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Seeing No D's? (new 60cx)


planewood
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35 is the highest number satellite I'm seeing (I'm out west of Houston). Seeing it as a hollow bar.

 

I did not see 35 at all until about 5:00pm. Now it's coming in strong showing in the ESE position at about 45° from the horizon.

 

I was getting 8' stated accuracy for a while, now it's varying from 14' to 20'.

 

But, I have not yet seen any d's in any of the bars since I first turned it on.

 

How many WAAS should I be seeing? And shouldn't I have seen some D's by now?

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Hi Planewood

 

I have the same problem (and so do a lot of other X series sirf owners). Apparently it is a known bug, and we should see a firmware update in the next couple of weeks. Here is a reply I got from Garmin. Please email Garmin with your observations, as it doesn't hurt to have too much info when debugging this stuff

Link on garmin tech support reply about WAAS and 60cx

Edited by drbugs
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I am in Western NY, and have not seen any WAAS satellites for the last week or so.

 

Was getting accuracy down to 8' with my Garmin V, but now it stays around 18' - 21'

 

I have checked to make sure that WAAS is enabled, so that's not the problem, have been in the same area were I as getting the signal, but not now.

 

Have an external antenna on it's way, to see if that will help.

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I was getting 8' stated accuracy for a while, now it's varying from 14' to 20'

 

It's my understanding ,that the 60CSx does not have D's and the WAAS sat will show as a hollow bar, just like in your pic. The numbers you stated as EPE are near the stated accuracy.

 

60CSx Specs state;

 

GPS accuracy:

 

Position: <10 meters, typical (32 feet)

Velocity: .05 meter/sec steady state

DGPS (WAAS) accuracy:

 

Position: <5 meters, typical (16 feet)

Velocity: .05 meter/sec steady state

 

The Manual also states that sometimes the waas signal will degrade the accuracy and in such cases the 60csx will automatically disregard the waas info. (page97)

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I guess the obvious questions are:

Did you enable WAAS? It is not the default on a 60C .... not sure of the x series.

After enabling, did you let it sit in a good location for 30 minutes to load a new almanac with the WAAS data in it? B) ImpalaBob

 

Yep, WAAS enabled.

 

When I was getting the 8' accuracy estimate, it had a full bars lock on about 10 satellites. But, still no D's were showing nor was 35, initially. When I first turned the unit on, it had a lock on 7 or 8 satellites in about 2 minutes. I didn't even have to prime it with the current location. But I still let it set out in the wide open spaces for at least 30 minutes. It was getting close to sundown when it first picked up #35. It was showing high in the ESE, which is not its current position. It must still be reporting its old position at 54°.

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To begin WAAS, you would have to have Satellites 33 or 47, and then 35 will work for you.

For me, I have to Lock onto 33, before I can receive data from 35, and today, I had D's going all the way across the Satellite Page on my GPSMap60Cx.

 

GOT GPS,

 

I have never seen D's on my 60CSx, would you mind posting a screen shot of this?

I don't often see 35 here in Colorado, and when I do it's short lived. I'm interested in learning more about how WAAS works on the x.

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The Manual also states that sometimes the waas signal will degrade the accuracy and in such cases the 60csx will automatically disregard the waas info. (page97)

The manual actually says that?

 

That's pathetic, since it is not true that the WAAS signal can degrade accuracy. My guess is that they stuck it in to counter a persistent myth that came from a bug in their earlier WAAS implementation.

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What are your thoughts after reading the actual text?

Ah. It doesn't say what I thought from your description. That's a relief!

 

All it is saying, basically, is that they have implemented the WAAS corrections properly; if you are outside the coverage region, it won't use them. Of course, that is how the WAAS system is supposed to be used; any GPS that would use the corrections outside the coverage area would be badly broken.

 

I mistakenly thought they were addressing another myth that has taken on the status of an urban legend: that when some of the satellites have WAAS corrections and others don't, the solution could be lower accuracy than the non-WAAS solution. The problem with that myth is that the most important WAAS corrections do not act on a per-satellite basis, so the idea that some satellites would be WAAS-corrected while others are not is pretty much nonsensical.

 

In fact, it may very well be that is why the D's don't show up on the satellite bars for the SiRF-chipset units; since the WAAS corrections are either on for all satellites or off for all satellites, putting a D on an individual satellite bar makes no sense.

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About 5 minutes ago, 33 & D's.

Was #33 the only SBAS signal you were receiving? Since #33 is an EGNOS bird rather than WAAS the correction data would be based on observations from the European ground stations and wouldn't be the best to use in Pennsylvania.

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What are your thoughts after reading the actual text?

Ah. It doesn't say what I thought from your description. That's a relief!

 

All it is saying, basically, is that they have implemented the WAAS corrections properly; if you are outside the coverage region, it won't use them. Of course, that is how the WAAS system is supposed to be used; any GPS that would use the corrections outside the coverage area would be badly broken.

 

I mistakenly thought they were addressing another myth that has taken on the status of an urban legend: that when some of the satellites have WAAS corrections and others don't, the solution could be lower accuracy than the non-WAAS solution. The problem with that myth is that the most important WAAS corrections do not act on a per-satellite basis, so the idea that some satellites would be WAAS-corrected while others are not is pretty much nonsensical.

 

In fact, it may very well be that is why the D's don't show up on the satellite bars for the SiRF-chipset units; since the WAAS corrections are either on for all satellites or off for all satellites, putting a D on an individual satellite bar makes no sense.

I own a 60csx and I just got 33 bird and D on 9 sats OUT OF 10 ,so I had no. 4 sat wich hasn't been corrected(D) I live in Europe

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I was getting 8' stated accuracy for a while, now it's varying from 14' to 20'

 

It's my understanding ,that the 60CSx does not have D's and the WAAS sat will show as a hollow bar, just like in your pic. The numbers you stated as EPE are near the stated accuracy.

 

 

I just received my CSx today.....I have a 60C also, but I was wondering if the CSx will show D's or not? I only had a little time to play with mine today and I could not get any D's with WAAS enabled or disabled.

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I was getting 8' stated accuracy for a while, now it's varying from 14' to 20'

 

It's my understanding ,that the 60CSx does not have D's and the WAAS sat will show as a hollow bar, just like in your pic. The numbers you stated as EPE are near the stated accuracy.

 

 

I just received my CSx today.....I have a 60C also, but I was wondering if the CSx will show D's or not? I only had a little time to play with mine today and I could not get any D's with WAAS enabled or disabled.

 

Where are you located? Not very good (if any) WAAS coverage for the central USA right now. Should be good coverage by the end of the year.

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right by DFW airport TX.......I was just wondering if the CSx will show any D's in the signal bar for any of the sats, not just WAAS

 

I'm out west of Houston. If WAAS corrections are being applied to a particular satellite, then that satellite should have a "D" showing. You might be seeing satellite #35 right now, but it is not broadcasting corrections (I don't think). It will be a few months before it gets going again. For commercial reasons, the owners of 35 wanted to park it at W142°.

 

I have not seen a D on any bar since my 60cx arrived a week+ ago. I have heard scutlebutt here that it may be a software problem which Garmin is working on.

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You might be seeing satellite #35 right now, but it is not broadcasting corrections (I don't think). It will be a few months before it gets going again. For commercial reasons, the owners of 35 wanted to park it at W142°.

 

I have not seen a D on any bar since my 60cx arrived a week+ ago. I have heard scutlebutt here that it may be a software problem which Garmin is working on.

Satellite #35 (PRN 122) has been sending WAAS correction data but not ranging data. My GPS V yesterday was receiving it as the only WAAS satellite and showed 'D's on all the other satellite bars and indicated 3D Differential operation. But it's understandably not sending ranging data since there's a higher uncertainty about its exact location during the move. As a result the signal bar remained gray on my receiver instead of turning black.

 

There does appear to be some problem with the WAAS operation of the new Garmins with SiRF chips. I expect they'll be coming out with another firmware release pretty soon to fix that and the problem with regaining lock after an extended no-signal condition such as going through a tunnel.

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I'm out west of Houston. If WAAS corrections are being applied to a particular satellite, then that satellite should have a "D" showing.

Sigh. I keep on trying to explain why the comcept of D's applied to individual satellites doesn't make much sense, yet people still seem to think WAAS is a per-satellite correction. What am I doing wrong?

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I'm out west of Houston. If WAAS corrections are being applied to a particular satellite, then that satellite should have a "D" showing.

Sigh. I keep on trying to explain why the comcept of D's applied to individual satellites doesn't make much sense, yet people still seem to think WAAS is a per-satellite correction. What am I doing wrong?

 

i can FEEL your frustration :mad: but remember 35 will be in its new location soon and everyone will think they recieved a magical fix for their GPSr :mad:

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I'm out west of Houston. If WAAS corrections are being applied to a particular satellite, then that satellite should have a "D" showing.

Sigh. I keep on trying to explain why the comcept of D's applied to individual satellites doesn't make much sense, yet people still seem to think WAAS is a per-satellite correction. What am I doing wrong?

 

i can FEEL your frustration :lol: but remember 35 will be in its new location soon and everyone will think they recieved a magical fix for their GPSr :lol:

Yes, as soon as #35 is "firmly" in its new location(approx. April 1) all of the X unit users will see differential correction for their units just like non X units.

 

http://gps.faa.gov/programs/waasnews.htm

 

While Garmin or Sirf may provide an update to address this, I can't see why they would want to address a temporary issue. The issue seems to be related to the fact that the WAAS satellite is moving currently, but as we know, the WAAS sats. are meant to be geostationary, so this won't be a consistant issue, only intermittent when they need to be moved. In the meantime my 60CSx still provides only 1-2ft less of accuracy than my other units even without WAAS corrections.

Edited by yeeoldcacher
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I'm out west of Houston. If WAAS corrections are being applied to a particular satellite, then that satellite should have a "D" showing.

Sigh. I keep on trying to explain why the comcept of D's applied to individual satellites doesn't make much sense, yet people still seem to think WAAS is a per-satellite correction. What am I doing wrong?

 

You know, my 60cx manual says absolutely nothing about little "D's" being shown in each bar. Maybe that is not to be a feature with the 'x' line?

 

This if a very complex technology especially for newbies such as I. I'm grasping to understand this stuff as best I can. I guess that having D's show in some bars and not others is kind of a misleading way of illustrating what's really happening?

 

So, one more time. What do the D's mean?

 

And, is my unit defective for not showing any?

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right by DFW airport TX.......I was just wondering if the CSx will show any D's in the signal bar for any of the sats, not just WAAS

 

I'm out west of Houston. If WAAS corrections are being applied to a particular satellite, then that satellite should have a "D" showing. You might be seeing satellite #35 right now, but it is not broadcasting corrections (I don't think). It will be a few months before it gets going again. For commercial reasons, the owners of 35 wanted to park it at W142°.

 

I have not seen a D on any bar since my 60cx arrived a week+ ago. I have heard scutlebutt here that it may be a software problem which Garmin is working on.

 

I live in Galveston (southeast of Houston) and I haven't gotten any WAAS satellites and never any D's on my 60cx. I wonder if this will change?

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I live in Galveston (southeast of Houston) and I haven't gotten any WAAS satellites and never any D's on my 60cx. I wonder if this will change?

 

Geo -

 

35 should come online in 30 to 60 days. A couple more are scheduled to come online this fall that we should see here in the central US.

 

Go see if you can find a bench mark close by and take some readings occasionally. When I have had good locks on 8 to 10 sats, I've gotten 5' or better actual accuracy under those conditions without WAAS.

 

The worse readings have been under heavy dark clouds and high humidity. Best readings were on cool, clear days.

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Geo -

 

35 should come online in 30 to 60 days. A couple more are scheduled to come online this fall that we should see here in the central US.

 

Go see if you can find a bench mark close by and take some readings occasionally. When I have had good locks on 8 to 10 sats, I've gotten 5' or better actual accuracy under those conditions without WAAS.

 

Planewood-

 

Thanks for the info. I'll check out some adjusted benchmarks...

Edited by Geo Knot
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for what it's worth when I received my 60csx in feb I got WAAS 35 to lock w/"D's" on just about all the sats. Then I updated the firmware when the first update came out and the "D's" went away. This also coincided w/ the moving of the 35 bird but I don't think that has anything to do with it as my legend C still gets a WAAS lock w/ "D's". I live in W/Houston btw.

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I'm out west of Houston. If WAAS corrections are being applied to a particular satellite, then that satellite should have a "D" showing.

Sigh. I keep on trying to explain why the comcept of D's applied to individual satellites doesn't make much sense, yet people still seem to think WAAS is a per-satellite correction. What am I doing wrong?

 

This is something that I am still trying to work out myself. You get D's on individual sats, showing that they are corrected. You do not achieve "Differential" status until you have 3 or 4 corrected. There are two types of corrections involved with WAAS. Clock-ephemeris corrections and Ionosphereic corrections. Clock corrections are dealling with the individual sats. Ionosheric corrections are dealing with where you and your GPS is in relation to the modeled grid.

As I see it the D's are showing Clock-Ephemeris corrected sats (individual corrections). You need a certain number of these to achieve certainty for the ionospheric corrections (global corrections) that are based on your location in the grid, thus you obtain Differential status.

 

If you are outside the grid (in USA recieving ENOS) you may get D's on some GPS's as the Clock errors can still be corrected, but you cannot have ENOS apply to the USA WAAS grid and thus your GPS will not apply the ENOS sats to the differential solution. Garmin blocks it because it would be an flawed correction.

 

Does this not make sense?

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I'm out west of Houston. If WAAS corrections are being applied to a particular satellite, then that satellite should have a "D" showing.

Sigh. I keep on trying to explain why the comcept of D's applied to individual satellites doesn't make much sense, yet people still seem to think WAAS is a per-satellite correction. What am I doing wrong?

 

This is something that I am still trying to work out myself. You get D's on individual sats, showing that they are corrected. You do not achieve "Differential" status until you have 3 or 4 corrected. There are two types of corrections involved with WAAS. Clock-ephemeris corrections and Ionosphereic corrections. Clock corrections are dealling with the individual sats. Ionosheric corrections are dealing with where you and your GPS is in relation to the modeled grid.

As I see it the D's are showing Clock-Ephemeris corrected sats (individual corrections). You need a certain number of these to achieve certainty for the ionospheric corrections (global corrections) that are based on your location in the grid, thus you obtain Differential status.

 

If you are outside the grid (in USA recieving ENOS) you may get D's on some GPS's as the Clock errors can still be corrected, but you cannot have ENOS apply to the USA WAAS grid and thus your GPS will not apply the ENOS sats to the differential solution. Garmin blocks it because it would be an flawed correction.

 

Does this not make sense?

 

This quote from the FAA seems to reverse my thinking on how this works, and seems to counter Fizzymagic as well:

"A. The WAAS supplies two different sets of corrections: 1) corrected GPS parameters (position, clock, etc) and 2) Ionospheric parameters. The first set of corrections is user position independent - they apply to all users located within the WAAS service area. The second set of corrections is area specific. WAAS supplies correction parameters for a number of points (organized in a grid pattern) across the WAAS service area. The user receiver computes ionospheric corrections for the received GPS signals based on algorithms which use the appropriate grid points for where the user is located. Further, the appropriate grid points may differ for each GPS satellite received and process by the user receiver as the GPS satellites are located at various positions in the sky relative to the user. The combination of the two sets of corrections allows for significantly increased user position accuracy and confidence anywhere in the WAAS service area. "

 

Thus the corrections for the ionosphere are applied seperately to each satelitte, depending on where it falls into the modeled grid above the users position. If it is to the east of the user, it may use a more eastern grid point. If to the west, than that sat uses a westerly grid point. Thus each sat is corrected independantly for both postion-clock errors, and position on the ionospheric grid. D's represent individual corrected sats. You need at least 3 or 4 before your unit will apply the WAAS correction to your position fix.

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My StreetPilot c550 has a SiRFstar III receiver. According to Garmin, it can't show any "D" symbols, since SiRF uses the data differently, compared to Garmin, hence there's no knowledge about when to display the "D".

 

What says SiRF is different in the 60CSX?

 

The 60c(s)x series do show D's when they can see a WAAS satellite that is sending ranging data. I had D's showing one day couple of weeks ago when Waas 35 was operating. Other than that one day, there have been no Waas satellites available to the mid-continent area for at least the last two months

 

However, if you have a hard lock on 6 or more satellites with a 60c(s)x GPSr, you probably don't need WAAS anyway. With 6 or more bars maxed out, I've been getting 3' accuracy probably 90% of the time.

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I have been recieving WAAS corrections and "D's" on my Map76 from 35 the whole time during it's move. No rangeing of course during the move. It has been and is working fine. You can and should get it mid continent. The only place you can not is the NE.

 

Please look at this for current realtime WAAS coverage-> : http://www.nstb.tc.faa.gov/vpl.html

 

Very telling!

This whole issue with the new chip seems to be a bug which Garmin has stated is a bug and are working on. No, clouds are not an issue with reception here. If you are really getting 3' accuracy that suggests to me that you are getting corrections but somehow its not showing.

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My StreetPilot c550 has a SiRFstar III receiver. According to Garmin, it can't show any "D" symbols, since SiRF uses the data differently, compared to Garmin, hence there's no knowledge about when to display the "D".

 

What says SiRF is different in the 60CSX?

Actually it can, it is just that it won't right now due to the WAAS sats. moving. I think the Garmin rep. that provided you with that information may be confused.

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I have been recieving WAAS corrections and "D's" on my Map76 from 35 the whole time during it's move. No rangeing of course during the move. It has been and is working fine. You can and should get it mid continent. The only place you can not is the NE.

 

Please look at this for current realtime WAAS coverage-> : http://www.nstb.tc.faa.gov/vpl.html

 

Very telling!

This whole issue with the new chip seems to be a bug which Garmin has stated is a bug and are working on. No, clouds are not an issue with reception here. If you are really getting 3' accuracy that suggests to me that you are getting corrections but somehow its not showing.

 

Era - I keep WAAS turned off generally when marking positions. I did mark positions with WAAS turn on that one day I saw that 35 was ranging. But, that said, I have seen no variations in readings based on waas being on or off. I don't think the 'x' series will do anything different with waas turned on if they are not receiving ranging data or it is bad data. The one day that I did see D's was a bright clear cool day.

 

The BIG difference I've seen is that the actual accuracy on bright clear days with low humidity is far better than on dark cloudy days and high humidity. I suspect that waas will definitely help on those latter type days. I hope to see that whenever they get the dadburn things turned on!

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What ever is going on with the new chips in relation to WAAS is not normal or consistant with other units. But whatever it is, it is the chip, not WAAS which is on the fritz. Still, I have seen the new units working and they are impressive.

 

Eraseek -

 

I know I read somewhere that 35 would in test mode for 1 to 2 months after reaching final position. Everything I've read lately has said that 35 is not broadcasting range data, or not data marked as 'good' data.

 

On thing that may be different with the 'x' series is I think they do not use data from a waas satellite if it is marked as 'not good'. It could be that only the elevation data is marked 'not good' and that is causing the 'x' series to reject it all. I think we'll know what's going on in a month or so.

 

Anyway, at this location and under clear skys, I don't need waas. Next week when I'm in the deep woods of OKLA, I'll probably wish I had it! At least when I get back I may know a little more about these things. Got my Trimble charts all printed and ready to go!

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I know I read somewhere that 35 would in test mode for 1 to 2 months after reaching final position. Everything I've read lately has said that 35 is not broadcasting range data, or not data marked as 'good' data.

You seem once again to be confusing ranging data with WAAS correction data. Ranging data allows the WAAS satellite to be used just like a "regular" GPS satellite in reaching a position solution; the WAAS correction data is entirely separate. Lack of ranging data from a WAAS satellite is no big deal. It doesn't affect the WAAS corrections in any way!

 

The WAAS correction data has been continuously available from satellite 35 during its move, and it continues to be available now. It is not marked as bad data. It is not going into test mode. My Magellans are picking up the WAAS corrections from it perfectly well.

 

The new WAAS satellites, on the other hand, have been broadcasting in test mode. Their WAAS corrections are marked "do not use" and will be until sometime this summer or early fall.

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Enjoy the degraded signals while you can. Once technology gives us 1-2' accuracy geocaching won't be challenging enough to be any fun. <_<

 

I've heard this ever since WAAS first came out. In fact every since The military set SA to 0. Still people continue to have fun. There are many way to find a challenge. Micros, puzzles, no clues, disguises, terrain, awe inspiring places.

 

Regarding Fizzy's comment above. He is quite correct. WAAS keeps happily functioning even when not rangeing. In fact, the WAAS sats rangeing quality is not as good as normal GPS sats, so no big deal as long as they broadcast the corrections.

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In fact, the WAAS sats rangeing quality is not as good as normal GPS sats ...

Never heard this before. What's your source of information?

 

I have read it several places. The WAAS ranging signal is not the same as a GPS signal. It mimics it, but is different. Here is one source I have re-found dealing with the quality:

 

WAAS Geostationary Satellites (GEOSAT)

 

The current WAAS geostationary communications satellite (GEOSAT) constellation consists of two Inmarsat-3 satellites, leased through September 2006. The non-optimal coverage area provided by these satellites result in a potential single thread of failure for the entire WAAS system in the eastern four-fifths of the CONUS. (The 2 Inmarsat satellites are equivalent to one optimally placed satellite between the orbital slots of 119 and 129 degrees West.)

 

 

The FAA is pursuing the Independent Review Board (IRB) recommendations regarding WAAS geostationary satellites as listed in the Principle Findings and Recommendations in the IRB Executive Summary (#4).

 

Excerpt from IRB Executive Summary

 

"The greatest near-term risk to system availability is the current dependence on only two International Maritime Satellite Organization (INMARSAT) communications-relay satellites (called bent-pipes) for transmission of integrity and ranging corrections. These geosynchronous satellites (GEO) have poor ranging accuracy and vulnerable uplinks. If one of them fails, about half of the United States will loose coverage until service is restored.

 

Studies on the best satellite configuration for the FAA were presented to the IRB. We found that the optimal long-term configuration is four satellites with autonomous navigation payloads, broadcasting all three civil GPS signals. The IRB recommends that an additional, "bent-pipe "satellite be procured as soon as possible as an interim measure. At the same time, planning and initial actions should be undertaken to deploy the final four-satellite WAAS constellation, with autonomous payloads that broadcast all three civil signals."

 

FAA's Response to the IRB: In regard to the IRB recommendation to procure an additional, bent-pipe satellite as soon as possible as an interim measure, the FAA is actively pursuing the acquisition of a near-term additional GEOSAT service for on-orbit capability in early FY04. The benefits of the 3rd GEO include:

 

Additional Availability (Performance) and Coverage (Capability)

Incorporation of L5 Signal Capability for Increased Performance and Interference Mitigation

Mitigation of single thread of failure of existing Inmarsat satellites

Potential near-term GEO-hosted opportunities are limited for on-orbit operations in FY04 and include the following satellites - NIMIQ-2, Inmarsat I-4, AND ANIK F3. Due to long lead times required for satellite payload development, this effort requires expenditure of funds in October 2001. "Lost" GEO opportunities include: NASA TDRS H, I, & J; Navy UHF-11; NOAA GOES M, N, O, P; and ANIK F2.

 

The coverage area of the potential 3rd and 4th additional GEO satellites is depicted below:

 

 

The FAA WAAS models show increased coverage and availability in Maine, Washington, Southeast Alaska, southern Florida, and southwest California with the addition of the optimally-placed GEO.

 

Status of Long Term Solution: In regard to the IRB recommendation to deploy a final four-satellite WAAS constellation, the FAA is pursuing acquisition of GEOSAT service capability to replace the INMARSAT-3 constellation at the end of its lease period. These additional satellites will supplement the near-term GEO acquisition. The additional GEO satellites, integrated within the WAAS architecture will provide additional performance availability and coverage.

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