

I'm not an expert but if 33 isn't showing up on the satellite page I have no WAAS correction or a "D" indication as soon as it appears I start receiving WAAS correction. Same goes when I see 35.

 

So are you saying that even though my unit is receiving a correction it is not improving the accuracy of my position?

Edited by team fuzzybunny
Link to comment
I'm not an expert but if 33 isn't showing up on the satellite page I have no WAAS correction or a "D" indication as soon as it appears I start receiving WAAS correction. Same goes when I see 35.

Garmin's pathetic WAAS implementation strikes again.

 

So are you saying that even though my unit is receiving a correction it is not improving the accuracy of my position?

Well, your unit can make use of the clock and ephemeris corrections, but the main correction is the ionospheric correction, which will only be valid over Europe.

 

But, as I said before, there is no reason your unit cannot receive corrections from AOR-W (35) now. It just won't show up as a "lock" on your screen.

Edited by fizzymagic
Link to comment

On my 60C, the Hollow bars mean that it is receiving data, but not LOCKED on those satellites.

 

MY 60C has seen 33, 35, and 36 before, and lately it does not get a LOCK, but shows a hollow bar for 35.

 

MY 60Cx has shown abolutely nothing since the firmware upgrade to V 2.50, as far as any WAAS indication, with NO "D" on the screen at all.

 

So a Hollow bar with the satellite number at the bottom, means, it's receiving Data.

A solid Bar, means it has a LOCK on that satellite, to use that satellite for Ranging information.

 

-

Geoff

Link to comment

On my 60C, the Hollow bars mean that it is receiving data, but not LOCKED on those satellites.

 

MY 60C has seen 33, 35, and 36 before, and lately it does not get a LOCK, but shows a hollow bar for 35.

 

MY 60Cx has shown abolutely nothing since the firmware upgrade to V 2.50, as far as any WAAS indication, with NO "D" on the screen at all.

 

So a Hollow bar with the satellite number at the bottom, means, it's receiving Data.

A solid Bar, means it has a LOCK on that satellite, to use that satellite for Ranging information.

 

-

Geoff

 

Mine did this all day today and it wouldn't lock on any other Sat...weird :laughing: and I just went outside to see if I could lock onto any Sats and it is still the same, not even one.

Edited by HighlandTrailBuster
Link to comment

Hmmmm.... What a bummer. Look's like I'll have to get used to poor WAAS reception until this fall (I'm on the east coast). At least there is a new bird scheduled to be launched. Of course when I really need the accuracy I you can't see 35 anyways! Thanks for the good info all.

Link to comment

I am 20 miles south of Cle. I have seen Satellite 33 several times with no lock on. I have not seen 35 at all. Several people I Cache with have not been locked on to any WAAS sat. We are using 60 csx, 76 cs, and blue tooth pda setup. I have had accuracy down to 9' without WAAS. Not to bad. But most of the time, accuracy is usually around 14'. I am looking forward to a lock on a WAAS and see how accurate the 60 csx can be. Happy Hunting. Willlllmmmaaa were's my DINNER!!!!!

Link to comment

The LyngSat SatTracker page for AOR-W PRN 122 (GARMIN 35) Inmarsat 3 f4 shows it being at 63.2°W today (small blue text beside upper right corner of map).

 

I'm able to get a signal from it at 53N 117W with "D"s indicating correction signals. As expected no lock (solid bar) indicating ranging signals.

 

I have been wondering about WAAS lately so i'm glad I found this thread. I just got my first GPS, a Vista CX and am about 10 miles west of Boston. Looking at my satellite page I see the sat. numbers and the hollow and solid bars indicating a lock. I also see a round icon with a red (I think) center. Is this WAAS, or is WAAS just appear as the rest of the other satellites? What then is the round icon?

 

How else would I know that I'm actually taking advantage of WAAS? The accuracy on the satellite page I have not seen go below 15 feet.

Link to comment

I had both the 60C and 60Cx out today, and the 60C never saw WAAS 33, but had a good signal bar from WAAS 35, since it is higher in my sky now at N42 W83, the 60Cx though, still rejects WAAS 35, but tries to get a lock on WAAS 33, so it's not using 35 for some reason. WAAS 33 is only 7 deg above the horizon according to my SporTrak Color.

 

It will be something, to be without WAAS in the Northeast USA including Michigan, until after summer is over.

In this case my 60Cx will be the better unit.

 

Another thing I noticed, is that the elevation reported on the 60Cx is more accurate than the 60C, even though the 60Cx was showing worse accuracy.

 

-

Geoff

Edited by GOT GPS?
Link to comment

I also see a round icon with a red (I think) center. Is this WAAS, or is WAAS just appear as the rest of the other satellites? What then is the round icon?

 

The outer circle can serve as a crude compass by either setting the choices to track up on the local menu or by noticing the small circle on the outer ring present on later units that shows the direction of movement.(link)

 

My satellite page looks like this:

vistacx.jpg

 

I am talkign about the small gray circle with the red dot in the middle that is to the left of N, above the green #15 satellite.

 

 

EDIT: Bah, nevermind... I just found this at the link that you posted:

 

"small circle on the outer ring present on later units that shows the direction of movement."

Edited by mcewen98
Link to comment

actualy garmin has better sat reception than megallin. meg will say you have a lock when actualy you dont, i have seen this first hand. we have 2 tunnels where i live and a friend had just bought a new meg and we were compairing them side by side. when we entered the first tunnel mine lost signal but his still said locked untill we got to the other side then mine started tracking again and so did his. the same thing happened when we entered the second tunnel. several gps forums talk about this.

Link to comment

Anyone know what "38" might be? (the second WAAS being tested?) I was out today with my old Vista and my 60CS (not the 60CSx; it's back for replacement). The Vista was doing a complete search for WAAS satellites, starting with 31 and 32. When it got to 38 it showed a very strong signal, but the 38 was shown at the top of the screen, never went solid and the Vista kept searching. Once it got to 47 it received it's ephemeris data and showed 47 and 35, with 35 in its current position as it moves to its new location. I forget whether the 60CS did any searching, but if it did it found 35 and 47 pretty quickly, never saw 38. Both receivers saw 35 sparodically, but never went "black".

Link to comment

There's gonna be a lot of ticked off East Coast fisherman this spring/summer. :mad:

 

A lot of the lastest (last 4 years or so) generation of low to mid-level Chartplotters and combo units rely on WAAS to match/beat the accuracy of DGPS.

 

I think I'm gonna head to the shore this weekend to see if I can get a WAAS lock or not...

If I cannot, it's going to mean more motoring around using a depth finder to get on my desired spot or wreck, and will really cut into the quality fishing time until they turn the new birds on.

Link to comment

Just took my 60cs (no x yet) with me to lunch after reading this, I locked on 12 sats, and had 35 hollow but would not lock. If my memory serves me right I had the good ole "D" on 4 and 34 and sometimes one in the 20's i think. dadgum I knew I should have typed this up as soon as I got back.... :D

 

But the point being no 35 lock.

 

I am in Northern, UT.

Edited by kgag
Link to comment

I'm sounding like a broken record, but out surveying today in the Albany, NY area, with my 60CX along, I was getting SV 33 and had WAAS corrections at noon Eastern. After reading all the info found on the Forum I'm not sure anymore from which SV I get corrections!?? In any event, I had WAAS corrections, and had 33 (no 35) today!

Link to comment

Just took my 60cs (no x yet) with me to lunch after reading this, I locked on 12 sats, and had 35 hollow but would not lock.

...

But the point being no 35 lock.

Was there something in the earlier posts in this thread that led you to expect a lock on 35? If so, then perhaps I am not being clear enough. One more time:
  • The satellite that Garmin users see as #35 is moving.
  • While it is moving, the ranging data is turned off. The WAAS correction data, however, is still being transmitted.
  • Garmin units won't show a lock unless the ranging for a satellite is on.
  • Therefore, Garmin units will not show a lock on 35 even though WAAS corrections are being received.

Is that clear enough now?

Link to comment

Was there something in the earlier posts in this thread that led you to expect a lock on 35? If so, then perhaps I am not being clear enough. One more time:

  • The satellite that Garmin users see as #35 is moving.
  • While it is moving, the ranging data is turned off. The WAAS correction data, however, is still being transmitted.
  • Garmin units won't show a lock unless the ranging for a satellite is on.
  • Therefore, Garmin units will not show a lock on 35 even though WAAS corrections are being received.

Is that clear enough now?

 

Thanks Fizzy! This is what I thought you had explained earlier somewhere. I see the light now, and finally understand! Keep up the great work, and for all the education on a complex subject we get from you.

Link to comment
[*]While it is moving, the ranging data is turned off. The WAAS correction data, however, is still being transmitted.

[*]Garmin units won't show a lock unless the ranging for a satellite is on.

Things should be pretty clear now after Fizzy's latest explanation. But could someone explain what ranging data is?
Link to comment
But could someone explain what ranging data is?

Oh. Sorry. In addition to sending correction data, the geostationary WAAS satellites can also be used as part of the position calculation in a GPS. That's the "ranging data." In order for it to work, the satellite and the GPS both have to know exactly where the satellite is and how fast it is moving. Since that can't be guaranteed during the move, they turned it off.

Link to comment

"The ranging codes broadcast by the satellites enable a GPS receiver to measure the transit time of

the signals and thereby determine the range between each satellite and the receiver."

 

The WAAS satellites send both the WAAS corrections and function as a "regular" GPS SV most of the time.

 

Drat, can't delete my post that became superfluous after fizzy beat me by a minute... :D

Edited by Rotareneg
Link to comment

My 60Cx hasn't worked properly with 35 since it started started moving to the west either. According to the FAA it's not in a test mode and is still good for aviation use, and that the only difference is that it's not transmitting ranging data (so it can't be used as part of the GPS fix.) Apparently this is enough to cause SiRF receivers to ignore it.

 

For comparasion my Legend still receives 35 just fine and gets corrections without any problems. Only difference is that it doesn't get a "solid bar" on the satellite page indicating that it isn't being used in part of the GPS fix. Oh, and the Legend has shown the location of 35 moving westward while the 60Cx still shows 35 in it's orginal location.

Link to comment

My 60Cx hasn't worked properly with 35 since it started started moving to the west either. According to the FAA it's not in a test mode and is still good for aviation use, and that the only difference is that it's not transmitting ranging data (so it can't be used as part of the GPS fix.) Apparently this is enough to cause SiRF receivers to ignore it.

 

I've been able to get corrections on my 60CSx from 35, including today. I think what is happening with the SiRF models is that they only look at one of the WAAS satellites, so for me it usually is looking at 47 and won't bother with 35; when I get out where I can get a strong signal from 35 it will sometimes use it instead of 47 (not sure why; maybe 47 goes away for a while and then it looks at 35).

 

For comparasion my Legend still receives 35 just fine and gets corrections without any problems. Only difference is that it doesn't get a "solid bar" on the satellite page indicating that it isn't being used in part of the GPS fix. Oh, and the Legend has shown the location of 35 moving westward while the 60Cx still shows 35 in it's orginal location.

 

I had a similar experience with my 60CSx this weekend. I had gotten a replacement unit late last week, and from my condo it would sparodically receive 35, but not for long. Whenever it did, 35 would show up in it's original position. Sunday I went to the beach and it got a lock on 35 for extended periods of time; that apparently allowed it to load new almanac data, because it now is showing up in the current position.

Link to comment
Any idea as to why WAAS 35 is not working? Also, is there anyway to set a BT338 to ignore EGNOS 33.

WAAS 35 (AOR-W) is working fine. It's moving now, so the ranging data has been disabled, but it is still sending WAAS corrections. The problem is not with the satellite, it's with the maker of your GPS unit.

 

Garmin has a long, bad history of doing WAAS wrong. If I were you I'd let them know you are Not Happy.

Link to comment
Any idea as to why WAAS 35 is not working? Also, is there anyway to set a BT338 to ignore EGNOS 33.

Garmin has a long, bad history of doing WAAS wrong. If I were you I'd let them know you are Not Happy.

 

Complaining to Garmin about a GlobalSat BT338 receiver isn't likely to be very useful.

 

And while I agree that Garmin's implementation of WAAS hasn't been the best in the past, the current problem with the 60&76 'x' models and sat#35 seems like it's likely to be an issue with the SiRFstarIII chip used in those models and in the BT338.

Link to comment
Complaining to Garmin about a GlobalSat BT338 receiver isn't likely to be very useful.

I got confused when he referred to it as "35," which I thought was a Garmin-only designation. oops. Is PRN - 87 actually some kind of standard designation?

And while I agree that Garmin's implementation of WAAS hasn't been the best in the past, the current problem with the 60&76 'x' models and sat#35 seems like it's likely to be an issue with the SiRFstarIII chip used in those models and in the BT338.

From what I can gather, this is the risk you take when you offload processing from the CPU to the chipset. And you can't fix it with a firmware upgrade, either.

Link to comment

All in all, you're saying we are still receiving WAAS corrections despite the number 35 for Garmin is moving.

 

Should I expect to see "D"s in my satellite page? I didn't see any since I got my unit (January 19th). How do I know I get the corrections then?

 

EDIT: and yes, WAAS is turned on on the unit

Edited by cron
Link to comment

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
Followers 3
×
×
  • Create New...