60csx - Waas? D's? Decipher My Picture Please!

[chetwynd]

Hi all,

 

Bought my first GPS unit, the 60csx. Finally figured most of it out after playing with it and reading the directions, but one thing I don't fully understand is what you guys mean when you say WAAS and SIRF? What is that? What do the D's that you guys talk about mean? I assume it's good that I'm picking them up?

 

The conditions of the picture below...rooftop of a condo building in the bay area, mostly cloudy skies, took about 2 minutes to get to this signal. Should I expect better reception or better +/- distance? Thanks for the help in advance!

[chetwynd]

sorry for the WAY huge picture...

[HOGCAT]

Ever eat at the Happy Dragon?? As far as I know, if ya got the D's showing you are getting the WAAS signal for correction. I found the Dragon by the lat-longs on the picture of your screen.

[+YuccaPatrol]

Since you are picking up satellite 47, you are getting the WAAS signal.

 

At this point, I would simply be more concerned with the accuracy estimate in the upper left corner of your screen.

 

SIRF is the brand/type of receiver chip in the unit. It is a newer design that is very sensitive.

 

WAAS is a series of satellites that broadcast information that helps your unit to account for some slight errors it receives from other satellites, giving you somewhat better accuracy.

 

I have had 7 foot accuracy with a solig WAAS signal with my 60CS in the past. For me, anything better than 20ft is great and more than enough for anything I plan to do.

 

Since this is your first GPS, be assured that you have what may very well be the finest consumer model ever created. I've been fooling around with these things since the first week they became available and just got my 60csx yesterday. It exceeds my wildest dreams in terms of accuracy and ability to lock on satellites in terrain that would have been impossible even for my 60cs.

Edited April 15, 2006 by YuccaPatrol

[chetwynd]

Ever eat at the Happy Dragon?? As far as I know, if ya got the D's showing you are getting the WAAS signal for correction. I found the Dragon by the lat-longs on the picture of your screen.

 

Ha, yeah that place is right next to me. It's OK, a little questionable. Their vent aims up towards our back door. Always smells nice

[+Sputnik 57]

The unit is showing eight satellites, including number 47. Any satellite number higher than 33 is a WAAS satellite, meaning that instead of just sending position information, it is communicating with a fixed ground location and transmitting data that helps determine and correct the differential between the apparent and actual position. In other words, it is giving the GPS unit info to improve its accuracy. The 'D' symbol means that the GPS unit is using that "Differential" information to correct the signal. Yes, it is a good thing.

 

SiRF III is the name of the micro processor (chip) inside the GPS unit. Unlike other chips, the SiRF III has better reception. When it gets reception from a weak signal (like your no. 24), it starts playing "what if." For example, it says, "What if the signal from satellite 11 is really being bounced off of a building? What if satellite 30's signal is being bent by the ionosphere even more than the correction data from satellite 47 suggests?" It does this millions of times per second, all to get you the very best estimate of your position. Again, its a good thing.

 

You may want to jump on Garmin's site and download xImage. It lets you take screen shots straight from your GPSr.