Oregon betas

[+PDOP's]

... I often see a solid green bar on either 48 or 51.

Thanks. I guess I wasn't paying enough attention before as I just set my 200 outside for a while and it does show a solid bar on 48. Still no 'D' on 48.

[jholly]

... I often see a solid green bar on either 48 or 51.

Thanks. I guess I wasn't paying enough attention before as I just set my 200 outside for a while and it does show a solid bar on 48. Still no 'D' on 48.

 

How can the satellite that provides the correction information for location calculations and does not transmit GPS data have a "D"?

[+PDOP's]

How can the satellite that provides the correction information for location calculations and does not transmit GPS data have a "D"?

IIRC it does transmit the ranging data similar to a regular GPS satellite and that is indicated by the solid bar on Garmin receivers. I'll try and dig up a link to confirm this.

 

Edited to add

 

http://www.gpsinformation.org/dale/dgps.htm#waas

 

"While the GEO-SV is in view the receiver will download corrections for additional SV's and the current ephemeris data for the GEO satellites themselves as well as correction data for the GEO satellites. Once ephemeris data is loaded the satellite bar will turn dark which means that it can also be used as part of the computed solution. Note that the GEO satellite can download correction data without, itself, being part of the GPS solution. A WAGPS satellite may or may not ever show a dark bar depending on the current ablitity of that SV to be used as part of GPS lock"

Edited June 2, 2010 by PDOP's

[+g-o-cashers]

Solid bar on my 550t but no "D":

 

http://www.gpsfix.net/wp-content/uploads/2...WAAS-Works1.jpg

[+PDOP's]

Solid bar on my 550t but no "D":

No "D" on my Oregon200 but otherwise it's fine with the beta firmware.

[+Bullygoat29]

Never have soooooooo many D's looked this good.

 

 

I can think of a couple.

[+ecanderson]

I've wondered about this with the Oregon series. I can see the WAAS satellites (48 & 51) but have never seen them with a 'D' or a solid bar on my Oregon200. I just pulled out my old 76C and it will do both (I'm currently seeing a solid bar with a 'D' for 48). So the 76 series can use the WAAS satellites for ranging (as indicated by the solid bar) but I'm not sure about the newer chipsets.

 

Has anyone seen a solid bar for a WAAS satellite on their Oregon?

Rarely, until this most recent update. Both 48 and 51 would appear as a tall "white" bar (solid signal, no data being interpreted successfully) most of the time. Now it will turn green (indicating a live data signal is not only present but is being understood by your Oregon), and the Ds will begin to appear for the other satellites as their correction data is received by your unit from 48 or 51 (or whatever they toss up there next).

 

You should never see a "D" associated with 48 or 51. They are the satellites that are SENDING the correction data, and not subject to it. Again, they provide the data that causes the "D" on all of the U.S. GPS satellites. 48 and 51 are NOT GPS satellites wandering about in the constellation of GPS satellites. They are (or were, until 48 went schizophrenic a while back) geostationary satellites.

Edited June 3, 2010 by ecanderson

[+PDOP's]

You should never see a "D" associated with 48 or 51. They are the satellites that are SENDING the correction data, and not subject to it. Again, they provide the data that causes the "D" on all of the U.S. GPS satellites. 48 and 51 are NOT GPS satellites wandering about in the constellation of GPS satellites. They are (or were, until 48 went schizophrenic a while back) geostationary satellites.

As I mentioned above the WAAS geos also transmit ranging data and function as 'normal' GPS satellites. As such they would also need correction data. Older Garmins do display a "D" with 48 or 51.

 

Screenshot of Garmin Map76C

 

[jholly]

As I mentioned above the WAAS geos also transmit ranging data and function as 'normal' GPS satellites. As such they would also need correction data. Older Garmins do display a "D" with 48 or 51.

 

My 76CSx does not display the "D" on 48 or 51.

 

Think of 48 or 51 being like the transmitter for DGPS. That sent correction information about the satellites used to calculate the position information. It did not send any ranging information, just correction information, likewise for 48 and 51.

[+Red90]

Think of 48 or 51 being like the transmitter for DGPS. That sent correction information about the satellites used to calculate the position information. It did not send any ranging information, just correction information, likewise for 48 and 51.

 

48 and 51 DO send ranging data......

[+PDOP's]

From Trimble's website (link)

 

But wait a second! If we've got the geosynchronous satellite already transmitting on the GPS frequency, why not use it for positioning purposes too? Adding another satellite helps with positioning accuracy and it ensures that plenty of satellites are always visible around the country.

[+ecanderson]

Since 48 and 51 already "know" where they are due to the data they are receiving from the ground stations, they'd already be sending the corrected data for themselves to begin with, not correction data about their inaccurately reported position, right?

 

As a result, what sense would it make to put a "D" on them? As I understand it, the point of the "D" is to indicate that the received data has been subject to the correction data. For 48 and 51, that correction is assumed, yes? Hence, if there was an intelligible data stream from 48 or 51, either the "D" makes no sense, or it should always be there no matter what, although that would be redundant.

[savant9]

Since 48 and 51 already "know" where they are due to the data they are receiving from the ground stations, they'd already be sending the corrected data for themselves to begin with, not correction data about their inaccurately reported position, right?

 

As a result, what sense would it make to put a "D" on them? As I understand it, the point of the "D" is to indicate that the received data has been subject to the correction data. For 48 and 51, that correction is assumed, yes? Hence, if there was an intelligible data stream from 48 or 51, either the "D" makes no sense, or it should always be there no matter what, although that would be redundant.

 

Exactly my thoughts as well.

[+Red90]

Since 48 and 51 already "know" where they are due to the data they are receiving from the ground stations, they'd already be sending the corrected data for themselves to begin with, not correction data about their inaccurately reported position, right?

 

The correction data is not only about the wrong position of the satellite. It is about how the radio signal is distorted by the atmosphere, which varies depending on your location.

[+ecanderson]

Since 48 and 51 already "know" where they are due to the data they are receiving from the ground stations, they'd already be sending the corrected data for themselves to begin with, not correction data about their inaccurately reported position, right?

 

The correction data is not only about the wrong position of the satellite. It is about how the radio signal is distorted by the atmosphere, which varies depending on your location.

OK - a bit of semantics there. There isn't technically a "wrong" position, it's an error in assumption about position by a ground receiver based upon environmental and clock factors. Point is that 48 and 51 aren't sending data with these errors incorporated and then sending correction data for themselves - none of which matters unless they're being used for a position solution anyway. Hence, a "D" has no real meaning for those two satellites.

[+Z_Statman]

New beta 3.52 for x50 units with GPS software still at 4.46 available

 

Can now filter caches and the POI access crash looks to be fixed

 

http://www8.garmin.com/support/download_details.jsp?id=4743

Edited June 5, 2010 by Z_Statman

[+Z_Statman]

A cross posting

 

Sat access: Seems that this is still 'somewhat' dependent in the GPS software version, location (out in the open v under cover) and movement (somewhat mutually exclusive).

 

Battery: With my 550 and its initial firmware (3.40 & 3.70, I believe) there was a noticeable battery drain if WAAS was turned on but this has gotten much better with the current betas of 3.52 & 4.46.

 

Out and About-

WAAS enabled: Out all morning yesterday and the error was down to 6-8' out in the open and driving but went up to about 8-10' when walking in the open the up over 15' under cover. All Ds as well as a consistent lock on sat 51.

 

WAAS disabled: Periodically off & on and did see a jump in error though slight, obviously lost 51 but still had 6-8 solid green bars.

 

HTH

[+smstext]

has anyone tried waypoint averaging since the latest beta? seemed a bit jumpy to me today.

[+ryan3295]

Tried my Oregon 450t today against my Colorado using the 3.52/4.46 beta software. All I can say is I am impressed!! Both my gpsr's agreed (within reason) on the distance traveled as well stopped and moving time. Even more impressive, was both recorded track log distances nearly matched the trip odometer!! I was even able to retain a WASS lock, although not the entire trip (I believe the Colorado did). My track was about 1 mile through the woods were my Oregon had trouble recording moving time in the spring with no leaves on the trees.

 

The proof is in the pictures:

 

 

WASS lock on the forest floor:

[+Entropy512]

Since 48 and 51 already "know" where they are due to the data they are receiving from the ground stations, they'd already be sending the corrected data for themselves to begin with, not correction data about their inaccurately reported position, right?

 

The correction data is not only about the wrong position of the satellite. It is about how the radio signal is distorted by the atmosphere, which varies depending on your location.

OK - a bit of semantics there. There isn't technically a "wrong" position, it's an error in assumption about position by a ground receiver based upon environmental and clock factors. Point is that 48 and 51 aren't sending data with these errors incorporated and then sending correction data for themselves - none of which matters unless they're being used for a position solution anyway. Hence, a "D" has no real meaning for those two satellites.

Some environmental factors (mainly ionospheric delay) are receiver location dependent, so you can't send a "precorrected" ranging signal that is common to all receiver locations. Plus this would break non-WAAS-capable units (which may be able to range off of the WAAS bird but not apply its corrections), so the ranging signal must be a normal one that has correction data broadcast for it.

 

If it is true that these sats are sending ranging data, it makes sense to send location-dependent ionospheric correction data for that ranging data.

[+kywaterfowler]

Upgraded mine this morning and I now have D's and accuracy at about 5 to 9 feet!!!!

[+ecanderson]

Some environmental factors (mainly ionospheric delay) are receiver location dependent, so you can't send a "precorrected" ranging signal that is common to all receiver locations. Plus this would break non-WAAS-capable units (which may be able to range off of the WAAS bird but not apply its corrections), so the ranging signal must be a normal one that has correction data broadcast for it.

I've always been under the impression that the of the two primary sources for error, the clock error was considerably more significant than the propagation error. It would be fascinating to see the actual data used across the entire service area. That would allow one to get the answer to the above very quickly since on a per-satellite basis, the total error for all geographic areas would be biased equally by the clock error in the total.

[+PDOP's]

Oops - double posted

Edited June 8, 2010 by PDOP's

[+PDOP's]

I've always been under the impression that the of the two primary sources for error, the clock error was considerably more significant than the propagation error.

Error Budget(link)

 

Ionosphere - 4.0 meters

Clock - 2.1 meters

Ephemeris - 2.1 meters

Troposphere - 0.7 meters

Receiver - 0.5 meters

Multipath - 1.0 meter

Total - 10.4 meters

[+Entropy512]

Some environmental factors (mainly ionospheric delay) are receiver location dependent, so you can't send a "precorrected" ranging signal that is common to all receiver locations. Plus this would break non-WAAS-capable units (which may be able to range off of the WAAS bird but not apply its corrections), so the ranging signal must be a normal one that has correction data broadcast for it.

I've always been under the impression that the of the two primary sources for error, the clock error was considerably more significant than the propagation error. It would be fascinating to see the actual data used across the entire service area. That would allow one to get the answer to the above very quickly since on a per-satellite basis, the total error for all geographic areas would be biased equally by the clock error in the total.

I'll see if I can dig up my old notebooks from GPS theory class, but the main contributors to GPS error are multipath and ionospheric delay. Ionospheric delay is such a major contributor that the military designed the system specifically with ways to auto-correct it (but didn't give civilians that capability - autocorrecting for iono delay is what the military L2 signal is for. Once L2C goes live civilians will be able to autocorrect iono errors without external corrections.)

[+Curioddity]

I must be getting addled in my old age....

 

I vaguely recall installing a beta update long ago but the rest of my updates have all been done with WebUpdater. The bottom line is I can't remember how to update an Oregon 400t with a downloaded beta update and I can't seem to find the procedure anywhere. I'm sure it's here in this GPS and Technology forum and I'm sure it can be found in the Garmin website, but I'll be damned if I can come up with the search criteria to find it.

 

Can someone help me out?

 

Thanks!

 

Pete

[+2Wheel'in]

I must be getting addled in my old age....

 

I vaguely recall installing a beta update long ago but the rest of my updates have all been done with WebUpdater. The bottom line is I can't remember how to update an Oregon 400t with a downloaded beta update and I can't seem to find the procedure anywhere. I'm sure it's here in this GPS and Technology forum and I'm sure it can be found in the Garmin website, but I'll be damned if I can come up with the search criteria to find it.

 

Can someone help me out?

 

Thanks!

 

Pete

Pete...Once you downloaded the beta file to your computer...connect your Oregon/Dakota in Mass Storage - then double click the beta file. Select "Run", and it will install on your GPS receiver. Once finished, disconnect/eject your Oregon/Dakota...turn it on, and the beta upgrade will load.

 

Bill

[+Curioddity]

Pete...Once you downloaded the beta file to your computer...connect your Oregon/Dakota in Mass Storage - then double click the beta file. Select "Run", and it will install on your GPS receiver. Once finished, disconnect/eject your Oregon/Dakota...turn it on, and the beta upgrade will load.

Thanks, Bill.

 

I figured as much, but I didn't want to try to proceed based on assumptions. Last time I did that I bricked my iPod Touch.

 

Pete

[+Red90]

And....make sure you have good batteries. If it dies during the first bootup, it can be a pain to get the unit working.

[+ecanderson]

I've always been under the impression that the of the two primary sources for error, the clock error was considerably more significant than the propagation error.

Error Budget(link)

 

Ionosphere - 4.0 meters

Clock - 2.1 meters

Ephemeris - 2.1 meters

Troposphere - 0.7 meters

Receiver - 0.5 meters

Multipath - 1.0 meter

Total - 10.4 meters

Interesting stats. Another way of looking at it:

 

Satellite errors: 4.2m

Propagation errors: 4.7m

Local topology (natural and man-made) and receiver errors: 1.5m

 

Obviously, there's no way to know what the correction data should or could be for the last bit, but being able to deal with 8.9m of a total 10.4m of error - slick.

 

As to the correction data being location specific -- that's kinda true and kinda not. It isn't like the SBAS satellites are sending out multiple location specific corrections.

 

I've seen the ionospheric TEC maps, and was originally surprised at how that information is reflected in the WAAS signal. As I understand it, the correction data we receive isn't actually location specific at all -- our receivers are all picking up the same correction information... but in addition, they pick up a copy of the TEC grid that our receivers then have to use to compute what level of correction would be appropriate for each of our receivers' own specific locations given the location of each satellite and the point at which that signal passes through the ionosphere on its way to our receivers. Some mighty fast math going on there.

[+The Chaos Crew]

 

Pete...Once you downloaded the beta file to your computer...connect your Oregon/Dakota in Mass Storage - then double click the beta file. Select "Run", and it will install on your GPS receiver. Once finished, disconnect/eject your Oregon/Dakota...turn it on, and the beta upgrade will load.

 

Bill

 

I'm glad Pete asked because I have no idea what I'm doing either

 

Before I upgrade to the new beta, which does look great on paper, is there any way of "backing up" my current settings on my Oregon (450) first, just in case the new software doesn't work for me for any reason and I want to go back?

 

Sarah

[Dr Jeckyl and Mr Hide]

 

Pete...Once you downloaded the beta file to your computer...connect your Oregon/Dakota in Mass Storage - then double click the beta file. Select "Run", and it will install on your GPS receiver. Once finished, disconnect/eject your Oregon/Dakota...turn it on, and the beta upgrade will load.

 

Bill

 

I'm glad Pete asked because I have no idea what I'm doing either

 

Before I upgrade to the new beta, which does look great on paper, is there any way of "backing up" my current settings on my Oregon (450) first, just in case the new software doesn't work for me for any reason and I want to go back?

 

Sarah

 

I don't think you can backup the system software but you will be able to use the WedUpdater to go back to the previous production version of the software if necessary.

 

I have the beta version on mine, and have not found any reason to complain or go back to the previous version.

[+dfx]

Before I upgrade to the new beta, which does look great on paper, is there any way of "backing up" my current settings on my Oregon (450) first, just in case the new software doesn't work for me for any reason and I want to go back?

from what i've seen, performing the update will leave your settings alone, so there's no need to back them up really. as for the firmware itself, you can always download the regular firmware and install that to go back.

 

however, i assume you can just connect the oregon to the PC and copy off some of the files to do an actual backup. the *.gpf files in the garmin/profiles/ directory seem to contain all the settings, so backup and restore of them should be a matter of simply copying the files off and then back on. but, i'm still an oregon noob myself and have never tried that.

Edited June 10, 2010 by dfx

[+The Chaos Crew]

Before I upgrade to the new beta, which does look great on paper, is there any way of "backing up" my current settings on my Oregon (450) first, just in case the new software doesn't work for me for any reason and I want to go back?

from what i've seen, performing the update will leave your settings alone, so there's no need to back them up really. as for the firmware itself, you can always download the regular firmware and install that to go back.

 

however, i assume you can just connect the oregon to the PC and copy off some of the files to do an actual backup. the *.gpf files in the garmin/profiles/ directory seem to contain all the settings, so backup and restore of them should be a matter of simply copying the files off and then back on. but, i'm still an oregon noob myself and have never tried that.

 

thanks for the help everyone, I've now updated to version 3.52 and everything seems to be working great - I LOVE the quick filter!

[+Z_Statman]

Was out in a preserve yesterday with my 550 running 3.52b & GPS v4.46 and believe I have found something (will let those techy types verify).

 

There were vast open areas as well as pine and oak areas with a lot of overhead coverage. I found that while the GPS accuracy would vary from about 8' to 20' (WAAS on) the Dist to Dest and Lat/Long Location was pretty spot on.

 

Was seeking caches and we know how owner placement readings are so critical but I was impressed with my 550's operation.