WAAS in AUS?

Kerry · Post by **Kerry** » 10 September 05 9:06 pm

The Canadians in the last few days have managed to launch a WAAS capable geo satellite, which hopefully won't bother us as we shouldn't be able to see the thing as it should only cover North America from it's location at about 107 degress West.

Quite a complex web we weave? A Canadian satellite, built in Europe, launched by the Russians from Kazakhstan and as part of it's payload will broadcast WAAS corrections based on GPS.

Cheers, Kerry.

arthurking83 · Post by **arthurking83** » 11 September 05 2:52 am

i'm currently tracking this phantom 'W' sat at the moment with my MeriColor (with WAAS enabled).
I haven't seen it before, as I disabled WAAS, the first thing I did when I recieved the GPSr.
It hasn't budged from it's position at 352(Az) and 46(El). There's no way to tell if it's PRN 129 or 137?? Both appear to be in the same location

as per the Meridians WAAS screen.
My location is Melb.
I've yet to recieve a lock, and I'm going to leave the GPS on all night and logging to VisualGPS.

Kerry · Post by **Kerry** » 11 September 05 9:32 am

352(az) @ 46(el) from Melbourne would make that PRN 129 (MTSAT1R) and it won;t budge from that position either, well there'll be problems if it does.

PRN 137 (MTSAT2) as far as I'm aware is still on the ground?

Cheers, Kerry.

arthurking83 · Post by **arthurking83** » 16 September 05 2:05 am

Oops my bad!

Not PRN 137, it was in fact PRN 134! Sorry for the confusion!
And thanks for the info Kerry, much appreciated.

Although I ran with WAAS enabled all day today, and I didn't notice much difference either way in terms of accuracy (after downloading the track file and checking it on the map, as I do every day!)....But!! It does take longer to initialise (warm start and cold start) so yes! WAAS is better off than on!

I finally got a lock on the W sat and it's indeed 129(MTSAT1R)
I briefly get a lock on the 134 but it loses it in 2 minutes, won't hold the lock. only on 129.

cheers.

GIN51E · Post by **GIN51E** » 13 December 05 8:56 pm

probably shouldn't be bringing this back up but i can't get it out of my mind.

The other day on the way back to the car after finding a cache i thought i would turn WAAS on again, turned it back on and straight away i picked up sat 129 at full signal, minute later and WAAS came up on the accuracy screen. just turned it on again tonight outside in the rain and straight away it picked up sat 129 again, then 1 minute late came up with WAAS in the screen.

Now if i remember correctly when i first got this GPS it always came up with a sat called W on the status screen ever since i've had the GPS and it always had fairly good signal most of the time, and i never knew what the W meant and thought it must be something that comes up when the unit has a lock. but never did it ever say WAAS in the accuracy screen.

Then about 2 months after having the GPS unit for the first ever time it said WAAS in the accuracy screen. so from when i first got the unit it always picked up the WAAS sat but it wasn't until two months later that it actually started to use it and put the WAAS message in the accuracy screen. hmm still makes me wonder, i want it on because i like the WAAS message on the screen and the 3m accuracy displayed but then i want it off because people tell me that it should be off, what to do what to do. maybe i should start using my old Magellan 3000XL doesn't have WAAS so i don't have to think about it and it says 0m in the accuracy screen

riblit · Post by **riblit** » 13 December 05 9:35 pm

GIN51E wrote:probably shouldn't be bringing this back up but i can't get it out of my mind.

The other day on the way back to the car after finding a cache i thought i would turn WAAS on again, turned it back on and straight away i picked up sat 129 at full signal, minute later and WAAS came up on the accuracy screen. just turned it on again tonight outside in the rain and straight away it picked up sat 129 again, then 1 minute late came up with WAAS in the screen.

Now if i remember correctly when i first got this GPS it always came up with a sat called W on the status screen ever since i've had the GPS and it always had fairly good signal most of the time, and i never knew what the W meant and thought it must be something that comes up when the unit has a lock. but never did it ever say WAAS in the accuracy screen.

Then about 2 months after having the GPS unit for the first ever time it said WAAS in the accuracy screen. so from when i first got the unit it always picked up the WAAS sat but it wasn't until two months later that it actually started to use it and put the WAAS message in the accuracy screen. hmm still makes me wonder, i want it on because i like the WAAS message on the screen and the 3m accuracy displayed but then i want it off because people tell me that it should be off, what to do what to do. maybe i should start using my old Magellan 3000XL doesn't have WAAS so i don't have to think about it and it says 0m in the accuracy screen

I think you should read up on WAAS, specificially what is, how it works, why it works, and why the correction signal must eminate from a point near the receiver.

http://gpsinformation.net/exe/waas.html is a start and Brian has added an update at http://www.gpsoz.com.au/WAAS.htm

GIN51E · Post by **GIN51E** » 14 December 05 6:02 pm

Kerry wrote:
PRN 137 (MTSAT2) as far as I'm aware is still on the ground?

Cheers, Kerry.

Not anymore,

When ever i get sat 129 i get a WAAS displayed on the screen, now last night i picked up a signal from 137 and this afternoon i've been getting 137 still. with a SNR between 130-440 now in my sat display 137 was always on top and 129 at the bottom, and when ever i got 129 i got a waas lock, now i can't get 129 but i'm picking up 137 and its giving me good signal but still no WAAS display in the screen, but the strange thing is whilst i was watching the screen 129 and 137 swapped position so now 137 is displayed at the bottom and its AZ and FL have both changed to the exactly the same figure as sat 129. so now 129 and 137 both read AZ=340 FL=49 where 137 used to be AZ=332 FL=47

i just thought that was strange how they have both swapped positions on the screen and the location of the "fixed" sat has changed and they are both meant to be in the same position now hmmmm.

anyway waas will still be turned off whilst caching and i will try and forget about it until i turn it on again in a month or so to see what has changed.

riblit · Post by **riblit** » 14 December 05 8:51 pm

GIN51E wrote:'''i turn it on again in a month or so to see what has changed.

You would be better off reading Brian's words at the link I posted and keep it off until 2007

Kerry · Post by **Kerry** » 16 December 05 10:57 am

GIN51E wrote:
Kerry wrote:
PRN 137 (MTSAT2) as far as I'm aware is still on the ground?

Cheers, Kerry.
Not anymore,

When ever i get sat 129 i get a WAAS displayed on the screen, now last night i picked up a signal from 137 and this afternoon i've been getting 137 still. with a SNR between 130-440 now in my sat display 137 was always on top and 129 at the bottom, and when ever i got 129 i got a waas lock, now i can't get 129 but i'm picking up 137 and its giving me good signal but still no WAAS display in the screen, but the strange thing is whilst i was watching the screen 129 and 137 swapped position so now 137 is displayed at the bottom and its AZ and FL have both changed to the exactly the same figure as sat 129. so now 129 and 137 both read AZ=340 FL=49 where 137 used to be AZ=332 FL=47

i just thought that was strange how they have both swapped positions on the screen and the location of the "fixed" sat has changed and they are both meant to be in the same position now hmmmm.

anyway waas will still be turned off whilst caching and i will try and forget about it until i turn it on again in a month or so to see what has changed.

All this is explainable and be assured that MTSAT2 is definately not in orbit and still sitting on the ground. Launch date is now Feb 15, 2006.

Now what you are seeing, or think you are seeing MTSAT2 (PRN137) is that MTSAT-1R and MTSAT2 have the capability to transmit both PRN129 and PRN137 if either satellite is off line. So PRN129 can be either MTSAT1R or 2 and similar for PRN137. When both are operating PRN129 is MTSAT-1R and PRN137 is MTSAT2 only, when one is shutdown the remaining MTSAT actually broadcasts both PRN's.

There's nothing strange with what you are seeing, it's simply MTSAT1 transmitting 2 PRN signals at present.

Cheers, Kerry.

GIN51E · Post by **GIN51E** » 16 December 05 8:45 pm

that makes a great deal of sense thats why the postition of 137 when i started picking the signal up was showing the same position as 129

Kerry · Post by **Kerry** » 17 December 05 8:14 am

Apart from not being useable in Oz anyway even when operational, right now with the system incomplete and still going through testing anything could be happenning?

Cheers, Kerry.

energizer61 · Post by **energizer61** » 17 December 05 9:01 am

here's a link for future test transmissions of PRN129;
http://www.kasc.go.jp/MSAS/link2_e.html

& from the same site,

MSAS signals achieve intended purpose and performance only if used by the airborne SBAS receiver conforming to TSO-C145a/146a. Please also note that non-aviation receivers using MSAS signals may NOT provide better positioning performance

so, unless the caches you are searching for are Airborne, just turn off WAAS & forget about it

Edit - I just read the link from Riblit above @ GPSOZ, it says all that there, lol... I should of read that before posting

Kerry · Post by **Kerry** » 20 February 06 11:13 am

Bit of an update as things are going to change.

MTSAT-2 is now in orbit (as of today) and will join MTSAT-1R so when both are operational they will normally appear as distinct satellites in different locations.

Inmarsat 3-F4 (AOR-W PRN122) is currently being moved from 54W (east coast of Brazil) to 142W (mid pacific) and be parked up to the east of POR (3-F3 PRN 134). AOR-W is still currently on its 60 day trek and presently just to the west of South America.

A Garmin will see PRN122 as 35, PRN 134 as 47, MTSAT-1R as 42, MTSAT-2 as 50, IOR-E as 44 and IOR-W as 39.

So for users in Oz there will be 2 WAAS sats, 2 MTSAT and 1 EGNOS (3-F1) all "possibly" in view (from the north of the country) at one time and to think there was confusion before.

Cheers, Kerry.

TeamAstro · Post by **TeamAstro** » 20 February 06 8:27 pm

Do we have a ground base for this?

clear skies (soon??)
Astro.

Kerry · Post by **Kerry** » 21 February 06 9:05 am

TeamAstro wrote:Do we have a ground base for this?

Ground base? as in a WADGPS monitoring type ground bases? No we don't and not likely to either from all indications. To cover Oz 1 simply wouldn't do the job. Just compare the size of CONUS with something like 25 ground stations to the size of Australia.

In any case who is going to pay for it all? Air Services Australia have no intention of developing a WAAS type system in Australia as they have developed a much cheaper solution as WAAS is extremely expensive and Australia's population simply couldn't absorb the cost.

Cheers, Kerry.

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