Vista Cx /waas Reception

[+timk54]

I was caching today and watching my sattelite page to see if it found a WAAS signal. I had solid bars on 10 sattilites and d's on most of them but they were all numbered less than 28 I did have a hollow bar with a 48 below it. Did I have a lock on a WAAS signal? Found 5 caches today and the GPSr distance on the compass page lead me to as close as 1 foot in one instance and 2 feet in another. So I'm not complaining about the way it is working just curious if WAAS is working.

timk54

[+Puddlewalkers]

Check other threads on the site about WAAS. They are moving satellites so WAAS isn't always available for everyone in North America. If you had D's in your bars you were in error correction mode. I am not sure why Garmin doesn't put this in their manuals.

[peter]

I was caching today and watching my sattelite page to see if it found a WAAS signal. I had solid bars on 10 sattilites and d's on most of them but they were all numbered less than 28 I did have a hollow bar with a 48 below it. Did I have a lock on a WAAS signal?

Yes you did. The satellite labeled #48 (PRN 135) is the PanAmSat Galaxy15 launched last fall and it is providing WAAS correction data. It's still in a test phase period so it doesn't always provide sufficiently accurate information (i.e. ephemeris data) on its own position to be used for ranging the way the regular GPS satellites are and that's why you saw a hollow bar. But the 'Ds' on other satellite bars is an indication that you were getting correction data for them and if #48 was the only WAAS satellite signal received then that's the source of the correction data.

 

Note that the moment you see a signal strength bar of any kind it means that your receiver has locked onto the signal from that satellite. If it's a solid bar then you know that in addition the receiver has valid ephemeris data for that satellite and can use its signal in calculating a position. Conversely a hollow bar either means that the ephemeris data has not yet been received or that it's marked as invalid in some way and therefore shouldn't be used.

[+timk54]

I was caching today and watching my sattelite page to see if it found a WAAS signal. I had solid bars on 10 sattilites and d's on most of them but they were all numbered less than 28 I did have a hollow bar with a 48 below it. Did I have a lock on a WAAS signal?

Yes you did. The satellite labeled #48 (PRN 135) is the PanAmSat Galaxy15 launched last fall and it is providing WAAS correction data. It's still in a test phase period so it doesn't always provide sufficiently accurate information (i.e. ephemeris data) on its own position to be used for ranging the way the regular GPS satellites are and that's why you saw a hollow bar. But the 'Ds' on other satellite bars is an indication that you were getting correction data for them and if #48 was the only WAAS satellite signal received then that's the source of the correction data.

 

Note that the moment you see a signal strength bar of any kind it means that your receiver has locked onto the signal from that satellite. If it's a solid bar then you know that in addition the receiver has valid ephemeris data for that satellite and can use its signal in calculating a position. Conversely a hollow bar either means that the ephemeris data has not yet been received or that it's marked as invalid in some way and therefore shouldn't be used.

Thank you for the informative response.

timk54

[ImpalaBob]

For most units the factory default is WAAS turned OFF. Please check your setup and make sure WAAS is turned ON and give the unit a good long look at a clear sky (20 - 30 minutes) to reload a new Almanac (coarse position chart) which includes the WAAS birds. ImpalaBob